java - Spring Web应用程序初始化器

Question

最近在学习基于spring java的配置。我尝试用 WebConfig 和 WebApplicationInitializer 替换 web.xml。

每当我请求网址时:http://localhost:8080/spring-demo/greeting.html我收到 404 描述 请求的资源不可用。 以下是我的项目详细信息。

WebConfig.java

package com.soumya.spring;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;

@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.soumya.spring")
public class WebConfig {

}

WebAppInitializer.java

package com.soumya.spring;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;

import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class WebAppInitializer implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext servletContext) throws ServletException {      
        WebApplicationContext context = getContext();
        servletContext.addListener(new ContextLoaderListener(context));
        ServletRegistration.Dynamic dispatcher = servletContext.addServlet("DispatcherServlet", new DispatcherServlet(context));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("*.html");
    }

    private AnnotationConfigWebApplicationContext getContext() {
        AnnotationConfigWebApplicationContext context = new AnnotationConfigWebApplicationContext();
        context.setConfigLocation("com.soumya.spring.WebConfig");
        return context;
    }

}

Controller

package com.soumya.spring.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
public class HelloController {

    @RequestMapping(value = "/greeting")
    public String greeting(Model model) {
        model.addAttribute("greeting", "Hello World!");
        return "greeting.jsp";
    }

}

项目结构图

Answer 1

首先，您的网址末尾不应有 .html 或 .jsp。网址将为http://localhost:8080/spring-demo/greeting

在您的特定 WebApplicationInitalizer 中，您的 DispatcherServlet 应映射到 /greeting Controller 而不是“*.html ”。

dispatcher.addMapping("/greeting");

此外，您的 DispatcherServlet(代码中的 WebConfig.class)没有定义 ViewResolver Bean。 ViewResolver 负责将 View 名称(如 HelloController 返回的“greeting.jsp”)映射到 View 实现(实际的“greeting.jsp”文件，可能存在于/WEB-INF/文件夹中。

我已经更改了您的 WebConfig 类以包含 ViewResolver bean-

package com.soumya.spring;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.servlet.view.InternalResourceViewResolver;


@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.soumya.spring")
public class WebConfig extends WebMvcConfigurerAdapter {

@Bean
public ViewResolver viewResolver() {

        InternalResourceViewResolver irvr = new InternalResourceViewResolver();

        irvr.setPrefix("/WEB-INF/views/"); //your "greeting.jsp" file should be here
        irvr.setSuffix(".jsp");
        irvr.setExposeContextBeansAsAttributes(true);
        return irvr;

    }
}