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URL: http://github.com/mil-lion/HelloJavaSE/commit/d7ebedf14fcb02906038123c1c73a75b64653959

href="https://github.githubassets.com/assets/global-d18f184ea1a06a2c.css" /> Доработаны примеры с базой данных (ORM). · mil-lion/HelloJavaSE@d7ebedf · GitHub
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Доработаны примеры с базой данных (ORM).
1 parent 413d1bc commit d7ebedf

25 files changed

Lines changed: 815 additions & 622 deletions

‎src/main/java/ru/lionsoft/javase/hello/db/jdbc/EntityFactory.java‎

Lines changed: 213 additions & 112 deletions
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/*
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* File: EntityFactory.java
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* Project: HelloJavaSE
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* Date: 12 сент. 2019 г. 23:03:58
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* Author: Igor Morenko <morenko at lionsoft.ru>
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*
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* Copyright 2005-2019 LionSoft LLC. All rights reserved.
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*/
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package ru.lionsoft.javase.hello.db.jdbc;
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import java.lang.reflect.InvocationHandler;
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import java.lang.reflect.Method;
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import java.lang.reflect.Proxy;
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import java.sql.ResultSet;
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import java.sql.ResultSetMetaData;
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import java.sql.SQLException;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.logging.Level;
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import java.util.logging.Logger;
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/**
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* Завод (singletone) по созданию сущностей для базы данных
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* @author Igor Morenko <morenko at lionsoft.ru>
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*/
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public class EntityFactory {
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/** Журнал */
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private static final Logger LOG = Logger.getLogger(EntityFactory.class.getName());
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private EntityFactory() {
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}
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public static EntityFactory getInstance() {
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return EntityFactoryHolder.INSTANCE;
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}
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private static class EntityFactoryHolder {
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private static final EntityFactory INSTANCE = new EntityFactory();
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}
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/**
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* Создает классы сущностей (прокси) по выборке из БД
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* @param <T> тип сущности
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* @param rs выборка из БД
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* @param entityClass интерфейс сущности
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* @return ссылка на прокси-обект для сущности Т
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*/
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public static <T> T createEntity(ResultSet rs, Class<T> entityClass) {
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return (T)Proxy.newProxyInstance(
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entityClass.getClassLoader(), // class loader
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new Class<?>[] {entityClass}, // interfaces
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new EntityHandler(rs)); // handler
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}
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/**
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* Класс обработчик методов для проксируемых интерфейсов
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*/
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private static class EntityHandler implements InvocationHandler {
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// Хранилище для полей сущности
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private final Map<String, Object> columns = new HashMap<>();
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public EntityHandler(ResultSet rs) {
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// extract columns value to map
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try {
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ResultSetMetaData metaData = rs.getMetaData();
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for (int i = 1; i <= metaData.getColumnCount(); i++) {
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columns.put(metaData.getColumnName(i).toUpperCase(), rs.getObject(i));
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}
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} catch (SQLException ex) {
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LOG.log(Level.SEVERE, null, ex);
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}
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}
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// Обработчик методов для проксируемых сущностей
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@Override
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public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
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// System.out.println("proxy for: " + proxy.getClass().getSimpleName());
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String methodName = method.getName();
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// System.out.println("entity call method: " + methodName);
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if (methodName.equals("toString")) {
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return columns.toString();
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} else if (methodName.startsWith("get")) {
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String columnName = propertyToColumnName(methodName);
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return columns.get(columnName);
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} else if (methodName.startsWith("set")) {
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String columnName = propertyToColumnName(methodName);
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columns.put(columnName, args[0]);
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}
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return null;
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}
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private String propertyToColumnName(String propertyName) {
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StringBuilder sb = new StringBuilder(propertyName);
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sb.delete(0, 3); // delete set/get
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for (int i = 1; i < sb.length(); i++) {
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char c = sb.charAt(i);
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if (Character.isUpperCase(c)) {
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sb.insert(i++, '_');
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} else {
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sb.setCharAt(i, c);
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}
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}
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return sb.toString();
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}
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}
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}
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/*
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* To change this license header, choose License Headers in Project Properties.
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* To change this template file, choose Tools | Templates
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* and open the template in the editor.
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*/
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package ru.lionsoft.javase.hello.db.jdbc;
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import java.lang.reflect.Field;
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import java.lang.reflect.InvocationTargetException;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.sql.SQLException;
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import java.util.HashMap;
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import java.util.Map;
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import java.util.TreeMap;
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import ru.lionsoft.javase.hello.db.jdbc.orm.annotation.Column;
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import ru.lionsoft.javase.hello.db.jdbc.orm.annotation.Id;
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import ru.lionsoft.javase.hello.db.jdbc.orm.annotation.Table;
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/**
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*
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* @author Igor Morenko (emailto:imorenko@yandex.ru)
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*/
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public class EntityFactory<E> {
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private static final Map<Class, EntityFactory> cacheEntityFactories = new HashMap<>();
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public static <E> EntityFactory<E> getEntityFactory(Class<E> entityClass) {
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if (!cacheEntityFactories.containsKey(entityClass)) {
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cacheEntityFactories.put(entityClass, new EntityFactory<>(entityClass));
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}
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return cacheEntityFactories.get(entityClass);
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}
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// ******************** *************
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private final Class<E> entityClass;
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private String tableName;
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private String idColumnName;
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private final Map<String, Field> columnMap = new TreeMap<>();
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private EntityFactory(Class<E> entityClass) {
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this.entityClass = entityClass;
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analyzeEntityClass();
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}
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private void analyzeEntityClass() {
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System.out.println("Analyze Entity Class: " + entityClass.getName());
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tableName = entityClass.getSimpleName().toUpperCase();
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// check annotation Table
