转账业务的实现

1.首页

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
	<div align="center">
		<form action="${pageContext.request.contextPath }/count"  method="post" >
			付款人:<input type="text" value="小明" name="from"/></br>
			收款人:<input type="text" value="小红" name="to"/></br>
			金额:<input type="text" value="100" name="money"/></br>
			<input type="submit" value="转账"/>
		</form>
	</div>
</body>
</html>

2.servlet

package yynh.com.pal.web.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import yynh.com.pal.service.PalService;
import yynh.com.pal.service.PalServiceIml;

/**
 * Servlet implementation class Count
 */
public class Count extends HttpServlet {
	private static final long serialVersionUID = 1L;

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

	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		try {
			// 防止乱码
			request.setCharacterEncoding("utf-8");
			response.setContentType("text/html;charset=utf-8");
			// 获取数据
			String from = request.getParameter("from");
			String to = request.getParameter("to");
			String money = request.getParameter("money");
			// 调用service
			PalService ps = new PalServiceIml();
			ps.pal(from, to, money);
			// 回显数据
			response.getWriter().print("转账成功");

		} catch (Exception e) {
			response.getWriter().print("转账失败");
		}
	}

}

3.service

package yynh.com.pal.service;

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

import org.apache.commons.dbutils.DbUtils;

import yynh.com.pal.dao.PalDao;
import yynh.com.pal.dao.PalDaoIml;
import yynh.com.pal.utils.C3p0Utils;

public class PalServiceIml implements PalService {

	/**
	 * 使用DBUtils的事务管理来处理转账业务
	 */
	public void pal(String from, String to, String money) {
		// 获取连接,保证付款和收款是用的同一个事务
		Connection conn = C3p0Utils.getConnection();
		PalDao pd = new PalDaoIml();
		// 开启事务
		try {
			conn.setAutoCommit(false);
			// 调用扣钱
			pd.reduce(conn, from, money);
			// 调用加钱
			pd.increase(conn, to, money);
			// 提交业务 并且关闭资源
			DbUtils.commitAndCloseQuietly(conn);
		} catch (SQLException e) {
			// 回滚业务,关闭资源
			DbUtils.rollbackAndCloseQuietly(conn);
			e.printStackTrace();
			throw new RuntimeException();
		}

	}

	/*
	 * @Override public void pal(String from, String to, String money) { // 获取连接,保证付款和收款是用的同一个事务 Connection conn = C3p0Utils.getConnection(); PalDao pd = new PalDaoIml(); try { // 关闭自动连接,开启手动事务
	 * conn.setAutoCommit(false); // 调用扣钱 pd.reduce(conn, from, money); // 调用加钱 pd.increase(conn, to, money); // 提交事务 conn.commit(); } catch (Exception e) { // 设置回滚 try { conn.rollback(); } catch
	 * (SQLException e1) { // TODO Auto-generated catch block e1.printStackTrace(); } e.printStackTrace(); // 抛出异常 throw new RuntimeException(); } finally { if (conn != null) { // 关闭资源 try {
	 * conn.close(); } catch (Exception e) { e.printStackTrace(); } }
	 * 
	 * }
	 * 
	 * }
	 */
}

4.dao

package yynh.com.pal.dao;

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

import org.apache.commons.dbutils.QueryRunner;

public class PalDaoIml implements PalDao {

	// 由于需要使用同一个事务,所以不需要传递新的事务了
	QueryRunner run = new QueryRunner();

	@Override
	public void reduce(Connection conn, String from, String money) {
		// 减钱业务
		String sql = "update account set money=money-? where name=?";
		Object[] param = { money, from };
		try {
			run.update(conn, sql, param);
		} catch (SQLException e) {
			e.printStackTrace();
			throw new RuntimeException();
		}

	}

	// 加钱业务
	public void increase(Connection conn, String to, String money) {
		String sql = "update account set money=money+? where name=?";
		Object[] param = { money, to };
		try {
			run.update(conn, sql, param);
		} catch (SQLException e) {
			e.printStackTrace();
			throw new RuntimeException();
		}
	}

}

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