Spring boot 从0到0.1 part(1)

用户9691112

发布于 2023-05-18 14:00:06

6290

发布于 2023-05-18 14:00:06

文章被收录于专栏：quan9i的安全笔记

Day 01

第一个Spring boot项目

首先新建项目，选择Spring Initializr

随便填一下包名，选版本号后点击Next即可

开启Spring Web服务。

这里需要注意一点，去修改Spring boot版本，使其小于3.0.5(如果其他配置与我前面配置一致的话)，否则会报错

运行后发现Tomcat服务开启于8080端口，访问之

这是因为并没有写什么东西，接下来在这个主java文件新建文件夹controller，并创建文件HelloController，写一个hello路由，内容如下

package com.example.qwq.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
        @RequestMapping("/hello") 
        public String hello(){
            return "Hello, Spring Boot !";
        }
}

启动项目，访问**/hello**路由

简化配置

在application.properties中写入内容如下

server.port=8888

此时重新运行项目，就会从8080端口变为8888端口

自动配置原理

参考https://www.yuque.com/atguigu/springboot/qb7hy2即可

Day02

属性赋值

小trick分享:Alt+Insert可以快捷写出一些方法

常规

首先写Dog.java

package com.qwq.cs;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Dog {
    @Value("柯基")
    private String name;
    @Value("3")
    private Integer age;
    public Dog(){
    }
    public Dog(String name, Integer age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "dog{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

我们这里通过**@Value(‘xxx’)对实例化的类进行赋值，接下来去Test**文件夹下的java文件中进行调用

import com.qwq.cs.Dog;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class QwqApplicationTests {
    @Autowired
    private Dog dog;
    @Test
    void contextLoads() {
        System.out.println(dog);
    }

}

方法二（application.yaml）

我们这里在cs文件夹下再写一个Person.java文件

package com.qwq.cs;

import com.sun.org.apache.xpath.internal.operations.Bool;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Objects;

@Component
public class Person {
    private  String name;
    private  Integer age;
    private  Boolean happy;
    private Date birth;
    private Map<String, Object> maps;
    private List<Object> lists;
    private Dog dog;

    public Person(){
    }

    public Person(String name, Integer age, Boolean happy, Date birth, Map<String, Object> maps, List<Object> lists, Dog dog) {
        this.name = name;
        this.age = age;
        this.happy = happy;
        this.birth = birth;
        this.maps = maps;
        this.lists = lists;
        this.dog = dog;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Boolean getHappy() {
        return happy;
    }

    public void setHappy(Boolean happy) {
        this.happy = happy;
    }

    public Date getBirth() {
        return birth;
    }

    public void setBirth(Date birth) {
        this.birth = birth;
    }

    public Map<String, Object> getMaps() {
        return maps;
    }

    public void setMaps(Map<String, Object> maps) {
        this.maps = maps;
    }

    public List<Object> getLists() {
        return lists;
    }

    public void setLists(List<Object> lists) {
        this.lists = lists;
    }

    public Dog getDog() {
        return dog;
    }

    public void setDog(Dog dog) {
        this.dog = dog;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", happy=" + happy +
                ", birth=" + birth +
                ", maps=" + maps +
                ", lists=" + lists +
                ", dog=" + dog +
                '}';
    }
}

而后，我们在src/resources新建一个application.yaml文件，写入内容如下

person:
  name: quan9i
  age: 19
  happy: true
  birth: 2023/4/17
  maps: {k1: v1,k2: v2}
  list:
    -code
    -guitar
    -girl
  dog:
    name: 柯基
    age: 3

而后我们在Person.java中前面加上一句话

@ConfigurationProperties(prefix = "person")
//这个将配置文件中的值与java文件进行绑定，可以给其赋值

这个的话就是将值写入到person类中

此时会爆红，但不影响使用，接下来去Test下的Java文件中进行调用，只需把Dog类换成Person类即可

package com.qwq;

import com.qwq.cs.Dog;
import com.qwq.cs.Person;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class QwqApplicationTests {
    @Autowired
    private Person person;
    @Test
    void contextLoads() {
        System.out.println(person);
    }

}

这里还需要做一点，就是设置文件编码格式为UTF-8，否则就会报错(找了半小时，nnd)

而后运行即可

方法三（加载特定配置文件）

//加载特定配置文件
@PropertySource(value = "classpath:quan9i.properties")
public class Person {
    @Value("${name}") //SPEL表达式取出配置文件值

java文件整体内容如下

import com.sun.org.apache.xpath.internal.operations.Bool;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.PropertySource;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.List;
import java.util.Map;
import java.util.Objects;

