【微服务~远程调用】RestTemplate基本操作快速入门

陶然同学

发布于 2023-02-27 10:46:14

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发布于 2023-02-27 10:46:14

文章被收录于专栏：陶然同学博客

👀专栏介绍

【微服务~远程调用】目前主要更新微服务，一起学习一起进步。

👀本期介绍

本期主要介绍RestTemplate基本操作快速入门

文章目录

SpringBoot整合HttpClient

概述

配置

测试：get请求

RestTemplate整合HttpClient

案例：管理员登录

分析

数据库

RestTemplate

概述

RestTemplate是Spring提供的用于访问Rest服务的客户端，RestTemplate提供了多种便捷访问远程Http服务的方法,能够大大提高客户端的编写效率。

搭建环境

拷贝BaseResult
编写测试类：TestRest

package com.czxy;

public class TestRest {
}

基本操作

GET请求

注意：使用RestTemplate封装数据时，BaseResult必须提供==无参构造==。

@Test
    public void testFindAll(){
        String url = "http://localhost:7778/user";
        //1 创建对象
        RestTemplate restTemplate = new RestTemplate();
        //2 发送请求并获得数据
        ResponseEntity<BaseResult> entity = restTemplate.getForEntity(url, BaseResult.class);
        //3.1 状态
        System.out.println(entity.getStatusCode());
        //3.2 响应数据
        System.out.println(entity.getBody().getData());
    }

GET请求：转换泛型异常

查询用户时，如果返回类型为BaseResult，默认不支持泛型信息。及不支持 BaseResult<List<User>>
- 需要使用 exchange 设置具体的泛型信息

 @Test
    public void testFindAll2(){
        String url = "http://localhost:7778/user";
        //1 创建对象
        RestTemplate restTemplate = new RestTemplate();
        //2 发送请求并获得数据
        ResponseEntity<BaseResult<List<User>>> entity = restTemplate.exchange(url, HttpMethod.GET, null, new ParameterizedTypeReference<BaseResult<List<User>>>() {});
        //3 获得响应，并打印
        BaseResult<List<User>> baseResult = entity.getBody();
        List<User> data = baseResult.getData();
        for (User user : data) {
            System.out.println(user);
        }

    }

POST请求

@Test
    public void testAdd(){
        String url = "http://localhost:7778/user";
        RestTemplate restTemplate = new RestTemplate();

        User user = new User(1,"jack","1234",18);
        ResponseEntity<BaseResult> entity = restTemplate.postForEntity(url ,user , BaseResult.class);

        System.out.println(entity.getStatusCode());
        System.out.println(entity.getBody());
    }

PUT请求

 @Test
    public void testUpdate(){
        String url = "http://localhost:7778/user";
        RestTemplate restTemplate = new RestTemplate();
        User user = new User(1,"jack","1234",18);
        restTemplate.put(url ,user);
        System.out.println("修改成功");
    }

Delete请求

 @Test
    public void testDelete(){
        String url = "http://localhost:7778/user/1";
        RestTemplate restTemplate = new RestTemplate();
        restTemplate.delete(url);
        System.out.println("删除成功");
    }

HttpClient高级

HttpClient 关闭日志输出

基于spring boot 测试启动器，自动开启日志输出
spring boot 默认采用logback 进行日志管理的
如何管理日志输出：关闭日志输出
- 在resources/logback.xml

<configuration debug="false"></configuration>

HttpClient连接池

分析
- 使用HttpClients.custom()可以构建自定义 CloseableHttpClient 对象
  - setConnectionManager 用于配置连接
  - setDefaultRequestConfig 用于配置请求
- 通过PoolingHttpClientConnectionManager 可以为连接配置连接数和并发数
- 通过 RequestConfig.custom() 可以配置各种超时时间
代码

    @Test
    public void testDemo01() throws IOException {
        //1 配置连接管理
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
        // 1.1 设置最大连接数
        connectionManager.setMaxTotal(1000);
        // 1.2 设置并发访问数
        connectionManager.setDefaultMaxPerRoute(20);

        //2 请求配置
        RequestConfig requestConfig = RequestConfig.custom()
                .setConnectTimeout(1000)
                .setConnectionRequestTimeout(500)
                .setSocketTimeout(10 * 1000)
                .build();

        // 3 获得工具类
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(connectionManager)
                .setDefaultRequestConfig(requestConfig)
                //重定向策略
                .setRedirectStrategy(new LaxRedirectStrategy())
                .build();

        // 4 发送请求
        CloseableHttpResponse response = null;
        try {
            HttpGet httpGet = new HttpGet("http://localhost:7778/user");

            response = httpClient.execute(httpGet);

            if(response.getStatusLine().getStatusCode() == 200){
                String str = EntityUtils.toString(response.getEntity(),"UTF-8");
                System.out.println(str);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            response.close();
        }

    }

SpringBoot整合HttpClient

概述

SpringBoot官方并没有对HttpClient的启动器。所以我们需要自己完成配置

配置

步骤一：修改yml文件，添加连接池配置

# http配置
http:
  maxTotal: 300
  defaultMaxPerRoute: 50
  connectTimeout: 1000
  connectionRequestTimeout: 500
  socketTimeout: 5000

步骤二：编写配置类

package com.czxy.config;

import lombok.Setter;
import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.conn.HttpClientConnectionManager;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.client.LaxRedirectStrategy;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
@ConfigurationProperties(prefix = "http")
@Setter
public class HttpConfig {

    private Integer maxTotal;
    private Integer defaultMaxPerRoute;
    private Integer connectTimeout;
    private Integer connectionRequestTimeout;
    private Integer socketTimeout;
    private Integer staleConnectionCheckEnabled;

