javaweb之request获取请求头和请求数据

javaweb之request获取请求头和请求数据

翻译  2014年03月07日 22:43:22

• 6527

 package test.request;

 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.reflect.InvocationTargetException;
 import java.util.Enumeration;
 import java.util.Map;

 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.sun.org.apache.commons.beanutils.BeanUtils;
 //HttpServletRequest获取请求头和请求数据
 //请求数据一半来说要先检查再使用，检查非空和不是空格

 public class RequestDemo2 extends HttpServlet {

     public void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         System.out.println("---------获取请求数据方式1-------------");
         // 获取指定的请求数据
         String value = request.getParameter("username");
         if (value != null && !value.trim().equals("")) {
             System.out.println(value);
         }

         System.out.println("---------获取请求数据方式2-------------");
         // 获取所有的请求数据
         Enumeration e = request.getParameterNames();
         while (e.hasMoreElements()) {
             String paramName = (String) e.nextElement();
             String value2 = request.getParameter(paramName);
             System.out.println(paramName + "=" + value2);
         }

         System.out.println("---------获取请求数据方式3-------------");
         // 获取所有的请求数据，同名的只能获取一次，就是第一次
         String[] values = request.getParameterValues("username");
         for (int i = 0; values != null && i < values.length; i++) {
             System.out.println(values[i]);
         }

         System.out.println("---------获取请求数据方式4-------------");
         // 这个特别实用，框架的模型驱动，这个Map的value肯定是String数组类型，因为有同名的请求数据
         // 实际开发中是不会 request.getParameter("username");用这种方式的，都是要创建一个model的
         Map map = request.getParameterMap();
         User user = new User();
         try {
             // 用map中的数据填充bean
             BeanUtils.populate(user, map);
         } catch (IllegalAccessException e1) {
             e1.printStackTrace();
         } catch (InvocationTargetException e1) {
             e1.printStackTrace();
         }
         System.out.println(user.getPassword());

         System.out.println("---------获取请求数据方式5-------------");
         // request.getInputStream();是上传文件的时候获取数据的方式
         // 普通数据是获取不到的
         InputStream in = request.getInputStream();
         int len = 0;
         byte[] buffer = new byte[1024];
         while ((len = in.read(buffer)) > 0) {
             System.out.println(new String(buffer, 0, len));
         }
     }

     // 获取请求头
     private void test1(HttpServletRequest request) {
         System.out.println("---------获取请求头方式1-------------");
         // 拿到指定的请求头
         System.out.println(request.getHeader("cache-control"));

         System.out.println("---------获取请求头方式2-------------");
         // 拿到所有指定的请求头
         Enumeration e = request.getHeaders("cache-control");
         while (e.hasMoreElements()) {
             String headValue = (String) e.nextElement();
             System.out.println(headValue);
         }

         System.out.println("---------获取请求头方式3-------------");
         // 拿到所有请求头
         Enumeration e1 = request.getHeaderNames();
         while (e1.hasMoreElements()) {
             String headerName = (String) e1.nextElement();
             String headValue = request.getHeader(headerName);
             System.out.println(headerName + "=" + headValue);
         }
     }

     public void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         doGet(request, response);
     }

 }

 package test.request;

 public class User {
     private String[] username;
     public String[] getUsername() {
         return username;
     }
     public void setUsername(String[] username) {
         this.username = username;
     }
     public String getPassword() {
         return password;
     }
     public void setPassword(String password) {
         this.password = password;
     }
     private String password;
 }

 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
 >
 <html>
   <head>
     <title>给RequestDemo2发送请求数据title>
   head>

   <body>

     <a href="/day06/servlet/RequestDemo2?username=xxx">点点a><br/>
     <form action="/day06/servlet/RequestDemo2" method="post">
         用户名1：<input type="text" name="username"/><br/>
         用户名2：<input type="text" name="username"/><br/>
         密码：<input type="password" name="password"/><br/>
         <input type="submit" value="提交"/>
     form>
   body>
 html>

此程序还需用到commons-beanutils-1.9.0.jar和commons-logging-1.1.3.jar这两个jar包