SpringMVC笔记：annotation注解式开发

一、配置式开发

　　在我们之前的学习中，springmvc使用配置式开发模式，需要在核心配置文件中springmvc.xml注册大量的bean来注入controller控制器，工作繁琐容易出错，下面我们学习一下注解式开发来简化我们的工作。

。。。

　　案例：

1.控制器

public class MyMultiController extends MultiActionController {
    /*第一个方法*/
    public String doFirst(HttpServletRequest request, HttpServletResponse response){
        System.out.println("执行方法一！！！");
        return "first";
    }
    /*第二个方法*/
    public String doSecond(HttpServletRequest request, HttpServletResponse response){
        System.out.println("执行方法二！！！");
        return "second";
    }
}

2.spring注册

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!--控制器映射-->
    <bean class="cn.springmvc.day02handler.MyPropertiesController" id="myPropertiesController">
        <property name="methodNameResolver" ref="methodNameResolver"></property>
    </bean>
    <!--方法名称解析器-->
    <bean class="org.springframework.web.servlet.mvc.multiaction.ParameterMethodNameResolver" id="methodNameResolver">
        <!--<property name="paramName" value="action"></property>-->
    </bean>
    <!--处理器映射器-->
    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/hello.do">myPropertiesController</prop>
            </props>
        </property>
    </bean>
    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    </bean>
</beans>

3.访问

localhost:8080/hello.do?action=doFirst

-----------------------------------------------------------------------------------

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
    <!--porperties-->
    <bean class="org.springframework.web.servlet.mvc.multiaction.PropertiesMethodNameResolver" id="propertiesMethodNameResolver">
        <property name="mappings">
            <props>
                <prop key="/first.do">doFirst</prop>
                <prop key="/second.do">doSecond</prop>
            </props>
        </property>
    </bean>
    <!--控制器映射器-->
    <bean class="cn.springmvc.day02handler.MyPropertiesController" id="myPropertiesController">
        <property name="methodNameResolver" ref="propertiesMethodNameResolver"></property>
    </bean>
    <!--映射器配置-->
    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <property name="mappings">
            <props>
                <prop key="/*.do">myPropertiesController</prop>
            </props>
        </property>
    </bean>

    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <!--前缀 prefix-->
        <property name="prefix" value="/"></property>
        <!--后缀 suffix-->
        <property name="suffix" value=".jsp"></property>
    </bean>
</beans>

访问：

localhost:8080/first.do | second.do

----------------------------------------------------

二、注解式开发

　　1.在控制器的类和方法上添加注解

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Controllerpublic class MyAnnontation {
    /*方法一*/
    @RequestMapping("/first.do")
    public ModelAndView getModel(HttpServletRequest request, HttpServletResponse response){
        System.out.println("注解方法一！");
        ModelAndView mv = new ModelAndView("first");
        return mv;
    }

    /*方法一*/
    @RequestMapping("/second.do")
    public ModelAndView getView(HttpServletRequest request, HttpServletResponse response){
        System.out.println("注解方法二！");
        ModelAndView mv = new ModelAndView("second");
        return mv;
    }
}

　　2.配置文件中添加注解驱动<mvc:annotation-driven/>

<?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: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/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
    <!--扫描controller-->
    <context:component-scan base-package="cn.springmvc.annotation"></context:component-scan>

    <!--视图解析器-->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

    <!--注解驱动-->
    <mvc:annotation-driven></mvc:annotation-driven>
</beans>

　　3.简单访问

。。。

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Annotation</title>
</head>
<body>
<h1>未标明命名空间</h1>
<form action="/first.do" method="get">
    <input type="submit" value="执行方法一">
</form>
<form action="/second.do" method="get">
    <input type="submit" value="执行方法一">
</form>
<hr/>
<h1>已标明命名空间</h1>
<form action="/annotation/first.do" method="get">
    <input type="submit" value="执行方法一">
</form>
<form action="/annotation/second.do" method="get">
    <input type="submit" value="执行方法一">
</form>
</body>
</html>

三、注解式开发中引入命名空间来避免重名方法的混淆

　　1.在类名上添加RequestMapping("/name")注解即可区分

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

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Controller
/*命名空间*/
@RequestMapping("/annotation")
public class MyAnnontation {
    /*方法一*/
    @RequestMapping("/first.do")
    public ModelAndView getModel(HttpServletRequest request, HttpServletResponse response){
        System.out.println("注解方法一！");
        ModelAndView mv = new ModelAndView("first");
        return mv;
    }

    /*方法一*/
    @RequestMapping("/second.do")
    public ModelAndView getView(HttpServletRequest request, HttpServletResponse response){
        System.out.println("注解方法二！");
        ModelAndView mv = new ModelAndView("second");
        return mv;
    }
}