自身一对多关联模型的JSON转换

       最近又遇到了一个问题， 这里有一个一对多自身关联的模型

 1 Class Tree
 2 {
 3   private String id;
 4   private String name;
 5   private Set<tree> children = new HashSet<Tree>();
 6   public void setId(String id)
 7   {
 8         this.id = id;
 9   }
10   public String getId()
11   {
12         return this.id;
13   }
14    
15}

然后我用JSON把这个模型转换成string的时候会报错：will throw a JSONException if a cycle is found.后来去查了下JSON的API发现是我的JSON转换策略有问题。原文是这样的：

public abstract class CycleDetectionStrategy

extends Object

Base class for cycle detection in a hierarchy.
The JSON spec forbides cycles in a hierarchy and most parsers will raise and error when a cycle is detected. This class defines a contract for handling those cycles and two base implementations:

• STRICT - will throw a JSONException if a cycle is found.
• LENIENT - will return an empty array or null object if a cycle is found.

说的很清楚了所以必须做点修改像这样：

 1 public   class  TreeAction  extends  BaseActionSupport {
 2    private static final CycleDetectionStrategy CycleDetectionStrategy = null;
 3    public String getAllTree()
 4    {
 5        JsonConfig jsonConfig=new JsonConfig();
 6        jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);
 7        tree = regionService.getTreeChildren("402881821a7fbf10011a7fc2d3ae0001");
 8        JSONObject array = JSONObject.fromObject(tree,jsonConfig);
 9        System.out.println("$$$$$$$$$$"+array.toString()+"$$$$$$$$$$$$$$");
10        return SUCCESS;
11    }
12}

这样修改以后转换就正常啦~~~。呵呵，HIBERNATE还有好多问题我没解决烦恼中。。。。。。