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这里的联网应用程序使用java.net包下的URL/HttpURLConnection类实现get/post请求
1、创建一个RUL对象
URL url = new URL(reqUrl);2、获取URLConnection实例，与URL引用的远程对象的连接。
HttpURLConnection conn = (HttpURLConnection)url.openConnection();3、HttpURLConnection打开指向此引用的资源的通信链接
conn.connect();4、从此打开的连接读取的输入流。
conn.getInputStream()5、处理输入流
根据业务处理输入流
关键代码
public static String doGet(URL url, String encoding) throws IOException { BufferedReader reader = null; HttpURLConnection conn = null; try { conn = (HttpURLConnection)url.openConnection(); setConnectionParameter("GET", conn); setHeader(encoding, conn); conn.connect(); reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding)); return getResult(reader); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException(e); } finally { if (reader != null){ reader.close(); } if (conn != null){ conn.disconnect(); } }}关键代码
public static String doPost(URL url, Map<String, String> params, String encoding) throws IOException { DataOutputStream out = null; BufferedReader reader = null; HttpURLConnection conn = null; try { conn = (HttpURLConnection)url.openConnection(); setConnectionParameter("POST", conn); setHeader(encoding, conn); conn.connect(); if ((null != params) && (!params.isEmpty())) { out = new DataOutputStream(conn.getOutputStream()); String stringParams = buildParams(params); out.write(stringParams.getBytes()); out.flush(); } reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding)); return getResult(reader); } catch (Exception e) { throw new RuntimeException(e); } finally { if (reader != null){ reader.close(); } if (out != null){ out.close(); } if (conn != null){ conn.disconnect(); } }}import java.io.BufferedReader;import java.io.DataOutputStream;import java.io.IOException;import java.io.InputStreamReader;import java.net.HttpURLConnection;import java.net.URL;import java.util.HashMap;import java.util.Map;public class HttpUtils { private static final String CHARSET = "UTF-8"; public static String doGet(String reqUrl) throws IOException { return doGet(reqUrl, CHARSET); } public static String doGet(String reqUrl, String encoding) throws IOException { URL url = new URL(reqUrl); return doGet(url, encoding); } public static String doGet(URL url, String encoding) throws IOException { BufferedReader reader = null; HttpURLConnection conn = null; try { conn = (HttpURLConnection)url.openConnection(); setConnectionParameter("GET", conn); setHeader(encoding, conn); conn.connect(); reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding)); return getResult(reader); } catch (IOException e) { e.printStackTrace(); throw new RuntimeException(e); } finally { if (reader != null){ reader.close(); } if (conn != null){ conn.disconnect(); } } } public static String doPost(String reqUrl, Map<String, String> params) throws IOException { return doPost(reqUrl, params, CHARSET); } public static String doPost(String reqUrl, Map<String, String> params, String encoding) throws IOException { URL url = new URL(reqUrl); return doPost(url, params, encoding); } public static String doPost(URL url, Map<String, String> params, String encoding) throws IOException { DataOutputStream out = null; BufferedReader reader = null; HttpURLConnection conn = null; try { conn = (HttpURLConnection)url.openConnection(); setConnectionParameter("POST", conn); setHeader(encoding, conn); conn.connect(); if ((null != params) && (!params.isEmpty())) { out = new DataOutputStream(conn.getOutputStream()); String stringParams = buildParams(params); out.write(stringParams.getBytes()); out.flush(); } reader = new BufferedReader(new InputStreamReader(conn.getInputStream(), encoding)); return getResult(reader); } catch (Exception e) { throw new RuntimeException(e); } finally { if (reader != null){ reader.close(); } if (out != null){ out.close(); } if (conn != null){ conn.disconnect(); } } } /** * 设置连接参数 * @param method * @param conn * @throws IOException */ private static void setConnectionParameter(String method, HttpURLConnection conn) throws IOException { conn.setDoOutput(true); conn.setDoInput(true); conn.setInstanceFollowRedirects(true); conn.setConnectTimeout(1000*10); conn.setReadTimeout(1000*10); conn.setRequestMethod(method); } /** * 设置请求属性 * @param encoding * @param conn */ private static void setHeader(String encoding, HttpURLConnection conn) { conn.setRequestProperty("Connection", "Keep-Alive"); conn.setRequestProperty("accept-language", "zh_CN"); conn.setRequestProperty("Charset", encoding); conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); //伪装浏览器 conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.83 Safari/537.36"); } private static String getResult(BufferedReader reader) throws IOException { StringBuffer buff = new StringBuffer(); String line = reader.readLine(); while (line != null) { // buff.append("\n"+ line); buff.append(line); line = reader.readLine(); } String result = buff.toString(); return result; } private static String buildParams(Map<String, String> params) { if (null == params || params.isEmpty()){ return ""; } StringBuilder sb = new StringBuilder(); int i = 0; for (Map.Entry entry : params.entrySet()) { if (i > 0){ sb.append("&"); } sb.append((String)entry.getKey()); sb.append("="); sb.append((String)entry.getValue()); i++; } return sb.toString(); }}转载地址：http://qeiwz.baihongyu.com/