HttpURLConnection为javaAPI提供的一种Rest访问的方式。其支持对Post,Delete,Get,Put等方式的访问。
以下为对于HttpURLConnection对Post等方式访问的一段代码。
view plain copy to clipboard print ? package com.sw.study.urlConnection; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.util.HashMap; import java.util.Map; public class URLConnectionUtil { private static final String SERVLET_POST = "POST" ; private static final String SERVLET_GET = "GET" ; private static final String SERVLET_DELETE = "DELETE" ; private static final String SERVLET_PUT = "PUT" ; private static String prepareParam(Map<String,Object> paramMap){ StringBuffer sb = new StringBuffer(); if (paramMap.isEmpty()){ return "" ; }else { for (String key: paramMap.keySet()){ String value = (String)paramMap.get(key); if (sb.length()< 1 ){ sb.append(key).append("=" ).append(value); }else { sb.append("&" ).append(key).append( "=" ).append(value); } } return sb.toString(); } } public static void doPost(String urlStr,Map<String,Object> paramMap ) throws Exception{ URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(SERVLET_POST); String paramStr = prepareParam(paramMap); conn.setDoInput(true ); conn.setDoOutput(true ); OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8" )); os.close(); BufferedReader br = new BufferedReader( new InputStreamReader(conn.getInputStream())); String line ; String result ="" ; while ( (line =br.readLine()) != null ){ result += "/n" +line; } System.out.println(result); br.close(); } public static void doGet(String urlStr,Map<String,Object> paramMap ) throws Exception{ String paramStr = prepareParam(paramMap); if (paramStr == null || paramStr.trim().length()< 1 ){ }else { urlStr +="?" +paramStr; } System.out.println(urlStr); URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(SERVLET_PUT); conn.setRequestProperty("Content-Type" , "text/html; charset=UTF-8" ); conn.connect(); BufferedReader br = new BufferedReader( new InputStreamReader(conn.getInputStream())); String line ; String result ="" ; while ( (line =br.readLine()) != null ){ result += "/n" +line; } System.out.println(result); br.close(); } public static void doPut(String urlStr,Map<String,Object> paramMap) throws Exception{ URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(SERVLET_PUT); String paramStr = prepareParam(paramMap); conn.setDoInput(true ); conn.setDoOutput(true ); OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8" )); os.close(); BufferedReader br = new BufferedReader( new InputStreamReader(conn.getInputStream())); String line ; String result ="" ; while ( (line =br.readLine()) != null ){ result += "/n" +line; } System.out.println(result); br.close(); } public static void doDelete(String urlStr,Map<String,Object> paramMap) throws Exception{ String paramStr = prepareParam(paramMap); if (paramStr == null || paramStr.trim().length()< 1 ){ }else { urlStr +="?" +paramStr; } System.out.println(urlStr); URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setDoOutput(true ); conn.setRequestMethod(SERVLET_DELETE); //屏蔽掉的代码是错误的，java.net.ProtocolException: HTTP method DELETE doesn't support output /* OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); */ if (conn.getResponseCode() == 200 ){ System.out.println("成功" ); }else { System.out.println(conn.getResponseCode()); } } public static void main(String[] args) throws Exception{ String urlStr = "http://localhost:8080/SwTest/ReceiveDataServlet" ; Map<String,Object> map = new HashMap<String,Object>(); map.put("username" , "张三" ); map.put("password" , "88888" ); // URLConnectionUtil.doGet(urlStr, map); // URLConnectionUtil.doPost(urlStr, map); // URLConnectionUtil.doPut(urlStr, map); URLConnectionUtil.doDelete(urlStr, map); } }package com.sw.study.urlConnection; import java.io.BufferedReader; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.net.URLConnection; import java.util.HashMap; import java.util.Map; public class URLConnectionUtil { private static final String SERVLET_POST = "POST" ; private static final String SERVLET_GET = "GET" ; private static final String SERVLET_DELETE = "DELETE" ; private static final String SERVLET_PUT = "PUT" ; private static String prepareParam(Map<String,Object> paramMap){ StringBuffer sb = new StringBuffer(); if(paramMap.isEmpty()){ return "" ; }else{ for(String key: