把以前的笔记整理一下，做个备份方便以后查阅：

    要测试的代码如下：

   

package dao.jdbc;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import util.DBUtil;

import dao.IAccountDAO;

import entity.Account;

public class AccountDAOImpl implements IAccountDAO{

 @Override

 public Account findByAccountNo(

   String accountNo) throws Exception {

  Account a = null;

  Connection conn = null;

  PreparedStatement stat = null;

  ResultSet rst = null;

  try{

   conn = DBUtil.getConnection();

   String sql = "select * from t_account " +

     "where accountNo=?";

   stat = conn.prepareStatement(sql);

   stat.setString(1, accountNo);

   rst = stat.executeQuery();

   if(rst.next()){

    a = new Account();

    a.setAccountNo(accountNo);

    a.setBalance(rst.getInt("balance"));

    a.setId(rst.getInt("id"));

   }

  }catch(Exception e){

   e.printStackTrace();

   throw e;

  }finally{

   if(rst != null){

    rst.close();

   }

   if(stat != null){

    stat.close();

   }

   DBUtil.close(conn);

  }

  return a;

 }

 @Override

 public void modify(Account a) throws Exception {

  Connection conn = null;

  PreparedStatement stat = null;

  try{

   conn = DBUtil.getConnection();

   String sql = "update t_account set " +

     "balance=? where accountNo=?";

   stat = conn.prepareStatement(sql);

   stat.setInt(1, a.getBalance());

   stat.setString(2, a.getAccountNo());

   stat.executeUpdate();

  }catch(Exception e){

   e.printStackTrace();

   throw e;

  }finally{

   if(stat != null){

    stat.close();

   }

   DBUtil.close(conn);

  } 

 }

}

测试代码：

package dao.jdbc;

import org.junit.Test;

import util.Factory;

import dao.IAccountDAO;

import entity.Account;

public class AccountDAOImplTest {

 @Test

 public void testFindByAccountNo() throws Exception {

  IAccountDAO dao =

   (IAccountDAO) Factory.getInstance(

     "IAccountDAO");

  Account a = dao.findByAccountNo(

    "6225881003192000");

  System.out.println(a);

 }

 

 @Test

 public void testModify() throws Exception{

  IAccountDAO dao =

   (IAccountDAO) Factory.getInstance(

     "IAccountDAO");

  Account a = dao.findByAccountNo(

    "6225881003192000");

  a.setBalance(a.getBalance() - 800);

  dao.modify(a);

 }

}