JSON-lib学习（三）循环引用

如果A对象持有B的引用，B对象持有A的引用，这样就形成了循环引用，如果直接使用json-lib转换，会报错：

net.sf.json.JSONException: There is a cycle in the hierarchy!

import java.util.HashSet;import java.util.Set;public class Aclass{    private String name;    private int age;    private Set<Bclass> policyGoals = new HashSet<Bclass>();    public Aclass()    {    }    public Aclass(String name, int age)    {        this.name = name;        this.age = age;    }    public String getName()    {        return name;    }    public Set<Bclass> getPolicyGoals()    {        return policyGoals;    }    public void setPolicyGoals(Set<Bclass> policyGoals)    {        this.policyGoals = policyGoals;    }    public void setName(String name)    {        this.name = name;    }    public int getAge()    {        return age;    }    public void setAge(int age)    {        this.age = age;    }    @Override    public String toString()    {        return name + "----" + age;    }

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public class Bclass{    private String sex;    private int address;    private Aclass aclass;    public Bclass()    {    }    public String getSex()    {        return sex;    }    public void setSex(String sex)    {        this.sex = sex;    }    public int getAddress()    {        return address;    }    public void setAddress(int address)    {        this.address = address;    }    public Aclass getAclass()    {        return aclass;    }    public void setAclass(Aclass aclass)    {        this.aclass = aclass;    }}

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 public static void main(String[] args) throws Exception    {        Aclass aObj = new Aclass();        aObj.setName("xiu");        aObj.setAge(20);        // cretae b        Bclass bObj = new Bclass();        bObj.setSex("girl");        bObj.setAddress(100);        bObj.setAclass(aObj);        aObj.getPolicyGoals().add(bObj);        JsonConfig jsonConfig = new JsonConfig();        // jsonConfig.setExcludes(new String[]{"bclass"});        jsonConfig.setCycleDetectionStrategy(CycleDetectionStrategy.LENIENT);        JSONObject jsonObj = JSONObject.fromObject(aObj,jsonConfig);        System.out.println(jsonObj.toString());}

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