springMVC笔记（一）

今天写一个springMVC的入门日志，使用spring4.1.6。

加入maven依赖，pom.xml如下：

<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</groupId>
    <artifactId>springmvc</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>springmvc Maven Webapp</name>
    <url>http://maven.apache.org</url>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.1.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>4.1.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.1.6.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>

        <!-- START SERVLET -->
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>taglibs</groupId>
            <artifactId>standard</artifactId>
            <version>1.1.2</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet.jsp</groupId>
            <artifactId>jsp-api</artifactId>
            <version>2.2</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.tomcat.maven</groupId>
                <artifactId>tomcat7-maven-plugin</artifactId>
                <version>2.1</version>
                <configuration>
                    <port>8080</port>
                    <path>/springmvc</path>
                    <uriEncoding>UTF-8</uriEncoding>
                    <finalName>springmvc</finalName>
                    <server>tomcat7</server>
                </configuration>
            </plugin>
        </plugins>
        <finalName>springmvc</finalName>
    </build>
</project>

springMVC依赖的jar包如下：

一、配置web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <display-name>Archetype Created Web Application</display-name>

  <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/root-context.xml</param-value>
    </context-param>
    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/mvc-context.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
</web-app>

二、mvc-context.xml配置：

<?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: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.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <context:component-scan base-package="com.springmvc.demo.controller" />
    <mvc:annotation-driven />
    <!-- <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter" /> -->
    <!-- <mvc:default-servlet-handler/> -->

    <mvc:resources location="/resource/images/" mapping="/images/**" />

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        <property name="prefix" value="/" />
        <property name="suffix" value=".jsp" />
    </bean>
</beans>

说明：

<context:component-scan base-package="com.springmvc.demo.controller" />是将controller让spring去扫描这个包下的@Controller注解的bean，交给spring上下文去管理（依赖注入）。

<mvc:annotation-driven />这句话其实做了很多事，它注册了下面这些特殊用途的bean：

1. RequestMappingHandlerMapping处理controller内的@RequestMapping注解，将请求url映射为相应的controller内的方法

2. BeanNameUrlHandlerMapping 将请求url映射为bean的name 

3. RequestMappingHandlerAdapter 负责调用controller相应的方法并处理方法的其他注解

还有其他一些bean，在此不列出。

新建一controller:

package com.springmvc.demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.springmvc.demo.model.User;

@Controller
@RequestMapping("/user")
public class UserController {

    @RequestMapping("/add")
    public ModelAndView addUser(@RequestParam String username,@RequestParam String password,@RequestParam int id){

        ModelAndView mv = new ModelAndView();
        mv.setViewName("hello");
        User u = new User();
        u.setUsername(username);
        u.setPassword(password);
        u.setId(id);
        mv.addObject("user", u);

        return mv;
    }

}

输入url:http://localhost:8080/springmvc/user/add?username=yang&password=123&id=1234将跳转到hello.jsp:

<!DOCTYPE html>
<html>
<body>
${user.username},${user.password},${user.id}
</body>
</html>

可以看g以提交的参数。