FastJson禁用循环引用检测

我们先来看一个例子：

package com.elong.bms;

import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

import com.alibaba.fastjson.JSON;

public class Test {
  public static void main(String[] args) {
    Map<String, Student> maps = new HashMap<String, Student>();
    Student s1 = new Student("s1", 16);

    maps.put("s1", s1);
    maps.put("s2", s1);

    byte[] bytes = JSON.toJSONBytes(maps);

    System.out.println(new String(bytes));
  }
}

输出：

{"s1":{"age":16,"name":"s1"},"s2":{"$ref":"$.s1"}}

可以看到，这个json如果发到前端是无法使用的，幸好FastJson提供了解决办法，我们来看下，解决办法为禁用循环引用检测，代码如下：

package com.elong.bms;

import java.io.OutputStream;
import java.util.HashMap;
import java.util.Map;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializerFeature;

public class Test {
  public static void main(String[] args) {
    Map<String, Student> maps = new HashMap<String, Student>();
    Student s1 = new Student("s1", 16);

    maps.put("s1", s1);
    maps.put("s2", s1);
    
    SerializerFeature feature = SerializerFeature.DisableCircularReferenceDetect;

    byte[] bytes = JSON.toJSONBytes(maps,feature);

    System.out.println(new String(bytes));
  }
}

输出如下：

{"s1":{"age":16,"name":"s1"},"s2":{"age":16,"name":"s1"}}

问题是如果我们在spring mvc中使用的时候，需要将SerializerFeature注入到MessageConverter里面，FastJsonHttpMessageConverter。
但是SerializerFeature是一个enum类型的，又是一个array，考虑到大部分人对这个不熟悉，直接上代码了。

   <bean id="jsonConverter"
     class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
      <property name="supportedMediaTypes" value="application/json;charset=UTF-8"/>
      <property name="features">
        <array value-type="com.alibaba.fastjson.serializer.SerializerFeature">
           <value>DisableCircularReferenceDetect</value>
        </array>
      </property>
   </bean>
   <bean id="DisableCircularReferenceDetect" class="org.springframework.beans.factory.config.FieldRetrievingFactoryBean">
      <property name="staticField" value="com.alibaba.fastjson.serializer.SerializerFeature.DisableCircularReferenceDetect"></property>
   </bean>

转载地址：http://asialee.iteye.com/blog/2101915?utm_source=tuicool&utm_medium=referral