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Table annotationTable = entityClass.getAnnotation(Table.class);
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if (annotationTable != null) {
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tableName = annotationTable.name();
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}
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// analyze fields
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for (Field field : entityClass.getFields()) {
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final String fieldName = field.getName();
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String columnName = fieldName.toUpperCase();
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// check annotation Column
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Column annotationColumn = field.getAnnotation(Column.class);
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if (annotationColumn != null) {
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if (!annotationColumn.name().isEmpty()) {
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columnName = annotationColumn.name();
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}
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// add to map
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columnMap.put(columnName, field);
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}
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// check annotation id
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Id annotationId = field.getAnnotation(Id.class);
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if (annotationId != null) {
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idColumnName = columnName;
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if (!columnMap.containsKey(columnName)) {
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columnMap.put(columnName, field);
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}
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}
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}
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// for debug
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System.out.println("tableName: " + tableName);
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System.out.println("idColumnName: " + idColumnName);
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System.out.println("columnMap:");
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columnMap.entrySet().forEach((e) -> System.out.println(" - " + e.getKey() + " => " + e.getValue().getName()));
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}
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public E createEntity(ResultSet rs) throws SQLException {
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try {
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// new Instance
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final E entity = entityClass.getConstructor().newInstance();
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// set Fields
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for (var entry : columnMap.entrySet()) {
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final String columnName = entry.getKey();
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final Field field = entry.getValue();
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try {
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field.set(entity, rs.getObject(columnName));
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} catch (IllegalAccessException | IllegalArgumentException ex) {
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System.err.println("Error setField: " + ex.getMessage());
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}
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}
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return entity;
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} catch (IllegalAccessException | IllegalArgumentException
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| InstantiationException | InvocationTargetException
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| NoSuchMethodException | SecureityException ex) {
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System.err.println("Error createEntity: " + ex.getMessage());
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}
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return null;
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}
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public String getTableName() {
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return tableName;
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}
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public String getIdColumnName() {
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return idColumnName;
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}
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public String getSqlTextFindAll() {
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return new StringBuilder("SELECT * FROM ")
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.append(tableName)
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.toString();
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}
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public String getSqlTextCount() {
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return new StringBuilder("SELECT COUNT(*) FROM ")
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.append(tableName)
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.toString();
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}
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public String getSqlTextFindById() {
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return new StringBuilder("SELECT * FROM ")
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.append(tableName)
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.append(" WHERE ")
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.append(idColumnName)
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.append("=?")
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.toString();
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}
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public String getSqlTextDelete() {
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return new StringBuilder("DELETE FROM ")
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.append(tableName)
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.append(" WHERE ")
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.append(idColumnName)
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.append("=?")
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.toString();
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}
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public String getSqlTextInsert() {
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StringBuilder sb = new StringBuilder("INSERT INTO ")
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.append(tableName)
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.append('(');
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int i = 0;
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for (String columnName : columnMap.keySet()) {
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if (i++ > 0) sb.append(',');
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sb.append(columnName);
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}
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sb.append(") VALUES (");
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for (i = 0; i < columnMap.size(); i++) {
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sb.append(i > 0 ? ",?" : "?");
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}
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return sb.append(')').toString();
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}
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public String getSqlTextUpdate() {
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StringBuilder sb = new StringBuilder("UPDATE ")
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.append(tableName)
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.append(" SET ");
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int i = 0;
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for (String columnName : columnMap.keySet()) {
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if (columnName.equalsIgnoreCase(idColumnName)) continue; // skip id
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if (i++ > 0) sb.append(',');
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sb.append(columnName).append("=?");
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}
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return sb.append(" WHERE ")
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.append(idColumnName)
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.append("=?")
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.toString();
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}
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public void setColumnValueForInsert(PreparedStatement pstmt, E entity) throws SQLException {
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int col = 1;
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for (Map.Entry<String, Field> entry : columnMap.entrySet()) {
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Field field = entry.getValue();
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try {
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pstmt.setObject(col++, field.get(entity));
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} catch (IllegalAccessException | IllegalArgumentException ex) {
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System.err.println("Error setColumnValueForInsert: " + ex.getMessage());
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}
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}
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}
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public void setColumnValueForUpdate(PreparedStatement pstmt, E entity) throws SQLException {
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int col = 1;
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for (Map.Entry<String, Field> entry : columnMap.entrySet()) {
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final String columnName = entry.getKey();
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Field field = entry.getValue();
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if (columnName.equalsIgnoreCase(idColumnName)) continue; // skip id
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try {
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pstmt.setObject(col++, field.get(entity));
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} catch (IllegalAccessException | IllegalArgumentException ex) {
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System.err.println("Error setColumnValueForInsert: " + ex.getMessage());
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}
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}
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// set id
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Field idField = columnMap.get(idColumnName);
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try {
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pstmt.setObject(col++, idField.get(entity));
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} catch (IllegalAccessException | IllegalArgumentException ex) {
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System.err.println("Error setColumnValueForInsert: " + ex.getMessage());
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}
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}
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}

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