Similar to a jdbc tool class encapsulated by hibernate for database operations

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. properti Es; /*** encapsulate the database-connection/Add/delete/modify/query/** @ author MartinDong ** @ param <T> * data object to be operated */public class BaseDAOUtil <T> {/*** declares the database Connection object */private static connection Connection; /*** declare the preprocessing object */private static PreparedStatement preparedStatement;/*** declare the SQL statement to return the result set object */private static ResultSet resultSet; /*** load the default configuration. properties resource file ** @ return */public static Properties getProperties () {return getPro Perties (null);}/*** load resource file *** @ param propertyName * input the name of the resource file to be loaded; * @ return properties returns a property configuration object */public static Properties getProperties (String propertyName) {/*** sets the default file name of the configuration resource file */if (propertyName = null) {propertyName = "configuration. properties ";}/*** declares the attribute File class, and reads the configuration using */Properties properties = new Properties (); try {/*** currentThread () is a static method of Thread. The returned result is the current process object */properties. load (Thread. cu R0000thread (). getContextClassLoader (). getResourceAsStream (propertyName);} catch (IOException e) {System. out. println (propertyName + "file loading error! "); E. printStackTrace ();} return properties;}/*** get the default database Connection object ** @ return */public static Connection getConnection () {return getConnection (getProperties ();}/*** obtain the database connection object ** @ param properties * to pass in the configured property configuration object; * @ return <B> connection </B> database Connection object */public static connection getConnection (Properties properties) {if (connection = null) {/*** load the database driver file */try {Class. forName (properties. getProperty ("j Dbc. driver ");/*** create a database connection object */try {connection = DriverManager. getConnection (properties. getProperty ("jdbc. url "), properties. getProperty ("jdbc. user "), properties. getProperty ("jdbc. password "); System. out. println ("database connection succeeded >>>>>>>>>>>>");} catch (SQLException e) {System. out. println ("database connection parameter error! "); E. printStackTrace () ;}} catch (ClassNotFoundException e) {System. out. println ("the database driver file is missing:" + properties. getProperty ("jdbc. driver ") + "! "); E. printStackTrace () ;}} return connection;}/*** Method for releasing resources; <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 basic business // /// // *** use the default connection, and the database table name is consistent with the object class name [case insensitive] ** @ param entity * @ throws SQLException * @ throws InvocationTargetException * @ throws IllegalArgumentException * @ throws IllegalAccessException */public void save (T entity) throws IllegalAccessException, Illeg AlArgumentException, InvocationTargetException, SQLException {save (entity, getConnection ();}/*** use the database table name and object class name to [case insensitive] import external database connections; ** @ param entity * @ param connection * @ throws IllegalAccessException * @ throws exceptions * @ throws InvocationTargetException * @ throws SQLException */public void save (T entity, Connection connection) throws limit, illegalArgumentExcept Ion, InvocationTargetException, SQLException {save (entity, connection, null );} /*** Save the object to the database ** @ param entity * The data object to be operated * @ param connection * transfers the name of the table to be operated by the database connection * @ param tableName, if null is input, perform operations on tables with the same names as the input object * @ throws SQLException * @ throws InvocationTargetException * @ throws IllegalArgumentException * @ throws IllegalAccessException */public void save (T entity, connection connection, String tableNa Me) throws SQLException, IllegalAccessException, IllegalArgumentException, InvocationTargetException {/*** obtain the type of the operation entity */Class <? Extends Object> clazz = entity. getClass ();/*** obtain all public methods of the input object; */Method [] methods = clazz. getDeclaredMethods ();/*** get all the public attributes in the input object */Field [] fields = clazz. getDeclaredFields ();/*** use the class name if the specified data table name is not input */if (tableName = null) {tableName = clazz. getSimpleName (). toLowerCase ();}/*** attribute field in the splicing class, that is, the field name in the data table */String fieldsName = ""; /*** placeholder settings */String placeholder = ""; for (int I = 0; I <fields. Length; I ++) {fieldsName = fieldsName + fields [I]. getName () + ","; placeholder = placeholder + "? "+", ";}/*** Remove unnecessary punctuation points */fieldsName = fieldsName. substring (0, fieldsName. length ()-1); placeholder = placeholder. substring (0, placeholder. length ()-1);/*** concatenate an SQL statement */String SQL = "insert into" + tableName + "(" + fieldsName + ") "+" values "+" ("+ placeholder +") "; System. out. println (SQL);/*** precompiled SQL statement */PreparedStatement pst = connection. prepareStatement (SQL);/*** assign a value to the pre-compiled statement */int index = 1; f Or (int j = 0; j <fields. length; j ++) {String str = "get" + fields [j]. getName ();/*** compare the cyclic method name */for (int k = 0; k <methods. length; k ++) {/*** if the get method name spelled out by the current attribute is the same as that in the method description set */if (str. equalsIgnoreCase (methods [k]. getName () {/*** receives the data after the specified method is executed */Object propertyObj = methods [k]. invoke (entity);/*** assign a value to the specified placeholder */pst. setObject (index ++, propertyObj) ;}}/ *** run the loaded SQL statement */pst.exe cuteUpdate ();}/* ** Use the default database connection for deletion, the passed object ** @ param entity * @ throws IllegalAccessException * @ throws exception * @ throws InvocationTargetException * @ throws SQLException */public void delete (T entity) throws entity, entity, InvocationTargetException, SQLException {deleteById (entity, getConnection ();}/*** use the input database connection to delete the specified object. ** @ param entity * @ param connection * @ Throws interval * @ throws InvocationTargetException * @ throws SQLException */public void deleteById (T entity, Connection connection) throws interval, interval, InvocationTargetException, SQLException {delete (entity, connection, null);}/***** @ param entity * object of the input operation * @ param connection * object of the input database connection * @ param id * Id * @ param tableName * Name of the table to be operated. If null is