发送 GET 和 POST请求

最新推荐文章于 2023-05-24 21:30:16 发布

原创最新推荐文章于 2023-05-24 21:30:16 发布 · 421 阅读

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本文介绍了如何使用Java实现HTTP GET和POST请求的方法，包括设置请求头、发送请求参数及处理响应数据等关键步骤。


/**
	 *@param url 发送请求的url
	 *@param param 请求参数 请求参数应该是 name=xx&pass=xxxx 
	 */
	public static String sendGet(String url,String param){
		String result="";
		BufferedReader bfr=null;
		try {
			String urlName=url+"?"+param;
			URL realUrl=new URL(urlName);
			URLConnection conn=realUrl.openConnection();
			conn.setRequestProperty("accept", "*/*");
			conn.setRequestProperty("connection", "Keep-Alive");
			conn.setRequestProperty("user-age", "Mozilla/4.0 (compatible;MSIE 6.0;Window NT 5.1;SV1)");
			
			//建立实际的连接
			conn.connect();
			Map<String,List<String>> map=conn.getHeaderFields();
			//遍历所有的响应头字段
			for (String key: map.keySet()) {
				System.out.println(key+"--->"+map.get(key));
			}
			//定义 BufferedRead输入流来读取URL的响应
			bfr=new BufferedReader(new InputStreamReader(conn.getInputStream()));
			
			String line;
			while((line=bfr.readLine())!=null){
				result+="\n"+line;
			}
		} catch (Exception e) {
			System.out.print("发送GET请求出现异常:"+e);
			e.printStackTrace();
		}finally{
			try {
				if(bfr!=null)
					bfr.close();
			} catch (IOException ex) {
				ex.printStackTrace();
			}
		}
		return result;
		
	}
	
	/**
	 *@param url 发送请求的url
	 *@param param 请求参数 请求参数应该是 name=xx&pass=xxxx 
	 */
	public static String sendPost(String url,String param){
		PrintWriter out=null;
		BufferedReader in=null;
		String result="";
		try {
			URL realUrl=new URL(url);
			URLConnection conn=realUrl.openConnection();
			//设置通用的请求属性
			conn.setRequestProperty("accept", "*/*");
			conn.setRequestProperty("connection", "Keep-Alive");
			conn.setRequestProperty("user-age", "Mozilla/4.0 (compatible;MSIE 6.0;Window NT 5.1;SV1)");
			
			//发送POST请求必须设置如下两行
			conn.setDoOutput(true);
			conn.setDoInput(true);
			out=new PrintWriter(conn.getOutputStream());
			out.print(param);
			out.flush();
			in=new BufferedReader(new InputStreamReader(conn.getInputStream()));
			String line;
			while((line=in.readLine())!=null){
				result+="\n"+line;
			}
		} catch (Exception e) {
			System.out.println("发送POST请求出现异常:"+e);
			e.printStackTrace();
		}finally{
			try {
				if(out!=null)
					out.close();
				if(in!=null)
					in.close();
				
			} catch (IOException ex) {
				ex.printStackTrace();
			}
		}
		return result;
	}

Get 发送数据


public String getJosnByUrl(String url) {
		StringBuffer josn = new StringBuffer();
		BufferedReader reader = null;
		InputStream inputStream = null;
		HttpURLConnection httpURLConnection = null;
		try {
			URL httpUrl = new URL(url);
			URLConnection connection = httpUrl.openConnection();
			httpURLConnection = (HttpURLConnection) connection;
			httpURLConnection.setDoOutput(true);
			httpURLConnection.setDoInput(true);
			httpURLConnection.setReadTimeout(30000);// 无响应30秒，断开会话
			httpURLConnection.setConnectTimeout(30000);
			httpURLConnection.setRequestMethod("GET");
			httpURLConnection.setRequestProperty("Referer","http://taobao.51bi.com");
			httpURLConnection.setRequestProperty("Accept-Language","zh-cn");
			httpURLConnection.setRequestProperty("User-Agent","Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; MALC)");
			httpURLConnection.connect();
			inputStream = httpURLConnection.getInputStream();// 发送连接
			reader = new BufferedReader(new InputStreamReader(inputStream,"utf-8"));
			String line = null;
			while ((line = reader.readLine()) != null) {
				josn.append(line);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if(reader != null)
					reader.close();
				if(inputStream != null)
					inputStream.close();
				if(httpURLConnection != null)
					httpURLConnection.disconnect();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return josn.toString().trim();
	}

post 发送数据xml 或者json 然后读取返回值


public String getJosnByUrl(String url,String param) {
		StringBuffer josn = new StringBuffer();
		BufferedReader reader = null;
		PrintWriter out=null;
		InputStream inputStream = null;
		HttpURLConnection httpURLConnection = null;
		try {
			URL httpUrl = new URL(url);
			URLConnection connection = httpUrl.openConnection();
			httpURLConnection = (HttpURLConnection) connection;
			httpURLConnection.setDoOutput(true);
			httpURLConnection.setDoInput(true);
			httpURLConnection.setReadTimeout(30000);// 无响应30秒，断开会话
			httpURLConnection.setConnectTimeout(30000);
			httpURLConnection.setRequestMethod("POST");
			
			//httpURLConnection.setRequestProperty("Referer","http://taobao.51bi.com");
			httpURLConnection.setRequestProperty("Accept-Language","zh-cn");
			httpURLConnection.setRequestProperty("User-Agent","Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0; MALC)");
			httpURLConnection.connect();
			out=new PrintWriter(httpURLConnection.getOutputStream());
			out.write(param);//数据写入缓存中
			out.flush();
			inputStream = httpURLConnection.getInputStream();// 发送连接
		
			reader = new BufferedReader(new InputStreamReader(inputStream,"utf-8"));
			String line = null;
			while ((line = reader.readLine()) != null) {
				josn.append(line);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if(out!=null)
					out.close();
				if(reader != null)
					reader.close();
				if(inputStream != null)
					inputStream.close();
				if(httpURLConnection != null)
					httpURLConnection.disconnect();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return josn.toString().trim();
	}