Java DButils 封装工具类

落日映苍穹つ 2024-03-23 12:33 85阅读 0赞

一、含有的功能

(1) 获取连接数据库的对象

(2) 关闭资源

(3) 开启手动提交事务

(4) 回滚事务

(5) 提交事务

package com.bdqn.utils;
    
    import java.io.IOException;
    import java.io.InputStream;
    import java.sql.*;
    import java.util.Properties;
    
    public class DBUtilsPlus {
        // 使用Properties类对象操作properties文件
        private final static Properties PROPERTIES = new Properties();
    
        //  定义一个ThreadLocal<Connection>对象存放数据库连接对象
        private final static ThreadLocal<Connection> threadLocal = new ThreadLocal<>();
    
        // 使用静态代码块注册驱动
        static {
            // 通过复用本类自带流，读取配置文件中的数据
            InputStream is = DBUtilsPlus.class.getResourceAsStream("/jdbc.properties");
    
            try {
                // 通过prop对象将流中的配置信息分隔成键值对,将配置文件内容加载到properties集合
                PROPERTIES.load(is);
                // 注册驱动，通过driverName的键获取对应的值（com.mysql.jdbc.Driver）
                Class.forName(PROPERTIES.getProperty("driver"));
            } catch (IOException | ClassNotFoundException e) {
                e.printStackTrace();
            }
        }
    
        /**
         * 获取连接对象的方法
         *
         * @return
         */
        public static Connection getConnection() {
            // 从ThreadLocal对象中获取connection连接对象
            Connection connection = threadLocal.get();
            // 如果为空 则创建
            if (connection == null) {
                try {
                    connection = DriverManager.getConnection(
                            PROPERTIES.getProperty("url"),
                            PROPERTIES.getProperty("user"),
                            PROPERTIES.getProperty("password")
                    );
                    // 将获取的连接对象存放ThreadLocal中
                    threadLocal.set(connection);
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            return connection;
        }
    
    
        /**
         * 关闭资源
         *
         * @param resultSet  存放执行SQL语句的结果集合
         * @param connection 连接数据库对象
         * @param statement  发送SQL对象
         */
        public static void closeAll(ResultSet resultSet, Connection connection, Statement statement) {
            if (resultSet != null) {
                try {
                    resultSet.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            if (connection != null) {
                try {
                    connection.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
            if (statement != null) {
                try {
                    statement.close();
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        }
    
    
        /**
         * 开启手动提交事务
         */
        public static void startTransaction() {
            Connection connection = null;
            try {
                connection = getConnection();
                connection.setAutoCommit(false);
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    
    
        /**
         * 提交事务
         */
        public static void commitTransaction() {
            Connection connection = getConnection();
            try {
                connection.commit();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally {
                DBUtils.closeAll(null, connection, null);
            }
        }
    
    
        /**
         * 回滚事务
         */
        public static void rollbackTransaction() {
            Connection connection = getConnection();
            try {
                connection.rollback();
            } catch (SQLException e) {
                e.printStackTrace();
            } finally {
                DBUtils.closeAll(null, connection, null);
            }
        }
    }