Java JDBC 学习笔记

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本文是用的数据库为 MySQL

涉及到的知识点如下：

1.连接数据库

//连接数据库
//加载数据库
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/air?useUnicode=true&characterEncoding=UTF-8", "root", "root");

2.数据库查找操作

 //执行数据库的查找功能
 sql = con.prepareStatement("select * from airinfo");
 res = sql.executeQuery();

3.数据库的删除操作

 //删除一条数据
 sql = con.prepareStatement("DELETE FROM airinfo WHERE air_id = ?");
 sql.setInt(1, 1);
 sql.executeUpdate();

4.数据库的增加操作

 //增加一条数据
 sql = con.prepareStatement("INSERT INTO airinfo(air_flight_number,air_destination,air_flight_date) VALUES(?,?,?);");
 sql.setString(1, "Test");
 sql.setString(2, "BJ");
 sql.setString(3, "2014-12-24");
 sql.executeUpdate();

5.数据库的修改操作

 //改
 sql = con.prepareStatement("update airinfo set air_flight_date = ? WHERE air_id = ?");
 sql.setString(1, "2222-02-22");
 sql.setInt(2,5);
 sql.executeUpdate();6.数据库的预处理语句，这里用增加操作来举例子：static PreparedStatement sql;
 //增加一条数据
 sql = con.prepareStatement("INSERT INTO airinfo(air_flight_number,air_destination,air_flight_date) VALUES(?,?,?);");
 sql.setString(1, "Test");
 sql.setString(2, "BJ");
 sql.setString(3, "2014-12-24");
 sql.executeUpdate();
数据库的预处理是结合通配符完成的，当然前提是要声明一个预处理的变量，这里是 sql
VALUES(?,?,?) 中有3个问号，这是通配符
setString(1,"Test") 是指第一个通配符代表的是 Test 字符串

代码全文如下，当然数据库需要自己建，可以参考我的另一篇数据库建立博文虽然很渣 嘿嘿~~~：

import java.sql.Connection;import java.sql.DriverManager;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;public class Test {/** * @param args */static Connection con;static PreparedStatement sql;static ResultSet res;public static void main(String[] args) {Test c = new Test();//创建本类对象con = c.getConnection();try { //要执行 SQL 语句，首先要获得 Statement 类对象 sql = con.prepareStatement("select * from airinfo"); //执行数据库的查找功能 res = sql.executeQuery(); System.out.println("执行操作前的数据"); while(res.next()){ String id = res.getString("air_id"); System.out.println("air_id is:"+id); String air_flight_number = res.getString("air_flight_number"); System.out.println("air_flight_number is:"+air_flight_number); String air_destination = res.getString("air_destination"); System.out.println("air_id is:"+air_destination); String air_flight_date = res.getString("air_flight_date"); System.out.println("air_flight_date is:"+air_flight_date);  } //增加一条数据 sql = con.prepareStatement("INSERT INTO airinfo(air_flight_number,air_destination,air_flight_date) VALUES(?,?,?);"); sql.setString(1, "Test"); sql.setString(2, "BJ"); sql.setString(3, "2014-12-24"); sql.executeUpdate();  //删除一条数据 sql = con.prepareStatement("DELETE FROM airinfo WHERE air_id = ?"); sql.setInt(1, 1); sql.executeUpdate();  //改 sql = con.prepareStatement("update airinfo set air_flight_date = ? WHERE air_id = ?"); sql.setString(1, "2222-02-22"); sql.setInt(2,5); sql.executeUpdate();  //执行数据库的查找功能 sql = con.prepareStatement("select * from airinfo"); res = sql.executeQuery(); System.out.println("执行操作后的数据"); while(res.next()){ String id = res.getString("air_id"); System.out.println("air_id is:"+id); String air_flight_number = res.getString("air_flight_number"); System.out.println("air_flight_number is:"+air_flight_number); String air_destination = res.getString("air_destination"); System.out.println("air_id is:"+air_destination); String air_flight_date = res.getString("air_flight_date"); System.out.println("air_flight_date is:"+air_flight_date);  }} catch (SQLException e) {e.printStackTrace();}}//连接数据库的工具类private Connection getConnection() {try {//连接数据库//加载数据库Class.forName("com.mysql.jdbc.Driver");con = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/air?useUnicode=true&characterEncoding=UTF-8", "root", "root");System.out.println("数据库加载成功");} catch (ClassNotFoundException e) {e.printStackTrace();} catch (SQLException e) {e.printStackTrace();}return con;}}

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