@Component
//@ConfigurationProperties(prefix = "person")
//加载指定配置文件
@PropertySource(value = "classpath:quan9i.properties")
public class Person {
    @Value("${name}")
    private  String name;
    private  Integer age;
    private  Boolean happy;
    private Date birth;
    private Map<String, Object> maps;
    private List<Object> lists;
    private Dog dog;

    public Person(){

    }

    public Person(String name, Integer age, Boolean happy, Date birth, Map<String, Object> maps, List<Object> lists, Dog dog) {
        this.name = name;
        this.age = age;
        this.happy = happy;
        this.birth = birth;
        this.maps = maps;
        this.lists = lists;
        this.dog = dog;
    }

    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", happy=" + happy +
                ", birth=" + birth +
                ", maps=" + maps +
                ", lists=" + lists +
                ", dog=" + dog +
                '}';
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public Boolean getHappy() {
        return happy;
    }

    public void setHappy(Boolean happy) {
        this.happy = happy;
    }

    public Date getBirth() {
        return birth;
    }

    public void setBirth(Date birth) {
        this.birth = birth;
    }

    public Map<String, Object> getMaps() {
        return maps;
    }

    public void setMaps(Map<String, Object> maps) {
        this.maps = maps;
    }

    public List<Object> getLists() {
        return lists;
    }

    public void setLists(List<Object> lists) {
        this.lists = lists;
    }

    public Dog getDog() {
        return dog;
    }

    public void setDog(Dog dog) {
        this.dog = dog;
    }
}

静态资源导入

静态资源目录

只要静态资源放在类路径下： called /static (or /public or /resources or /META-INF/resources

访问：当前项目根路径/ + 静态资源名

寻找方法如下：

双击Shift搜MVC，找到这个文件

而后找到自动配置类中的添加资源方法

webjar

自动映射 /webjars/**

接下来访问

https://www.webjars.org/

将Maven方式的jquery复制下来，具体内容如下

<dependency>
            <groupId>org.webjars</groupId>
            <artifactId>jquery</artifactId>
            <version>3.4.1</version>
        </dependency>

然后粘贴到Pom.xml中，接下来可以发现自动加载Maven后，成功导入

访问地址：http://localhost:8080/webjars/jquery/3.4.1/jquery.js 后面地址要按照依赖里面的包路径

接下来看代码

发现这还有一个静态定义方法，跟进它这个**getStaticPathPattern()**方法进行查看

发现是根目录下的全部，然后接下来再回MVC这个文件中找一些其他的，这里发现WebProperties

发现三个其他目录，这里的话也就可以理解大致含义了，就是说在resources下新建resources、static、public目录，其下面的内容都可被直接访问

这里随便写一个1.js，然后访问http://127.0.0.1:8888/1.js

他们的优先级顺序是resources>static(默认)>public

首页相关

从WEBMVC文件中查看有关首页的

这里发现*getWelcomepage()*有关首页，然后它引用了getIndexHtml函数，然后这个函数用了getResource函数，这个函数引用了index.html，那我们接下来在映射对应的目录下新建一个index.html文件，按理说访问首页即可加载，接下来进行尝试

对于图标的话，直接在static文件下放置ico图标即可

这里的话接着说首页

首页的话它是需要用一个模板引擎进行数据交互的，这里用的是thymeleaf模板引擎，双击shift搜索Thymelaf

这里可以看到它是对templates文件夹下的所有.html后缀的文件使用了这个模板，接下来进行尝试

尝试之前首先在pom.xml中添加jar包

<dependency>
    <groupId>org.thymeleaf</groupId>
    <artifactId>thymeleaf-spring5</artifactId>
</dependency>
<dependency>
    <groupId>org.thymeleaf.extras</groupId>
    <artifactId>thymeleaf-extras-java8time</artifactId>
</dependency>

然后接下来在这个templates目录下写个文件命名为test.html。

然后我们想要主java文件去实现跳转到这个html界面，这个时候就需要用到一个controller，其实就是新建一个Controller文件夹，在里面写内容即可实现跳转。具体代码为

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

//在templates目录下的所有文件，只能通过controller来跳转!
//这个需要模板引擎的支持，这里使用的是thymeleaf
@Controller
public class IndexController {
    @RequestMapping("/test")
    public String test() {
        return "test";
    }
}

