详解HttpClient用法

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.wo</groupId>
  <artifactId>HttpClient_test</artifactId>
  <version>1.0-SNAPSHOT</version>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.3.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
  </parent>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.5</version>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.47</version>
    </dependency>
  </dependencies>
</project>

@RequestMapping("findAll")
  public String findAll() throws Exception{
    //获得Http客户端
    CloseableHttpClient build = HttpClientBuilder.create().build();
    //创建get请求
    HttpGet httpGet = new HttpGet("http://localhost:8088/lunbo/findAll");
    //执行请求
    CloseableHttpResponse execute = build.execute(httpGet);
    //解析返回值
    StatusLine statusLine = execute.getStatusLine();
    //获取到返回状态码
    System.out.println("状态码为："+statusLine.getStatusCode());
    String s = EntityUtils.toString(execute.getEntity());
    build.close();
    execute.close();
    return s;
  }

//post路径传参
  @RequestMapping("/findAllPost/{page}/{size}")
  public String findAll(@PathVariable("page") int page,@PathVariable("size") int size) throws Exception {
    //获得Http客户端
    CloseableHttpClient build = HttpClientBuilder.create().build();
    //创建post请求
    HttpPost httpPost = new HttpPost("http://localhost:8088/position/findAll/"+page+"/"+size);
    //执行请求
    CloseableHttpResponse execute = build.execute(httpPost);
    //解析返回值
    StatusLine statusLine = execute.getStatusLine();
    //获取到返回状态码
    System.out.println("状态码为："+statusLine.getStatusCode());
    String s = EntityUtils.toString(execute.getEntity());
    build.close();
    execute.close();
    return s;
  }

  //post map传参
  @RequestMapping("findById")
  public String findById(@RequestParam("id") Integer id)throws Exception{
    //创建httpclicent请求对象
    CloseableHttpClient build = HttpClientBuilder.create().build();
    //声明请求方式
    HttpPost httpPost = new HttpPost("http://localhost:8088/position/findById");
    //声明携带参数
    Map map=new HashMap<>();
    map.put("id",id);
    //将map转换为json格式
    Object o = JSONObject.toJSON(map);
    //设置请求 参数的编码格式
    StringEntity stringEntity = new StringEntity(o.toString(), "utf-8");
    //将参数设置到请求对象中
    httpPost.setEntity(stringEntity);
    //设置content-Type
    httpPost.setHeader("Content-Type","application/json");
    //执行请求
    CloseableHttpResponse execute = build.execute(httpPost);
    //解析返回值
    StatusLine statusLine = execute.getStatusLine();
    //获取到返回状态码
    System.out.println("状态码为："+statusLine.getStatusCode());
    String s = EntityUtils.toString(execute.getEntity());
    build.close();
    execute.close();
    return s;
  }