目录

浏览器与servlet交互 

request获取请求数据

request通用方法请求参数的使用

idea快速创建servlet

解决中文乱码问题（post解决方案）

---

 浏览器与servlet交互 

package com.mwy.web;
 
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;
 
//http和servlet进行数据交互，动态显示页面内容
 
@WebServlet("/demo03")
public class ServletDemo03 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String name = req.getParameter("username");
 
        resp.setHeader("content-type","text/html;charset=utf-8");
        resp.getWriter().write("
"+name+"欢迎您！
");
    }
}

request获取请求数据

get方法：使用getQueryString方法获取参数

post方法：使用字符输入流获取参数 

package com.mwy.web;
 
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.BufferedReader;
import java.io.IOException;
 
//request请求方式，获取请求行
//输出结果：
//GET
//        /Tomcat_demo1_war
//        http://localhost:8085/Tomcat_demo1_war/req1
//        /Tomcat_demo1_war/req1
//        usernamezhangsan&password=123456
 
@WebServlet("/req1")
public class ServletDemo04 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取方法：get或者post
        String method = req.getMethod();
        System.out.println(method);
//获取访问资源路径
        String contextPath = req.getContextPath();
        System.out.println(contextPath);
 
        StringBuffer url = req.getRequestURL();
        System.out.println(url);
 
        String uri = req.getRequestURI();
        System.out.println(uri);
 
//        参数
        String queryString = req.getQueryString();
        System.out.println(queryString);
 
        //--------------获取请求头,user-agent:浏览器的版本信息-----------
        String header = req.getHeader("user-agent");
        System.out.println(header);
//输出：
// Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/104.0.5112.102 Safari/537.36 Edg/104.0.1293.70
 
 
    }
 
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //获取post参数
 
//        获取字符输入流
        BufferedReader br = req.getReader();
//        读取数据
        String line=br.readLine();
        System.out.println(line);
        
//        输出：username=111&password=111
    }
}

request通用方法请求参数的使用

使用的最多的方法是getParameter（）获取单个参数值

get和post中方法一样，所以可以只写get中的方法，然后在doPost使用this.doGet(res,req)来直接使用get中已经写好的方法，提高效率。 

package com.mwy.web;
 
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.Map;
 
//request通用方法请求参数的使用
 
@WebServlet("/demo2")
public class ServletDemo2 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //get请求逻辑
        System.out.println("get...");
 
//        1. 获取所有参数的map集合
        Map map = req.getParameterMap();
        for(String key:map.keySet()){
            System.out.println(key+":");
 
            String[] values=map.get(key);
            for(String value:values){
                System.out.println(value+" ");
            }
        }
        System.out.println("------------------");
 
        //2. 获取对应的参数值
        String hobbies[]=req.getParameterValues("hobby");
        for(String hobby:hobbies){
            System.out.println(hobby);
        }
 
//        ------------------
//             1
//             2
 
//        3. 根据key获取单个参数值
        String psw = req.getParameter("password");
        String usn = req.getParameter("username");
        System.out.println(psw+" "+usn);
 
 
    }
 
//    get...
//username:
//19120543075
//
//password:
//111
//
//hobby:
//1
 
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //post请求逻辑
        //get请求逻辑
        System.out.println("post...");
//直接使用get中的方法
        this.doGet(req, resp);
        1. 获取所有参数的map集合
//        Map map = req.getParameterMap();
//        for(String key:map.keySet()){
//            System.out.println(key+":");
//
//            String[] values=map.get(key);
//            for(String value:values){
//                System.out.println(value+" ");
//            }
//        }
//        System.out.println("------------------");
//
//        //2. 获取对应的参数值
//        String hobbies[]=req.getParameterValues("hobby");
//        for(String hobby:hobbies){
//            System.out.println(hobby);
//        }
//
        ------------------
             1
             2
//
        3. 根据key获取单个参数值
//        String psw = req.getParameter("password");
//        String usn = req.getParameter("username");
//        System.out.println(psw+" "+usn);
    }
//post
// username:
//19120543075
//password:
//qqqq
//hobby:
//1
//2
//------------------
//1
//2
//qqqq 19120543075
}

idea快速创建servlet

new中没有servlet的解决方法：

(163条消息) idea中右键new列表里面没有Servlet选项的问题_佐月儿的博客-CSDN博客

修改模板

 

 

解决中文乱码问题（post解决方案）

package com.mwy.web;
 
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
 
@WebServlet("/RequestDemo1")
public class RequestDemo1 extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//        1. 解决乱码：getReader()
        request.setCharacterEncoding("UTF-8");
        
        //       2. 获取username
        String username = request.getParameter("username");
        System.out.println(username);
    }
 
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}