paramMap.keySet()){ String value = (String)paramMap.get(key); if(sb.length()<1){ sb.append(key).append("=").append(value); }else{ sb.append("&").append(key).append("=").append(value); } } return sb.toString(); } } public static void doPost(String urlStr,Map<String,Object> paramMap ) throws Exception{ URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(SERVLET_POST); String paramStr = prepareParam(paramMap); conn.setDoInput(true); conn.setDoOutput(true); OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream())); String line ; String result =""; while( (line =br.readLine()) != null ){ result += "/n"+line; } System.out.println(result); br.close(); } public static void doGet(String urlStr,Map<String,Object> paramMap ) throws Exception{ String paramStr = prepareParam(paramMap); if(paramStr == null || paramStr.trim().length()<1){ }else{ urlStr +="?"+paramStr; } System.out.println(urlStr); URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(SERVLET_PUT); conn.setRequestProperty("Content-Type","text/html; charset=UTF-8"); conn.connect(); BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream())); String line ; String result =""; while( (line =br.readLine()) != null ){ result += "/n"+line; } System.out.println(result); br.close(); } public static void doPut(String urlStr,Map<String,Object> paramMap) throws Exception{ URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setRequestMethod(SERVLET_PUT); String paramStr = prepareParam(paramMap); conn.setDoInput(true); conn.setDoOutput(true); OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream())); String line ; String result =""; while( (line =br.readLine()) != null ){ result += "/n"+line; } System.out.println(result); br.close(); } public static void doDelete(String urlStr,Map<String,Object> paramMap) throws Exception{ String paramStr = prepareParam(paramMap); if(paramStr == null || paramStr.trim().length()<1){ }else{ urlStr +="?"+paramStr; } System.out.println(urlStr); URL url = new URL(urlStr); HttpURLConnection conn = (HttpURLConnection)url.openConnection(); conn.setDoOutput(true); conn.setRequestMethod(SERVLET_DELETE); //屏蔽掉的代码是错误的，java.net.ProtocolException: HTTP method DELETE doesn't support output /* OutputStream os = conn.getOutputStream(); os.write(paramStr.toString().getBytes("utf-8")); os.close(); */ if(conn.getResponseCode() ==200){ System.out.println("成功"); }else{ System.out.println(conn.getResponseCode()); } } public static void main(String[] args) throws Exception{ String urlStr = "http://localhost:8080/SwTest/ReceiveDataServlet"; Map<String,Object> map = new HashMap<String,Object>(); map.put("username","张三"); map.put("password","88888"); // URLConnectionUtil.doGet(urlStr, map); // URLConnectionUtil.doPost(urlStr, map); // URLConnectionUtil.doPut(urlStr, map); URLConnectionUtil.doDelete(urlStr, map); } }
方法中是存在重复的。有些方法是可以通过参数的改变来达到统一，但是那样的做法对于程序的扩展性会有很大的局限性。
还是对于每一种方式提供一个单独的方法进行访问比较好。
在Servlet端，获取参数可以通过
request.getInputStream,及request.getParamter来进行。
其中，当Rest访问传入参数是通过conn的outputStream来进行的，可以通过request.getInputStream来进行参数获取（Post方式可通用）；
当以url?key=value方法传递参数时，可以通过request.getParamter来进行参数获取。（Post方式可通用）
其中request.getInputStream和request.getParamter两种方式不能同时出现。当request.getParamter运行的过程，也是输入流的读取过程。当输入流读取完成后，再次调用时无效的。
附上Servlet端程序
view plain copy to clipboard print ? package com.sw.servlet; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class ReceiveDataServlet */ public class ReceiveDataServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ReceiveDataServlet() { super (); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------get--------------" ); String username = new String(request.getParameter( "username" ).getBytes( "iso-8859-1" ), "utf-8" ); String password = new String(request.getParameter( "password" ).getBytes( "iso-8859-1" ), "utf-8" ); System.out.println(username); System.out.println(password); OutputStream os = response.getOutputStream(); os.write("get" .getBytes( "utf-8" )); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------post--------------" ); BufferedReader br = new BufferedReader( new InputStreamReader((ServletInputStream)request.getInputStream())); String line = null ; StringBuilder sb = new StringBuilder(); while ((line = br.readLine())!