HttpServletRequest概述：
service方法中的request的类型是ServletRequest，而doGet/doPost方法的request的类型是HttpServletRequest，HttpServletRequest是ServletRequest的子接口。
通过request获得请求行：
package com.oracle.demo01; 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 LineServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取请求方式 System.out.println("请求方式为"+request.getMethod()); //获取请求URI System.out.println("URI为"+request.getRequestURI()); //获取请求URL System.out.println("URL为"+request.getRequestURL()); //获取WEB应用名称 System.out.println("WEB应用名称为"+request.getContextPath()); //获取get请求后URL后的字符串 System.out.println("get请求参数为"+request.getQueryString()); //获取客户端的ip地址 System.out.println("ip地址为"+request.getRemoteAddr()); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
运行结果：
package com.oracle.demo01; 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 RefereServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //获取refer头 String refere=request.getHeader("Referer"); String content=null; if(refere.startsWith("http://localhost:8080")){ content="真的离婚了！"; }else{ content="你是小偷！"; } //解决response中文乱码 response.setContentType("text/html;charset=utf-8"); response.getWriter().write(content); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <a href="/WEB06/RefereServlet">宋仲基和宋慧乔分手了</a> </body> </html>
通过request获得请求体：
package com.oracle.demo01; import java.io.IOException; import java.util.Map; import java.util.Set; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class BodyServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //post请求解决中文乱码问题 //request.setCharacterEncoding("utf-8"); //获取请求参数 //1.获取单个值的参数 String name=request.getParameter("username"); name=new String(name.getBytes("ISO-8859-1"), "UTF-8"); String sex=request.getParameter("sex"); sex=new String(sex.getBytes("ISO-8859-1"), "UTF-8"); System.out.println(name+"..."+sex); //2.获取多个值 String[] hobbys=request.getParameterValues("hobby"); //遍历 for(String s:hobbys){ System.out.println(s); } //3.获取所有的请求参数Map Map<String, String[]> map=request.getParameterMap(); //遍历 Set<String> set=map.keySet(); for(String str:set){ String[] value=map.get(str); for(String v:value){ System.out.println(str+"..."+v); } } } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="/WEB06/BodyServlet" method="get"> <input type="text" name="username"><br> <input type="radio" name="sex" value="man">男 <input type="radio" name="sex" value="woman">女 <br> <input type="checkbox" name="hobby" value="ppq"> 乒乓球 <input type="checkbox" name="hobby" value="pq"> 排球 <input type="checkbox" name="hobby" value="wq"> 网球 <br> <input type="submit" value="提交"> </form> </body> </html>
request是一个域对象
package com.oracle.demo02; 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 Servlet01 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //向request域中存值 request.setAttribute("name", "袁一鸣"); //请求转发 request.getRequestDispatcher("/Servlet02").forward(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
package com.oracle.demo02; 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 Servlet02 extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //从request域中取值 String name=(String)request.getAttribute("name"); response.setContentType("text/html;charset=utf-8"); response.getWriter().write("hello"+name); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } }
运行结果：
request生命周期：
创建：访问时创建request
销毁：响应结束request销毁
域的作用范围：一次请求中
转发与重定向的区别:
1）重定向两次请求，转发一次请求
2）重定向地址栏的地址变化，转发地址不变
3）重新定向可以访问外部网站 转发只能访问内部资源
4）转发的性能要优于重定向
原文：https://www.cnblogs.com/boss-H/p/11147514.html