自定义的jdbc连接工具类JDBCUtils【java 工具类】

package com.test.utils;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public final class JDBCUtils {
    private static String driver="com.mysql.jdbc.Driver";
    private static String url="jdbc:mysql://localhost:3306/store28";
    private static String user="root";
    private static String password="root1234";
    
    private JDBCUtils(){}
    
    static {
        /**
         * 驱动注册
         */
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            throw new ExceptionInInitializerError(e);
        }
        
    }
    
    /**
     * 获取 Connetion
     * @return
     * @throws SQLException
     */
    public static Connection getConnection() throws SQLException{
        return DriverManager.getConnection(url, user, password);
    }
    
    /**
     * 释放资源
     * @param conn
     * @param st
     * @param rs
     */
    public static void colseResource(Connection conn,Statement st,ResultSet rs) {
        closeResultSet(rs);
        closeStatement(st);
        closeConnection(conn);
    }
    
    /**
     * 释放连接 Connection
     * @param conn
     */
    public static void closeConnection(Connection conn) {
        if(conn !=null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        //等待垃圾回收
        conn = null;
    }
    
    /**
     * 释放语句执行者 Statement
     * @param st
     */
    public static void closeStatement(Statement st) {
        if(st !=null) {
            try {
                st.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        //等待垃圾回收
        st = null;
    }
    
    /**
     * 释放结果集 ResultSet
     * @param rs
     */
    public static void closeResultSet(ResultSet rs) {
        if(rs !=null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        //等待垃圾回收
        rs = null;
    }
}

package com.test.utils;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import org.junit.Test;

public class JdbcTest {
    @Test
    public void add() {
        Connection conn = null;
        PreparedStatement st = null;
        ResultSet rs = null;
        
        try {
            // 获取连接
            conn = JDBCUtils.getConnection();
            
            // 编写sql
            String sql = "insert into category values (?,?)";
            
            // 创建语句执行者
            st= conn.prepareStatement(sql);
            
            //设置参数
            st.setString(1, "10");
            st.setString(2, "测试目录");
            
            // 执行sql
            int i = st.executeUpdate();
            
            if(i==1) {
                System.out.println("数据添加成功！");
            }else {
                System.out.println("数据添加失败！");
            }
            
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            JDBCUtils.colseResource(conn, st, rs);
        }
        
    }
}