jt-day17

1.HttpClient

1.HttpClient 是 Apache Jakarta Common 下的子项目，用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包
业务需求说明

1. HttpClient入门案例
   1）### 导入jar包
   2）### HttpClient入门案例

package com.jt.test;
import com.sun.scenario.effect.impl.sw.sse.SSEBlend_SRC_OUTPeer;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.io.IOException;
//@SpringBootTest   //从spring容器中获取bean对象,以后完成测试业务.
public class TestHttpClient {
    /**
     * 1.实例化HttpClient对象
     * 2.定义远程访问的url地址
     * 3.定义请求类型的对象
     * 4.发起http请求,获取响应的结果
     * 5.对返回值结果进行校验.获取真实的数据信息.
     * */
    @Test
    public void testGet() throws IOException {
       HttpClient httpClient = HttpClients.createDefault();
       String url = "http://www.baidu.com";
       HttpGet httpGet = new HttpGet(url);
       HttpResponse httpResponse = httpClient.execute(httpGet);
       //常见结果状态 200 404 406参数异常  500后端服务器异常 504超时  502访问的网址不存在
        //获取状态码
        int status = httpResponse.getStatusLine().getStatusCode();
        if(status == 200){
            //获取响应结果
            HttpEntity entity = httpResponse.getEntity();
            String result = EntityUtils.toString(entity,"UTF-8");
            System.out.println(result);
        }
    }
}

3.HttpClient实现业务逻辑（前端【controller--service】--后端【controller--service】）
1）### 业务需求
用户经过http://www.jt.com/user/testHt...
JT-WEB服务器 访问JT-SSO时的请求http://sso.jt.com/user/testHt...
2）### 编辑前端Controller

@RequestMapping("/testHttpClient")
    @ResponseBody
    public List<User> testHttpClient(){

        return userService.testHttpClient();
    }

3) ### 编辑前端Service

package com.jt.service;
import com.jt.pojo.User;
import com.jt.util.ObjectMapperUtil;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.springframework.stereotype.Service;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
@Service
public class UserServiceImpl implements UserService{
    @Override
    public List<User> testHttpClient() {
        List userList = new ArrayList<>();
        //由jt-web服务器去连接jt-sso的服务器
        String url = "http://sso.jt.com/user/testHttpClient";
        HttpClient httpClient = HttpClients.createDefault();
        HttpGet httpGet = new HttpGet(url);
        try {
            HttpResponse httpResponse =httpClient.execute(httpGet);
            if(httpResponse.getStatusLine().getStatusCode() == 200){
            HttpEntity httpEntity = httpResponse.getEntity();
            String result = EntityUtils.toString(httpEntity, "UTF-8");
            userList = ObjectMapperUtil.toObject(result, userList.getClass());
           /* for (LinkedHashMap<String,Object> map : userList){
                    User userTemp = new User();
                    userTemp.setId( Long.parseLong(map.get("id")+""));
                    userTemp.setUsername((String)map.get("username"));
                    userTemp.setPassword((String)map.get("password"));
                    userTemp.setPhone((String)map.get("phone"));
                    userTemp.setEmail((String)map.get("phone"));
                    userList2.add(userTemp);
                }*/
            }
        } catch (IOException e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
        return userList;
    }
}

4) ### 编辑后端Controller

/**
     * http://sso.jt.com/user/testHttpClient
     * 返回List<User>
     */
    @RequestMapping("testHttpClient")
    public List<User> testHttpClient(){

        return userService.findAll();
    }

5) ### 编辑后端Service

@Override
    public List<User> findAll() {

        return userMapper.selectList(null);
    }