input, perform operations on tables with the same names as the input object * @ 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, id1_1_pst.exe cuteUpdate ();}/*** use the default database connection to modify the input object. ** @ param entity * @ throws IllegalAccessException * @ throws Ill Optional * @ throws InvocationTargetException * @ throws SQLException */public void update (T entity) throws IllegalAccessException, expiration, InvocationTargetException, SQLException {update (entity, getConnection ());} /*** use the input database connection to modify the database. ** @ param entity * @ param connection * @ throws IllegalAccessException * @ throws IllegalArgumentException * @ throws InvocationTargetE Xception * @ throws SQLException */public void update (T entity, Connection connection) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException {update (entity, connection, null );} /***** @ param entity * object entity for the input operation * @ param connection * Name of the table to be operated when the input database connection object * @ param tableName * is null, perform operations on tables with the same names as the input object * @ throws InvocationTargetException * @ throws IllegalArgument Exception * @ throws IllegalAccessException * @ throws SQLException */public void update (T entity, Connection connection, String tableName) throws IllegalAccessException, expiration, 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 = ""; // create the default data Object id of the id field = 1; // obtain the public attribute for (int I = 0; I <fields. length; I ++) {// nested loop, compares public attribute names with public method names after splicing for (int j = 0; j <methods. length; j ++) {// use attribute name + get for spelling String getFieldName = "get" + fields [I]. getName (); if (getFieldName. equalsIgnoreCase (methods [j]. getName () {// concatenate the set field in a more SQL statement and use the placeholder fieldsName = fieldsName + fields [I]. getName () + "= ?, ";} // Obtain the value of the id field 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 (); // compare the names of cyclic methods for (int k = 0; k <methods. length; k ++) {// if the get Method Name of the current attribute is spelled out, the execution of if (str. equalsIgnoreCase (methods [k]. getName () {// receives the Data Object propertyObj = methods [k] after the specified method is executed. invoke (entity); // assign a value to pst for the specified placeholder. setObj Ect (index ++, propertyObj) ;}} pst. setObject (index ++, id1_1_pst.exe cute ();} /*** use the default database connection to query the specified id data ** @ 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, Illegal ArgumentException, InvocationTargetException, SQLException {return findById (entity, null, id);}/***** query data using the input database connection and input id; ** @ param entity * @ param connection * @ param id * @ return * @ throws InstantiationException * @ throws IllegalAccessException * @ throws IllegalArgumentException * @ throws InvocationTargetException * @ throws SQLException */public T findById (T entity, connection connection, In Teger id) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException {return findById (entity, connection, id, null );} /***** query data by id ** @ param entity * the object to be queried * @ param connection * database connection object * @ param id * The queried id * @ param tableName * the database table name of the operation * @ return returns a query result object * @ throws SQLException * @ throws InstantiationException * @ throws IllegalAcce SsException * @ throws syntax * @ throws InvocationTargetException */public T findById (T entity, Connection connection, Integer id, String tableName) throws SQLException, InstantiationException, IllegalAccessException, conflict, invocationTargetException {Class <? Extends Object> clazz = entity. getClass (); Method [] methods = clazz. getDeclaredMethods (); Field [] fields = clazz. getDeclaredFields (); // declare the query result object 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.exe cuteQuery (); 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"; // prevent null pointer exceptions when data is null Constant} for (int j = 0; j <methods. length; j ++) {if ("set" + fieldName ). equalsIgnoreCase (methods [j]. getName () {methods [j]. invoke (resultObject, resultSet. getObject (fieldName) ;}}} return resultObject ;} /*** use the default database connection for Data Query ** @ param entity * @ return * @ throws InstantiationException * @ throws IllegalAccessException * @ throws IllegalArgumentException * @ throws InvocationTargetException * @ throws SQLEx Ception */public List <T> findAll (T entity) throws InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException {return findAll (entity, getConnection ());} /*** use the input database connection for Data Query ** @ param entity * @ param connection * @ return * @ throws InstantiationException * @ throws IllegalAccessException * @ throws IllegalArgumentException * @ throws InvocationTarg EtException * @ throws SQLException */public List <T> findAll (T entity, Connection connection) throws InstantiationException, IllegalAccessException, exceptions, InvocationTargetException, SQLException {return findAll (entity, connection, null );} /*** query all data in the data table ** @ param entity * the object to be queried * @ param connection * database connection object * @ param tableName * The Name Of The database table for the operation * @ return * @ throws SQLException * @ thro Ws 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 (); // declare the query result object 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 resultSe T = pst.exe cuteQuery (); 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 (resultObj Ect, resultSet. getObject (fieldName) ;}}} resultObjects. add (resultObject);} return resultObjects;} public List <T> query (T entity, Connection connection, String tableName, String SQL) {return null ;} /*** you need to manually enter SQL and parameter statements: add/delete/modify/operate ** @ 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.exe cuteUpdate ();} catch (SQLException e) {// TODO Auto-generated catch blocke. printStackTrace ();} return 0;}/*** input custom SQL statements and parameters for query; ** @ param SQL * SQL statement * @ param args * input parameter condition * @ return returns a set */public static ResultSet getObject (String SQL, Object [] args) {System. out. println (SQL); try {preparedState Ment = JDBCUtil. getConnection (). prepareStatement (SQL); if (args! = Null) {for (int I = 1; I <= args. length; I ++) {preparedStatement. setObject (I, args [I-1]) ;}} resultSet = preparedStatement.exe cuteQuery () ;} catch (SQLException e) {// TODO Auto-generated catch blocke. printStackTrace ();} return resultSet ;}}

Configuration. properties configuration file

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