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;/** * 加载默认的configuration.properties资源文件 *  * @return */public static Properties getProperties() {return getProperties(null);}/** * 加载资源文件 *  * @param propertyName *            传入要加载的资源文件名称; * @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 */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 + "文件加载出现错误!");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) {/** * 加载数据库驱动文件 */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("数据库连接参数错误!");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//////////////////////////////** * 采用默认的连接,并且数据库表名与实体类名一致[不区分大小写] *  * @param entity * @throws SQLException * @throws InvocationTargetException * @throws IllegalArgumentException * @throws IllegalAccessException */public void save(T entity) throws IllegalAccessException,IllegalArgumentException, InvocationTargetException, SQLException {save(entity, getConnection());}/** * 采用数据库表名与实体类名一致[不区分大小写]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,如果传入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();/** * 获取传入实体的所有公开的方法; */Method[] methods = clazz.getDeclaredMethods();/** * 获取传入实体中的所有公开的的属性 */Field[] fields = clazz.getDeclaredFields();/** * 如果没有输入指定的数据表名酒采用类名进行操作 */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++) {/** * 如果当前的属性拼出的get方法名,与方法明集合中的有一样的执行 */if (str.equalsIgnoreCase(methods[k].getName())) {/** * 接收指定的方法执行后的数据 */Object propertyObj = methods[k].invoke(entity);/** * 为指定的占位符进行赋值 */pst.setObject(index++, propertyObj);}}}/** * 执行已经加载的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,如果传入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修改传入的对象. *  * @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修改; *  * @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,如果传入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,比较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++) {// 如果当前的属性拼出的get方法名,与方法明集合中的有一样的执行if (str.equalsIgnoreCase(methods[k].getName())) {// 接收指定的方法执行后的数据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);}/** *  * 根据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);}/** * 查询数据表所有的数据 *  * @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;}/** * 一个需要用户手动输入sql和参数语句的: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 blocke.printStackTrace();}return 0;}/** * 传入自定义的sql语句和参数进行查询; *  * @param sql *            sql语句 * @param args *            传入的参数条件 * @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 blocke.printStackTrace();}return resultSet;}}

configuration.properties配置文件

jdbc.url=jdbc\:mysql\://localhost\:3306/order_managerjdbc.user=rootjdbc.password=adminjdbc.driver=com.mysql.jdbc.Driver