Java如何使用JDBC連線更新（刪除，插入或更新）表的資料內容？

在Java程式設計中，如何搜尋表中的資料內容？假定資料庫名稱是：testdb，其中有一個表:employee，這個表中有4條記錄。

建立資料庫表的語句 -

use testdb;
create table if not exists employees (
  id int not null,
  age int not null,
  first varchar (255),
  last varchar (255)
);
INSERT INTO Employees VALUES (100, 28, 'Max', 'Su');
INSERT INTO Employees VALUES (101, 25, 'Wei', 'Wang');
INSERT INTO Employees VALUES (102, 30, 'Kida', 'Su');
INSERT INTO Employees VALUES (103, 28, 'Kobe', 'Bryant');

以下方法使用sql的where和like條件語句來搜尋資料庫表中的資料。

package com.yiibai;

import java.sql.*;

public class SearchTableContents {
    public static void main(String[] args) throws Exception {
        String JDBC_DRIVER = "com.mysql.jdbc.Driver";
        String DB_URL = "jdbc:mysql://localhost/testdb?useSSL=false";
        String User = "root";
        String Passwd = "123456";
        try {
            Class.forName(JDBC_DRIVER);
        } catch (ClassNotFoundException e) {
            System.out.println("Class not found " + e);
        }
        Connection con = DriverManager.getConnection(DB_URL, User, Passwd);
        Statement stmt = con.createStatement();
        String query[] = { "SELECT * FROM employees where id = 101", 
                "select * from employees where first like 'Ma_'",
                "select * from employees where last like 'Brya%'" };

        for (String q : query) {
            ResultSet rs = stmt.executeQuery(q);
            System.out.print("Names for query " + q + " , Results : ");

            while (rs.next()) {
                String name = rs.getString("first");
                System.out.print(name + "  ");
            }
            System.out.println();
        }
    }
}

上述程式碼範例將產生以下結果。

Names for query SELECT * FROM employees where id = 101 , Results : Wei  
Names for query select * from employees where first like 'Ma_' , Results : 
Names for query select * from employees where last like 'Brya%' , Results : Kobe

註：如果JDBC驅動程式安裝不正確，將獲得ClassNotfound異常。

Class not found java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
JDBC Class found
SQL exception occuredjava.sql.SQLException: No suitable driver found for jdbc:mysql://localhost/testdb