JDBC练习五

墨蓝 2022-09-12 08:54 184阅读 0赞

## JDBC练习五 ##

/*
    	执行DQL语句
    */
    
    import java.sql.*;
    import java.util.*;
    
    public class JDBCTest05 {
        
        public static void main(String[] args) {
        
            // 1、注册驱动
            // 2、建立连接
            // 3、获取数据库操作对象
            // 4、执行sql语句
            // 5、获取查询结果集
            // 6、释放资源
            Connection conn = null;
            Statement stmt = null;
            ResultSet rs = null;
    
            try{
        
                ResourceBundle rb = ResourceBundle.getBundle("jdbc");
                String driver = rb.getString("driver");
                String url = rb.getString("url");
                String user = rb.getString("user");
                String password = rb.getString("password");
    
                Class.forName(driver);
    
                conn = DriverManager.getConnection(url,user,password);
    
                stmt = conn.createStatement();
    
                rs = stmt.executeQuery("select * from student");
    
                while(rs.next()){
        
    				/*
    				String studentid = rs.getString(1);
    				String studentname = rs.getString(2);
    				System.out.println(studentid + "," + studentname);
    				*/
    
    				/*
    				// 按下标取出，程序不健壮
    				String studentid = rs.getString("studentid");
    				String studentname = rs.getString("studentname");
    				System.out.println(studentid + "," + studentname);
    				*/
    
    				/*
    				// 以指定的格式取出
    				int studentid = rs.getInt(1);
    				String studentname = rs.getString(2);
    				System.out.println(studentid + "," + studentname);
    				*/
    
                    int studentid = rs.getInt("studentid");
                    String studentname = rs.getString("studentname");
                    System.out.println(studentid + "," + studentname);
                }
    
            } catch(Exception e){
        
                e.printStackTrace();
            }finally{
        
                if(rs != null){
        
                    try{
        
                        rs.close();
                    } catch (Exception e){
        
                        e.printStackTrace();
                    }
                }
                if(stmt != null){
        
                    try{
        
                        stmt.close();
                    } catch (Exception e){
        
                        e.printStackTrace();
                    }
                }
                if(conn != null){
        
                    try{
        
                        conn.close();
                    } catch (Exception e){
        
                        e.printStackTrace();
                    }
                }
            }
        }
    }

#### 运行结果: ####

![image-20210920191144745][]

[image-20210920191144745]: /images/20220828/14e8f6a04d0440f8b1d57a0e9bb7082d.png