SpringMVC入门概述+案例
1.概述
Spring为展现层提供的基于MVC设计理念的优秀的Web框架,目前最主流的MVC框架之一;
Spring3.0后全面超越Struts2,成为最优秀的MVC框架;
SpringMVC通过一套MVC注解,让POJO(JavaBeans)成为处理请求的控制器,而无需实现任何接口;
支持Rest风格的Url请求;
采用了松散耦合可插拔组件结构,比其他MVC框架更具有扩展性和灵活性;
2.案例
2.1开发步骤
1. 引入依赖的jar包; 2. 在web.xml中配置DispatcherServlet; 3. 加入SpringMVC的配置文件; 4. 编写处理请求的处理器,并标识为处理器; 5. 编写视图
2.2添加依赖jar包
<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.yikuan</groupId> <artifactId>SPRING-MVC-01</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>war</packaging> <!-- 配置JDK插件 --> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <version>3.5.1</version> <configuration> <source>1.8</source> <target>1.8</target> <encoding>UTF-8</encoding> </configuration> </plugin> </plugins> </build> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>4.3.12.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-beans</artifactId> <version>4.3.12.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>4.3.12.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>4.3.12.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-expression</artifactId> <version>4.3.12.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-web</artifactId> <version>4.2.4.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>4.2.4.RELEASE</version> </dependency> <dependency> <groupId>commons-logging</groupId> <artifactId>commons-logging</artifactId> <version>1.2</version> </dependency> </dependencies> </project>
2.3配置web.xml文件
<?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" version="3.0"> <display-name>SPRING-MVC-01</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <!-- 配置DispatcherServlet --> <servlet> <servlet-name>springDispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!-- 配置DispatcherServlet的一个初始化参数 --> <!-- 作用:配置springMVC配置文件的位置和名称 --> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springDispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
2.4springmvc.xml配置文件
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context" xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xmlns:mvc="http://www.springframework.org/schema/mvc" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd http://code.alibabatech.com/schema/dubbo http://code.alibabatech.com/schema/dubbo/dubbo.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.2.xsd"> <!-- 配置自动扫描的包 --> <context:component-scan base-package="com.yk.springmvc"></context:component-scan> <!-- 配置视图解析器:如何把handler方法返回值解析为实际的物理视图 --> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/views/"></property> <property name="suffix" value=".jsp"></property> </bean> </beans>
2.5处理器
package com.yk.springmvc.handlers; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; @Controller //控制器的标识 public class HelloWorld { /** * 1.使用@RequestMapping来映射请求的url、 * 2.返回值会通过视图解析器解析为实际的物理视图,对于InternalResourceViewResolver视图解析器而言,会做如下的解析: * 通过 < 前缀prefix + returnValue + 后缀suffix >这样的方式,会得到实际的物理视图,然后做转发操作; * 格式:/WEB-INF/views/success.jsp * ("/helloworld") == <a href="helloworld">Hello World</a> * @return */ @RequestMapping("/helloworld") public String hello(){ System.out.println("HelloWorld.hello()"); return "success"; } }
2.6视图
index.jsp <%@ 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> <a href="helloworld">Hello World</a> </body> </html>
views/success.jsp <%@ 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> <h1>Success page</h1> </body> </html>
3.案例总结
优化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" version="3.0"> <display-name>SPRING-MVC-01</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> <welcome-file>default.html</welcome-file> <welcome-file>default.htm</welcome-file> <welcome-file>default.jsp</welcome-file> </welcome-file-list> <!-- 配置DispatcherServlet --> <servlet> <servlet-name>springDispatcherServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <!-- 配置DispatcherServlet的一个初始化参数 --> <!-- 作用:配置springMVC配置文件的位置和名称 --> <!-- <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc.xml</param-value> </init-param> --> <!-- 实际上也可以不通过 contextConfigLocation来配置springMVC的配置文件,而使用默认的 默认的配置文件为:/WEB-INF/<servlet-name>-servlet.xml --> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springDispatcherServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app> 将springmvc.xml放入WEB-INF下,并且修改名字为{<servlet-name>的值}如: /WEB-INF/springDispatcherServlet-servlet.xml