声明式事务管理例题

在确保可运行项目能够正确无误地运行之后，再严格照着教程的步骤，对代码模仿一遍。模仿过程难免代码有出入，导致无法得到期望的运行结果，此时此刻通过比较正确答案 ( 可运行项目 ) 和自己的代码，来定位问题所在。采用这种方式，学习有效果，排错有效率，可以较为明显地提升学习速度，跨过学习路上的各个槛。

源码：

链接：https://pan.baidu.com/s/1Y0RpFa0RpL0vZ2pVDJmhYQ?pwd=qvek
提取码：qvek

 这是项目依赖的jar包 

 1.创建一个动态web项目命名为chapter05，在src目录下创建一个jdbc包，在包内创建一个Hero实体类

package jdbc;

public class Hero {
private int id;
private String name;
private float hp;
private int damage;
public int  getid() {
	return id;
}
public void setid(int id) {
	this.id=id;
}
public String getname() {
	return name;
}
public void setname(String name) {
	this.name=name;
}
public float gethp() {
	return hp;		
}
public void sethp(float hp) {
	this.hp=hp;
}
public int getdamage() {
	return damage;
}
public void setdamage(int damage) {
	this.damage=damage;
}
public String toString() {
	return "id: "+id+" name: "+name+" hp: "+hp+" damage: "+damage;
}
}

2.创建一个HeroDao接口，声明方法。

package jdbc;

import java.util.List;

public interface HeroDao {
public int addHero(Hero hero) ;
public int updateHero(Hero hero);	
public int deleteHero(int id) ;

public Hero findHeroById(int id) ;
public List findAllHero() ;	

}

3.创建一个HeroDaoImpl类来实现方法

package jdbc;

import java.util.List;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

public class HeroDaoImpl implements HeroDao{
private JdbcTemplate jdbcTemplate;
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
	this.jdbcTemplate=jdbcTemplate;
}
	@Override
	public int addHero(Hero hero) {
		// TODO Auto-generated method stub
		String sql="insert into hero(name,hp,damage) value(?,?,?)";
		Object []objects=new Object[] {
				hero.getname(),
				hero.gethp(),
				hero.getdamage()
		};
		int num=this.jdbcTemplate.update(sql,objects);
		if (num>0) {
			System.out.println("添加成功");
		}else {
			System.out.println("添加失败");
		}
		return num;
	}

	@Override
	public int updateHero(Hero hero) {
		// TODO Auto-generated method stub
		String sql="update hero set name=?,hp=?,damage=? where id=?";
		Object []objects=new Object[] {
			hero.getname(),
			hero.gethp(),
			hero.getdamage(),
			hero.getid()
		};
		int num=this.jdbcTemplate.update(sql,objects);
		if (num>0) {
			System.out.println("更新成功");
		}else {
			System.out.println("更新失败");
		}
		return num;
	}

	@Override
	public int deleteHero(int id) {
		// TODO Auto-generated method stub
		String sql="delete from hero where id=?";
		int num=this.jdbcTemplate.update(sql,id);
		if (num>0) {
			System.out.println("删除"+num+"条数据");
		}else {
			System.out.println("删除失败");
		}
		return num;
	}
	@Override
	public Hero findHeroById(int id) {
		// TODO Auto-generated method stub
		String sql="select * from hero where id=?";
		int n=1/0;
		RowMapper rowMapper=new BeanPropertyRowMapper(Hero.class);
		return this.jdbcTemplate.queryForObject(sql, rowMapper,id);
	}
	@Override
	public List findAllHero() {
		// TODO Auto-generated method stub
		String sql="select * from hero";
		RowMapper rowMapper=new BeanPropertyRowMapper(Hero.class);
		return this.jdbcTemplate.query(sql,rowMapper);
	}

}

4.创建一个切面用来通知

package jdbc;
import org.aspectj.lang.JoinPoint;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.AfterReturning;
import org.aspectj.lang.annotation.AfterThrowing;
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 MyAspect {
	//定义切入点表达式
	@Pointcut("execution(* annotation.*.*(..))")
	//使用一个返回值为void、方法体为空的方法来命名切入点
	public void myPointCut(){}
	//前置通知
	@Before("myPointCut()")
	public void myBefore(JoinPoint joinPoint){
		System.out.print("前置通知：模拟执行权限检查..，");
		System.out.print("目标类是："+joinPoint.getTarget());
		System.out.println("，被植入增强处理的目标方法为："+joinPoint.getSignature().getName());
	}
	//后置通知
	@AfterReturning(value="myPointCut()")
	public void myAfterReturning(JoinPoint joinPoint) {
		System.out.print("后置通知：模拟记录日志..，");
		System.out.println("被植入增强处理的目标方法为：" + joinPoint.getSignature().getName());
	}
	
