JDBC基础学习（一） 第一个JDBC示例代码

package jdbcdemo;

import java.sql.*;

public class FirstExample {
   // JDBC驱动名称和数据库地址
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
   static final String DB_URL = "jdbc:mysql://localhost/mylibrary";

   // 数据库登录验证
   static final String USER = "root";
   static final String PASS = "123456";
   
   public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   try{
      //STEP 2: 注册数据库驱动
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: 打开连接
      System.out.println("连接数据库...");
      conn = DriverManager.getConnection(DB_URL,USER,PASS);

      //STEP 4: 执行一个查询
      System.out.println("创建 statement...");
      stmt = conn.createStatement();
      String sql;
      sql = "SELECT authID,authName,ts FROM authors";
      ResultSet rs = stmt.executeQuery(sql);

      //STEP 5: 从结果集提取数据
      while(rs.next()){
         //根据列名取得数据
         int id  = rs.getInt("authID");
         String authname = rs.getString("authName");
         String ts = rs.getString("ts");         

         //显示数据
         System.out.print("ID: " + id);
         System.out.print(", authname: " + authname);
         System.out.print(", ts: " + ts);
         System.out.println();
      }
      //STEP 6: 清理环境
      rs.close();
      stmt.close();
      conn.close();
   }catch(SQLException se){
      //处理JDBC异常
      se.printStackTrace();
   }catch(Exception e){
      //处理class.foname()异常
      e.printStackTrace();
   }finally{
      //finally块负责关闭资源
      try{
         if(stmt!=null)
            stmt.close();
      }catch(SQLException se2){
      }
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }
   }
   System.out.println("再见!");
}
}