JDBC基础篇（MYSQL）——使用statement执行DML语句（insert/update/delete）

注意：其中的JdbcUtil是我自定义的连接工具类：代码例子链接：

package day02_statement;

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

import util.JdbcUtil;
/**
 * 使用Statement对象执行DML语句（insert/update/delete）
 * @author mzy
 *
 */
public class Demo03 {
	public static void main(String[] args) {
		// createTable();

		// insertIntoTable();

		// deleteFromTable();

		// updateFromTable();
	}

	private static void deleteFromTable() {
		Connection conn = null;
		Statement stmt = null;
		// String id = "1";
		Object id = 1; // 从这里我们可以看出传入的类型会被转换不会造成影响
		// 猜测是有一个instanceof
		try {
			// 1) 获取连接
			conn = JdbcUtil.getConnection();
			// 准备sql
			String sql = "update employee set age = 80 where id="+id+"";

			// 创建statement对象
			stmt = conn.createStatement();
			int count = stmt.executeUpdate(sql);
			System.out.println(""+count+"行被影响了！");

		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.close(stmt, conn);
		}
	}

	private static void insertIntoTable() {
		Connection conn = null;
		Statement stmt = null;

		try {
			// 1) 获取连接
			conn = JdbcUtil.getConnection();
			// 准备sql
			String sql = "INSERT INTO employee(NAME, gender, age, title, email, phone) VALUES"+
					"('张三', '男', 20, '软件工程师', '123@qq.com', '12345'),"+
					"('李四', '男', 30, '前端工程师', '456@qq.com', '12345'),"+
					"('王五', '男', 40, '测试工程师', '789@qq.com', '12345'),"+
					"('陈六', '男', 50, '数据库工程师', '123@qq.com', '12345')";

			// 创建statement对象
			stmt = conn.createStatement();
			int count = stmt.executeUpdate(sql);
			System.out.println(""+count+"行被影响了！");

		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.close(stmt, conn);
		}
	}

	private static void createTable() {
		Connection conn = null;
		Statement stmt = null;

		try {
			// 1) 获取连接
			conn = JdbcUtil.getConnection();
			// 准备sql
			String sql = "CREATE TABLE employee("+
					"id INT PRIMARY KEY AUTO_INCREMENT,"+
					"NAME VARCHAR(20),"+
					"gender VARCHAR(2),"+
					"age INT,"+
					"title VARCHAR(20),"+
					"email VARCHAR(50),"+
					"phone VARCHAR(11)"+
				")";
			// 创建statement对象
			stmt = conn.createStatement();
			int count = stmt.executeUpdate(sql);
			System.out.println(""+count+"行被影响了！");

		} catch (SQLException e) {
			e.printStackTrace();
		} finally {
			JdbcUtil.close(stmt, conn);
		}
	}
}