dao层代码如下：

package beyond.transfer.dao;import java.sql.Connection;
import java.sql.SQLException;import org.apache.commons.dbutils.QueryRunner;import beyond.utils.DataSourceUtils;
import beyond.utils.MyDataSourceUtils;public class TransferDao {public void out( String out, double money) throws SQLException {QueryRunner runner = new QueryRunner();//不用穿参数Connection conn = MyDataSourceUtils.getCurrentConnection();String sql = "update account set money= money-? where name=?";runner.update(conn, sql, money,out);}public void in(String in, double money) throws SQLException {QueryRunner runner = new QueryRunner();//不用穿参数Connection conn = MyDataSourceUtils.getCurrentConnection();String sql = "update account set money= money+? where name=?";runner.update(conn, sql, money,in);}}

service层代码如下：

package beyond.transfer.service;import java.sql.Connection;
import java.sql.SQLException;import beyond.transfer.dao.TransferDao;
import beyond.utils.DataSourceUtils;
import beyond.utils.MyDataSourceUtils;public class TransferService {public boolean transfer(String out, String in, double money) {//创建dao层对象TransferDao dao = new TransferDao();boolean isTransferSuccess = true;Connection conn = null;try {//进行事务控制，开启事务//conn = DataSourceUtils.getConnection();//不自动开启事务，也就是手动开启事务//conn.setAutoCommit(false);//开启事务MyDataSourceUtils.startTransaction();//调用dao层的转出钱的方法,只需要知道 转钱的人是谁 跟 钱数 就行dao.out(out,money);//调用dao层的转入钱的方法,只需要知道 转给谁 跟 钱数 就行dao.in(in,money);} catch (SQLException e) {isTransferSuccess = false;try {//当出现事务错误，进行事务的回滚；回滚本身内部不包含提交的功能MyDataSourceUtils.rollback();} catch (SQLException e1) {e1.printStackTrace();}e.printStackTrace();}finally{try {MyDataSourceUtils.commit();} catch (SQLException e) {e.printStackTrace();}}return isTransferSuccess;}}

web层代码如下：

package beyond.transfer.web;import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import beyond.transfer.service.TransferService;public class TransferServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//接收转账的参数String out = request.getParameter("out");String in = request.getParameter("in");String moneyStr = request.getParameter("money");double money=Double.parseDouble(moneyStr);//进行将转账金额强转//调用业务层的转账方法TransferService service = new TransferService();boolean isTransferSuccess = service.transfer(out,in,money);//解决乱码问题response.setContentType("text/html;charset=UTF-8");if(isTransferSuccess){response.getWriter().write("转账成功！！！");}else{response.getWriter().write("转账失败！！！");}}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}