java发送http请求

1.spring中的RestTemplate发送请求

    @Test
    public void testRestplateGet() throws IOException {
        // String url = "http://localhost:8080/test2?id=111111";
        String url = "http://localhost:8080/test2?id={id}";

        RestTemplate restTemplate = new RestTemplate();
        // get 无参数请求
        //Map result = restTemplate.getForObject(url,Map.class);
        Map<String,Object> params = new HashMap<>();
        params.put("id",66666);

        Map result = restTemplate.getForObject(url,Map.class,params);
        System.out.println(result);
    }

    @Test
    public void testRestplatePost() throws IOException {
        String url = "http://localhost:8080/test1";

        Map params = new HashMap();
        params.put("id","xiaochi");

        RestTemplate restTemplate = new RestTemplate();
        // post 无参数请求
        //Map map = restTemplate.postForObject(url, new HashMap(), Map.class);
        Map map = restTemplate.postForObject(url, params, Map.class);
        System.out.println(map);
    }

2.HttpComponents-Client的发送请求

导包：

<dependency>
      <groupId>org.apache.httpcomponents</groupId>
      <artifactId>httpclient</artifactId>
      <version>4.5.10</version>
</dependency>
<!-- StringEntity设置传输参数时，使用fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.62</version>
</dependency>

创建工具类HttpUtils

package com.springboot.demo;

import com.alibaba.fastjson.JSON;
import org.apache.http.HttpEntity;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.HttpClientUtils;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

/**
 * httpClient工具类
 */
public class HttpUtils {

    /**
     * 发送 get 请求（无参数）
     * @param url
     * @return
     * @throws IOException
     */
    public static Map<String,Object> doGet(String url) throws IOException {
        return doGet(url,new HashMap<>());
    }

    /**
     * 发送 get 请求（有参数）
     * @param url
     * @param params
     * @return
     * @throws IOException
     */
    public static Map<String,Object> doGet(String url, Map<String,Object> params) throws IOException {
        if (params.size() > 0){
            url = url + "?" + handleParams(params);
        }
        //start get
        //1、创建客户端
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 超时设置（可不设置）
        RequestConfig requestConfig =  RequestConfig.custom().setConnectTimeout(5000) //连接超时
                .setConnectionRequestTimeout(5000)//请求超时
                .setSocketTimeout(5000)
                .setRedirectsEnabled(true)  //允许自动重定向
                .build();
        //2、创建Http的请求方式get,post etc... 需要传入请求地址
        HttpGet httpGet = new HttpGet(url);
        httpGet.setConfig(requestConfig);// 设置配置
        //3、httpClient执行请求,并获取返回结果
        CloseableHttpResponse response = httpClient.execute(httpGet);
        //4、输出获取到的结果
        //从response中取出返回的entity
        HttpEntity entity = response.getEntity();
        String result = EntityUtils.toString(entity);
        //输出
        //System.out.println("get返回状态行:"+response.getStatusLine());
        //System.out.println("get返回结果:"+ result);

        //5、关闭连接 也可以直接调用close（）方法
        HttpClientUtils.closeQuietly(response);

        Map<String,Object> map = new HashMap<>();
        map.put("result",JSON.parseObject(result, Map.class));
        map.put("status",response.getStatusLine().getStatusCode());
        return map;
    }

    /**
     * 拼接 get参数
     * @param params
     * @return
     */
    private static String handleParams(Map<String,Object> params){
        // 处理参数
        StringBuffer buffer = new StringBuffer();
        if (params.size() > 0){
            Iterator<Map.Entry<String, Object>> iterator = params.entrySet().iterator();
            while (iterator.hasNext()){
                Map.Entry<String, Object> entry  = iterator.next();
                buffer.append(entry.getKey()).append("=").append(entry.getValue()).append("&");
            }
        }
        return buffer.toString().substring(0,buffer.length()-1);
    }