	@Around("myPointCut()")
	public Object myAround(ProceedingJoinPoint proceedingJoinPoint) throws Throwable{
		//开始
		System.out.println("环绕开始：执行目标方法之前，模拟开启事务..，");
		//执行当前目标方法
		Object obj=proceedingJoinPoint.proceed();
		//结束
		System.out.println("环绕结束：执行目标方法之后，模拟关闭事务..，");
		return obj;
	}
	//异常通知
	@AfterThrowing(value="myPointCut()",throwing="e")
	public void myAfterThrowing(JoinPoint joinPoint,Throwable e){
		System.out.println("异常通知：出错了"+e.getMessage());
	}
	//最终通知
	@After("myPointCut()")
	public void myAfter(){
		System.out.println("最终通知：模拟方法结束后释放资源..");
	}
}

5.创建一个applicationContext.xml文件来配置声明式事务处理

 6.创建一个类测试功能

package jdbc;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class TransactionTest {
public static void main(String[] args) {
	ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");
	HeroDao heroDao=(HeroDao) applicationContext.getBean("heroDao");
	Hero hero=new Hero();
	hero.setname("zyy");
	hero.sethp(100f);
	hero.setdamage(50);
	heroDao.addHero(hero);
}
}

 运行结果：

 1.对HeroDaoImpl类进行修改，对一些方法进行注释

@Transactional(propagation = Propagation.REQUIRED,isolation = Isolation.DEFAULT,readOnly = false)

package jdbc;

import java.util.List;
import org.springframework.jdbc.core.RowMapper;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

public class HeroDaoImpl implements HeroDao{
private JdbcTemplate jdbcTemplate;
public void setJdbcTemplate(JdbcTemplate jdbcTemplate) {
	this.jdbcTemplate=jdbcTemplate;
}
	@Override
	@Transactional(propagation = Propagation.REQUIRED,isolation = Isolation.DEFAULT,readOnly = false)
	public int addHero(Hero hero) {
		// TODO Auto-generated method stub
		String sql="insert into hero(name,hp,damage) value(?,?,?)";
		Object []objects=new Object[] {
				hero.getname(),
				hero.gethp(),
				hero.getdamage()
		};
		int num=this.jdbcTemplate.update(sql,objects);
		if (num>0) {
			System.out.println("添加成功");
		}else {
			System.out.println("添加失败");
		}
		return num;
	}

	@Override
	public int updateHero(Hero hero) {
		// TODO Auto-generated method stub
		String sql="update hero set name=?,hp=?,damage=? where id=?";
		Object []objects=new Object[] {
			hero.getname(),
			hero.gethp(),
			hero.getdamage(),
			hero.getid()
		};
		int num=this.jdbcTemplate.update(sql,objects);
		if (num>0) {
			System.out.println("更新成功");
		}else {
			System.out.println("更新失败");
		}
		return num;
	}

	@Override
	public int deleteHero(int id) {
		// TODO Auto-generated method stub
		String sql="delete from hero where id=?";
		int num=this.jdbcTemplate.update(sql,id);
		if (num>0) {
			System.out.println("删除"+num+"条数据");
		}else {
			System.out.println("删除失败");
		}
		return num;
	}
	@Override
	public Hero findHeroById(int id) {
		// TODO Auto-generated method stub
		String sql="select * from hero where id=?";
		int n=1/0;
		RowMapper rowMapper=new BeanPropertyRowMapper(Hero.class);
		return this.jdbcTemplate.queryForObject(sql, rowMapper,id);
	}
	@Override
	public List findAllHero() {
		// TODO Auto-generated method stub
		String sql="select * from hero";
		RowMapper rowMapper=new BeanPropertyRowMapper(Hero.class);
		return this.jdbcTemplate.query(sql,rowMapper);
	}

}

2.对applicationContext.xml文件进行修改

3.运行一遍测试类，运行结果与基于XML方式的声明式事务结果相同。