延迟加载问题，用json过滤解决

2014-06-16 15:58:49,761 [http-8080-3] ERROR [org.hibernate.LazyInitializationException] - failed to lazily initialize a collection of role: com.wiseweb.pom.entity.Role.docInfos, no session or session was closed
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.wiseweb.pom.entity.Role.docInfos, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)
    at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:368)
    at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:111)
    at org.hibernate.collection.PersistentBag.iterator(PersistentBag.java:272)
    at org.apache.struts2.json.JSONWriter.process(JSONWriter.java:158)
    at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
    at org.apache.struts2.json.JSONWriter.add(JSONWriter.java:390)
    at org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
    at org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
    at org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
    at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
    at org.apache.struts2.json.JSONWriter.add(JSONWriter.java:390)
    at org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
    at org.apache.struts2.json.JSONWriter.processCustom(JSONWriter.java:178)
    at org.apache.struts2.json.JSONWriter.process(JSONWriter.java:168)
    at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
    at org.apache.struts2.json.JSONWriter.write(JSONWriter.java:102)
    at org.apache.struts2.json.JSONUtil.serialize(JSONUtil.java:116)
    at org.apache.struts2.json.JSONResult.createJSONString(JSONResult.java:197)
    at org.apache.struts2.json.JSONResult.execute(JSONResult.java:171)

··················································

Caused by: org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.wiseweb.pom.entity.Role.docInfos, no session or session was closed
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)
    at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)
    at org.hibernate.collection.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:368)
    at org.hibernate.collection.AbstractPersistentCollection.read(AbstractPersistentCollection.java:111)
    at org.hibernate.collection.PersistentBag.iterator(PersistentBag.java:272)
    at org.apache.struts2.json.JSONWriter.process(JSONWriter.java:158)
    at org.apache.struts2.json.JSONWriter.value(JSONWriter.java:134)
    at org.apache.struts2.json.JSONWriter.add(JSONWriter.java:390)
    at org.apache.struts2.json.JSONWriter.bean(JSONWriter.java:231)
    ... 110 more

今天做项目遇到这个问题，第一反应是延迟加载问题，应该是没有设置lazy-init，过去看看确实没有设置，再到Action中查看报错方法，发现方法根本就没有使用这个，研究了好长时间发现我的实体是存在session中的，类似于一个json串，所以在使用的时候就会报这个错，最终的解决方法是做json过滤，把报错的这个字段给过滤掉就不会有这个问题了。过滤的代码如下：

loginRole = ((LoginUser) ((SecurityContext) ServletActionContext
                .getRequest().getSession().getAttribute(
                        "SPRING_SECURITY_CONTEXT")).getAuthentication()
                .getPrincipal()).getRole();
       
        JsonConfig jsonConfig = new JsonConfig();
        jsonConfig.setRootClass(Role.class);
        jsonConfig.setJsonPropertyFilter(new net.sf.json.util.PropertyFilter() {
           
            @Override
            public boolean apply(Object arg0, String arg1, Object arg2) {
                if(arg1.equals("docInfos")){
                    return true;
                }else {
                    return false;
                }
            }
        });
        net.sf.json.JSON jsonObject = JSONSerializer.toJSON(loginRole, jsonConfig);
        loginRole = (Role)JSONSerializer.toJava(jsonObject, jsonConfig);