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', '[email protected]', '1999-09-09')");
            //5.处理结果
            if (count > 0) {
                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

 1 package com.zhangbz.util;
 2 
 3 import java.sql.Connection;
 4 import java.sql.DriverManager;
 5 import java.sql.ResultSet;
 6 import java.sql.SQLException;
 7 import java.sql.Statement;
 8 import java.util.Properties;
 9 
10 public class JDBCUtils {
11     public static Properties prop = null;
12     private JDBCUtils() {
13     }
14     //使用配置文件
15     static {
16         try {
17             prop = new Properties();
18             prop.load(JDBCUtils.class.getClassLoader().getResourceAsStream("config.properties"));
19         } catch (Exception e) {
20             e.printStackTrace();
21             throw new RuntimeException(e);
22         }
23     }
24     /**
25      * 获取连接
26      * @return
27      * @throws ClassNotFoundException
28      * @throws SQLException
29      */
30     public static Connection getConn() throws ClassNotFoundException, SQLException {
31         //1.注册数据库驱动
32         Class.forName(prop.getProperty("driver"));
33         //2.获取连接
34         return DriverManager.getConnection(prop.getProperty("url"), prop.getProperty("user"), prop.getProperty("password"));
35     }
36     /**
37      * 关闭连接
38      */
39     public static void close(ResultSet rs, Statement stat, Connection conn) {
40         if (rs != null) {
41             try {
42                 rs.close();
43             } catch (SQLException e) {
44                 // TODO Auto-generated catch block
45                 e.printStackTrace();
46             } finally {
47                 rs = null;
48             }
49         }
50         if (stat != null) {
51             try {
52                 stat.close();
53             } catch (SQLException e) {
54                 // TODO Auto-generated catch block
55                 e.printStackTrace();
56             } finally {
57                 stat = null;
58             }
59         }
60         if (conn != null) {
61             try {
62                 conn.close();
63             } catch (SQLException e) {
64                 // TODO Auto-generated catch block
65                 e.printStackTrace();
66             } finally {
67                 conn = null;
68             }
69         }
70     }
71 }

config.properties

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