SpringMVC的讲解

springmvc的介绍：

    和struts一样是一个轻量级的web框架，但是springmvc基于注解，更加简单方便，所以取代了stuts。

springmvc的原理：

    1、Http请求：客户端请求提交到DidpatcherServlet

    2、寻找处理器：由DispatcherServlet控制器查询一个或多个HandleMapping找到处理请求的Controller

    3、调用处理器：DispatcherServlet将请求提交到Controller

    4、调用业务处理和返回结果：Controller调用业务逻辑处理后，返回ModelAndView.

    5、处理视图映射并返回模型：DispatcherServlet查询一个或多个ViewResoler视图，找到ModelAndView指定的视图。

    6、Http响应：视图负责将结果显示到客户端

常用注解：

    1、@RequestMapping（用在类上或者方法上可以作为匹配url，当用rest风格时候，还可以绑定访问方式）

    2、@RequestParam（用于当前台传来的参数与方法中的形参名不一致时，放在形参前面，统一参数名）

    3、@RequestBody(接收前台传来的json格式的数据)。

    4、@ResponseBody(以json格式返回数据到前台)

    5、@Controller（放在类上面）

入门：

    1、配置springmvc.xml

<?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:context="http://www.springframework.org/schema/context"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	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/aop
        http://www.springframework.org/schema/aop/spring-aop.xsd
        http://www.springframework.org/schema/tx
        http://www.springframework.org/schema/tx/spring-tx.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">
        
     <!-- 配置Spring MVC自动扫描的路径 -->
	<context:component-scan base-package="com.hsia.springmvc" />   
	<bean id="freemarkerConfig" class="org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer">
		<property name="templateLoaderPath">
			<value>/view/</value>
		</property>
	</bean>
	<bean id="htmlviewResolver"
		class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
		<property name="suffix" value=".html" />
		<property name="order" value="0"></property>
		<property name="contentType" value="text/html;charset=UTF-8"></property>
	</bean>


	<bean id="stringConverter"
		class="org.springframework.http.converter.StringHttpMessageConverter">
		<property name="supportedMediaTypes">
			<list>
				<value>text/plain;charset=UTF-8</value>
			</list>
		</property>
	</bean>
	<bean id="jsonConverter"
		class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
	</bean>
	<bean
		class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
		<property name="messageConverters">
			<list>
				<ref bean="stringConverter" />
				<ref bean="jsonConverter" />
			</list>
		</property>
	</bean>

	<mvc:annotation-driven>
		<mvc:message-converters register-defaults="true">
			<bean class="org.springframework.http.converter.StringHttpMessageConverter">
				<property name="supportedMediaTypes" value="text/html;charset=UTF-8"/>
			</bean>
		</mvc:message-converters>
	</mvc:annotation-driven>
</beans>

    2、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_2_5.xsd" id="WebApp_ID" version="2.5">
	<display-name>springmvc-param4</display-name>
	<servlet>
		<servlet-name>dispatcherServlet</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath:springmvc.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup><!-- 启动时自动加载配置文件 -->
	</servlet>
	<servlet-mapping>
		<servlet-name>dispatcherServlet</servlet-name>
		<url-pattern>*.action</url-pattern>
	</servlet-mapping>

	<filter>
    <filter-name>HiddenHttpMethodFilter</filter-name>
    <filter-class>
        org.springframework.web.filter.HiddenHttpMethodFilter
    </filter-class>
</filter>
<filter-mapping>
    <filter-name>HiddenHttpMethodFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>
	
	
</web-app>

3、java测试类

package com.hsia.springmvc.action;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("action")
public class TestController{
	@RequestMapping(value="user",method=RequestMethod.POST)
	public String addUser() {
		System.out.println("add ");
		return "index";
	}
	@RequestMapping(value="user",method=RequestMethod.DELETE)
	public String deleteUser() {
		System.out.println("delete ");
		return "index";
	}
	@RequestMapping(value="user",method=RequestMethod.GET)
	public String queryUser() {
		System.out.println("query ");
		return "index";
	}
	@RequestMapping(value="user",method=RequestMethod.PUT)
	public String UpdateUser() {
		System.out.println("update ");
		return "index";
	}

}