面向對象的模式查詢數據

package JDBC;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.Scanner;

public class JDBCTest {
    //1.main方法
    //2.判斷查詢方式輸入 1 根據ID查詢 2，根據名字查詢
    //3.組成sql 語句 執行查詢
    public void TestGetstudent() throws Exception{
        //獲得查詢方式
        int serchType = getSearchType();
        students students = getSearchStudentType(serchType);
        prinStudents(students);
    }
    //打印學生信息
    public void prinStudents(students students){
        if (students != null) {
            System.out.println(students);
        } else {
            System.out.println("查無此人!");
        }
    }
    private int getSearchType(){
        //查詢的方式1，ID。 2 根據姓名查詢
        System.out.println("請輸入查詢的方式：1 ID查詢  2 姓名查詢");
        Scanner scanner = new Scanner(System.in);
        int type = scanner.nextInt();
        if (type != 1&& type !=2 ){
            System.out.println("輸入的代碼錯誤");
            throw  new RuntimeException();
        }
        return type;
    }
    //判斷查詢的方式

    private students getSearchStudentType(int type) throws Exception{
        String sql = "SELECT * FROM students WHERE ";
        Scanner scanner = new Scanner(System.in);
        if (type==1){
            System.out.println("請輸入學生的ID");
            int exam = scanner.nextInt();
            sql = sql+"id = '" + exam + "'";
            System.out.println(sql);
        }else {
            System.out.println("請輸入學生的姓名");
            String name = scanner.next();
            sql = sql+"name = '" + name + "'";
            System.out.println(sql);
        }
        //執行查詢
        students students = getStudents(sql);
        return students;
    }

    private students getStudents(String sql) throws Exception{
        students students = null;
        Connection connection = null;
        Statement statement = null;
        ResultSet resultSet = null;
        try{
            connection = JDBCTools.getConnection();
            statement = connection.createStatement();
            resultSet = statement.executeQuery(sql);
            if (resultSet.next()){
                students = new students(resultSet.getInt(1), resultSet.getString(2), resultSet.getString(3));
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            JDBCTools.release(resultSet, statement, connection);
        }
        return students;
    }
}