他这里的话，是我们访问test，然后它会返回test，然后它会自动去拼接.html后缀，然后去templates下找是否存在此文件，如果存在，此时就会直接加载

接下来说一下thy这个模板的引用，它需要在我们的html文件头部首先声明

<html lang="en" xmlns:th="http://www.thymeleaf.org">

而后，对于一些值的引用，比如我们这里的java文件写入一个msg参数

package com.qwq.Controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

//在templates目录下的所有文件，只能通过controller来跳转!
//这个需要模板引擎的支持，这里使用的是thymeleaf
@Controller
public class IndexController {
    @RequestMapping("/test")
    public String test(Model model) {
        model.addAttribute("msg","hello,Springboot");
        return "test";
    }
}

想调用的话，此时需要在html中声明th:text，具体代码如下

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1 th:text="${msg}"></h1>
</body>
</html>

实现效果

thymeleaf部分语法

th:text 对参数值进行获取
th:utext 如果参数中含有<h1></h1>这种标签，会进行解析
th:each 遍历输出

表达式名字	语法	用途
变量取值	${…}	获取请求域、session域、对象等值
选择变量	*{…}	获取上下文对象值
消息	#{…}	获取国际化等值
链接	@{…}	生成链接
片段表达式	~{…}	jsp:include 作用，引入公共页面片段

条件运算

If-then: (if) ? (then)
If-then-else: (if) ? (then) : (else)
Default: (value) ?: (defaultvalue)

示例：java文件代码

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.Arrays;

//在templates目录下的所有文件，只能通过controller来跳转!
//这个需要模板引擎的支持，这里使用的是thymeleaf
@Controller
public class IndexController {
    @RequestMapping("/test")
    public String test(Model model) {
        model.addAttribute("msg","hello,Springboot");
        model.addAttribute("users", Arrays.asList("quan9i","is","the","best"));
        return "test";
    }
}

主要是这一行

model.addAttribute("users", Arrays.asList("quan9i","is","the","best"));

然后接下来看html，其内容如下

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div th:each="user:${users}" th:text="${user}"></div>
</body>
</html>

th:each中用user挨个获取了users的参数名，然后呢，我们这里用th:text对它再进行挨个的值的输出，实现效果如下。

也可以这么写

<div th:each="user:${users}" >[[${user}]]</div>

MVC相关

装配原理

查看Contentxx

在这个Contentxxx中发现ViewResolver解析器，跟进

public interface ViewResolver 实现了视图解析器的类，我们就可以认为是视图解析器，接下来继续跟进它内部的这个函数，我们将它这个函数名进行复制，然后看Contentxx中哪里调用了这个

可以发现它这里是当内容非空时，getCandidateViews函数先对其进行处理，而后用getBestView函数处理，接下来首先跟进一下第一个函数

它这里的话其实就是遍历了所有的视图解析器，遍历完后封装为对象，添加到视图，而后返回视图。它这里最后的获取是需要通过bean来进行获取的

所以我们最后的示例代码如下

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.View;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.util.Locale;

//想添加自定义功能，只需要写一个组件，而后交给Springboot，即可自动实现
//扩展Spring MVC
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {

    //public interface ViewResolver 实现了视图解析器的类，我们就可以认为是视图解析器
    @Bean
    public ViewResolver myViewResolver(){
        return new MyViewResolver();
    }
    public static class MyViewResolver implements ViewResolver{
        @Override
        public View resolveViewName(String viewName, Locale locale) throws Exception{
            return null;
        }
    }
}

小扩展

实现视图跳转，示例代码如下

public class MyMvcConfig implements WebMvcConfigurer {

    //视图跳转
    @Override
    public void addViewControllers(ViewControllerRegistry registry){
        registry.addViewController("/quan").setViewName("/test");
    }
}

这里的话，**/test**会直接匹配到我们的那个templates下的test.html文件，我们这里注册了一个视图，当访问/quan时，就会跳转到对应html界面

这里因为我们没有设置参数，所以为空白

还有一个@EnableWebMvc，这个轻易不能开启，他会使得默认的mvc配置失效。

Day03(员工管理系统)

准备工作

后续用到的index.html及其他代码可在https://getbootstrap.com/docs/4.0/examples/中进行获取

先写一下部门的基本参数（部门ID及部门昵称）

#Department.java
public class Department {
    private Integer id;
    private String departmentName;
}

配置一下pom.xml,导入lombok

<dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
</dependency>

接下来放入java文件中，同时我们还要添加两个，一个是有参导入，一个是无参导入，代码如下

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import javax.annotation.sql.DataSourceDefinition;

//部门表
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Department {
    private Integer id;
    private String departmentName;
}

部门表写好后，此时我们还需要写一个员工表，此时新建一个文件，命名为Employee.java文件，写一些基础的参数

#Employee.java
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.util.Date;

