[Java] Spring_1700_Spring_DataSource

最新推荐文章于 2022-09-11 21:31:17 发布

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本文介绍了一个基于Spring框架的应用示例，展示了如何利用AOP（面向切面编程）进行日志拦截，并通过IOC（控制反转）管理Bean的生命周期及依赖注入。同时，还涉及了数据库连接池的配置和使用。

package com.bjsxt.aop;

LogInterceptor 这里有源码。其实： XML 的好处是没有源码的时候照样，可以AOP，所以IOC-Annotation 比较好， AOP-XML比较好

package com.bjsxt.aop;

import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Before;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.stereotype.Component;

@Aspect
@Component
public class LogInterceptor {
	@Pointcut("execution(public * com.bjsxt.service..*.add(..))")
	public void myMethod(){};
	
	@Before("myMethod()")
	public void before() {
		System.out.println("method before");
	}
	
	@Around("myMethod()")
	public void aroundMethod(ProceedingJoinPoint pjp) throws Throwable {
		System.out.println("method around start");
		pjp.proceed();
		System.out.println("method around end");
	}
}
//

package com.bjsxt.dao;

interface UserDAO

package com.bjsxt.dao;

import com.bjsxt.model.User;

public interface UserDAO { // 和数据库打交道
	public void save(User u); // 访问  mysql 的代码
}

package com.bjsxt.dao.impl;

UserDAOImpl

package com.bjsxt.dao.impl;

import java.sql.Connection;
import java.sql.SQLException;

import javax.annotation.Resource;
import javax.sql.DataSource;

import org.springframework.stereotype.Component;

import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;

@Component("u") 
public class UserDAOImpl implements UserDAO {

	private DataSource dataSource;
	
	public DataSource getDataSource() {
		return dataSource;
	}
	@Resource
	public void setDataSource(DataSource dataSource) {
		this.dataSource = dataSource;
	}
	
	public void save(User user) {
		//Hibernate
		//JDBC
		//XML
		//NetWork
		try {
			Connection conn = dataSource.getConnection();
			conn.createStatement().executeUpdate("insert into user values (null, 'zhangsan')");
			conn.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("user saved!");
		//throw new RuntimeException("exeption!");
	}

}

packagecom.bjsxt.model;

User (用户类：具有名字和密码两个属性)

package com.bjsxt.model;

public class User {
	private String username;
	private String password;

	public String getUsername() {
		return username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

	public String getPassword() {
		return password;
	}

	public void setPassword(String password) {
		this.password = password;
	}

}

package com.bjsxt.service;
UserService 用户服务层

package com.bjsxt.service;
import javax.annotation.Resource;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Component;

import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;


@Component("userService")
public class UserService {
	
	private UserDAO userDAO;  
	
	public void init() {
		System.out.println("init");
	}
	
	public void add(User user) {
		userDAO.save(user);
	}
	public UserDAO getUserDAO() {
		return userDAO;
	}
	
	@Resource(name="u")
	public void setUserDAO( UserDAO userDAO) {
		this.userDAO = userDAO;
	}
	

	
	public void destroy() {
		System.out.println("destroy");
	}
}

beans.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:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"

	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
        http://www.springframework.org/schema/aop     
        http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/context     
        http://www.springframework.org/schema/context/spring-context-3.0.xsd">
	<context:annotation-config />
	<context:component-scan base-package="com.bjsxt" />

	<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"
		destroy-method="close">

		<!-- results in a setDriverClassName(String) call -->
		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
		<property name="url" value="jdbc:mysql://localhost:3306/spring" />
		<property name="username" value="root" />
		<property name="password" value="root" />
	</bean>

	<bean id="logInterceptor" class="com.bjsxt.aop.LogInterceptor"></bean>
	<aop:config>
		<aop:aspect id="logAspect" ref="logInterceptor">
			<aop:before method="before"
				pointcut="execution(public * com.bjsxt.service..*.add(..))" />
		</aop:aspect>
	</aop:config>
</beans>

Test 目录

package com.bjsxt.service;

UserServiceTest

package com.bjsxt.service;

import static org.junit.Assert.*;

import org.junit.Test;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User;

public class UserServiceTest {

	@Test
	public void testAdd() throws Exception {
		
		ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		
		UserService service = (UserService) ctx.getBean("userService"); // new UserService();
		System.out.println(service.getClass());
		service.add(new User());
		
		ctx.destroy();
	}
}

写程序推荐，面向接口编程。

输出如下：

mysql-notes

create database spring;
use spring;
create table user (id int primary key auto_increment, name varchar(20));

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

数据库连接池的三种实现方式之一 dbcp 的使用，小例子

SRC目录下

beans.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:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"

	xsi:schemaLocation="http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-3.0.xsd 
        http://www.springframework.org/schema/aop     
        http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/context     
        http://www.springframework.org/schema/context/spring-context-3.0.xsd">
	<context:annotation-config />
	<context:component-scan base-package="com.bjsxt" />

	<!-- 
		<bean id="dataSource"
		class="org.apache.commons.dbcp.BasicDataSource"
		destroy-method="close">
		
		
		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
		<property name="url" value="jdbc:mysql://localhost:3306/spring" />
		<property name="username" value="root" />
		<property name="password" value="bjsxt" />
		</bean>
	-->

	<bean
		class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
		<property name="locations">
			<value>classpath:jdbc.properties</value>
		</property>
	</bean>

	<bean id="dataSource" destroy-method="close"
		class="org.apache.commons.dbcp.BasicDataSource">
		<property name="driverClassName"
			value="${jdbc.driverClassName}" />
		<property name="url" value="${jdbc.url}" />
		<property name="username" value="${jdbc.username}" />
		<property name="password" value="${jdbc.password}" />
	</bean>

	
</beans>

jdbc.properties

jdbc.driverClassName=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/spring
jdbc.username=root
jdbc.password=root