Java连接MySQL数据库及简单操作代码_MySQL
1.Java连接MySQL数据库
Java连接MySql需要下载JDBC驱动MySQL-connector-java-5.0.5.zip（举例，现有新版本）。然后将其解压缩到任一目录。我是解压到D盘，然后将其目录下的MySQL-connector-java-5.0.5-bin.jar加到classpath里，具体如下：
“我的电脑”-> “属性” -> “高级” -> “环境变量”，在系统变量那里编辑classpath，将D:/MySQL-connector-java-5.0.5/MySQL-connector-java-5.0.5-bin.jar加到最后，在加这个字符串前要加“;”，以与前一个classpath区分开。然后确定。
package hqs;import java.sql.*;public class DataBasePractice { public static void main(String[] args) { //声明Connection对象 Connection con; //驱动程序名 String driver = "com.mysql.jdbc.Driver"; //URL指向要访问的数据库名mydata String url = "jdbc:mysql://localhost:3306/mydata"; //MySQL配置时的用户名 String user = "root"; //MySQL配置时的密码 String password = "root"; //遍历查询结果集 try { //加载驱动程序 Class.forName(driver); //1.getConnection()方法，连接MySQL数据库！！ con = DriverManager.getConnection(url,user,password); if(!con.isClosed()) System.out.println("Succeeded connecting to the Database!"); //2.创建statement类对象，用来执行SQL语句！！ Statement statement = con.createStatement(); //要执行的SQL语句 String sql = "select * from student"; //3.ResultSet类，用来存放获取的结果集！！ ResultSet rs = statement.executeQuery(sql); System.out.println("-----------------"); System.out.println("执行结果如下所示:"); System.out.println("-----------------"); System.out.println(" 学号" + "/t" + " 姓名"); System.out.println("-----------------"); String name = null; String id = null; while(rs.next()){ //获取stuname这列数据 name = rs.getString("stuname"); //获取stuid这列数据 id = rs.getString("stuid"); //首先使用ISO-8859-1字符集将name解码为字节序列并将结果存储新的字节数组中。 //然后使用GB2312字符集解码指定的字节数组。 name = new String(name.getBytes("ISO-8859-1"),"gb2312"); //输出结果 System.out.println(id + "/t" + name); } rs.close(); con.close(); } catch(ClassNotFoundException e) { //数据库驱动类异常处理 System.out.println("Sorry,can`t find the Driver!"); e.printStackTrace(); } catch(SQLException e) { //数据库连接失败异常处理 e.printStackTrace(); }catch (Exception e) { // TODO: handle exception e.printStackTrace(); }finally{ System.out.println("数据库数据成功获取！！"); } }}2.添加、修改、删除操作
在上面while代码段后面添加以下代码段：
String name = null; String id = null; while(rs.next()){ //获取stuname这列数据 name = rs.getString("stuname"); //获取stuid这列数据 id = rs.getString("stuid"); //首先使用ISO-8859-1字符集将name解码为字节序列并将结果存储新的字节数组中。 //然后使用GB2312字符集解码指定的字节数组。 name = new String(name.getBytes("ISO-8859-1"),"gb2312"); //输出结果 System.out.println(id + "/t" + name); } PreparedStatement psql; ResultSet res; //预处理添加数据，其中有两个参数--“？” psql = con.prepareStatement("insert into student values(?,?)"); psql.setInt(1, 8); //设置参数1，创建id为5的数据 psql.setString(2, "xiaogang"); //设置参数2，name 为小明 psql.executeUpdate(); //执行更新 //预处理更新（修改）数据 psql = con.prepareStatement("update student set stuname = ? where stuid = ?"); psql.setString(1,"xiaowang"); //设置参数1，将name改为王五 psql.setInt(2,10); //设置参数2，将id为2的数据做修改 psql.executeUpdate(); //预处理删除数据 psql = con.prepareStatement("delete from student where stuid = ?"); psql.setInt(1, 5); psql.executeUpdate(); //查询修改数据后student表中的数据 psql = con.prepareStatement("select*from student"); res = psql.executeQuery(); //执行预处理sql语句 System.out.println("执行增加、修改、删除后的数据"); while(res.next()){ name = res.getString("stuname"); id = res.getString("stuid"); name = new String(name.getBytes("ISO-8859-1"),"gb2312"); System.out.println(id + "/t" + name); } res.close(); psql.close();con.prepareStatement(String sql);
这样生成数据库底层的内部命令，并将该命令封装在preparedStatement对象中，可以减轻数据库负担，提高访问数据库速度。
运行结果：
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