在j2se环境中ejb3.0操作entity bean的通用类 PerfectEntityManager

在j2se环境中ejb3.0操作entity bean的通用类 PerfectEntityManager

package com.vsc.study.ejb.util;

import com.vsc.study.ejb.entitybean.Function;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;

public class PerfectEntityManager {
    
    private EntityManagerFactory emf;
    private EntityManager em;
    
    public PerfectEntityManager() {
        emf = Persistence.createEntityManagerFactory("study-ejbPU");
        em = emf.createEntityManager();
    }
    
    public PerfectEntityManager(String utinName) {
        emf = Persistence.createEntityManagerFactory(utinName);
        em = emf.createEntityManager();
    }
    
    public Map<Integer, List> getCurrentResults(int currentPage, int pageSize,
            int maxResults, String querySql) {
        if (maxResults == 0) {
            maxResults = em.createQuery(querySql).getResultList().size();
        }
        List list = em.createQuery(querySql).setFirstResult(
                (currentPage - 1) * pageSize).setMaxResults(pageSize)
                .getResultList();
        HashMap<Integer, List> hashMap = new HashMap<Integer, List>();
        hashMap.put(maxResults, list);
        return hashMap;
    }
    
    public Map<Integer, List> getCurrentResults(int currentPage, int pageSize,
            int maxResults, Object object) {
        
        if (maxResults == 0) {
            maxResults = em.createQuery("from " + object.getClass())
            .getResultList().size();
        }
        List list = em.createQuery("from " + object.getClass()).setFirstResult(
                (currentPage - 1) * pageSize).setMaxResults(pageSize)
                .getResultList();
        HashMap<Integer, List> hashMap = new HashMap<Integer, List>();
        hashMap.put(maxResults, list);
        return hashMap;
    }
    
    String separator = " ";
    
    public String setEjbql(Object object, List<Ejbql> ejbqlList) {
        StringBuilder sb = new StringBuilder("select o from "
                + object.getClass() + " as o where 1=1 ");
        for (Ejbql ejbql : ejbqlList) {
            if (ejbql == null) {
                continue;
            }
            if (ejbql.getCloumns() == null) {
                continue;
            }
            if (ejbql.getOperator() == null) {
                continue;
            }
            if (ejbql.getValues() == null) {
                continue;
            }
            sb.append(ejbql.getAndOr() + separator);
            sb.append("o." + ejbql.getCloumns());
            if (ejbql.getOperator().equals("like")) {
                sb.append(separator + ejbql.getOperator() + separator);
                sb.append("'%" + ejbql.getValues() + "%'" + separator);
            } else {
                sb.append(ejbql.getOperator() + separator);
                if (ejbql.getValues() instanceof String) {
                    sb.append("'" + ejbql.getValues() + "'" + separator);
                } else {
                    sb.append(ejbql.getValues() + separator);
                }
            }
        }
        return sb.toString();
    }
    
    public String setEjbql(String classname, List<Ejbql> ejbqlList) {
        StringBuilder sb = new StringBuilder("select o from " + classname
                + " as o where 1=1 ");
        for (Ejbql ejbql : ejbqlList) {
            if (ejbql == null) {
                continue;
            }
            if (ejbql.getCloumns() == null) {
                continue;
            }
            if (ejbql.getOperator() == null) {
                continue;
            }
            if (ejbql.getValues() == null) {
                continue;
            }
            sb.append(ejbql.getAndOr() + separator);
            sb.append("o." + ejbql.getCloumns());
            if (ejbql.getOperator().equals("like")) {
                sb.append(separator + ejbql.getOperator() + separator);
                sb.append("'%" + ejbql.getValues() + "%'" + separator);
            } else {
                sb.append(ejbql.getOperator() + separator);
                if (ejbql.getValues() instanceof String) {
                    sb.append("'" + ejbql.getValues() + "'" + separator);
                } else {
                    sb.append(ejbql.getValues() + separator);
                }
            }
        }
        return sb.toString();
    }
    
    public int remove(Object object) {
        if (object == null)
            throw new NullPointerException();
        try {
            em.getTransaction().begin();
            em.remove(this.search(object));
            em.getTransaction().commit();
            em.close();
            emf.close();
            return 0;
        } catch (Exception e) {
            return -2;
        }
    }
    
    public int update(Object object) {
        if (object == null || this.getId(object) == null)
           throw new NullPointerException();
        Object obj = this.search(object);
        this.updateBean(object, obj);
        try {
            em.getTransaction().begin();
            em.merge(obj);
            em.getTransaction().commit();
            em.close();
            emf.close();
            return 0;
        } catch (Exception e) {
            return -1;
        }
    }
    
    public Object search(Object object) {
        if (object == null)
           throw new NullPointerException();
        try {
            Object obj = em.find(object.getClass(), this.getId(object));
            return obj;
        } catch (Exception e) {
            e.printStackTrace();
            return -1;
        }
    }
    
    public List searchAll(Object object) {
        if (object == null)
            throw new NullPointerException();
        try {
            em.getTransaction().begin();
            List list = em.createQuery("from " + object.getClass()).getResultList();
            em.getTransaction().commit();
            em.close();
            emf.close();
            return list;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }
    
    public Long insert(Object object) {
        try {
            em.getTransaction().begin();
            em.persist(object);
            em.getTransaction().commit();
            em.close();
            emf.close();
            return this.getId(object);
        } catch (Exception e) {
            e.printStackTrace();
            return -1l;
        }
    }
    
    public Long getId(Object object) {
        if (object == null)
            throw new NullPointerException();
        try {
            return (Long) object.getClass().getDeclaredMethod("getId").invoke(object);
        } catch (Exception e) {
            e.printStackTrace();
            return -5l;
        }
    }
    
    /**
     * obj is update Object
     *
     * @param object
     * @param obj
     */
    public void updateBean(Object object, Object obj) {
        try {
            Method[] methods = object.getClass().getDeclaredMethods();
            Method method;
            Object objectMethodValue;
            Object objMethodValue;
            for (int i = 0; i < methods.length; i++) {
                if (methods[i].getName().trim().startsWith("get")) {
                    if (methods[i].invoke(object) == null) {
                        System.out
                                .println("----------this field is null--------------");
                        continue;
                    }
                    objectMethodValue = methods[i].invoke(object);
                    objMethodValue = methods[i].invoke(obj);
                    if (objectMethodValue.equals(objMethodValue)) {
                        System.out
                                .println("----------field is equals--------------");
                        continue;
                    }
                    method = obj.getClass().getDeclaredMethod(
                            methods[i].getName().trim().replaceFirst("g", "s"),
                            methods[i].getReturnType());
                    method.invoke(obj, objectMethodValue);
                    System.out.println("==============="
                            + methods[i].invoke(obj));
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}