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为什么外国人还要写那些框架进行代码封装,他们不就是为了别人使用时可以更简单么!如果要达到一个企业级项目的不用框架是很难的。小一些的项目还行,大的光是MVC模式的设计的编码量就够大的了。还有性能方面,单轮windows,这个工具是微软写的,。
在利用Ajax:HibernateEntity=>json, FlexRemoteObject: HibernateEntity=>ActionScriptObject的历程,常常碰着以下成绩:
成绩:
1.Hibernate碰着提早加载的属性会见时假如session被封闭则抛出LazyInitializationException
2.Hibernate中的one-to-many等联系关系干系在序列化时假如没有把持,则将全部数据库都有大概被全体序列化
3.过量的利用DTO/ValueObject办理这个成绩.
办理举措:
对Entity对象天生一个静态代办署理,拦阻getXXXX()办法,假如会见的是提早加载的属性,则returnnull,而不抛出LazyInitializationException,递回天生属性的代码,只需碰着未提早加载的属性,而序列化会主动中断.制止将全部Entity序列化传布,招致大概序列化全部数据库的成绩.
相似办理计划:
dwr中HibernateConverter,在序列化时如上相似,碰着提早加载的属性主动中断convert事情.而HibernateBeanSerializer则与日俱增,不管object=>json都能够事情.
利用用例:
Java代码
//role为原始对象
role = (Role)roleDao.getById(new Long(1));
//天生的静态代办署理proxyRole,会见提早加载的属性将return null
Role proxyRole = (Role)new HibernateBeanSerializer<Role>(role).getProxy();
assertNotNull(role.getResource());
assertNull(proxyRole.getResource()); //提早加载,为null
Hibernate.initialize(role.getResource()); //抓取出去
assertNotNull(proxyRole.getResource()); //不为null
源码.
Java代码
package cn.org.rapid_framework.util;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.hibernate.Hibernate;
import org.hibernate.collection.PersistentCollection;
import org.hibernate.proxy.HibernateProxy;
import org.springframework.aop.framework.ProxyFactory;
import org.springframework.util.StringUtils;
/**
* 用于Hibernate Object 的序列化,会见提早加载的属性不会抛出LazyInitializationException,而会前往null值.
* 利用:
* <pre>
* Blog proxyBlog = new HibernateBeanSerializer(blog).getProxy();
* </pre>
* @author badqiu
* @param <T>
*/
public class HibernateBeanSerializer <T> {
T proxy = null;
/**
*/
public HibernateBeanSerializer(T object,String... excludesProperties) {
if(object == null) {
this.proxy = null;
}else {
ProxyFactory pf = new ProxyFactory();
pf.setTargetClass(object.getClass());
pf.setOptimize(true);
pf.setTarget(object);
pf.setProxyTargetClass(true);
pf.setOpaque(true);
pf.setExposeProxy(true);
pf.setPreFiltered(true);
HibernateBeanSerializerAdvice beanSerializerAdvice = new HibernateBeanSerializerAdvice();
beanSerializerAdvice.setExcludesProperties(excludesProperties);
pf.addAdvice(beanSerializerAdvice);
this.proxy = (T)pf.getProxy();
}
}
public T getProxy(){
return this.proxy;
}
static private class HibernateBeanSerializerAdvice implements MethodInterceptor {
private String[] excludesProperties = new String[0];
public String[] getExcludesProperties() {
return excludesProperties;
}
public void setExcludesProperties(String[] excludesProperties) {
this.excludesProperties = excludesProperties == null ? new String[0] : excludesProperties;
}
public Object invoke(MethodInvocation mi) throws Throwable {
String propertyName = getPropertyName(mi.getMethod().getName());
Class returnType = mi.getMethod().getReturnType();
if(propertyName == null) {
return mi.proceed();
}
if(!Hibernate.isPropertyInitialized(mi.getThis(), propertyName)) {
return null;
}
if(isExclude(mi, propertyName)) {
return null;
}
Object returnValue = mi.proceed();
return processReturnValue(returnType, returnValue);
}
private Object processReturnValue(Class returnType, Object returnValue) {
if(returnValue == null)
return null;
if(returnType != null && Modifier.isFinal(returnType.getModifiers())) {
return returnValue;
}
//This might be a lazy-collection so we need to double check
if(!Hibernate.isInitialized(returnValue)) {
return null;
}
//this is Hibernate Object
if(returnValue instanceof HibernateProxy) {
return new HibernateBeanSerializer(returnValue).getProxy();
}else if(returnValue instanceof PersistentCollection) {
if(returnType.isAssignableFrom(Map.class)) {
Map proxyMap = new LinkedHashMap();
Map map = (Map)returnValue;
Set<Map.Entry> entrySet = map.entrySet();
for(Map.Entry entry : entrySet) {
proxyMap.put(entry.getKey(), new HibernateBeanSerializer(entry.getValue()));
}
return proxyMap;
}
Collection proxyCollection = null;
if(returnType.isAssignableFrom(Set.class)) {
proxyCollection = new LinkedHashSet();
}else if(returnType.isAssignableFrom(List.class)) {
proxyCollection = new ArrayList();
}else {
return returnValue;
}
for(Object o : (Collection)returnValue) {
proxyCollection.add(new HibernateBeanSerializer(o).getProxy());
}
return proxyCollection;
}else {
return returnValue;
}
}
private boolean isExclude(MethodInvocation mi, String propertyName)
throws Throwable {
for(String excludePropertyName : excludesProperties) {
if(propertyName.equals(excludePropertyName)) {
return true;
}
}
return false;
}
private static String getPropertyName(String methodName) {
String propertyName = null;
if(methodName.startsWith("get")) {
propertyName = methodName.substring("get".length());
}else if(methodName.startsWith("is")) {
propertyName = methodName.substring("is".length());
}else if(methodName.startsWith("set")) {
propertyName = methodName.substring("set".length());
}
return propertyName == null ? null : StringUtils.uncapitalize(propertyName);
}
}
}
另这个类属于rapid-framework的一部分,v2.0版本的flexRemoteObject将接纳这个举措.preview版本行将公布
Java的桌面程序开发在java程序员里通常叫swing开发,主要用的swing包里的类开发的,也就是通常说的c/s架构开发 |
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