程序员社区

【Servlet-2】HttpServletRequest接口

2022-01-22 分类：未分类 阅读(187)

在这里插入图片描述

文章目录

      • 1.HttpServletRequset请求参数的获取
      • 2.HttpServletRequest设置域属性
      • 3.HttpServletRequest接口中的其他方法：
      • 4.HttpServletRequest请求端中文乱码

1.HttpServletRequset请求参数的获取

根据表单中的name获取表单中的value，注意是针对请求参数而言的。
在这里插入图片描述

package HttpServlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Map;
import java.util.Set;

@WebServlet("/ServletDemo1")
public class ServletDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取指定名称的请求参数值
        String name = request.getParameter("name");
        String age = request.getParameter("age");
        System.out.println("name="+name);
        System.out.println("age="+age);


        //获取所有请求名称的请求参数值
        Enumeration<String> parameterNames = request.getParameterNames();
        while (parameterNames.hasMoreElements()){
            String eleName = parameterNames.nextElement();
            String eleValue = request.getParameter(eleName);
            System.out.println(eleName+"="+eleValue);
        }

        //获取指定参数的所有值
        String[] hobbies = request.getParameterValues("hobby");
        for(String hobby:hobbies){
            System.out.println(hobby);
        }

        //获取存放请求参数的Map
        Map<String, String[]> parameterMap = request.getParameterMap();
        Set<String> set = parameterMap.keySet();
        for(String key:set){
            System.out.println(key+"="+request.getParameter(key));
        }
    }

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

在这里插入图片描述

2.HttpServletRequest设置域属性

ServletRequestDemo1文件：在其中设置域属性，如果想在其他Servlet中获取域属性就要使用请求转发，否则不能获取到域属性的值。request对象的生命周期是一次请求。
而ServletContext中设置的域属性，可以在任何一个Servlet中获取。

在这里插入图片描述
在这里插入图片描述

package HttpServletRequest;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/ServletRequestDemo1")
public class ServletRequestDemo1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setAttribute("username","zhangsan");
        request.setAttribute("password","123");

        //从请求中删除域属性
        request.removeAttribute("password");

        //将请求转发给ServletRequestDemo2
     	request.getRequestDispatcher("/ServletRequestDemo2").forward(request,response);

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

ServletRequestDemo2文件：

package HttpServletRequest;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Enumeration;

@WebServlet("/ServletRequestDemo2")
public class ServletRequestDemo2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        Object username = request.getAttribute("username");
        Object password = request.getAttribute("password");
        System.out.println("username="+username);
        System.out.println("password="+password);

        Enumeration<String> attributeNames = request.getAttributeNames();
        while (attributeNames.hasMoreElements()){
            String name = attributeNames.nextElement();
            System.out.println(name+"="+request.getAttribute(name));
        }
    }

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

3.HttpServletRequest接口中的其他方法：

package HttpServletRequest;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/ServletRequestDemo3")
public class ServletRequestDemo3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //获取请求的URL
        StringBuffer requestURL = request.getRequestURL();
        System.out.println("requestURL="+requestURL);

        //获取请求的URI
        String requestURI = request.getRequestURI();
        System.out.println("requestURI="+requestURI);

        //获取当前web应用的根路径
        String contextPath = request.getContextPath();
        System.out.println("contextPath="+contextPath);

        //获取客户端IP
        String remoteAddr = request.getRemoteAddr();
        System.out.println("remoteAddr="+remoteAddr);

        //获取ServletPath
        String servletPath = request.getServletPath();
        System.out.println("servletPath="+servletPath);
    }

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

在这里插入图片描述

4.HttpServletRequest请求端中文乱码

乱码.html：表单Post方式提交

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<form action="/34/ServletErrorCode1" method="post">
    姓名： <input type="text" name="name"><br>
    年龄： <input type="text" name="age"><br>
    爱好：
    <input type="checkbox" name="hobby" value="running">跑步
    <input type="checkbox" name="hobby" value="reading">看书
    <input type="checkbox" name="hobby" value="listening">听歌
    <input type="submit" value="提交">
</form>
</body>
</html>

ServletErrorCode1文件：

package 中文乱码;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/ServletErrorCode1")
public class ServletErrorCode1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String name = request.getParameter("name");
        String age = request.getParameter("age");
        System.out.println("name="+name);
        System.out.println("age="+age);
    }

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

在这里插入图片描述
解决Post提交时的中文乱码问题，该方法设置了请求体中的编码
request.setCharacterEncoding("UTF-8");

		//解决Post提交时的中文乱码问题，该方法设置了请求体中的编码
        request.setCharacterEncoding("UTF-8");
        
        String name = request.getParameter("name");
        String age = request.getParameter("age");
        System.out.println("name="+name);
        System.out.println("age="+age);

在这里插入图片描述

赞(0) 打赏
未经允许不得转载：IDEA激活码 » 【Servlet-2】HttpServletRequest接口

相关推荐

  • 暂无文章

IDEA永久激活破解教程,IDEA激活码

pycharm激活破解教程,pycharm激活码

Java视频资源

Java电子书

DataGrip激活教程 Docker Git教程 IntellIJ idea IntelliJ IDEA激活码 Java Java IO Java基础 Java基础面试题 Java集合面试题 Java面试题 JVM JVM面试题 Linux MySQL MySQL面试题 Nginx PyCharm PyCharm激活 Redis redis SpringBoot SpringBoot SpringBoot面试题 Web开发 剑指Offer系列 多线程 多线程并发面试题 字符串面试题 数据库 数据库 数据结构与算法 未分类 爬虫 电子书 软件下载

一个分享Java & Python知识的社区