java 三层架构模拟转账

使用JdbcTemplat,druid连接池,事务...综合使用

编写工具类:

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

//数据库连接池工具类
public class JdbcUtil {
   private static Properties pro =null;
    static {
        //加载配置文件
         pro = new Properties();
        InputStream in = JdbcUtil.class.getClassLoader().getResourceAsStream("druid.properties");
        try {
            pro.load(in);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //获取数据源
    public static DataSource getDataSource() throws Exception {
        DataSource ds = DruidDataSourceFactory.createDataSource(pro);
        return ds;
    }
    //获取连接池对象
    public static Connection getConnection() throws Exception {

        DataSource ds = DruidDataSourceFactory.createDataSource(pro);
        Connection connection = ds.getConnection();
        return connection;

    }
    //释放资源
    public static void closeZY(ResultSet resultSet, Statement statement,Connection connection){
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        try {
            statement.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        try {
            connection.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }

    }

}

dao层类代码:

import cn.itcast.utils.JdbcUtil;
import cn.itcast.utils.TestUtil;
import org.springframework.jdbc.core.JdbcTemplate;

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

public class MoneyDao {
    //根据姓名查询账户余额,并返回
    public double blanceChecked(String name) throws Exception {
        JdbcTemplate jdbcTemplate = new JdbcTemplate(JdbcUtil.getDataSource());
        String sql = "select money from account where name = ?";
        Double count = jdbcTemplate.queryForObject(sql, double.class, name);
        return count;
    }
    //转出
    public  int outMoney(String name, double money,Connection connection) throws Exception {

        String sql = "update account set money = money-?  where name =?";
        PreparedStatement ps = connection.prepareStatement(sql);
        ps.setDouble(1,money);
        ps.setString(2,name);
        int i = ps.executeUpdate();
        return i;
    }
    //转入
    public  int inMoney(String name, double money,Connection connection) throws Exception {
        JdbcTemplate jdbcTemplate = new JdbcTemplate(JdbcUtil.getDataSource());
        String sql = "update account  set money = money +?  where name =?";
        PreparedStatement ps = connection.prepareStatement(sql);
        ps.setDouble(1,money);
        ps.setString(2,name);
        int i = ps.executeUpdate();
        return i;
    }
}

service层类代码:

import cn.itcast.dao.MoneyDao;
import cn.itcast.utils.TestUtil;

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

public class MoneyService {
    //查询传入名字的账户的余额是否够转账
    public boolean outMoney(String name,double money) throws Exception {
        MoneyDao md = new MoneyDao();
       double blance =  md.blanceChecked(name);
        if (blance < money) {
            System.out.println("余额不足,无法转账");
            return false;
        }
        return true;
    }
    //转账业务
    public void rotateMoney(double money, String nameOut, String nameIn)  {
        MoneyDao md = new MoneyDao();
        Connection connection = TestUtil.getConnection();

        try {
            connection.setAutoCommit(false);//开启事务
             md.outMoney(nameOut, money,connection);
            //int j =1/0;//模拟事务中间故障
            md.inMoney(nameIn, money,connection);
            connection.commit();
            System.out.println("转账成功");
        }  catch (Exception e) {
            e.printStackTrace();
            System.out.println("转账失败");
            try {
                connection.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
        }


    }

}

web层类代码:

import cn.itcast.service.MoneyService;

/*
三层架构模拟转账
 */
public class MoneyTest {
    public static void main(String[] args) throws Exception {
        double money =100;//转账的钱数
        String name = "jack";//转出人
        String name2 = "rose";//收款人
        MoneyService ms = new MoneyService();
        boolean b = ms.outMoney(name, money);
        if (b) {//余额足够转账
            ms.rotateMoney(money,name,name2);
        }
    }
}

数据库图片:

运行测试结果:

修改转账金额为:1000运行结果为:

经转账金额改成100,把业务层  模拟事务故障的注释去掉后运行结果为:

加上注释后再次运行: