新建BaseDao

package cn.wingfly.dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class BaseDao {
  Connection con = null;
  Statement st = null;
  ResultSet rs = null;

  /**
   * 获得联接
   * 
   * @return
   */
  public Connection getConnection() {
    try {
      // 加载驱动，这一句也可写为：Class.forName("com.mysql.jdbc.Driver"); 
      Class.forName("com.mysql.jdbc.Driver").newInstance();

      // 建立到MySQL的连接 
      con = DriverManager.getConnection("jdbc:mysql://localhost:3306/money_note?characterEncoding=UTF-8", "root", "root");
    } catch (Exception e) {
      e.printStackTrace();
    }
    return con;
  }

  /**
   * 关闭数据源
   */
  public void CloseConnection(Connection con, Statement s, ResultSet rs) {
    try {
      if (rs != null) {
        rs.close();
      }
      if (s != null) {
        s.close();
      }
      if (con != null) {
        con.close();
      }
    } catch (SQLException e) {
      e.printStackTrace();
    }
  }
}

测试类

package cn.wingfly.dao;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class Test extends BaseDao {

  Connection con = null;
  Statement st = null;
  ResultSet rs = null;

  /**
   * 查询数据
   */
  public void find() {
    con = getConnection();  // 获得联接
    try {
      st = con.createStatement();
      rs = st.executeQuery("select * from app_user");
      while (rs.next()) {
        System.out.println("编号：" + rs.getInt("uuid") + ", 姓名：" + rs.getString("userName") + ", 性别：" + rs.getString("sex") + ", 生日：" + rs.getString("birthday") + ", 住址：" + rs.getString("address"));
      }
    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      CloseConnection(con, st, rs); // 关闭联接
    }
  }

  /**
   * 添加数据
   */
  public void add() {
    con = getConnection();
    try {
      st = con.createStatement();
      int result = st.executeUpdate("insert into app_user(userName,passWord,sex,birthday,address) values('赵丽颖','wanying','女','1992-02-03','北京市')");
      if (result > 0) {
        System.out.println("插入成功");
      } else {
        System.out.println("插入失败");
      }
    } catch (SQLException e) {
      System.out.println("插入失败");
      e.printStackTrace();
    } finally {
      CloseConnection(con, st, rs);
    }
  }

  /**
   * 更新数据
   */
  public void update() {
    con = getConnection();
    try {
      st = con.createStatement();
      int result = st.executeUpdate("update app_user set address = '河南' where uuid = '3'");
      if (result > 0) {
        System.out.println("更新成功");
      } else {
        System.out.println("更新失败");
      }
    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      CloseConnection(con, st, rs);
    }
  }

  /**
   * 删除数据
   */
  public void delete() {
    con = getConnection();
    try {
      st = con.createStatement();
      int result = st.executeUpdate("delete from app_user where uuid = '3'");
      if (result > 0) {
        System.out.println("删除成功");
      } else {
        System.out.println("删除失败");
      }
    } catch (SQLException e) {
      e.printStackTrace();
    } finally {
      CloseConnection(con, st, rs);
    }
  }

  public static void main(String[] args) {
    Test test = new Test();
    //test.add();
    // test.update();
     test.delete();
    test.find();

  }

}