Spring Boot 进阶之 Web 进阶笔记

solocoder

发布于 2022-04-06 12:53:09

2030

发布于 2022-04-06 12:53:09

文章被收录于专栏：大前端客栈

一、表单验证

改造 Girl 对象，给 age 字段加校验最小值为18，并给出错误提示。

@Entity
public class Girl {

@Id
@GeneratedValue
private Integer id;

private String cupSize;

@M<span class="hljs-keyword">in</span>(value = 18, message = <span class="hljs-string">"未成年少女禁止入内"</span>)
private Integer age;

public <span class="hljs-function"><span class="hljs-title">Girl</span></span>() {
}

//getter、setter 方法省略

}

相应的 Controller 方法，用 Girl 对象接收传递过来的参数，并加上 @Validated 注解。BindingResult 用来接收错误信息

@PostMapping(value = "/girl/add")
public Girl add(@Validated Girl girl, BindingResult bindingResult) {
    if(bindingResult.hasErrors()){
        System.out.println(bindingResult.getFieldError().getDefaultMessage());
        return null;
    }
    return repository.save(girl);
}

如果传递的 age 小于 18，则会报错。

注意：@NotNull 和 @NotEmpty 和@NotBlank 区别 @NotEmpty 用在集合类上面 @NotBlank 用在String上面 @NotNull 用在基本类型上

二、使用 AOP 处理请求

先在 pom.xml 文件中添加 AOP 依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-aop</artifactId>
</dependency>

新建 HttpAspect.java

package com.solo.test01.aspect;

import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import javax.servlet.http.HttpServletRequest;
@Aspect
@Component
public class HttpAspect {
private static final Logger logger = LoggerFactory.getLogger(HttpAspect.class);

//指定切点
@Pointcut(<span class="hljs-string">"execution(public * com.solo.test01.controller.GirlController.*(..))"</span>)
public void <span class="hljs-function"><span class="hljs-title">log</span></span>() {

}

@Before(<span class="hljs-string">"log()"</span>)
public void <span class="hljs-keyword">do</span>Before(JoinPoint joinPoint) {
    logger.info(<span class="hljs-string">"doBefore-----"</span>);
    
    //获取 http 请求的内容
    ServletRequestAttributes attributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
    HttpServletRequest request = attributes.getRequest();
    //url
    logger.info(<span class="hljs-string">"url: {}"</span>, request.getRequestURL());
    //method
    logger.info(<span class="hljs-string">"method: {}"</span>, request.getMethod());
    // ip
    logger.info(<span class="hljs-string">"ip: {}"</span>, request.getRemoteAddr());
    //方法
    logger.info(<span class="hljs-string">"class_method: {}"</span>, joinPoint.getSignature().getDeclaringTypeName() + <span class="hljs-string">","</span> + joinPoint.getSignature().getName());
    //参数
    logger.info(<span class="hljs-string">"params: {}"</span>, joinPoint.getArgs());
}

@After(<span class="hljs-string">"log()"</span>)
public void <span class="hljs-function"><span class="hljs-title">doAfter</span></span>() {
    logger.info(<span class="hljs-string">"doAfter-----"</span>);
}

@AfterReturning(returning = <span class="hljs-string">"object"</span>, pointcut = <span class="hljs-string">"log()"</span>)
public void <span class="hljs-keyword">do</span>AfterReturning(Object object){
    logger.info(<span class="hljs-string">"response: {}"</span>, object.toString());
}

}

@Pointcut 指定切点，在 @Before 中获取 http 请求的内容，@AfterReturning 获取返回的内容。

三、指定统一返回格式

创建 Result 对象为统一返回数据格式

public class Result<T> {
    private Integer code;
    private String msg;
    private T data;
    
// get, <span class="hljs-built_in">set</span>方法省略

}

封装工具类 ResultUtils

/**
 * 返回结果的工具类封装
 */
public class ResultUtils {

    public static Result success(Object obj) {
        Result result = new Result();
        result.setCode(0);
        result.setMsg("成功");
        result.setData(obj);
        return result;
    }

    public static Result success() {
        return success(null);
    }

    public static Result error(Integer code, String msg) {
        Result result = new Result();
        result.setCode(code);
        result.setMsg(msg);
        return result;
    }
}

不同状态返回相同格式的结果

@PostMapping(value = "/girl/add")
public Result<Girl> add(@Validated Girl girl, BindingResult bindingResult) {
    if (bindingResult.hasErrors()) {
        return ResultUtils.error(1, bindingResult.getFieldError().getDefaultMessage());
    }
    return ResultUtils.success(repository.save(girl));
}

四、全局捕获异常处理

假如在 Service 中抛出了异常

@Component
public class GirlService {

@Autowired
GirlRepository repository;

public void getAge(Integer id){
    Girl girl = repository.findById(id).get();
    Integer age = girl.getAge();
    <span class="hljs-keyword">if</span>(age &lt;= 10){
        // 还在上小学吧
        throw new GirlException(ResultEnum.PRIMARY_SCHOOL);
    }<span class="hljs-keyword">else</span> <span class="hljs-keyword">if</span>(age &gt; 10 &amp;&amp; age &lt; 16){
        // 还在上中学吧
        throw new GirlException(ResultEnum.MIDDLE_SCHOOL);
    }
}

}

定义一个 ExceptionHandle 来全局捕获 GirlException 异常

@ControllerAdvice
public class ExceptionHandle {

    @ExceptionHandler(value = GirlException.class)
    @ResponseBody
    public Result handle(Exception e){
        if(e instanceof GirlException){
            GirlException girlException = (GirlException) e;
            return ResultUtils.error(girlException.getCode(), e.getMessage());
        }
        return ResultUtils.error(-1, "未知错误");
    }
}

这样当出现指定异常时就会被全局捕获到。

GirlException 是自定义异常，代码如下：

public class GirlException extends RuntimeException {

private Integer code;

public <span class="hljs-function"><span class="hljs-title">GirlException</span></span>() {
}

public GirlException(ResultEnum resultEnum) {
    super(resultEnum.getMsg());
    this.code = resultEnum.getCode();
}

public Integer <span class="hljs-function"><span class="hljs-title">getCode</span></span>() {
    <span class="hljs-built_in">return</span> code;
}

public void <span class="hljs-built_in">set</span>Code(Integer code) {
    this.code = code;
}

}

要继承 RuntimeException ，不要继承 Exception ，否则事务不会回滚。

将所有错误码和错误信息都封装到枚举类里，便于统一管理。

public enum ResultEnum {
    UNKNOWN(-1, "未知错误"),
    SUCCESS(0, "成功"),
    PRIMARY_SCHOOL(100, "还是小学生吧"),
    MIDDLE_SCHOOL(101, "是中学生吧")
    ;

private Integer code;
private String msg;

ResultEnum(Integer code, String msg) {
    this.code = code;
    this.msg = msg;
}

public Integer <span class="hljs-function"><span class="hljs-title">getCode</span></span>() {
    <span class="hljs-built_in">return</span> code;
}

public String <span class="hljs-function"><span class="hljs-title">getMsg</span></span>() {
    <span class="hljs-built_in">return</span> msg;
}

}

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原始发表：2018/08/13 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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