jdbc写的模拟银行转账系统

package bankproject; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class Transfer_Dom { Connection conn = null; PreparedStatement pstmt = null; String sql = null; int i = 0; ResultSet rs = null; int Money = 0; int bankincome = 0; public void Transfer(String name1, String name2, double money) throws SQLException { conn = Utils.getConnection(); conn.setAutoCommit(false); // 开始转账 sql = "update user set usermoney=usermoney-? where username=?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, money); pstmt.setObject(2, name1); i = pstmt.executeUpdate(); if (i > 0) { // 用户1余额 sql = "select usermoney from user where username=?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name1); rs = pstmt.executeQuery(); if (rs.next()) { Money = rs.getInt("usermoney"); if (Money > 0) { sql = "update user set usermoney=usermoney+? where username=?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, money); pstmt.setObject(2, name2); i = pstmt.executeUpdate(); sql = "select bankId from user where username=?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name2); rs = pstmt.executeQuery(); if (rs.next()) { String id1 = rs.getString("bankID"); System.out.println(id1); // 收款人存的银行 sql = "select bankId from user where username = ?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name2); rs = pstmt.executeQuery(); if (rs.next()) { String id2 = rs.getString("bankId"); System.out.println(id2); // 判断是否同行同地 if (id1 == id2) { // bankincome = 0; sql = "select bankareaId from bank where bankId = (select bankId from user where username = ?)"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name1); rs = pstmt.executeQuery(); if (rs.next()) { int areaid3 = rs.getInt("bankareaId"); // System.out.println(areaid1); sql = "select bankareaId from bank where bankId = (select bankId from user where username = ?)"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name2); rs = pstmt.executeQuery(); if (rs.next()) { int areaid4 = rs.getInt("bankareaId"); // System.out.println(areaid1); // if (areaid3 == areaid4 && money < // 2500) { // money = money * 0.01; // // } if (areaid3 == areaid4) { bankincome = 0; } if (areaid3 != areaid4 && money < 2500) { money = money * 0.01; } if (areaid3 != areaid4 && money > 2500 && money < 5000) { money = 25; } // if (areaid3 != areaid4&& money > // 5000) { // money = 75; // // } } // 不同地再判断 if (id1 != id2) { sql = "select bankareaId from bank where bankId = (select bankId from user where username = ?)"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name1); rs = pstmt.executeQuery(); if (rs.next()) { int areaid1 = rs .getInt("bankareaId"); System.out.println(areaid1); sql = "select bankareaId from bank where bankId = (select bankId from user where username = ?)"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name2); rs = pstmt.executeQuery(); if (rs.next()) { int areaid2 = rs .getInt("bankareaId"); System.out.println(areaid1); if (areaid1 == areaid2 && money < 2500) { money = money * 0.01; } if (areaid1 == areaid2 && money >= 2500) { money = 50; } if (areaid1 != areaid2 && money < 2500) { money = money * 0.01 + money * 0.01; } if (areaid1 != areaid2 && money > 2500 && money < 5000) { money = 25 + money * 0.01; } if (areaid1 != areaid2 && money > 5000) { money = 75; } sql = "update user set usermoney=usermoney - ? where username = ?"; pstmt = conn .prepareStatement(sql); pstmt.setObject(1, money); pstmt.setObject(2, name1); i = pstmt.executeUpdate(); sql = "select userId from user where username = ?"; pstmt = conn .prepareStatement(sql); pstmt.setObject(1, name1); rs = pstmt.executeQuery(); if (rs.next()) { int useroneID = rs .getInt("userId"); sql = "insert into bankincome (bankincomeId,bimoney,userId,bankId) values (?,?,?,?)"; pstmt = conn .prepareStatement(sql); pstmt.setObject(1, null); pstmt.setObject(2, money); pstmt.setObject(3, useroneID); pstmt.setObject(4, id1); i = pstmt.executeUpdate(); } } } } } } } sql = "update user set usermoney=usermoney - ? where username = ?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, money); pstmt.setObject(2, name1); i = pstmt.executeUpdate(); sql = "select userId from user where username = ?"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, name1); rs = pstmt.executeQuery(); if (rs.next()) { int useroneID = rs.getInt("userId"); sql = "insert into bankincome (bankincomeId,bimoney,userId,bankId) values (?,?,?,?)"; pstmt = conn.prepareStatement(sql); pstmt.setObject(1, null); pstmt.setObject(2, money); pstmt.setObject(3, useroneID); pstmt.setObject(4, id1); i = pstmt.executeUpdate(); } if (i > 0) { System.out.println("转账成功！！"); conn.commit(); } } } } else { System.out.println("转账失败！"); conn.rollback(); } } else { System.out.println("余额不足！"); conn.rollback(); } } public static void main(String[] args) { try { Transfer_Dom transfer = new Transfer_Dom(); transfer.Transfer("小明", "张三", 30); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }