JDBC连接数据库步骤并遍历

package testjdbc;

import java.sql.*;

import releseJDBC.ReleaseResource;

public class Test {

   public static void main(String[] args) {
       Connection conn = null;
       Statement st = null;
       ResultSet rs = null;
       try{
           //1注册驱动com.microsoft.sqlserver.jdbc.SQLServerDriver
           DriverManager.registerDriver(new com.microsoft.sqlserver.jdbc.SQLServerDriver());
//Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");//两种不同的注册方法，效果一样
           String url = "jdbc:sqlserver://localhost:1433;databaseName = shopping";
           String user = "root";
           String psw = "123456";

           //2建立连接参数一：协议参数二：用户名参数三：密码
           conn = DriverManager.getConnection(url,user,psw);


           //3创建statment，跟数据库打交道，一定需要这个对象
           st = conn.createStatement();

           //4执行查询得到结果集
           String sql = "select * from users";
           rs = st.executeQuery(sql);

           //5遍历每一条记录
           while(rs.next()){
               int id = rs.getInt("userID");
               int age = rs.getInt("age");
               String name = rs.getString("userName");
               String passWord = rs.getString("passWord");
               String sex = rs.getString("sex");
               String telNum = rs.getString("telNum");
               String mail = rs.getString("e_Mail");
               System.out.println("id=" + id +"===age=" + age + "==name=" + name + "== passWord="
                       +passWord +"==sex=" + sex + "== telNum=" + telNum + "==mail=" + telNum
                       + "==E Mail=" + mail);
           }
       }catch(SQLException e){
           e.printStackTrace();
       }finally{
           ReleaseResource.releaseSource(st, conn, rs);//此为释放资源，方法在下面
       }
   }

}

// 以上为测试是否连接上了数据库，以下为释放数据库方法

package releseJDBC;

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

public class ReleaseResource {
   /**
   * 释放资源
   * @param st
   * @param conn
   * @param rs
   */
   public static void releaseSource(Statement st,Connection conn, ResultSet rs){
       closeStatement(st);
       closeConnection(conn);
       closeResultSet(rs);
   }

   private static void closeStatement(Statement st){
       try{
           if(st != null)
               st.close();
       }catch(SQLException e){
           e.printStackTrace();
       }finally{
           st = null;
       }
   }

   private static void closeConnection(Connection conn){
       try{
           if(conn != null)
               conn.close();
       }catch(SQLException e){
           e.printStackTrace();
       }finally{
           conn = null;
       }
   }

   private static void closeResultSet(ResultSet rs){
       try{
           if(rs != null)
               rs.close();
       }catch(SQLException e){
           e.printStackTrace();
       }finally{
           rs = null;
       }
   }
}

//来源黑马

JDBC连接数据库步骤并遍历

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