jdbc工具类的封装:
package com.hyc.study02.utils;
import java.io.InputStream;
import java.sql.*;
import java.util.Properties;
public class JDBCUtils {
private static String driver = null;
private static String url = null;
private static String username = null;
private static String psw = null;
static {
try {
InputStream inputStream = JDBCUtils.class.getClassLoader().getResourceAsStream("db.properties");
Properties properties = new Properties();
properties.load(inputStream);
driver = properties.getProperty("driver");
//2、获取用户信息、url
url = properties.getProperty("url");
username = properties.getProperty("username");
psw = properties.getProperty("psw");
//驱动只用加载一次
//1、加载驱动
Class.forName(driver);
} catch (Exception e) {
e.printStackTrace();
}
}
//获取连接
public static Connection getConnection() throws SQLException {
return DriverManager.getConnection(url, username, psw);
}
//释放连接
public static void release(Connection connection, Statement statement, ResultSet resultSet) {
if (resultSet != null) {
try {
resultSet.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (statement != null) {
try {
statement.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
if (connection != null) {
try {
connection.close();
} catch (SQLException throwables) {
throwables.printStackTrace();
}
}
}
}
插入数据测试:
package com.hyc.study02;
import com.hyc.study02.utils.JDBCUtils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestInsert {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
//3、获取数据库连接
connection = JDBCUtils.getConnection();
//4、创建执行sql的对象
statement = connection.createStatement();
//5、执行sql语句
//6、返回执行结果集
String sql = "INSERT INTO `users`(`id`,`NAME`,`PASSWORD`,`email`,`birthday`) " +
"VALUES (4,'hyc','123456','1404733494@qq.com','2022-04-18')";
int num = statement.executeUpdate(sql);
if (num > 0) {
System.out.println("插入数据成功!");
}
} catch (SQLException throwables) {
throwables.printStackTrace();
} finally {
//7、释放连接
JDBCUtils.release(connection, statement, resultSet);
}
}
}
删除数据测试:
package com.hyc.study02;
import com.hyc.study02.utils.JDBCUtils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestDelete {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
//3、获取数据库连接
connection = JDBCUtils.getConnection();
//4、创建执行sql的对象
statement = connection.createStatement();
//5、执行sql语句
//6、返回执行结果集
String sql = "DELETE FROM `users` WHERE id=4";
int num = statement.executeUpdate(sql);
if (num > 0) {
System.out.println("删除数据成功!");
}
} catch (SQLException throwables) {
throwables.printStackTrace();
} finally {
//7、释放连接
JDBCUtils.release(connection, statement, resultSet);
}
}
}
修改数据测试:
package com.hyc.study02;
import com.hyc.study02.utils.JDBCUtils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestUpdate {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
//3、获取数据库连接
connection = JDBCUtils.getConnection();
//4、创建执行sql的对象
statement = connection.createStatement();
//5、执行sql语句
//6、返回执行结果集
String sql = "UPDATE `users` SET `NAME`='zxzb',`email`='1135656@qq.com' WHERE `id`=1";
int num = statement.executeUpdate(sql);
if (num > 0) {
System.out.println("更新数据成功");
}
} catch (SQLException throwables) {
throwables.printStackTrace();
} finally {
//7、释放连接
JDBCUtils.release(connection, statement, resultSet);
}
}
}
查询数据测试:
package com.hyc.study02;
import com.hyc.study02.utils.JDBCUtils;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class TestSelect {
public static void main(String[] args) {
Connection connection = null;
Statement statement = null;
ResultSet resultSet = null;
try {
//3、获取数据库连接
connection = JDBCUtils.getConnection();
//4、创建执行sql的对象
statement = connection.createStatement();
//5、执行sql语句
//6、返回执行结果集
String sql = "SELECT * FROM `users` WHERE id=1";
resultSet = statement.executeQuery(sql);
while (resultSet.next()) {
System.out.println(resultSet.getInt("id"));
System.out.println(resultSet.getString("NAME"));
System.out.println(resultSet.getString("PASSWORD"));
System.out.println(resultSet.getString("email"));
System.out.println(resultSet.getDate("birthday"));
}
} catch (SQLException throwables) {
throwables.printStackTrace();
} finally {
//7、释放连接
JDBCUtils.release(connection, statement, resultSet);
}
}
}