JDBC事务（二）转账示例

示例采用三层框架

web层：

package cn.sasa.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 cn.sasa.service.TransferService;

public class TransferServlet extends HttpServlet {

    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String outAccount = request.getParameter("outAccount");
        String inAccount = request.getParameter("inAccount");
        double money = Double.parseDouble(request.getParameter("money"));
        TransferService tran = new TransferService();
        boolean flag =  tran.doTran(outAccount, inAccount, money);
        if(flag) {
            response.getWriter().write("ok");
        }else {
            response.getWriter().write("no");
        }
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doGet(request, response);
    }
}

service层：

package cn.sasa.service;

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

import cn.sasa.dao.TransferDao;
import cn.sasa.util.C3P0Utils;

public class TransferService {

    public boolean doTran(String outAccount, String inAccount, double money) {
        Connection conn = C3P0Utils.getConnection();
        boolean flag = true;
        try {
            conn.setAutoCommit(false);
            TransferDao tran = new TransferDao();
            int rs1 = tran.doOutAccount(conn, outAccount, money);
            int rs2 = tran.doInAccount(conn, inAccount, money);
            
            if(rs1<=0 || rs2<=0) {
                conn.rollback();
                flag=false;
            }
            
        } catch (Exception e) {
            flag = false;
            try {
                conn.rollback();
            } catch (SQLException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
            e.printStackTrace();
        }finally {
            try {
                conn.commit();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
        return flag;
    }

}

dao层：

package cn.sasa.dao;

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

import org.apache.commons.dbutils.QueryRunner;

public class TransferDao {
    
    //资金转出
    public int doOutAccount(Connection conn, String outAccount, double money) throws SQLException {
        QueryRunner runner = new QueryRunner();
        String sql = "update account set money=money-? where name=?";
        int rs = runner.update(conn, sql, money,outAccount);
        return rs;
    }
    
    //资金转入
    public int doInAccount(Connection conn, String inAccount, double money) throws SQLException {
        QueryRunner runner = new QueryRunner();
        String sql = "update account set money=money+? where name=?";
        int rs = runner.update(conn, sql, money,inAccount);
        return rs;
    }
}

客户端jsp页：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
    <form action="${pageContext.servletContext.contextPath}/TransferServlet" method="post">
        转出账户：<input type="text" name="outAccount" value=""/><br/>
        转入账户：<input type="text" name="inAccount" value=""/><br/>
        转账金额：<input type="text" name="money" value=""/><br>
        <input type="submit" value="确定">
    </form>
</body>
</html>

事务的注意事项：

手动开启事务都用 conn.setAutoCommit(false);

要用同一个conn控制事务。

JDBC事务（二）转账示例

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