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：

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 
 public class DBHelper {
     public static final String url = "jdbc:mysql://localhost/test";
     public static final String name = "com.mysql.jdbc.Driver";
     public static final String user = "root";
     public static final String password = "123456";
 
     public Connection conn = null;
     public PreparedStatement pst = null;
 
     public DBHelper(String sql) {
         try {
             Class.forName(name);// 指定连接类型
             conn = DriverManager.getConnection(url, user, password);// 获取连接
             pst = conn.prepareStatement(sql);// 准备执行语句
         } catch (Exception e) {
             e.printStackTrace();
         }
     }
 
     public void close() {
         try {
             this.conn.close();
             this.pst.close();
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 }

三、查询数据：

代码如下：

 import java.sql.ResultSet;
 import java.sql.SQLException;
 
 public class Test {
     private static String sql = null;
     private static DBHelper helper = null;
     private static ResultSet rs = null;
 
     public static void main(String[] args) {
         sql = "select empno,ename from emp";
         helper = new DBHelper(sql);
 
         try {
             rs = helper.pst.executeQuery();
             while (rs.next()) {
                 String empno = rs.getString(1);
                 String ename = rs.getString(2);
                 System.out.println(empno + "\t" + ename + "\t");
             }
             rs.close();
             helper.close();
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 }

结果如下：

四、更新数据：

代码如下：

 import java.sql.SQLException;
 
 public class TestUpdate {
     private static String sql = null;
     private static DBHelper helper = null;
 
     public static void main(String[] args) {
         sql = "delete from emp where empno=1111";
         helper = new DBHelper(sql);
 
         try {
             int i = helper.pst.executeUpdate();
             if (i != 0) {
                 System.out.println("删除成功");
             } else {
                 System.out.println("删除失败");
             }
         } catch (SQLException e) {
             e.printStackTrace();
         }
     }
 }