仿照hibernate封装的一个对数据库操作的jdbc工具类

package project02_Order_management.util;

import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;

/**
 * 封装对数据库进行--连接/增/删/改/查/
 * 
 * @author MartinDong
 * 
 * @param <T>
 *            要操作的数据对象
 */
public class BaseDAOUtil<T> {
	/**
	 * 声明数据库连接对象
	 */
	private static Connection connection;
	/**
	 * 声明预处理对象
	 */
	private static PreparedStatement preparedStatement;
	/**
	 * 声明sql语句返回结果集对象
	 */
	private static ResultSet resultSet;

	/**
	 * 载入默认的configuration.properties资源文件
	 * 
	 * @return
	 */
	public static Properties getProperties() {
		return getProperties(null);
	}

	/**
	 * 载入资源文件
	 * 
	 * @param propertyName
	 *            传入要载入的资源文件名称称;
	 * @return properties 返回一个属性配置对象
	 */
	public static Properties getProperties(String propertyName) {
		/**
		 * 设置配置资源文件的默认文件名称
		 */
		if (propertyName == null) {
			propertyName = "configuration.properties";
		}
		/**
		 * 声明属性文件类,读取配置使用
		 */
		Properties properties = new Properties();
		try {
			/**
			 * currentThread()是Thread的一个静态方法。返回的是当前的进程对象
			 */
			properties.load(Thread.currentThread().getContextClassLoader()
					.getResourceAsStream(propertyName));
		} catch (IOException e) {
			System.out.println(propertyName + "文件载入出现错误!");
			e.printStackTrace();
		}
		return properties;
	}

	/**
	 * 获取默认的数据库连接对象
	 * 
	 * @return
	 */
	public static Connection getConnection() {
		return getConnection(getProperties());
	}

	/**
	 * 获取数据库连接对象
	 * 
	 * @param properties
	 *            传入已经配置好的属性配置对象;
	 * @return <b>connection</b> 数据库连接对象
	 */
	public static Connection getConnection(Properties properties) {
		if (connection == null) {
			/**
			 * 载入数据库驱动文件
			 */
			try {
				Class.forName(properties.getProperty("jdbc.driver"));
				/**
				 * 创建数据库连接对象
				 */
				try {
					connection = DriverManager.getConnection(
							properties.getProperty("jdbc.url"),
							properties.getProperty("jdbc.user"),
							properties.getProperty("jdbc.password"));
					System.out.println("数据库连接成功>>>>>>>>>>>");
				} catch (SQLException e) {
					System.out.println("数据库连接參数错误!");
					e.printStackTrace();
				}
			} catch (ClassNotFoundException e) {
				System.out.println("缺少数据库驱动文件:"
						+ properties.getProperty("jdbc.driver") + "!");
				e.printStackTrace();
			}
		}
		return connection;
	}

	/**
	 * 释放资源的方法;<br>
	 * 
	 * @param releaseSet
	 * @param preparedStatement
	 * @param connection
	 */
	public static void release(ResultSet releaseSet,
			PreparedStatement preparedStatement, Connection connection) {
		if (releaseSet != null) {
			try {
				releaseSet.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if (preparedStatement != null) {
			try {
				preparedStatement.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
		if (connection != null) {
			try {
				connection.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}
	}

	// /////////////////////////////////CRUD基础业务/////////////////////////////
	/**
	 * 採用默认的连接,而且数据库表名与实体类名一致[不区分大写和小写]
	 * 
	 * @param entity
	 * @throws SQLException
	 * @throws InvocationTargetException
	 * @throws IllegalArgumentException
	 * @throws IllegalAccessException
	 */
	public void save(T entity) throws IllegalAccessException,
			IllegalArgumentException, InvocationTargetException, SQLException {
		save(entity, getConnection());
	}

	/**
	 * 採用数据库表名与实体类名一致[不区分大写和小写]外部传入数据库连接;
	 * 
	 * @param entity
	 * @param connection
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public void save(T entity, Connection connection)
			throws IllegalAccessException, IllegalArgumentException,
			InvocationTargetException, SQLException {
		save(entity, connection, null);
	}