    @Bean
    public PoolingHttpClientConnectionManager connectionManager(){
        //1 配置连接管理
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
        // 1.1 设置最大连接数
        connectionManager.setMaxTotal(maxTotal);
        // 1.2 设置并发访问数
        connectionMan1ager.setDefaultMaxPerRoute(defaultMaxPerRoute);
        return connectionManager;
    }

    @Bean
    public RequestConfig requestConfig(){
        //2 请求配置
        RequestConfig requestConfig = RequestConfig.custom()
                .setConnectTimeout(connectTimeout)
                .setConnectionRequestTimeout(connectionRequestTimeout)
                .setSocketTimeout(socketTimeout)
                .build();
        return requestConfig;
    }

    @Bean
    public HttpClient httpClient(HttpClientConnectionManager connectionManager, RequestConfig requestConfig){
        // 3 获得工具类
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(connectionManager)
                .setDefaultRequestConfig(requestConfig)
                //重定向策略
                .setRedirectStrategy(new LaxRedirectStrategy())
                .build();
        return httpClient;
    }
}

测试：get请求

package com.czxy;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.util.EntityUtils;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.annotation.Resource;
import java.io.IOException;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = HttpApplication.class)
public class TestBootHttp {
    @Resource
    private HttpClient httpClient;

    @Test
    public void testDemo01() throws IOException {
        String url = "http://localhost:7778/user";
        HttpGet httpGet = new HttpGet(url);
        HttpResponse response = httpClient.execute(httpGet);
        if(response.getStatusLine().getStatusCode() == 200){
            String str = EntityUtils.toString(response.getEntity());
            System.out.println(str);
        }

    }

}

RestTemplate整合HttpClient

RestTemplate整合HttpClient -- 配置类

package com.czxy.config;

import lombok.Setter;
import org.apache.http.client.HttpClient;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.conn.HttpClientConnectionManager;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.client.LaxRedirectStrategy;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.client.ClientHttpRequestFactory;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.client.RestTemplate;

import java.nio.charset.Charset;
import java.util.List;

/**
 * @author 桐叔
 * @email liangtong@itcast.cn
 */
@Configuration
@ConfigurationProperties(prefix = "http")
@Setter
public class HttpConfig {

    private Integer maxTotal;
    private Integer defaultMaxPerRoute;
    private Integer connectTimeout;
    private Integer connectionRequestTimeout;
    private Integer socketTimeout;
    private Integer staleConnectionCheckEnabled;

    @Bean
    public PoolingHttpClientConnectionManager connectionManager(){
        //1 配置连接管理
        PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
        // 1.1 设置最大连接数
        connectionManager.setMaxTotal(maxTotal);
        // 1.2 设置并发访问数
        connectionManager.setDefaultMaxPerRoute(defaultMaxPerRoute);
        return connectionManager;
    }

    @Bean
    public RequestConfig requestConfig(){
        //2 请求配置
        RequestConfig requestConfig = RequestConfig.custom()
                .setConnectTimeout(connectTimeout)
                .setConnectionRequestTimeout(connectionRequestTimeout)
                .setSocketTimeout(socketTimeout)
                .build();
        return requestConfig;
    }

    @Bean
    public HttpClient httpClient(HttpClientConnectionManager connectionManager, RequestConfig requestConfig){
        // 3 获得工具类
        CloseableHttpClient httpClient = HttpClients.custom()
                .setConnectionManager(connectionManager)
                .setDefaultRequestConfig(requestConfig)
                //重定向策略
                .setRedirectStrategy(new LaxRedirectStrategy())
                .build();
        return httpClient;
    }


    @Bean
    public ClientHttpRequestFactory requestFactory(HttpClient httpClient ){
        return new HttpComponentsClientHttpRequestFactory(httpClient);
    }

    @Bean
    public RestTemplate restTemplate(ClientHttpRequestFactory requestFactory){
        RestTemplate template = new RestTemplate(requestFactory);
        //乱码处理
        List<HttpMessageConverter<?>> list = template.getMessageConverters();
        for (HttpMessageConverter<?> mc : list) {
            if (mc instanceof StringHttpMessageConverter) {
                ((StringHttpMessageConverter) mc).setDefaultCharset(Charset.forName("UTF-8"));
            }
        }
        return template;
    }

}

测试类

package com.czxy;

import com.czxy.domain.User;
import com.czxy.vo.BaseResult;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.http.ResponseEntity;
import org.springframework.test.context.junit4.SpringRunner;
import org.springframework.web.client.RestTemplate;

import javax.annotation.Resource;


@RunWith(SpringRunner.class)
@SpringBootTest(classes = HttpApplication.class)
public class TestBootRest {

    @Resource
    private RestTemplate restTemplate;

    @Test
    public void testAdd(){
        String url = "http://localhost:7778/user";

        User user = new User(1,"jack","1234",18);
        ResponseEntity<BaseResult> entity = restTemplate.postForEntity(url ,user , BaseResult.class);

        System.out.println(entity.getStatusCode());
        System.out.println(entity.getBody());
    }
}

案例：管理员登录

分析

数据库

CREATE TABLE t_user(
  uid INT PRIMARY KEY AUTO_INCREMENT,
  username VARCHAR(50),
  `password` VARCHAR(32),
  age INT
);
INSERT INTO t_user(uid,username,`password`,age) VALUES(1,'jack','1234',18);

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原始发表：2022-11-18，如有侵权请联系 cloudcommunity@tencent.com 删除

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