//员工表
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Employee {
    private Integer id;
    private String lastName;
    private String email;
    private Integer gender; //0代表女，1代表男

    private Department department;
    private Date bitrh;
}

接下来需要新建一个Dao文件夹，然后这个我之前不太了解，百度了一下

在java学习中，特别是接触到web开发的时候，我们会经常遇到DAO这个家伙。中文名：数据访问对象，英文名：Data Access Object，我们简称DAO。在这一类的java后缀文件中，主要是用来访问数据库的，从数据库中选取需要分析或是处理的数据

然后接下来在它这个目录夹下新建文件命名为DepartmentDao.java，内容如下

import com.qwq.pojo.Department;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

//部门dao
public class DepartmentDao {
    //模拟数据库中的数据
    private static Map<Integer, Department> departments = null;

    static {
        departments = new HashMap<Integer, Department>();//创建一个部门表
        departments.put(101,new Department(101,"教学部"));
        departments.put(102,new Department(102,"市场部"));
        departments.put(103,new Department(103,"教研部"));
        departments.put(104,new Department(104,"运营部"));
        departments.put(105,new Department(105,"后勤部"));
    }

    //查询部门所有信息
    public Collection<Department> getDepartments(){
        return  departments.values();
    }
    //查询部门所有id
    public Department getDepartmentById(Integer id){
        return  departments.get(id);
    }

接下来部门的写好了，还需要写一个员工的，所以再新建一个Employee.java，内容如下

//员工Dao
@Repository
public class EmployeeDao {

    //模拟数据库数据
    private  static Map<Integer, Employee> employees = null;
    //员工所属部门
    private DepartmentDao departmentDao;

    static{
        employees = new HashMap<Integer, Employee>();//创建一个部门表

        employees.put(1001,new Employee(1001,"AA","A123@qq.com",0,new Department(1001,"教学部")));
        employees.put(1001,new Employee(1002,"AA","B123@qq.com",1,new Department(1001,"市场部")));
        employees.put(1001,new Employee(1003,"AA","C123@qq.com",0,new Department(1001,"教研部")));
        employees.put(1001,new Employee(1004,"AA","D123@qq.com",1,new Department(1001,"运营部")));
        employees.put(1001,new Employee(1005,"AA","E123@qq.com",0,new Department(1001,"后勤部")));
    }

}

这里考虑到Date不能直接写死，所以这里采用直接按时间生成的方式，修改Employee.java内容如下

import lombok.Data;
import lombok.NoArgsConstructor;
import java.util.Date;

//员工表
@Data
@NoArgsConstructor
public class Employee {
    private Integer id;
    private String lastName;
    private String email;
    private Integer gender; //0代表女，1代表男

    private Department department;
    private Date bitrh;

    public Employee(Integer id, String lastName, String email, Integer gender, Department department) {
        this.id = id;
        this.lastName = lastName;
        this.email = email;
        this.gender = gender;
        this.department = department;
        this.bitrh = new Date();
        //默认日期
    }
}

然后此时就可以写入用户信息了，同时实现增删改查功能，EmployeeDao.java内容如下

//员工Dao
@Repository
public class EmployeeDao {

    //模拟数据库数据
    private  static Map<Integer, Employee> employees = null;
    //员工所属部门
    private DepartmentDao departmentDao;

    static{
        employees = new HashMap<Integer, Employee>();//创建一个部门表

        employees.put(1001,new Employee(1001,"AA","A123@qq.com",0,new Department(1001,"教学部")));
        employees.put(1001,new Employee(1002,"AA","B123@qq.com",1,new Department(1001,"市场部")));
        employees.put(1001,new Employee(1003,"AA","C123@qq.com",0,new Department(1001,"教研部")));
        employees.put(1001,new Employee(1004,"AA","D123@qq.com",1,new Department(1001,"运营部")));
        employees.put(1001,new Employee(1005,"AA","E123@qq.com",0,new Department(1001,"后勤部")));
    }

    //主键自增!
    private static Integer initId =1006;
    //添加一个员工
    public void save(Employee employee) {
        if (employee.getId() == null)
            employee.setId(initId++);
        employee.setDepartment(departmentDao.getDepartmentById(employee.getDepartment().getId()));

        employees.put(employee.getId(), employee);
    }
        //查询员工信息
        public Collection<Employee> getAll() {
            return employees.values();
        }
        //通过id查询员工
        public Employee getEmployeeById(Integer id){
            return employees.get(id);
        }
        //删除员工通过id
        public void delete(Integer id){
            employees.remove(id);
        }
    }

