SSM第1天 SpringMVC基本介绍

一、JavaEE常用框架文章推荐

1.Spring:企业级 Java 应用程序开发框架

https://www.w3cschool.cn/wkspring/

2.SpringMVC:Web端框架

https://www.w3cschool.cn/wkspring/9pf81ha5.html

3.Struts2:Web端框架

https://www.w3cschool.cn/struts_2/

4.MyBatis :数据库框架

https://www.w3cschool.cn/mybatis/

5.Hibernate:数据库框架

https://www.w3cschool.cn/hibernate/

6.log4j :日志采集

https://www.w3cschool.cn/java/log4j-installation.html

7. SSM与SSH

SSM:Spring SpringMVC MyBatis
SSH:Spring Struts2 Hibernate

目前有部分公司采用新型的SSH
Spring SpringMVC Hibernate

二、SpringMVC与Struts的区别

1.struts1基于Servlet，struts2基于Filter,Spring基于servlet
2.struts1的action是单例模式，线程不安全，
struts2的action是多例模式，每次访问创建对象以保证线程安全
SpringMVC是单例模式，线程安全
...

URL匹配规则

1. 精确匹配

<servlet-mapping>
    <url-pattern>/user/addUser.action</url-pattern>
</servlet-mapping>

http://localhost:8080/appDemo/user/users.html

2. 路径匹配

<servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/user/*</url-pattern>
</servlet-mapping>

http://localhost:8080/appDemo/user/users.html
http://localhost:8080/appDemo/user/addUser.action
http://localhost:8080/appDemo/user/updateUser.actionl

3. 扩展名匹配

<servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>*.jsp</url-pattern>
    <url-pattern>*.action</url-pattern>
</servlet-mapping>


http://localhost:8080/appDemo/user/users.jsp
http://localhost:8080/appDemo/toHome.action

4. 缺省匹配

<servlet-mapping>
    <servlet-name>MyServlet</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

三、创建第1个SpringMVC框架:hello world

1.添加jar包

2.配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://xmlns.jcp.org/xml/ns/javaee"
	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
	id="WebApp_ID" version="3.1">
	<display-name>SpringMVCDemo01</display-name>
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
	</welcome-file-list>
	<servlet>
		<servlet-name>aplicationContext</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>aplicationContext</servlet-name>
		<url-pattern>*.do</url-pattern>
	</servlet-mapping>
</web-app>

3.配置核心文件xxx-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<!-- 1.约束文件 -->
<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-3.2.xsd">
	
</beans>						

4.创建Controller

package com.zhiyou100.controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;
public class TestController extends AbstractController {
	@Override
	protected ModelAndView handleRequestInternal(HttpServletRequest arg0, HttpServletResponse arg1) throws Exception {
		ModelAndView modelAndView =new ModelAndView();
		modelAndView.setViewName("1");
		return modelAndView;
	}
}

5.创建JSP

6.在xxx-servlet.xml文件中添加映射

	<bean name="/hello.do" class="com.zhiyou100.controller.HelloController"></bean>

7.测试

http://localhost:8080/springmvc_01/hello.do

四、视图解析器

<bean id="jspView"
	class="org.springframework.web.servlet.view.InternalResourceViewResolver">
	<property name="prefix" value="/WEB-INF/view/"></property>
	<property name="suffix" value=".jsp"></property>
</bean>

五、原理

1.http://localhost:8080/springmvc_01/home.do
2.执行到web.xml   判断URL
3.如果是执行到框架里面--XXX-servlet.xml
4.通过HandlerMapping处理映射器找name叫做 home.action的bean
5.执行到对应的类里面handleRequestInternal方法里面
6.return视图 又回到xxx-servlet.xml里面
7.对视图进行拼接
8.执行到对应的jsp页面  --回到了浏览器

