Spring----Spring简化Mybatis

一.Spring简化Mybatis

1. 导入mybatis所有jar和spring基本包,spring-jdbc,spring-tx,spring-aop,spring-web,spring 整合 mybatis 的包等

2. 先配置 web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="4.0" xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee                       
	http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd">

	<!-- 上下文参数 -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<!-- spring配置文件 -->
		<param-value>classpath:applicationContext.xml</param-value>
	</context-param>

	<!-- 封装了一个监听器,帮助加载Spring的配置文件 -->
 	<listener>
 		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
 	</listener>
</web-app>

3. 编写 spring 配置文件 applicationContext.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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd">
 	<!-- 数据源封装类
 		数据源:获取数据库连接  spring-jdbc.jar中
 	 -->
 	<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
 		<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>
 		<property name="url" value="jdbc:mysql://localhost:3306/ssm"></property>
 		<property name="username" value="root"></property>
 		<property name="password" value="root"></property>
 	</bean>
 	<!-- 创建 SqlSessionFactory对象-->
 	<bean id="factory" class="org.mybatis.spring.SqlSessionFactoryBean">
 		<!-- 数据库连接信息来源于dataSource -->
 		<property name="dataSource" ref="dataSource"></property>
 	</bean>
 	<!-- 扫描器,相当于mybatis.xml中mappers下的package标签,扫描 com.kennosaur.mapper包后会给对应接口创建对象-->
 	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
 		<!-- 要扫描哪个包 -->
 		<property name="basePackage" value="com.kennosaur.mapper"></property>
 		<!-- 和 SqlSessionFactory产生关系-->
 		<property name="sqlSessionFactory" ref="factory"></property>
 		
 	</bean>
 	<!-- 由spring管理 service实现类-->
 	<bean id="airportService" class="com.kennosaur.service.impl.AirportServiceImpl">
 		<property name="airportMapper" ref="airportMapper"></property>
 	</bean>
    
</beans>
    

注意spring管理service实现类时,其中ref=airportMapper是在扫描器MapperScannerConfigurer扫描com.kennosaur.mapper包中内容时生成了接口对象,需要在service实例化类中生成airportMapper的set/get方法

package com.kennosaur.service.impl;

import java.util.List;

import com.kennosaur.mapper.AirportMapper;
import com.kennosaur.pojo.Airport;
import com.kennosaur.service.AirportService;

public class AirportServiceImpl implements AirportService{
	private  AirportMapper airportMapper;
	public AirportMapper getAirportMapper() {
		return airportMapper;
	}
	public void setAirportMapper(AirportMapper airportMapper) {
		this.airportMapper = airportMapper;
	}
	@Override
	public List<Airport> show() {
		
		return airportMapper.selAll();
	}

}

4. 编写代码
    4.1 正常编写 pojo
    4.2 编写 mapper 包下时必须使用接口绑定方案或注解方案(必须有接口)
    4.3 正常编写 Service 接口和 Service 实现类
        4.3.1 需要在 Service 实现类中声明 Mapper 接口对象,并生成get/set 方法
    4.4 spring 无法管理 Servlet,在 service 中取出 Servie 对象

package com.kennosaur.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.kennosaur.service.AirportService;
import com.kennosaur.service.impl.AirportServiceImpl;

@WebServlet("/airport")
public class AirportServlet extends HttpServlet{
	private AirportService airportService;
	
	@Override
	public void init() throws ServletException {
		//对service实例化
//		ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
		//spring和web整合后所有信息都存放在WebApplicationContext
		ApplicationContext ac = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
		airportService = ac.getBean("airportService", AirportServiceImpl.class);
	}
	
	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		req.setAttribute("list", airportService.show());
		req.getRequestDispatcher("index.jsp").forward(req, resp);
	}
}