dao層代碼如下：

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();//不用穿參數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();//不用穿參數Connection conn = MyDataSourceUtils.getCurrentConnection();String sql = "update account set money= money+? where name=?";runner.update(conn, sql, money,in);}}

service層代碼如下：

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) {//創建dao層對象TransferDao dao = new TransferDao();boolean isTransferSuccess = true;Connection conn = null;try {//進行事務控制，開啟事務//conn = DataSourceUtils.getConnection();//不自動開啟事務，也就是手動開啟事務//conn.setAutoCommit(false);//開啟事務MyDataSourceUtils.startTransaction();//調用dao層的轉出錢的方法,只需要知道 轉錢的人是誰 跟 錢數 就行dao.out(out,money);//調用dao層的轉入錢的方法,只需要知道 轉給誰 跟 錢數 就行dao.in(in,money);} catch (SQLException e) {isTransferSuccess = false;try {//當出現事務錯誤，進行事務的回滾；回滾本身內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層代碼如下：

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 {//接收轉賬的參數String out = request.getParameter("out");String in = request.getParameter("in");String moneyStr = request.getParameter("money");double money=Double.parseDouble(moneyStr);//進行將轉賬金額強轉//調用業務層的轉賬方法TransferService service = new TransferService();boolean isTransferSuccess = service.transfer(out,in,money);//解決亂碼問題response.setContentType("text/html;charset=UTF-8");if(isTransferSuccess){response.getWriter().write("轉賬成功！！！");}else{response.getWriter().write("轉賬失敗！！！");}}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}