Spring MVC 核心流程

如今的java web开发，大致和以往我们在学校学习的SSH已经大不一样了，现在基本成熟的大公司都使用Spring MVC 快速开发WEB应用。当然小编我也是**Spring MVC**的长期实践者。 首先想和大家普及下我眼中的Spring mcv整个流程过程

Spring MVC 的 restFul风格

说实话自己用了这个久的Spring mvc 只知道他请求的链接格式是和restful风格一致的，但是并没有想过它同时也和resteasy，支持标准的JAX，接下来就带大家体会下，并且指出可能存在的坑哈 搭建SpringMVC框架 本系统采用的是开发工具是idea 同时使用的是springmvc +maven的方式实现的简单demo 废话不多说，先给大家看看项目结构 项目和大多是项目一样，java下放类，resources放一些配置文件和资源，webapp下存放静态资源 当然这里需要和大家强调下web.xml的配置 <web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> <display-name>Spring MVC Application</display-name> <servlet> <servlet-name>springServlet</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath*:mvc-dispatcher-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <!--配置/和/*的区别在于是否会拦截静态资源 例如.jsp--> <servlet-mapping> <servlet-name>springServlet</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>

pom文件也有需要注意的地方，如果要支持json格式的restful，需要导入jackson的相关的包，后面再说实现原理的时候会进一步说明

<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.springapp</groupId> <artifactId>SpringWebFlow</artifactId> <packaging>war</packaging> <version>1.0-SNAPSHOT</version> <name>SpringWebFlow</name> <properties> <spring.version>4.1.1.RELEASE</spring.version> <jackson.version>2.1.4</jackson.version> </properties> <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>javax.servlet</groupId> <artifactId>servlet-api</artifactId> <version>2.5</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.1</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-webmvc</artifactId> <version>${spring.version}</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-test</artifactId> <version>${spring.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-core</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-annotations</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.module</groupId> <artifactId>jackson-module-jaxb-annotations</artifactId> <version>${jackson.version}</version> </dependency> <dependency> <groupId>com.fasterxml.jackson.jaxrs</groupId> <artifactId>jackson-jaxrs-json-provider</artifactId> <version>${jackson.version}</version> <!-- Jackson2.2.0 版本对于 CXF2.7.3 不支持 --> <!-- http://www.marshut.com/krrqx/fasterxml-jackson-2-2-provider-no-longer-works-with-cxf-jax-rs.pdf --> <!-- http://cxf.547215.n5.nabble.com/Creating-input-values-on-WADL-td5728910.html --> </dependency> <!-- Spring WebMVC 3.1.2 用到 --> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-mapper-asl</artifactId> <version>1.9.0</version> </dependency> <dependency> <groupId>org.codehaus.jackson</groupId> <artifactId>jackson-core-asl</artifactId> <version>1.9.0</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> </dependencies> <build> <finalName>SpringWebFlow</finalName> <plugins> <plugin> <artifactId>maven-compiler-plugin</artifactId> <configuration> <source>1.6</source> <target>1.6</target> </configuration> </plugin> <plugin> <artifactId>maven-surefire-plugin</artifactId> <configuration> <includes> <include>**/*Tests.java</include> </includes> </configuration> </plugin> </plugins> </build> </project>

最后一个需要注意的是spring的配置文件，里面需要加下mvc的自动驱动注解，不然后面有些注解没法用

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd"> <mvc:annotation-driven/> <context:component-scan base-package="com.springapp.mvc"/> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix" value="/WEB-INF/pages/"/> <property name="suffix" value=".jsp"/> </bean> </beans>

最后就是Controller的代码了

package com.springapp.mvc; import org.springframework.stereotype.Controller; import org.springframework.ui.ModelMap; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.ResponseBody; @Controller @RequestMapping("/test") public class HelloController { @RequestMapping(value = "/hello",method = RequestMethod.GET) public String printWelcome(ModelMap model) { model.addAttribute("message", "Hello world!"); return "hello"; } @RequestMapping(value = "userInfo",method = RequestMethod.POST) @ResponseBody public Person userInfo(@RequestBody Person person){ System.out.println("人的姓名:"+person.getName()+"，人的年龄"+person.getAge()); return person; } }

这里可以看到使用了@RequestBody 表明接受的请求会先进过消息转化器(http conversion),消息转化器根据请求过来的请求做解析，当然也可以通过consumes进行指定值解析哪种格式contest-type格式 这也是为什么需要导入上文中说的jackson的包，内部消息转化器使用的jackson的方式转化的

最后当然是用postman进行调用了哈哈