    /**
     * 发送 post 请求（无参数）
     * @param url
     * @return
     * @throws IOException
     */
    public static Map<String, Object> doPost(String url) throws IOException {
        return doPost(url,new HashMap<>());
    }

    /**
     * 发送 post 请求（有参数）
     * @param url
     * @param params
     * @return
     * @throws IOException
     */
    public static Map<String, Object> doPost(String url, Map<String,Object> params) throws IOException {
        //start post
        //1、创建客户端
        CloseableHttpClient httpClient = HttpClients.createDefault();
        // 超时设置（可不设置）
        RequestConfig requestConfig =  RequestConfig.custom().setConnectTimeout(5000) //连接超时
                .setConnectionRequestTimeout(5000)//请求超时
                .setSocketTimeout(5000)
                .setRedirectsEnabled(true)  //允许自动重定向
                .build();
        //1、创建post请求
        HttpPost httpPost = new HttpPost(url);
        httpPost.setConfig(requestConfig); // 设置配置
        httpPost.addHeader("Content-Type","text/html; chartset=UTF-8"); // 表单提交，默认方式是 json 格式
        //2、设置请求参数HttpEntity
        //StringEntity的方式,这种方式比较自由，可以传输自定义的数据格式，只需要后台能处理即可
        //这种方式是真正的post请求，请求参数是防止body中，后台通过流的方式获取数据
        //JSONObject使用阿里巴巴的fastjson
        //创建StringEntity，并设置ContentType
        StringEntity stringEntity = new StringEntity(JSON.toJSONString(params), ContentType.APPLICATION_JSON);
        //stringEntity加入http中
        httpPost.setEntity(stringEntity);
        //3、发送http请求
        CloseableHttpResponse response = httpClient.execute(httpPost);
        //4、获取返回结果
        String result = EntityUtils.toString(response.getEntity());
        //5、输出结果
        //System.out.println("StringEntity返回状态行:"+response.getStatusLine());
        //System.out.println("StringEntity返回结果:"+result);
        //6、关闭
        HttpClientUtils.closeQuietly(response);
        //end post

        Map<String,Object> map = new HashMap<>();
        map.put("result",JSON.parseObject(result, Map.class));
        map.put("status",response.getStatusLine().getStatusCode());
        return map;
    }
}

创建测试类HttpUtilsTest

package com.springboot.demo;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@SpringBootTest
@RunWith(SpringRunner.class)
public class HttpUtilsTest {

    private Logger logger = LoggerFactory.getLogger(getClass());

    @Test
    public void testHttpGet() throws IOException {
        String url = "http://localhost:8080/test2";
        // 发送 get 请求（无参数）
        // Map<String, Object> result = HttpUtils.doGet(url);
        Map params = new HashMap();
        params.put("id",111111);
        // 发送 get 请求（有参数）
        Map<String, Object> result = HttpUtils.doGet(url,params);
        //System.out.println(result);
        //System.out.println(result.get("status"));
        if (result.get("status").equals(200)){
            System.out.println(result.get("result"));
            Map result1 = (Map) result.get("result");
            System.out.println(result1.get("name"));
        }else{
            System.out.println("请求失败！状态码：" + result.get("status"));
        }
    }

    @Test
    public void testHttpPost() throws IOException {
        String url = "http://localhost:8080/test1";
        // 发送 post 请求（无参数）
        // Map<String, Object> result = HttpUtils.doPost(url);
        Map params = new HashMap();
        params.put("id",222222);
        // 发送 post 请求（有参数）
        Map<String, Object> result = HttpUtils.doPost(url,params);
        //System.out.println("结果"+result);
        //System.out.println(result.get("status"));
        if (result.get("status").equals(200)){
            System.out.println(result.get("result"));
            Map result1 = (Map) result.get("result");
            System.out.println(result1.get("name"));
        }else{
            System.out.println("请求失败！状态码：" + result.get("status"));
        }
    }
}

ok，到此完成