• 创建Web项目运行时出小错误及解决方法


    1、目录结构

    2、各文件内容

    index.jsp

    <%@ page contentType="text/html;charset=UTF-8" language="java" %>
    <html>
      <head>
        <title>$Title$</title>
      </head>
      <body>
        <form action="/Servlet" method="post">
          <input type="submit" value="提交">
        </form>
      </body>
    </html>

    web.xml

    <?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_3_1.xsd"
             version="3.1">
        <servlet>
            <servlet-name>Servlet</servlet-name>
            <servlet-class>web.servlet.Servlet</servlet-class>
        </servlet>
        <servlet-mapping>
            <servlet-name>Servlet</servlet-name>
            <url-pattern>/Servlet</url-pattern>
        </servlet-mapping>
    </web-app>

    Servlet.java

    package web.servlet;
    
    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(name = "Servlet")
    public class Servlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("doPost()...");
        }
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("doGet()...");
        }
    }

    正常运行后运行后,Server控制台会出现输出“doPost()...”字符

    3、当未配置web.xml时,出现的错误提示

    <?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_3_1.xsd"
             version="3.1">
    </web-app>

    解决方法:在web.xml中配置相关信息,或在Servlet.java注解中添加内容:

     @WebServlet(name = "Servlet",urlPatterns = "/Servlet") 

    4、配置web.xml文件但未覆写doGet()和doPost()方法,或未覆写相对应的方法出现的错误提示

    package web.servlet;
    
    @WebServlet(name = "Servlet")
    public class Servlet extends HttpServlet {
        
    }
    package web.servlet;
    
    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(name = "Servlet")
    public class Servlet extends HttpServlet {
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            System.out.println("doGet()...");
        }
    }

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  • 原文地址:https://www.cnblogs.com/gdwkong/p/7442697.html
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