java后台发送URL请求工具类

第一步引入http依赖

    <dependency>
        <groupId>commons-httpclient</groupId>
        <artifactId>commons-httpclient</artifactId>
        <version>3.0-rc4</version>
    </dependency>

    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.5.3</version>
    </dependency>

第二步创建工具类

	package com.len.utils;
	import com.alibaba.fastjson.JSON;
	import com.fasterxml.jackson.databind.ObjectMapper;
	import org.apache.http.HttpEntity;
	import org.apache.http.HttpResponse;
	import org.apache.http.client.ClientProtocolException;
	import org.apache.http.client.methods.HttpPost;
	import org.apache.http.entity.StringEntity;
	import org.apache.http.impl.client.DefaultHttpClient;
	import java.io.*;
	import java.net.HttpURLConnection;
	import java.net.URL;
	import java.util.List;
	import java.util.Map;
	
	/**
	 * @Author ful
	 * @Description:
	 * @Date in 16:11 2018/10/17
	 * @Modify By:
	 */
	public class HttpUtils {
	
	    private static ObjectMapper objectMapper = new ObjectMapper();
	
	    public static Map<String,Object> httpGet(String url, Map<String, String> parameters) {
	        String result="";
	        BufferedReader in = null;// 读取响应输入流
	        StringBuffer sb = new StringBuffer();// 存储参数
	        String params = "";// 编码之后的参数
	        try {
	            // 编码请求参数
	            if(parameters.size()==1){
	                for(String name:parameters.keySet()){
	                    sb.append(name).append("=").append(
	                            java.net.URLEncoder.encode(parameters.get(name),
	                                    "UTF-8"));
	                }
	                params=sb.toString();
	            }else{
	                for (String name : parameters.keySet()) {
	                    sb.append(name).append("=").append(
	                            java.net.URLEncoder.encode(parameters.get(name),
	                                    "UTF-8")).append("&");
	                }
	                String temp_params = sb.toString();
	                params = temp_params.substring(0, temp_params.length() - 1);
	            }
	            String full_url = url + "?" + params;
	            System.out.println(full_url);
	            // 创建URL对象
	            URL connURL = new URL(full_url);
	            // 打开URL连接
	            HttpURLConnection httpConn = (HttpURLConnection) connURL
	                    .openConnection();
	            // 设置通用属性
	            httpConn.setRequestProperty("Accept", "*/*");
	            httpConn.setRequestProperty("Connection", "Keep-Alive");
	            httpConn.setRequestProperty("User-Agent",
	                    "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1)");
	            // 建立实际的连接
	            httpConn.connect();
	            // 响应头部获取
	            Map<String, List<String>> headers = httpConn.getHeaderFields();
	            // 遍历所有的响应头字段
	            for (String key : headers.keySet()) {
	                System.out.println(key + "\t：\t" + headers.get(key));
	            }
	            // 定义BufferedReader输入流来读取URL的响应,并设置编码方式
	            in = new BufferedReader(new InputStreamReader(httpConn
	                    .getInputStream(), "UTF-8"));
	            String line;
	            // 读取返回的内容
	            while ((line = in.readLine()) != null) {
	                result +=line;
	            }
	        } catch (Exception e) {
	            e.printStackTrace();
	        }finally{
	            try {
	                if (in != null) {
	                    in.close();
	                }
	            } catch (IOException ex) {
	                ex.printStackTrace();
	            }
	        }
	        Map<String,Object> result_map = JSON.parseObject(result);
	        return result_map ;
	    }
	
	
	
	    /**
	     * http请求工具类，post请求
	     *
	     * @param url    url
	     * @param params 参数值 仅支持String和list两种类型
	     * @return
	     * @throws Exception
	     */
	    public static Map<String,Object> httpPost(String url, Map<String, Object> params) {
	        DefaultHttpClient defaultHttpClient = null;
	        BufferedReader bufferedReader = null;
	        try {
	            defaultHttpClient = new DefaultHttpClient();
	            HttpPost httpPost = new HttpPost(url);
	            httpPost.setHeader("Content-Type", "application/json;charset=ut-8");
	            if (params != null) {
	                //转换为json格式并打印，不需要的你们可以不要
	                String jsonParams = objectMapper.writeValueAsString(params);
	
	                HttpEntity httpEntity = new StringEntity(jsonParams, "utf-8");
	                httpPost.setEntity(httpEntity);
	            }
	            HttpResponse httpResponse = defaultHttpClient.execute(httpPost);
	            if (httpResponse.getStatusLine().getStatusCode() != 200) {
	                String errorLog="请求失败，errorCode:"+httpResponse.getStatusLine().getStatusCode();
	
	
	            }
	            //读取返回信息
	            String output;
	            bufferedReader=new BufferedReader(new InputStreamReader(httpResponse.getEntity().getContent(),"utf-8"));
	            StringBuilder stringBuilder=new StringBuilder();
	            while ((output=bufferedReader.readLine())!=null){
	                stringBuilder.append(output);
	            }
	            Map<String,Object> result_map = JSON.parseObject(stringBuilder.toString());
	            return result_map;
	        } catch (ClientProtocolException e) {
	            e.printStackTrace();
	          return null;
	        }catch (IOException e){
	            e.printStackTrace();
	         return null;
	        }finally {
	            if(defaultHttpClient!=null)
	                defaultHttpClient.getConnectionManager().shutdown();
	            if(bufferedReader!=null) {
	                try {
	                    bufferedReader.close();
	                } catch (IOException e) {
	                    e.printStackTrace();
	                }
	            }
	        }
	    }
	
	}