	/**
	 * 将实体存入数据库
	 * 
	 * @param entity
	 *            要操作的数据对象
	 * @param connection
	 *            传数据库连接
	 * @param tableName
	 *            要操作的表的名称,假设传入null,则对传入的对象名称一致的表进行操作
	 * @throws SQLException
	 * @throws InvocationTargetException
	 * @throws IllegalArgumentException
	 * @throws IllegalAccessException
	 */
	public void save(T entity, Connection connection, String tableName)
			throws SQLException, IllegalAccessException,
			IllegalArgumentException, InvocationTargetException {
		/**
		 * 获取操作实体的类型
		 */
		Class<? extends Object> clazz = entity.getClass();
		/**
		 * 获取传入实体的全部公开的方法;
		 */
		Method[] methods = clazz.getDeclaredMethods();
		/**
		 * 获取传入实体中的全部公开的的属性
		 */
		Field[] fields = clazz.getDeclaredFields();
		/**
		 * 假设没有输入指定的数据表名酒採用类名进行操作
		 */
		if (tableName == null) {
			tableName = clazz.getSimpleName().toLowerCase();
		}
		/**
		 * 拼接类中的属性字段,即数据表中的字段名
		 */
		String fieldsName = "";
		/**
		 * 占位符的设置
		 */
		String placeholder = "";
		for (int i = 0; i < fields.length; i++) {
			fieldsName = fieldsName + fields[i].getName() + ",";
			placeholder = placeholder + "?" + ",";
		}
		/**
		 * 去除多余的标点
		 */
		fieldsName = fieldsName.substring(0, fieldsName.length() - 1);
		placeholder = placeholder.substring(0, placeholder.length() - 1);
		/**
		 * 拼接sql语句
		 */
		String sql = "insert into " + tableName + "(" + fieldsName + ")"
				+ " values " + "(" + placeholder + ")";
		System.out.println(sql);

		/**
		 * 预编译sql语句
		 */
		PreparedStatement pst = connection.prepareStatement(sql);
		/**
		 * 给预编译语句赋值
		 */
		int index = 1;
		for (int j = 0; j < fields.length; j++) {
			String str = "get" + fields[j].getName();
			/**
			 * 循环方法名比对
			 */
			for (int k = 0; k < methods.length; k++) {
				/**
				 * 假设当前的属性拼出的get方法名,与方法明集合中的有一样的运行
				 */
				if (str.equalsIgnoreCase(methods[k].getName())) {
					/**
					 * 接收指定的方法运行后的数据
					 */
					Object propertyObj = methods[k].invoke(entity);
					/**
					 * 为指定的占位符进行赋值
					 */
					pst.setObject(index++, propertyObj);
				}
			}
		}
		/**
		 * 运行已经载入的sql语句
		 */
		pst.executeUpdate();
	}

	/**
	 * 使用默认的数据库连接进行删除,传入的对象
	 * 
	 * @param entity
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public void delete(T entity) throws IllegalAccessException,
			IllegalArgumentException, InvocationTargetException, SQLException {
		deleteById(entity, getConnection());
	}

	/**
	 * 使用传入的数据库连接,删除指定的对象.
	 * 
	 * @param entity
	 * @param connection
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public void deleteById(T entity, Connection connection)
			throws IllegalAccessException, IllegalArgumentException,
			InvocationTargetException, SQLException {

		delete(entity, connection, null);
	}

	/**
	 * 
	 * @param entity
	 *            传入操作的对象实体
	 * @param connection
	 *            传入数据库连接对象
	 * @param id
	 *            要删除数据的id
	 * @param tableName
	 *            要操作的表的名称,假设传入null,则对传入的对象名称一致的表进行操作
	 * @throws SQLException
	 * @throws InvocationTargetException
	 * @throws IllegalArgumentException
	 * @throws IllegalAccessException
	 * 
	 */
	public void delete(T entity, Connection connection, String tableName)
			throws SQLException, IllegalAccessException,
			IllegalArgumentException, InvocationTargetException {
		Class<? extends Object> clazz = entity.getClass();
		Method[] methods = clazz.getDeclaredMethods();
		Field[] fields = clazz.getDeclaredFields();
		if (tableName == null) {
			tableName = clazz.getSimpleName().toLowerCase();
		}
		String sql = "delete from " + tableName + " where id=?";
		System.out.println(sql);
		PreparedStatement pst = connection.prepareStatement(sql);

		Object id = null;
		for (int i = 0; i < fields.length; i++) {
			for (int j = 0; j < methods.length; j++) {
				if ("getId".equalsIgnoreCase(methods[j].getName())) {
					id = methods[j].invoke(entity);
				}
			}
		}
		pst.setObject(1, id);
		pst.executeUpdate();
	}

	/**
	 * 使用默认的数据库连接改动传入的对象.
	 * 
	 * @param entity
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public void update(T entity) throws IllegalAccessException,
			IllegalArgumentException, InvocationTargetException, SQLException {
		update(entity, getConnection());
	}

