Spring-IOC方式引入事务，实现银行转账业务

电玩女神 2022-12-02 04:26 205阅读 0赞

**业务描述**  
模拟银行两个用户转账业务，张三向李四转账，当双方转收状态均正常是，返回客户端转账成功，如果出现异常，回滚事务，返回转账失败，并说明失败的原因。

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

**代码实现**  
第一步，maven构建工程，导入依赖

<dependencies>
        
        <dependency>
          <groupId>mysql</groupId>
          <artifactId>mysql-connector-java</artifactId>
          <version>5.1.47</version>
        </dependency>
        
        <dependency>
          <groupId>com.mchange</groupId>
          <artifactId>c3p0</artifactId>
          <version>0.9.5.4</version>
        </dependency>
        
        <dependency>
          <groupId>commons-dbutils</groupId>
          <artifactId>commons-dbutils</artifactId>
          <version>1.7</version>
        </dependency>
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-context</artifactId>
          <version>5.0.2.RELEASE</version>
        </dependency>
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-test</artifactId>
          <version>5.0.2.RELEASE</version>
        </dependency>
        
        <dependency>
          <groupId>org.springframework</groupId>
          <artifactId>spring-webmvc</artifactId>
          <version>5.0.2.RELEASE</version>
        </dependency>
        
        <dependency>
          <groupId>junit</groupId>
          <artifactId>junit</artifactId>
          <version>4.12</version>
        </dependency>
      </dependencies>

第二步：工具类以及javaBean准备  
Result,用户返回给客户端的javaBean

public class Result {
        //代表此次请求结果
        private boolean flag;
        //此次请求结果说明
        private String message;
        //请求响应数据
        private Object data;
    
        //无参构造
        public Result() {
        }
    
        //无需结果返回构造
        public Result(boolean flag, String message) {
            this.flag = flag;
            this.message = message;
        }
        //需结果返回构造
    
        public Result(boolean flag, String message, Object data) {
            this.flag = flag;
            this.message = message;
            this.data = data;
        }
    
        public boolean isFlag() {
            return flag;
        }
    
        public void setFlag(boolean flag) {
            this.flag = flag;
        }
    
        public String getMessage() {
            return message;
        }
    
        public void setMessage(String message) {
            this.message = message;
        }
    
        public Object getData() {
            return data;
        }
    
        public void setData(Object data) {
            this.data = data;
        }
    
        @Override
        public String toString() {
            return "Result{" +
                    "flag=" + flag +
                    ", message='" + message + '\'' +
                    ", data=" + data +
                    '}';
        }
    }

User 用户信息的javaBean

public class User {
        //用户id
        private int id;
        //用户姓名
        private String username;
        //用户密码
        private String password;
        //用户账户余额
        private double money;
        public double getMoney() {
            return money;
        }
    
        public void setMoney(double money) {
            this.money = money;
        }
    
       
    
        public User() {
        }
    
        public User(int id, String username, String password, double money) {
            this.id = id;
            this.username = username;
            this.password = password;
            this.money = money;
        }
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        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;
        }
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    ", money=" + money +
                    '}';
        }
    }

第三步：dao层 以及 service层的准备  
dao层接口的编写：

/**
     * 处理User表的dao
     */
    public interface UserDao {
        //查询所有用户
        List<User> queryAll() throws SQLException;
    
        //收款功能
        void addMoneyByName(String username,double money) throws SQLException;
    
        //转账功能
        void reduceMoneyByName(String username,double money) throws SQLException;

dao层实现类的编写

//Spring ioc 注解方式表示
    @Repository("userDao")
    public class UserDaoImpl implements UserDao {
    
        //事务管理器
        @Autowired
        private TransactionManager transactionManager;
    
        //dbUtils
        @Autowired
        private QueryRunner queryRunner;
    
        /**
         *
         * @return  查询所有用户集合，注：此业务功能暂时没用到，可忽略
         * @throws SQLException
         */
        @Override
        public List<User> queryAll() throws SQLException {
    //        调用事务管理工具，并获取当前线程绑定的connection
            Connection connection = transactionManager.getConnection();
            //编写sql语句
            String sql = "select * from user";
            //执行sql,返回结果
            List<User> userList = queryRunner.query(connection,sql, new BeanListHandler<>(User.class));
            return userList;
        }
    