首页实现

这里可以采用在时java文件中进行一个跳转的，当访问/或/index.html时强制跳转到index，具体代码如下(但此方法并不推荐)

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class IndexController {
    @RequestMapping({"/","/index.html"})
    public String index(){
        return "index";
    }
}

此时开启服务，访问

还有一种方法，就是我们可以通过写控制器来实现，具体步骤如下，新建MyMvcConfig文件，具体内容如下

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addViewControllers(ViewControllerRegistry registry){
        registry.addViewController("/").setViewName("index");
        registry.addViewController("/index.html").setViewName("index");
    }
}

此时再开启

同样也是可以访问到的，然后就是说一下静态资源的问题

在这里的话，所有的页面中的静态资源都需要用thymeleaf，

比如，在html文件开头，我们需要加上

<html lang="en" xmlns:th="http://www.thymeleaf.org">

在引用链接时，我们需要修改链接，具体如下

修改前:    <link rel="stylesheet" href="./css/style.css">
修改后:    <link rel="stylesheet" th:href=@{/css/style.css}>

国际化

什么是国际化呢，它在这里被我们称为i18n，i18n实际上是国际化的英文缩写，中间有18个字符，故称为i18n，同类的还有K8s。国际化其实就是多语言模式，比如我们常见的网站都支持两种语言，一种是汉语，一种是英语。

接下来说一下具体操作，首先在根目录下新建文件夹，命名为i18n，此时新建文件，命名为login_zh_CN.properties，按理说可以实现自动装配

如上图所示，不过我这里的话没实现，我是手动引入的，接下来继续看，添加英文模式,首先右键

接下来点击加号，输入en_US

而后点击OK，即可看见自动加入了英文,然后引入这个的话，是需要在application.yaml添加message的，具体内容如下

server.port: 8888
#清除缓存
spring:
  thymeleaf:
    cache: false
  #配置信息
  messages:
    basename: i18n.login

而后我们在login.properties中可以实时更改三个文件

我们配置后在index.html中更改如下

<!doctype html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta name="description" content="">
    <meta name="author" content="">
    <link rel="icon" th:href="@{/favicon.ico}">

    <title>Signin Template for Bootstrap</title>

    <!-- Bootstrap core CSS -->
    <link th:href="@{/css/bootstrap.min.css}" rel="stylesheet">

    <!-- Custom styles for this template -->
    <link th:href="@{/css/signin.css}" rel="stylesheet">
</head>

<body class="text-center">
<form class="form-signin">
    <img class="mb-4" src="https://getbootstrap.com/docs/4.0/assets/brand/bootstrap-solid.svg" alt="" width="72" height="72">
    <h1 class="h3 mb-3 font-weight-normal" th:text="#{login.tip}">Please sign in</h1>
    <label for="inputEmail" class="sr-only">Email address</label>
    <input type="email" id="inputEmail" class="form-control" placeholder="Email address" required autofocus>
    <label for="inputPassword" class="sr-only">Password</label>
    <input type="password" id="inputPassword" class="form-control" placeholder="Password" required>
    <div class="checkbox mb-3">
        <label>
            <input type="checkbox" value="remember-me"> Remember me
        </label>
    </div>
    <button class="btn btn-lg btn-primary btn-block" type="submit">Sign in</button>
    <p class="mt-5 mb-3 text-muted">&copy; 2017-2018</p>
    <a class="btn btn-sm">中文</a>
    <a class="btn btn-sm">English</a>
</form>
</body>
</html>

开启服务后访问

此时已成功生效，接下来改其他的一些zh及en配置

接下来同理修改html代码，具体如下

<!doctype html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <meta name="description" content="">
    <meta name="author" content="">
    <link rel="icon" th:href="@{/favicon.ico}">

    <title>Signin Template for Bootstrap</title>

    <!-- Bootstrap core CSS -->
    <link th:href="@{/css/bootstrap.min.css}" rel="stylesheet">

    <!-- Custom styles for this template -->
    <link th:href="@{/css/signin.css}" rel="stylesheet">
</head>

<body class="text-center">
<form class="form-signin">
    <img class="mb-4" src="https://getbootstrap.com/docs/4.0/assets/brand/bootstrap-solid.svg" alt="" width="72" height="72">
    <h1 class="h3 mb-3 font-weight-normal" th:text="#{login.tip}">Please sign in</h1>
    <input type="text"  class="form-control" th:placeholder="#{login.username}" required autofocus>
    <input type="password" id="inputPassword" class="form-control" th:placeholder="#{login.password}" required>
    <div class="checkbox mb-3">
        <label>
            <input type="checkbox" value="remember-me">[[#{login.remember}]]
        </label>
    </div>
    <button class="btn btn-lg btn-primary btn-block" type="submit">[[#{login.btn}]]</button>
    <p class="mt-5 mb-3 text-muted">&copy; 2017-2018</p>
    <a class="btn btn-sm">中文</a>
    <a class="btn btn-sm">English</a>
</form>
</body>
</html>