	/**
	 * 使用传入的数据库连接进行数据库改动;
	 * 
	 * @param entity
	 * @param connection
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public void update(T entity, Connection connection)
			throws IllegalAccessException, IllegalArgumentException,
			InvocationTargetException, SQLException {
		update(entity, connection, null);
	}

	/**
	 * 
	 * @param entity
	 *            传入操作的对象实体
	 * @param connection
	 *            传入数据库连接对象
	 * @param tableName
	 *            要操作的表的名称,假设传入null,则对传入的对象名称一致的表进行操作
	 * @throws InvocationTargetException
	 * @throws IllegalArgumentException
	 * @throws IllegalAccessException
	 * @throws SQLException
	 */
	public void update(T entity, Connection connection, String tableName)
			throws IllegalAccessException, IllegalArgumentException,
			InvocationTargetException, SQLException {
		Class<? extends Object> clazz = entity.getClass();
		Method[] methods = clazz.getDeclaredMethods();
		Field[] fields = clazz.getDeclaredFields();
		if (tableName == null) {
			tableName = clazz.getSimpleName().toLowerCase();
		}
		String fieldsName = "";
		// 创建id字段的默认数据
		Object id = 1;
		// 循环遍历以获取的公开的属性
		for (int i = 0; i < fields.length; i++) {
			// 嵌套循环,比較公开属性名经过拼接后和公开的方法名进行匹配
			for (int j = 0; j < methods.length; j++) {
				// 使用属性名+get进行拼接
				String getFieldName = "get" + fields[i].getName();
				if (getFieldName.equalsIgnoreCase(methods[j].getName())) {
					// 拼接更行sql语句中的set字段,并用占位符
					fieldsName = fieldsName + fields[i].getName() + "=?
,";
				}
				// 获取id字段的值
				if ("getId".equalsIgnoreCase(methods[j].getName())) {
					id = methods[j].invoke(entity);
				}
			}
		}
		fieldsName = fieldsName.substring(0, fieldsName.length() - 1);
		String sql = "update " + tableName + " set " + fieldsName
				+ " where id=?";
		System.out.println(sql);
		PreparedStatement pst = connection.prepareStatement(sql);
		int index = 1;
		for (int j = 0; j < fields.length; j++) {
			String str = "get" + fields[j].getName();
			// 循环方法名比对
			for (int k = 0; k < methods.length; k++) {
				// 假设当前的属性拼出的get方法名,与方法明集合中的有一样的运行
				if (str.equalsIgnoreCase(methods[k].getName())) {
					// 接收指定的方法运行后的数据
					Object propertyObj = methods[k].invoke(entity);
					// 为指定的占位符进行赋值
					pst.setObject(index++, propertyObj);
				}
			}
		}
		pst.setObject(index++, id);
		pst.execute();
	}

	/**
	 * 使用默认的数据库连接查询指定的id数据
	 * 
	 * @param entity
	 * @param id
	 * @return
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public T findById(T entity, Integer id) throws InstantiationException,
			IllegalAccessException, IllegalArgumentException,
			InvocationTargetException, SQLException {
		return findById(entity, null, id);
	}

	/**
	 * 
	 * 使用传入的数据库连接以及传入的id查询数据;
	 * 
	 * @param entity
	 * @param connection
	 * @param id
	 * @return
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public T findById(T entity, Connection connection, Integer id)
			throws InstantiationException, IllegalAccessException,
			IllegalArgumentException, InvocationTargetException, SQLException {
		return findById(entity, connection, id, null);
	}

	/**
	 * 
	 * 依据id查询数据
	 * 
	 * @param entity
	 *            查询的实体对象
	 * @param connection
	 *            数据库连接对象
	 * @param id
	 *            查询的id
	 * @param tableName
	 *            操作的数据库表名
	 * @return 返回一个查询结果对象
	 * @throws SQLException
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 */
	public T findById(T entity, Connection connection, Integer id,
			String tableName) throws SQLException, InstantiationException,
			IllegalAccessException, IllegalArgumentException,
			InvocationTargetException {
		Class<? extends Object> clazz = entity.getClass();
		Method[] methods = clazz.getDeclaredMethods();
		Field[] fields = clazz.getDeclaredFields();
		// 声明查询的结果对象
		T resultObject = null;
		if (tableName == null) {
			tableName = clazz.getSimpleName().toLowerCase();
		}
		String sql = "select * from " + tableName + " where id=?
";
		System.out.println(sql);
		PreparedStatement pst = connection.prepareStatement(sql);
		pst.setObject(1, id);
		ResultSet resultSet = pst.executeQuery();
		if (resultSet.next()) {
			resultObject = (T) clazz.newInstance();
			for (int i = 0; i < fields.length; i++) {
				String fieldName = fields[i].getName();

