一：request
用来访问servlet，获取客户端的各种信息。
1、返回服务器信息
2、接收页面参数
3、跳转
1、返回服务器的各种信息
package com.haizhu.request;
import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletRequestDemo extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String headValue = request.getHeader("Accept-Encoding");
System.out.println(headValue);
System.out.println("******************************************");
Enumeration enu = request.getHeaders("Accept-Encoding");
while(enu.hasMoreElements()){
String value = (String)enu.nextElement();
System.out.println(value);
}
System.out.println("******************************************");
// 获取URL，这个可以用来控制访问权限，
String URI = request.getRequestURI();
StringBuffer URL = request.getRequestURL();
System.out.println(URI);
System.out.println(URL);
System.out.println("******************************************");
// 获取通过通过“?” 后跟参数的形式传递过来的参数
String queryString = request.getQueryString();
System.out.println(queryString);
System.out.println("******************************************");
// 获取客户机的IP地址、host、端口等
String ip = request.getRemoteAddr();
String host = request.getRemoteHost();
int port = request.getRemotePort();
System.out.println(ip);
System.out.println(host);
System.out.println(port);
System.out.println("******************************************");
// 请求方式
String method = request.getMethod();
System.out.println(method);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
2、接收页面传递过来的数据
web的配置文件就省略了，下面是param.html页面
<!DOCTYPE html>
<html>
<head>
<title>param.html</title>
</head>
<body>
<a href="/ServletDemo/ServletRequestParamDemo?username=Haizhu&password=1234" >点我</a>
<form action="/ServletDemo/ServletRequestParamDemo" method="post">
用户名：<input type="text" name="username"></input><br>
密 码：<input type="text" name="password"></input><br>
<input type="submit" value="提交">
</form>
</body>
</html>
ServletRequestParamDemo.java
package com.haizhu.request;
import java.io.IOException;
import java.util.Enumeration;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletRequestParamDemo extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
String password = request.getParameter("password");
System.out.println(username);
System.out.println(password);
Enumeration enu = request.getAttributeNames();
while(enu.hasMoreElements()){
String name = (String)enu.nextElement();
String word = request.getParameter(name);
System.out.println(name);
System.out.println(word);
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
3、实现跳转
web.xml省略，
ServletRequestAttribute.java
package com.haizhu.request;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletRequestAttribute extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// 定义一个变量，模拟从页面请求中接收的数据
String attrData = "myAttributeData";
// 将这个数据封装在 attribute 中
request.setAttribute("data", attrData);
// 转发，跳转到根目录下的 servletRequestAttribute.jsp 页面，
request.getRequestDispatcher("/servletRequestAttribute.jsp").forward(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}
servletRequestAttribute.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>My JSP 'servletRequestAttribute.jsp' starting page</title>
</head>
<body>
<!-- 第一种取值方法 -->
${data }
<!-- 第二种取值方法 -->
<%
String myData = (String)request.getAttribute("data"); // 注意是，getAttribute()，不是getParameter
out.write(myData); // 一个是request域的参数，一个是context域的参数
%>
</body>
</html>
二：response
servlet返回的各种信息。
范例：
package com.haizhu.response;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ServletResponseDemo extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
function2(response);
}
// 以 OutputSteam 输出
private void function1(HttpServletResponse response) throws IOException{
response.setHeader("Content-type", "text/html;charset=UTF-8"); // 设置浏览器的解析编码
String data = "你好！";
OutputStream out = response.getOutputStream();
out.write(data.getBytes("UTF-8")); // 设置字节编码
}
// 以 PrintWriter 输出
private void function2(HttpServletResponse response) throws IOException {
response.setCharacterEncoding("UTF-8"); // 设置response 的码表，以控制以什么码表向浏览器输出
//response.setHeader("Content-type", "text/html;charset=UTF-8"); // 设置浏览器以什么码表解析
response.setContentType("text/html;charset=UTF-8"); // 作用同上
String data = "中国！";
PrintWriter out = response.getWriter();
out.write(data);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request,response);
}
}