Spring 4 MVC HelloWorld - 註解/JavaConfig實例
阿新 • • 發佈：2017-09-22
protected root etl ble path 3.1 pom javac .class
在之前的Spring 4 MVC HelloWorld - 實例中，有spring-mvc.xml和web.xml這兩個xml文件。現在通過java配置，將刪除這個兩個xml文件。
1、pom.xml文件
<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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.demo.springmvc</groupId>
<artifactId>Spring4MVCHelloWorldDemo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<properties>
<springframework.version>4.0.6.RELEASE</springframework.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${springframework.version}</version>
</dependency>
<!-- Below declared dependencies are included for the servers who may complain about servlet/jstl missing dependency -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
</dependency>
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.1</version>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>jstl</artifactId>
<version>1.2</version>
</dependency>
</dependencies>
<build>
<pluginManagement>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.2</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<!-- 目的是，刪除web.xml（不管用，待解決。） -->
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>2.4</version>
<configuration>
<warSourceDirectory>src/main/webapp</warSourceDirectory>
<warName>Spring4MVCHelloWorldDemo</warName>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</pluginManagement>
<finalName>Spring4MVCHelloWorldDemo</finalName>
</build>
</project>
步驟2：添加控制器
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
@RequestMapping("/")
public class HelloWorldController {
@RequestMapping(method = RequestMethod.GET)
public String sayHello(ModelMap model) {
model.addAttribute("greeting", "Hello World from Spring 4 MVC");
return "welcome";
}
@RequestMapping(value = "/helloagain", method = RequestMethod.GET)
public String sayHelloAgain(ModelMap model) {
model.addAttribute("greeting", "Hello World Again, from Spring 4 MVC");
return "welcome";
}
}
步驟4：添加視圖
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
Greeting：${greeting}
</body>
</html>
步驟5：添加配置類
package configuration;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = "com.springmvc")
public class HelloWorldConfiguration {
@Bean
public ViewResolver viewResolver(){
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setViewClass(JstlView.class);
viewResolver.setPrefix("/WEB-INF/views/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
}
@Configuration @EnableWebMvc
相當於<mvc:annotation-driven />XML，目的是支持@Controller註解的類，用於@RequestMapping將傳入的請求映射到特定的方法。
@ComponentScan(basePackages = "com.springmvc")
相當於<context:component-scan base-package="com.springmvc" />
步驟6：添加初始化類
package configuration;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;
public class HelloWorldInitializer implements WebApplicationInitializer{
@Override
public void onStartup(ServletContext container) throws ServletException {
AnnotationConfigWebApplicationContext ctx = new AnnotationConfigWebApplicationContext();
ctx.register(HelloWorldConfiguration.class);
ctx.setServletContext(container);
ServletRegistration.Dynamic servlet = container.addServlet("dispatcher", new DispatcherServlet(ctx));
servlet.setLoadOnStartup(1);
servlet.addMapping("/");
}
}
上面的內容類似於上一個教程中的web.xml的內容，因為我們使用前端控制器DispatherServler，分配映射（xml中的url-pattern），而不是為spring配置文件（spring-mvc.xml）提供路徑，這裏我們正在註冊配置類。總的來說，我們正在做同樣的事情，只是方法是不同的。
更新：請註意，現在您可以更簡潔地編寫上述類[ 這是首選方式 ]，通過擴展AbstractAnnotationConfigDispatcherServletInitializer基類，如下所示：
package configuration;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class Initializer extends AbstractAnnotationConfigDispatcherServletInitializer{
@Override
protected Class<?>[] getRootConfigClasses() {
return new Class[]{HelloWorldConfiguration.class};
}
@Override
protected Class<?>[] getServletConfigClasses() {
return null;
}
@Override
protected String[] getServletMappings() {
return new String[]{"/"};
}
}
部署運行。
Spring 4 MVC HelloWorld - 註解/JavaConfig實例