JDBC增删查改（使用配置文件）

JDBCDemo2.java

package com.zhangbz.jdbc;

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

import org.junit.Test;

import com.zhangbz.util.JDBCUtils;

public class JDBCDemo2 {

    @Test
    public void delete() {
        Connection conn = null;
        Statement stat = null;

        try {
            conn = JDBCUtils.getConn();
            stat = conn.createStatement();
            stat.executeUpdate("delete from user where name = 'zhaoliu'");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(null, stat, conn);
        }
    }

    @Test
    public void find() {
        Connection conn = null;
        Statement stat = null;
        ResultSet rs = null;

        try {
            conn = JDBCUtils.getConn();
            stat = conn.createStatement();
            rs = stat.executeQuery("select* from user where name = 'zhaoliu'");
            while(rs.next()) {
                String name = rs.getString("name");
                String password = rs.getString("password");
                System.out.println(name + ":" + password);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(rs, stat, conn);
        }
    }
    @Test
    public void update() {
        Connection conn = null;
        Statement stat = null;

        try {
            conn = JDBCUtils.getConn();
            stat = conn.createStatement();
            stat.executeUpdate("update user set password=999 where name = 'zhaoliu'");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            JDBCUtils.close(null, stat, conn);
        }
    }

    @Test
    public void add() {
        Connection conn = null;
        Statement stat = null;

        try {
            //1.注册数据库驱动
            //2.获取连接
            conn = JDBCUtils.getConn();
            //3.获取传输器对象
            stat = conn.createStatement();
            //4.执行sql语句
            int count = stat.executeUpdate("insert into user values(null, 'zhaoliu', '123456', '[e-mail]', '1999-09-09')");
            //5.处理结果
            if (count > ) {
                System.out.println("执行成功！影响的行数为" + count);
            } else {
                System.out.println("执行失败！！");
            }

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            //6.关闭资源
            JDBCUtils.close(null, stat, conn);
        }
    }
}

JDBCUtils.java

 package com.zhangbz.util;

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

 public class JDBCUtils {
     public static Properties prop = null;
     private JDBCUtils() {
     }
     //使用配置文件
     static {
         try {
             prop = new Properties();
             prop.load(JDBCUtils.class.getClassLoader().getResourceAsStream("config.properties"));
         } catch (Exception e) {
             e.printStackTrace();
             throw new RuntimeException(e);
         }
     }
     /**
      * 获取连接
      * @return
      * @throws ClassNotFoundException
      * @throws SQLException
      */
     public static Connection getConn() throws ClassNotFoundException, SQLException {
         //1.注册数据库驱动
         Class.forName(prop.getProperty("driver"));
         //2.获取连接
         return DriverManager.getConnection(prop.getProperty("url"), prop.getProperty("user"), prop.getProperty("password"));
     }
     /**
      * 关闭连接
      */
     public static void close(ResultSet rs, Statement stat, Connection conn) {
         if (rs != null) {
             try {
                 rs.close();
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } finally {
                 rs = null;
             }
         }
         if (stat != null) {
             try {
                 stat.close();
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } finally {
                 stat = null;
             }
         }
         if (conn != null) {
             try {
                 conn.close();
             } catch (SQLException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             } finally {
                 conn = null;
             }
         }
     }
 }

config.properties

driver=com.mysql.jdbc.Driver
url=jdbc:mysql:///Day10
user=root
password=root