然后接下来配置国际化的语言，它这个的话去MVC这个文件下寻找

找到这个localeResolver方法，可以看出大致含义是当有配置的时候，就按自定义配置来，当没有配置的时候，就按照默认的来。

所以接下来我们重写一个localeResolver方法，我们在config文件夹下新建一个MylocaleResolver文件，内容如下

import org.springframework.cglib.core.Local;
import org.springframework.web.servlet.LocaleResolver;
import org.thymeleaf.util.StringUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Locale;

public class MyLocaleResolver implements LocaleResolver{
    //解析请求
    @Override
    public Locale resolveLocale(HttpServletRequest request) {
        //获取请求中的参数链接
        String language = request.getParameter("l");
        Locale locale = Locale.getDefault();//如果没有就使用默认的;

        //如果请求的参数携带了地区化的参数
        if(!StringUtils.isEmpty(language)){
            String[] split =  language.split("_");
            //国家，地区
           locale = new Locale(split[0],split[1]);
        }
        return locale;
    }

    @Override
    public void setLocale(HttpServletRequest request, HttpServletResponse response, Locale locale) {

    }
}

而后我们还需要去MyMvcConfig.java中配置@Bean，这样才能使得这个函数生效，MyMvcConfig.java内容如下

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addViewControllers(ViewControllerRegistry registry){
        registry.addViewController("/").setViewName("index");
        registry.addViewController("/index.html").setViewName("index");
    }
    //自定义的国际化组件生效了
    @Bean
    public LocaleResolver localeResolver(){
        return  new MyLocaleResolver();
    }
}

接下来打开网站

点击English

登录界面实现

首先我们更改login.html中，添加如下代码

<form class="form-signin" th:action="@{/user/login}">

接下来在Controller文件夹中写入loginController.java文件，通过RequestMapping写入路由，通过ResponseBody写入返回内容，具体内容如下

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class LoginController {
        @RequestMapping("/user/login")
        @ResponseBody
        public String login(){
            return "Ok";
        }
}

接下来运行项目，随便填写一下登录信息

成功写入

接收参数的话，我们需要在html中加入name字段，因此对html文件进行更改

<input type="text" name="username" class="form-control" th:placeholder="#{login.username}" required autofocus>
<input type="password" name="password" id="inputPassword" class="form-control" th:placeholder="#{login.password}" required>

然后接下来在LoginController.java文件中更改内容，添加校验，当登录成功时跳转到另一界面，登录失败则仍在当前登录界面，这里的话保险起见，在这里加入**RequestParam()**用于接收参数。

具体内容如下

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.thymeleaf.util.StringUtils;

@Controller
public class LoginController {
        @RequestMapping("/user/login")
        public String login(
                @RequestParam("username") String username,
                @RequestParam("password") String password,
                Model model){

            //具体的业务;
            if (!StringUtils.isEmpty(username) && "123456".equals(password)){
                return "dashboard";
            }else{
                //告诉用户，登录失败
                model.addAttribute("msg","登录失败");
                return "index";
            }
        }
}

接下来写一下跳转的界面，即dashboard.html文件，内容如下

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <meta name="description" content="">
  <meta name="author" content="">
  <link rel="icon" th:href="@{/favicon.ico}">

  <title>Dashboard Template for Bootstrap</title>


  <!-- Bootstrap core CSS -->
  <link th:href="@{/css/bootstrap.min.css}" rel="stylesheet">

  <!-- Custom styles for this template -->
  <link th:href="@{/css/dashboard.css}" rel="stylesheet">
</head>

<body>
<nav class="navbar navbar-dark sticky-top bg-dark flex-md-nowrap p-0">
  <a class="navbar-brand col-sm-3 col-md-2 mr-0" href="#">Company name</a>
  <input class="form-control form-control-dark w-100" type="text" placeholder="Search" aria-label="Search">
  <ul class="navbar-nav px-3">
    <li class="nav-item text-nowrap">
      <a class="nav-link" href="#">Sign out</a>
    </li>
  </ul>
</nav>

