基于创建Web项目运行时出错的解决方法(必看篇)

所属分类：软件编程 / java 阅读数： 19

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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()...");
 }
}