JAVA对MySQL数据库的操作

一、导包：

使用JDBC连接MySQL数据库时，首先需要导入一个第三方的JAR包（点击下载），下载解压得到一个JAR包，并导入到JAVA项目中，如下图：

二、DBHelper类：

代码如下：

 1 import java.sql.Connection;
 2 import java.sql.DriverManager;
 3 import java.sql.PreparedStatement;
 4 import java.sql.SQLException;
 5 
 6 public class DBHelper {
 7     public static final String url = "jdbc:mysql://localhost/test";
 8     public static final String name = "com.mysql.jdbc.Driver";
 9     public static final String user = "root";
10     public static final String password = "123456";
11 
12     public Connection conn = null;
13     public PreparedStatement pst = null;
14 
15     public DBHelper(String sql) {
16         try {
17             Class.forName(name);// 指定连接类型
18             conn = DriverManager.getConnection(url, user, password);// 获取连接
19             pst = conn.prepareStatement(sql);// 准备执行语句
20         } catch (Exception e) {
21             e.printStackTrace();
22         }
23     }
24 
25     public void close() {
26         try {
27             this.conn.close();
28             this.pst.close();
29         } catch (SQLException e) {
30             e.printStackTrace();
31         }
32     }
33 }

三、查询数据：

代码如下：

 1 import java.sql.ResultSet;
 2 import java.sql.SQLException;
 3 
 4 public class Test {
 5     private static String sql = null;
 6     private static DBHelper helper = null;
 7     private static ResultSet rs = null;
 8 
 9     public static void main(String[] args) {
10         sql = "select empno,ename from emp";
11         helper = new DBHelper(sql);
12 
13         try {
14             rs = helper.pst.executeQuery();
15             while (rs.next()) {
16                 String empno = rs.getString(1);
17                 String ename = rs.getString(2);
18                 System.out.println(empno + "\t" + ename + "\t");
19             }
20             rs.close();
21             helper.close();
22         } catch (SQLException e) {
23             e.printStackTrace();
24         }
25     }
26 }

结果如下：

四、更新数据：

代码如下：

 1 import java.sql.SQLException;
 2 
 3 public class TestUpdate {
 4     private static String sql = null;
 5     private static DBHelper helper = null;
 6 
 7     public static void main(String[] args) {
 8         sql = "delete from emp where empno=1111";
 9         helper = new DBHelper(sql);
10 
11         try {
12             int i = helper.pst.executeUpdate();
13             if (i != 0) {
14                 System.out.println("删除成功");
15             } else {
16                 System.out.println("删除失败");
17             }
18         } catch (SQLException e) {
19             e.printStackTrace();
20         }
21     }
22 }