<div class="container-fluid">
  <div class="row">
    <nav class="col-md-2 d-none d-md-block bg-light sidebar">
      <div class="sidebar-sticky">
        <ul class="nav flex-column">
          <li class="nav-item">
            <a class="nav-link active" href="#">
              <span data-feather="home"></span>
              Dashboard <span class="sr-only">(current)</span>
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="file"></span>
              Orders
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="shopping-cart"></span>
              Products
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="users"></span>
              Customers
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="bar-chart-2"></span>
              Reports
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="layers"></span>
              Integrations
            </a>
          </li>
        </ul>

        <h6 class="sidebar-heading d-flex justify-content-between align-items-center px-3 mt-4 mb-1 text-muted">
          <span>Saved reports</span>
          <a class="d-flex align-items-center text-muted" href="#">
            <span data-feather="plus-circle"></span>
          </a>
        </h6>
        <ul class="nav flex-column mb-2">
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="file-text"></span>
              Current month
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="file-text"></span>
              Last quarter
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="file-text"></span>
              Social engagement
            </a>
          </li>
          <li class="nav-item">
            <a class="nav-link" href="#">
              <span data-feather="file-text"></span>
              Year-end sale
            </a>
          </li>
        </ul>
      </div>
    </nav>

    <main role="main" class="col-md-9 ml-sm-auto col-lg-10 pt-3 px-4">
      <div class="d-flex justify-content-between flex-wrap flex-md-nowrap align-items-center pb-2 mb-3 border-bottom">
        <h1 class="h2">Dashboard</h1>
        <div class="btn-toolbar mb-2 mb-md-0">
          <div class="btn-group mr-2">
            <button class="btn btn-sm btn-outline-secondary">Share</button>
            <button class="btn btn-sm btn-outline-secondary">Export</button>
          </div>
          <button class="btn btn-sm btn-outline-secondary dropdown-toggle">
            <span data-feather="calendar"></span>
            This week
          </button>
        </div>
      </div>

      <canvas class="my-4" id="myChart" width="900" height="380"></canvas>

      <h2>Section title</h2>
      <div class="table-responsive">
        <table class="table table-striped table-sm">
          <thead>
          <tr>
            <th>#</th>
            <th>Header</th>
            <th>Header</th>
            <th>Header</th>
            <th>Header</th>
          </tr>
          </thead>
          <tbody>
          <tr>
            <td>1,001</td>
            <td>Lorem</td>
            <td>ipsum</td>
            <td>dolor</td>
            <td>sit</td>
          </tr>
          <tr>
            <td>1,002</td>
            <td>amet</td>
            <td>consectetur</td>
            <td>adipiscing</td>
            <td>elit</td>
          </tr>
          <tr>
            <td>1,003</td>
            <td>Integer</td>
            <td>nec</td>
            <td>odio</td>
            <td>Praesent</td>
          </tr>
          <tr>
            <td>1,003</td>
            <td>libero</td>
            <td>Sed</td>
            <td>cursus</td>
            <td>ante</td>
          </tr>
          <tr>
            <td>1,004</td>
            <td>dapibus</td>
            <td>diam</td>
            <td>Sed</td>
            <td>nisi</td>
          </tr>
          <tr>
            <td>1,005</td>
            <td>Nulla</td>
            <td>quis</td>
            <td>sem</td>
            <td>at</td>
          </tr>
          <tr>
            <td>1,006</td>
            <td>nibh</td>
            <td>elementum</td>
            <td>imperdiet</td>
            <td>Duis</td>
          </tr>
          <tr>
            <td>1,007</td>
            <td>sagittis</td>
            <td>ipsum</td>
            <td>Praesent</td>
            <td>mauris</td>
          </tr>
          <tr>
            <td>1,008</td>
            <td>Fusce</td>
            <td>nec</td>
            <td>tellus</td>
            <td>sed</td>
          </tr>
          <tr>
            <td>1,009</td>
            <td>augue</td>
            <td>semper</td>
            <td>porta</td>
            <td>Mauris</td>
          </tr>
          <tr>
            <td>1,010</td>
            <td>massa</td>
            <td>Vestibulum</td>
            <td>lacinia</td>
            <td>arcu</td>
          </tr>
          <tr>
            <td>1,011</td>
            <td>eget</td>
            <td>nulla</td>
            <td>Class</td>
            <td>aptent</td>
          </tr>
          <tr>
            <td>1,012</td>
            <td>taciti</td>
            <td>sociosqu</td>
            <td>ad</td>
            <td>litora</td>
          </tr>
          <tr>
            <td>1,013</td>
            <td>torquent</td>
            <td>per</td>
            <td>conubia</td>
            <td>nostra</td>
          </tr>
          <tr>
            <td>1,014</td>
            <td>per</td>
            <td>inceptos</td>
            <td>himenaeos</td>
            <td>Curabitur</td>
          </tr>
          <tr>
            <td>1,015</td>
            <td>sodales</td>
            <td>ligula</td>
            <td>in</td>
            <td>libero</td>
          </tr>
          </tbody>
        </table>
      </div>
    </main>
  </div>
</div>

