Question

我是第一次编写sping应用程序并且无法正常工作

这是我的控制器类

package com.programcreek.helloworld.controller;

import org.springframework.stereotype.Controller;

import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

@Controller
public class HelloWorldController {

    public HelloWorldController()
    {
        System.out.println("This is my constructor");
    }

    @RequestMapping(value = "/home")
     public String showMessage(Model model) {
        System.out.println("shiva");
    //  ModelAndView mv = new ModelAndView("helloworld");

        return "this is it";
    }
}

的index.jsp

     <%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>

 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "w3.org/TR/html4/loose.dtd">

 <html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Spring 4 MVC - HelloWorld Index Page</title> 
</head>
 <body> 
<center>
 <h2>Hello World</h2> 
<h3>
 <a href="home">Click Here</a> 
</h3> </center> 
</body> 
</html>

这是我的web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">


    <display-name>Archetype Created Web Application</display-name>

    <servlet>
    <servlet-name>dispatcher</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>2</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>dispatcher</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value></param-value>
    </context-param>

    <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
    </listener>
</web-app>

这是我的dispatcher-servlet.xml

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
                        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
                        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd
                        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">

<mvc:annotation-driven/>

<mvc:default-servlet-handler/>

<context:component-scan base-package="com.programcreek.helloworld.controller"></context:component-scan>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    <property name="prefix" value="/WEB-INF/views/"/>
    <property name="suffix" value=".jsp"/>
</bean>

</beans>

这是我的pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.programcreek</groupId>
    <artifactId>HelloWorld</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>HelloWorld Maven Webapp</name>
    <url>http://maven.apache.org</url>

    <properties>
        <spring.version>4.0.1.RELEASE</spring.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <!-- Spring dependencies -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>

    </dependencies>


    <build>
        <finalName>HelloWorld</finalName>
    </build>
</project>

我的控制台上没有收到任何错误日志

谢谢

Answer 1

您已在suffix中添加了web.xml，但未能在您的jsp中使用，请将您的链接网址更改为

<a href="home.jsp">Click Here</a>

Answer 2

未调用构造函数中System.out.println()的原因是Spring使用惰性初始化策略作为默认值，除非您在Spring上下文xml中另行声明。 {1}}在第一次访问之前不会被初始化。
您可以在浏览器中输入“your-application-context / home”，这样就会尝试调用controller。那时，您的控制台应该打印构造函数中声明的消息。但是，以后HTTP请求可能最终会被视为错误。当您声明视图解析器时，Spring将尝试在“declared-prefix / [来自mothod的返回字符串] .jsp中找到匹配的jsp文件。在您的情况下，它可能最终没有找到这样的文件，因此404或500服务器错误。

我认为你要做的就是执行HelloWorldController#showMessage()方法。你可能会考虑在这个方法上面添加一个注释，如下所示：

showMessage()

@RequestMapping(value = "/home") @ResponseBody public String showMessage(Model model) { System.out.println("shiva"); // ModelAndView mv = new ModelAndView("helloworld"); return "this is it"; }将告诉spring简单地将字符串作为响应主体返回。

Spring MVC控制器未被调用

2 个答案: