项目场景：

在javaweb学习过程中发现idea环境下配置servlet会导致jsp显示源码的问题，重启Tomcat只有问题并没有得到解决

servlet配置如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

<!--    定义servlet-->
    <servlet>
<!--        与servlet-mapping中的servlet-name相对应-->
        <servlet-name>welcome</servlet-name>

<!--        实际处理的servlet的类全名-->
        <servlet-class>com.example.servletproject25.WelcomeServlet</servlet-class>


    </servlet>
<!--    映射路径-->
    <servlet-mapping>
<!--        与servlet中的servlet-name相对应-->
        <servlet-name>welcome</servlet-name>

<!--        请求映射的路径，如action地址。其中“/”表示的是项目的根路径-->
        <url-pattern>/WelcomeServlet</url-pattern>
    </servlet-mapping>
</web-app>

servlet源码如下

package com.example.servletproject25;

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

public class WelcomeServlet extends HttpServlet {
    //处理Get方式的请求
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //通过response获取输出对象out（等价于JSP中的内置对象）
        PrintWriter out =response.getWriter();
        out.println("doGet -- HelloServlet");
        //关闭输出
        out.close();
    }
    //处理Post方式的请求
    @Override
    protected void doPost(HttpServletRequest request,HttpServletResponse response) throws IOException ,ServletException{
        //通过response获取输出对象out
        PrintWriter out=response.getWriter();
        out.println("doPost -- Hello Servlet");
        //关闭输出
        out.close();
    }
}