<!-- Bootstrap core JavaScript
================================================== -->
<!-- Placed at the end of the document so the pages load faster -->
<script th:href="@{/js/jquery-3.2.1.slim.min.js}" integrity="sha384-KJ3o2DKtIkvYIK3UENzmM7KCkRr/rE9/Qpg6aAZGJwFDMVNA/GpGFF93hXpG5KkN" crossorigin="anonymous"></script>
<script>window.jQuery || document.write('<script th:href="@{/js/jquery-3.2.1.slim.min.js}"><\/script>')</script>
<script th:href="@{/js/vendor/popper.min.js}"></script>
<script th:href="@{/js/bootstrap.min.js}"></script>

<!-- Icons -->
<script th:href="@{/js/feather.min.js}"></script>
<script>
  feather.replace()
</script>

<script>
  var ctx = document.getElementById("myChart");
  var myChart = new Chart(ctx, {
    type: 'line',
    data: {
      labels: ["Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"],
      datasets: [{
        data: [15339, 21345, 18483, 24003, 23489, 24092, 12034],
        lineTension: 0,
        backgroundColor: 'transparent',
        borderColor: '#007bff',
        borderWidth: 4,
        pointBackgroundColor: '#007bff'
      }]
    },
    options: {
      scales: {
        yAxes: [{
          ticks: {
            beginAtZero: false
          }
        }]
      },
      legend: {
        display: false,
      }
    }
  });
</script>
</body>
</html>

此时运行项目

点击登录后

成功进入后台，但此时如果输错密码，是没有提示的，所以我们需要再设置一个消息提示，当输入密码错误时回显错误信息。

此时再去index.html下添加一行代码

//如果登录成功，则不显示消息(通过th:if进行判断的)
<P style="color: red"th:text="${msg}" th:if="${not #strings.isEmpty(msg)}"></P>

打开界面再次进行尝试

但此时的URL不是很美观

我们可以添加一个在MyMvcConfig.java中添加一个视图

registry.addViewController("/main.html").setViewName("dashboard");

而后简单更改下LoginController.java，加一个页面重定向

登录拦截器

在Config文件下写入LoginHandleInterceptor.java文件，内容如下

import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.ws.handler.Handler;

public class LoginHandlerlnterceptor implements HandlerInterceptor {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response,Object handler) throws Exception{
        //登录成功后，应有用户的session
        Object loginUser = request.getSession().getAttribute("loginUser");

        if (loginUser==null){//没有登录
            request.setAttribute("msg","没有权限，请登录");
            request.getRequestDispatcher("/index.html").forward(request,response);//请求转发
            return false;
        }else{
            return true;
        }
    }
}

这个是通过session来校验是否登录的，所以我们需要在登录成功后添加session，修改LoginController.java内容如下

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.thymeleaf.util.StringUtils;

import javax.servlet.http.HttpSession;

@Controller
public class LoginController {
        @RequestMapping("/user/login")
        public String login(
                @RequestParam("username") String username,
                @RequestParam("password") String password,
                Model model, HttpSession session){

            //具体的业务;
            if (!StringUtils.isEmpty(username) && "123456".equals(password)){
                session.setAttribute("loginUser",username);
                return "redirect:/main.html";
            }else{
                //告诉用户，登录失败
                model.addAttribute("msg","登录失败");
                return "index";
            }
        }
}

而后我们这是自定义类，所以还需要在MyMvcConfig.java下添加@Bean注释，添加自定义函数，具体内容如下

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.LocaleResolver;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ViewControllerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class MyMvcConfig implements WebMvcConfigurer {

    @Override
    public void addViewControllers(ViewControllerRegistry registry){
        registry.addViewController("/").setViewName("index");
        registry.addViewController("/index.html").setViewName("index");
        registry.addViewController("/main.html").setViewName("dashboard");
    }
    //自定义的国际化组件生效了
    @Bean
    public LocaleResolver localeResolver(){
        return  new MyLocaleResolver();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new LoginHandlerlnterceptor()).addPathPatterns("/**").excludePathPatterns("/index.html","/","/user/login","/css/**","/js/**","");
    }
}

此时便已实现拦截器大致功能。

在前端加入[[${session.loginUser}]]，可以输出用户名。

本文参与腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。

原始发表：2023/04/17 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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