六、HandlerMapping处理映射器

6.1 name：BeanNameUrlHandlerMapping

默認的 通過beanName
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"></bean>

6.2 controller:ControllerClassNameHandlerMapping

根據類名來的   如果類名後面的controller.可以省略不寫；  首字母小寫
<bean class="org.springframework.web.servlet.mvc.support.ControllerClassNameHandlerMapping"></bean>

6.3 url:SimpleUrlHandlerMapping

<bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
	<property name="mappings">
		<props>
			<prop key="/a.do">home</prop>
			<prop key="/b.do">home1</prop>
		</props>
	</property>
</bean>
<bean id="spring" class="com.zhiyou100.controller.SpringController">

	</bean>

6.4 Annotation:DefaultAnnotationHandlerMapping

七、核心配置文件

7.1 默认的名称规范

默认根据DispatcherServlet的name去拼接xxx-servlet.xml
例如：
hello:hello-servlet.xml
aplicationContext:aplicationContext-servlet.xml
springMVC:springMVC-servlet.xml

7.2 指定文件名:仍然放在WEB-INF下

<servlet>
	<servlet-name>aplicationContext</servlet-name>
	<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
	<init-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>WEB-INF/springMVC-servlet.xml</param-value>
	</init-param>
</servlet>
<servlet-mapping>
	<servlet-name>aplicationContext</servlet-name>
	<url-pattern>*.do</url-pattern>
</servlet-mapping>

7.3 指定文件名:放在src下

<init-param>
	<param-name>contextConfigLocation</param-name>
	<param-value>classpath:springMVC-servlet.xml</param-value>
</init-param>

八、注解：代替配置

<?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: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-3.2.xsd 
						http://www.springframework.org/schema/mvc 
						http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd 
						http://www.springframework.org/schema/context 
						http://www.springframework.org/schema/context/spring-context-3.2.xsd ">

	<mvc:annotation-driven/>
	<context:component-scan base-package="com.zhiyou100"></context:component-scan>
	
	<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<property name="prefix" value="/WEB-INF/view/"></property>
		<property name="suffix" value=".jsp"></property>
	</bean>
</beans>

九、 Controller

package com.zhiyou100.controller;

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

@Controller
public class HController {

	@RequestMapping("/1.do")
	public String m1() {
		return "1";
	}

	@RequestMapping("2.do")
	public String m2() {
		return "2";
	}

	@RequestMapping("3.do")
	public String m3() {
		return "3";
	}

}

十、获取参数

10.1.获取表单或者超链接里面的参数

@RequestMapping("2.do")
public String m2(String username,Integer age) {
	System.out.println(username+":"+age);
	return "2";
}

10.2.表单里有多个参数， 这些参数刚好和model一样；

@RequestMapping("3.do")
public String m3(User user) {
	return "3";
}

10.3.表单里面的参既有model的也有model里面没有的

@RequestMapping("4.do")
public String m3(User user,Integer age) {
	return "3";
}

十一、传递参数

1.把参数传递会页面

@RequestMapping("/1.do")
public String m1(Model model) {
	model.addAttribute("name", "哈哈啊哈");
	return "1";
}

2.获取参数同时有传递参数

@RequestMapping("/1.do")
public String m1(String username,Model model) {
	model.addAttribute("name", "哈哈啊哈");
	return "1";
}

十二、返回内容

1.返回视图名称

@RequestMapping("/1.do")
public String m1(String username,Model model) {
	model.addAttribute("name", "哈哈啊哈");
	return "role/show";
}

2.返回文本

@ResponseBody
@RequestMapping("2.do")
public String m2(String username,Integer age) {
	System.out.println(username+":"+age);
	return "2";
}

3.返回JSON

springmvc-servlet.xml中添加
<mvc:annotation-driven />

@ResponseBody
@RequestMapping("3.do")
public Map<String, String> m3() {
	Map<String, String> map = new HashMap<>();
	map.put("name", "hahaha");
	return map;
}

作业：

1.独立能配置出SpringMVC框架
2.使用SpringMVC进行CRUD