        /**
         *
         * @param username  转账用户名
         * @param money  转账金额
         * @throws SQLException
         */
        @Override
        public void addMoneyByName(String username,double money) throws SQLException {
            //调用事务管理工具，并获取当前线程绑定的connection
            Connection connection = transactionManager.getConnection();
            //编写转账方sql语句
            String sql  = "update user set money = money-? where username=?";
            //执行sql语句
            queryRunner.update(connection,sql,money,username);
        }
    
        /**
         *
         * @param username  收款用户名
         * @param money  收款金额
         * @throws SQLException
         */
        @Override
        public void reduceMoneyByName(String username,double money) throws SQLException {
            //调用事务管理工具，并获取当前线程绑定的connection
            Connection connection = transactionManager.getConnection();
            //sql语句编写
            String sql  = "update user set money = money+? where username=?";
            //执行sql
            queryRunner.update(connection,sql,money,username);
        }
    }

service层

import com.gg.bean.Result;
    import com.gg.dao.UserDao;
    import com.gg.utils.TransactionManager;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import java.sql.SQLException;
    
    @Service("userServiceImpl")
    public class UserServiceImpl{
        //dao对象
        @Autowired
        private UserDao userDao;
        //事务管理器对象
        @Autowired
        private TransactionManager transactionManager;
    
        /**
         *
         * @param fromName  转账人新名
         * @param toName    收款人姓名
         * @param money 转账金额
         * @return 转账结果
         */
        public Result  transferMoney(String fromName,String toName,double money) {
            Result result = new Result();
            try {
                //开启事务
                transactionManager.startTransaction();
                //转账功能调起
                userDao.reduceMoneyByName(fromName,money);
                //收款功能调起
                //搞事情代码
    //            int i = 1/0;
                userDao.addMoneyByName(toName,money);
                //提交事务
                transactionManager.commitAndCloseTransaction();
                result.setFlag(true);
                result.setMessage("转账成功");
            } catch (Exception e) {
                //如果出现异常需回滚事务
                try {
                    transactionManager.rollbackAndCloseTransaction();
                    //仍然构建返回结果信息并返回给客户端
                    result.setFlag(false);
                    result.setMessage("转账失败，失败原因："+e.getMessage());
                } catch (SQLException throwables) {
                    throwables.printStackTrace();
                }
            }
            return result;
        }
    }

第四步：Spring核心配置文件

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
           xmlns:context="http://www.springframework.org/schema/context"
           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
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context.xsd">
    
        <context:component-scan base-package="com.gg"/>
        <context:property-placeholder location="classpath:jdbc.properties"/>
    
        <bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
            <property name="driverClass" value="${jdbc.driver}"/>
            <property name="jdbcUrl" value="${jdbc.url}"/>
            <property name="user" value="${jdbc.username}"/>
            <property name="password" value="${jdbc.password}"/>
        </bean>
    
        
        <bean id="queryRunner" class="org.apache.commons.dbutils.QueryRunner">
            <constructor-arg name="ds" ref="dataSource"/>
        </bean>
    </beans>

数据库属性文件jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://localhost/databasesName?characterEncoding=utf-8
    jdbc.username=root
    jdbc.password=root

第五步：测试类：

//单元测试类
    @RunWith(SpringJUnit4ClassRunner.class)
    //加载spring配置文件信息
    @ContextConfiguration("classpath:applicationConfig.xml")
    public class UserTest {
        //注解方式获取userServletImpl实现类对象
        @Autowired
        private UserServiceImpl userServiceImpl;
        @Test
        public void transferTest(){
            //传入参数调用转账方法
            Result result = userServiceImpl.transferMoney("张三", "李四", 100.00);
            System.out.println("此次操作结果："+result.isFlag());
            System.out.println("操作结果说明："+result.getMessage());
    
        }
    }

测试结果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpZXJlbmJpamkyMQ_size_16_color_FFFFFF_t_70_pic_center]  
![在这里插入图片描述][20200829232638888.png_pic_center]

如果出现异常，结果为：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpZXJlbmJpamkyMQ_size_16_color_FFFFFF_t_70_pic_center 1]  
数据库表的内如不变：![在这里插入图片描述][20200829232726369.png_pic_center]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpZXJlbmJpamkyMQ_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/d72eabcb0d4046f4a3c9add6519ffb95.png
[20200829232638888.png_pic_center]: /images/20221123/02e41c2148794cc5a99c7c2e1441166b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2xpZXJlbmJpamkyMQ_size_16_color_FFFFFF_t_70_pic_center 1]: /images/20221123/893539e7d5fe4f1d9b382408757fbbed.png
[20200829232726369.png_pic_center]: /images/20221123/7dec281801da468fb1618861b1249b28.png