= null ){ sb.append(line); } System.out.println(sb.toString()); br.close(); /* String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8"); String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8"); System.out.println(username); System.out.println(password); */ OutputStream os = response.getOutputStream(); os.write("post" .getBytes( "utf-8" )); } @Override protected void doDelete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------delete--------------" ); String username = new String(request.getParameter( "username" ).getBytes( "iso-8859-1" ), "utf-8" ); String password = new String(request.getParameter( "password" ).getBytes( "iso-8859-1" ), "utf-8" ); System.out.println(username); System.out.println(password); OutputStream os = response.getOutputStream(); os.write("delete" .getBytes( "utf-8" )); } @Override protected void doPut(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------put--------------" ); /* BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream())); String line = null; StringBuilder sb = new StringBuilder(); while((line = br.readLine())!=null){ sb.append(line); } System.out.println(sb.toString()); br.close();*/ String username = new String(request.getParameter( "username" ).getBytes( "iso-8859-1" ), "utf-8" ); String password = new String(request.getParameter( "password" ).getBytes( "iso-8859-1" ), "utf-8" ); System.out.println(username); System.out.println(password); OutputStream os = response.getOutputStream(); os.write("put" .getBytes( "utf-8" )); } }package com.sw.servlet; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.OutputStream; import javax.servlet.ServletException; import javax.servlet.ServletInputStream; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * Servlet implementation class ReceiveDataServlet */ public class ReceiveDataServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ReceiveDataServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------get--------------"); String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8"); String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8"); System.out.println(username); System.out.println(password); OutputStream os = response.getOutputStream(); os.write("get".getBytes("utf-8")); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------post--------------"); BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream())); String line = null; StringBuilder sb = new StringBuilder(); while((line = br.readLine())!=null){ sb.append(line); } System.out.println(sb.toString()); br.close(); /* String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8"); String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8"); System.out.println(username); System.out.println(password); */ OutputStream os = response.getOutputStream(); os.write("post".getBytes("utf-8")); } @Override protected void doDelete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------delete--------------"); String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8"); String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8"); System.out.println(username); System.out.println(password); OutputStream os = response.getOutputStream(); os.write("delete".getBytes("utf-8")); } @Override protected void doPut(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { System.out.println("----------put--------------"); /* BufferedReader br = new BufferedReader(new InputStreamReader((ServletInputStream)request.getInputStream())); String line = null; StringBuilder sb = new StringBuilder(); while((line = br.readLine())!=null){ sb.append(line); } System.out.println(sb.toString()); br.close();*/ String username = new String(request.getParameter("username").getBytes("iso-8859-1"),"utf-8"); String password = new String(request.getParameter("password").getBytes("iso-8859-1"),"utf-8"); System.out.println(username); System.out.println(password); OutputStream os = response.getOutputStream(); os.write("put".getBytes("utf-8")); } }
程序中对于request.getInputStream和getParameter的获取方式可能说明的会多少有些问题，我也是通过几组测试后得出的结论。肯定有我没有测试到得。如果有问题，请指出，我会再看到评论后进行测试，修改。
另外，Apache的HttpClient非常好。封装的详细。在我的工作中也用到过，在以后会对于HttpClient进行有些单独的程序笔记。
这里HttpUrlConnection是同事在别的项目中用到的，用法比较简单，我大体给他简单讲解了一下，简明扼要，功能完备，还是很方便，
所以在这里记下来，留个笔记吧。
btw,最近工作比较忙，有2个月没有写些东西了，在工作中确实还遇到了不少有意思的问题，最近刚好快闲下来了，慢慢整理一下。