				Object fieldObject = resultSet.getObject(i + 1);
				if (fieldObject == null) {
					fieldObject = "null";// 防止数据为null时引发空指针异常
				}
				for (int j = 0; j < methods.length; j++) {
					if (("set" + fieldName).equalsIgnoreCase(methods[j]
							.getName())) {
						methods[j].invoke(resultObject,
								resultSet.getObject(fieldName));
					}
				}
			}
		}
		return resultObject;
	}

	/**
	 * 使用默认的数据库连接进行数据查询
	 * 
	 * @param entity
	 * @return
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public List<T> findAll(T entity) throws InstantiationException,
			IllegalAccessException, IllegalArgumentException,
			InvocationTargetException, SQLException {
		return findAll(entity, getConnection());
	}

	/**
	 * 使用传入的数据库连接进行数据查询
	 * 
	 * @param entity
	 * @param connection
	 * @return
	 * @throws InstantiationException
	 * @throws IllegalAccessException
	 * @throws IllegalArgumentException
	 * @throws InvocationTargetException
	 * @throws SQLException
	 */
	public List<T> findAll(T entity, Connection connection)
			throws InstantiationException, IllegalAccessException,
			IllegalArgumentException, InvocationTargetException, SQLException {
		return findAll(entity, connection, null);
	}

	/**
	 * 查询数据表全部的数据
	 * 
	 * @param entity
	 *            查询的实体对象
	 * @param connection
	 *            数据库连接对象
	 * @param tableName
	 *            操作的数据库表名
	 * @return
	 * @throws SQLException
	 * @throws IllegalAccessException
	 * @throws InstantiationException
	 * @throws InvocationTargetException
	 * @throws IllegalArgumentException
	 */
	public List<T> findAll(T entity, Connection connection, String tableName)
			throws SQLException, InstantiationException,
			IllegalAccessException, IllegalArgumentException,
			InvocationTargetException {
		Class<? extends Object> clazz = entity.getClass();
		Method[] methods = clazz.getDeclaredMethods();
		Field[] fields = clazz.getDeclaredFields();
		// 声明查询的结果对象
		List<T> resultObjects = new ArrayList<T>();
		if (tableName == null) {
			tableName = clazz.getSimpleName().toLowerCase();
		}
		String sql = "select * from " + tableName;
		System.out.println(sql);
		PreparedStatement pst = connection.prepareStatement(sql);
		ResultSet resultSet = pst.executeQuery();
		while (resultSet.next()) {
			T resultObject = (T) clazz.newInstance();
			for (int i = 0; i < fields.length; i++) {
				String fieldName = fields[i].getName();
				Object fieldObject = resultSet.getObject(i + 1);
				if (fieldObject == null) {
					fieldObject = "null";
				}
				for (int j = 0; j < methods.length; j++) {
					if (("set" + fieldName).equalsIgnoreCase(methods[j]
							.getName())) {
						methods[j].invoke(resultObject,
								resultSet.getObject(fieldName));
					}

				}
			}
			resultObjects.add(resultObject);
		}
		return resultObjects;
	}

	public List<T> query(T entity, Connection connection, String tableName,
			String sql) {

		return null;
	}

	/**
	 * 一个须要用户手动输入sql和參数语句的:增/删/改/的操作
	 * 
	 * @param sql
	 * @param args
	 * @return
	 */
	public static int upDate(String sql, Object[] args) {
		try {
			preparedStatement = getConnection().prepareStatement(sql);
			for (int i = 1; i <= args.length; i++) {
				preparedStatement.setObject(i, args[i - 1]);
			}
			return preparedStatement.executeUpdate();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return 0;
	}

	/**
	 * 传入自己定义的sql语句和參数进行查询;
	 * 
	 * @param sql
	 *            sql语句
	 * @param args
	 *            传入的參数条件
	 * @return 返回一个set集合
	 */
	public static ResultSet getObject(String sql, Object[] args) {
		System.out.println(sql);
		try {
			preparedStatement = JDBCUtil.getConnection().prepareStatement(sql);
			if (args != null) {
				for (int i = 1; i <= args.length; i++) {
					preparedStatement.setObject(i, args[i - 1]);
				}
			}
			resultSet = preparedStatement.executeQuery();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return resultSet;
	}

}

configuration.properties配置文件

jdbc.url=jdbc:mysql://localhost:3306/order_manager
jdbc.user=root
jdbc.password=admin
jdbc.driver=com.mysql.jdbc.Driver