fastjson循环引用的解决办法

原文来自：http://code.alibabatech.com/wiki/pages/viewpage.action?pageId=3637281

 

fastjson网站

 

 

 

问题

 

在1.1.3版本之前,fastjson不支持循环引用。有些对象存在循环引用，例如：

 

?

public static class Department {

private int id;

private String name;

private Department parent;

private List<Department> children = new ArrayList<Department>();

public int getId() { return id; }

public void setId(int id) { this.id = id; }

public String getName() { return name; }

public void setName(String name) { this.name = name; }

public Department getParent() { return parent; }

public void setParent(Department parent) { this.parent = parent; }

public List<Department> getChildren() { return children; }

public void setChildren(List<Department> children) { this.children = children; }

}

 

这个代码中，parent和children之间存在循环应用了，执行JSON序列化时会报错：“com.alibaba.fastjson.JSONException: maybe circular references”

 

解决办法一

 

在parent字段上添加修饰符transient

 

?

public static class Department {

private int id;

private String name;

// 使用transient

private transient Department parent;

private List<Department> children = new ArrayList<Department>();

public int getId() { return id; }

public void setId(int id) { this.id = id; }

public String getName() { return name; }

public void setName(String name) { this.name = name; }

public Department getParent() { return parent; }

public void setParent(Department parent) { this.parent = parent; }

public List<Department> getChildren() { return children; }

public void setChildren(List<Department> children) { this.children = children; }

}

 

解决办法二

 

使用Annotation @JSONField标注不需要序列化getParent属性

 

?

public static class Department {

private int id;

private String name;

private Department parent;

private List<Department> children = new ArrayList<Department>();

public int getId() { return id; }

public void setId(int id) { this.id = id; }

public String getName() { return name; }

public void setName(String name) { this.name = name; }

// 使用@JSONField

@JSONField(serialize=false)

public Department getParent() { return parent; }

public void setParent(Department parent) { this.parent = parent; }

public List<Department> getChildren() { return children; }

public void setChildren(List<Department> children) { this.children = children; }