Java代码模拟HTTP请求的常见两种请求方式：GET/POST

刺骨的言语ヽ痛彻心扉 2022-01-29 14:49 435阅读 0赞

package com.jarvis.base.util;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.PrintWriter;
    import java.util.Map;
    
    /**
     * 用于模拟HTTP请求中GET/POST方式 
     * @author landa
     *
     */
    public class HttpUtils {  
        /** 
         * 发送GET请求 
         *  
         * @param url 
         *            目的地址 
         * @param parameters 
         *            请求参数，Map类型。 
         * @return 远程响应结果 
         */  
        public static String sendGet(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  
                java.net.URL connURL = new java.net.URL(full_url);  
                // 打开URL连接  
                java.net.HttpURLConnection httpConn = (java.net.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();  
                }  
            }
            return result ;
        }  
      
        /** 
         * 发送POST请求 
         *  
         * @param url 
         *            目的地址 
         * @param parameters 
         *            请求参数，Map类型。 
         * @return 远程响应结果 
         */  
        public static String sendPost(String url, Map<String, String> parameters) {  
            String result = "";// 返回的结果  
            BufferedReader in = null;// 读取响应输入流  
            PrintWriter out = null;  
            StringBuffer sb = new StringBuffer();// 处理请求参数  
            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);  
                }  
                // 创建URL对象  
                java.net.URL connURL = new java.net.URL(url);  
                // 打开URL连接  
                java.net.HttpURLConnection httpConn = (java.net.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)");  
                // 设置POST方式  
                httpConn.setDoInput(true);  
                httpConn.setDoOutput(true);  
                // 获取HttpURLConnection对象对应的输出流  
                out = new PrintWriter(httpConn.getOutputStream());  
                // 发送请求参数  
                out.write(params);
    //            System.out.println(params);
                // flush输出流的缓冲  
                out.flush();  
                // 定义BufferedReader输入流来读取URL的响应，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 (out != null) {  
                        out.close();  
                    }  
                    if (in != null) {  
                        in.close();  
                    }  
                } catch (IOException ex) {  
                    ex.printStackTrace();  
                }  
            }  
            return result;  
        }
        
        /**
         *Author:Jack
         *Time:2017年9月5日下午2:20:26
         *@param url
         *@param parameters
         *@return
         *Return:String
         *Description:发送Post请求，并且发送的是Json格式的数据。
         */
    	public static String sendPostJson(String url, Map<String, String> parameters) {
    		 String result = "";// 返回的结果  
    	        BufferedReader in = null;// 读取响应输入流  
    	        PrintWriter out = null;  
    	        String params = "";// 编码之后的参数  
    	        try {  
    	            if(parameters!=null && parameters.size()>0){
    	            	params = FastJsonUtil.toJSONString(parameters);
    	            }
    	            // 创建URL对象  
    	            java.net.URL connURL = new java.net.URL(url);  
    	            // 打开URL连接  
    	            java.net.HttpURLConnection httpConn = (java.net.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)");  
    	            // 设置POST方式  
    	            httpConn.setDoInput(true);  
    	            httpConn.setDoOutput(true);  
    	            // 获取HttpURLConnection对象对应的输出流  
    	            out = new PrintWriter(httpConn.getOutputStream());  
    	            // 发送请求参数  
    	            out.write(params);
    //	            System.out.println(params);
    	            // flush输出流的缓冲  
    	            out.flush();  
    	            // 定义BufferedReader输入流来读取URL的响应，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 (out != null) {  
    	                    out.close();  
    	                }  
    	                if (in != null) {  
    	                    in.close();  
    	                }  
    	            } catch (IOException ex) {  
    	                ex.printStackTrace();  
    	            }  
    	        }  
    	        return result;  
    	}
      
        /** 
         * 主函数，测试请求 
         *  
         * @param args 
         */  
    //    public static void main(String[] args) {  
    //        Map<String, String> parameters = new HashMap<String, String>();  
    //        parameters.put("name", "sarin");  
    //        String result =sendGet("http://www.baidu.com", parameters);
    //        System.out.println(result); 
    //    }  
    }