1、jdbc连接步骤
package cn.jdbc;
import java.sql.Connection;
import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.Statement;
public class Demo1 {
public static void main(String[] args) throws Exception {
//注册驱动(可省略)
Class.forName("com.mysql.jdbc.Driver");
//定义sql语句
String sql = "update stu set salary = 500 where id = 2";
//获取Connection对象
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/db1", "root", "");
//获取执行sql的对象Statement
Statement stmt = conn.createStatement();
//执行sql,返回的是影响的行数
int count = stmt.executeUpdate(sql);
System.out.println(count);
stmt.close();
conn.close();
}
}
2、添加数据库表中数据
package cn.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Demo2 {
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try {
Class.forName("com.mysql.jdbc.Driver");
String sql = "insert into stu values(null, '狗狗', 3000)";
conn = DriverManager.getConnection("jdbc:mysql:///db1", "root", "");
stmt = conn.createStatement();
int count = stmt.executeUpdate(sql);
System.out.println(count);
if (count > 0) System.out.println("添加成功");
else System.out.println("添加失败");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
3、修改表中信息
package cn.jdbc;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;
public class Demo3 {
public static void main(String[] args) {
Connection conn = null;
Statement stmt = null;
try {
//1.注册驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获取连接对象
conn = DriverManager.getConnection("jdbc:mysql:///db1", "root", "");
//3.定义sql
String sql = "update stu set salary = 1500 where id = 4";
//4.获取执行sql对象
stmt = conn.createStatement();
//5.执行sql
int count = stmt.executeUpdate(sql);
//6.处理结果
System.out.println(count);
if (count > 0) System.out.println("修改成功");
else System.out.println("修改失败");
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
} finally {
//7.释放资源,防止空指针异常
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
if (conn != null) {
try {
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}