一、实现代码
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 DBUtil {
private static final String DRIVER = "com.mysql.jdbc.Driver";
private static final String URL = "jdbc:mysql://localhost:3306/databasename?";
private static final String USER = "root";
private static final String PASSWORD = "123456";
// 静态加载驱动
static {
try {
Class.forName(DRIVER);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
// 把连接对象赋给类属性,以避免重复连接
public static Connection conn = getConnection();
// 连接jdbc
private static Connection getConnection() {
Connection conn = null;
try {
conn = DriverManager.getConnection(URL, USER, PASSWORD);
System.out.println("MySQL数据库连接成功!");
} catch (SQLException e) {
e.printStackTrace();
}
return conn;
}
// 关闭连接对象
public static boolean closeAll(ResultSet rs, PreparedStatement ps, Statement st, Connection conn) {
boolean flag = false;
try {
if(rs != null) {
rs.close();
}if(ps != null) {
ps.close();
}if(st != null) {
st.close();
}if(conn != null) {
conn.close();
}flag = true;
} catch (SQLException e) {
e.printStackTrace();
} finally {
// 即使抛出异常,GC也会对null对象快速回收
rs = null;
ps = null;
st = null;
conn = null;
}
return flag;
}
public static void main(String[] args) {
}
}
二、前置条件
1、MySQL连接jar包
<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.47</version>
</dependency>
2、MySQL数据库配置
(1)账户密码 (2)数据库名
三、运行结果