springmvc json返回死循环

错误描述：两个多对多的实体，他们没有关联的时候，返回没有问题，当关联后，返回第一个实体（已json返回），报死循环错误。

控制器代码：

    // 输入框的模糊匹配
    @ResponseBody
    @RequestMapping("/inputFuzzyQuery")
    public List<School> inputFuzzyQuery(String keyword) {
        List<School> schs = schoolService.fuzzyQueryMaxFive(keyword);//schs有数据
        for (School sch : schs) {
            System.out.println(sch.toString());
        }
        return schs;
    }

错误信息

 at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150)
    at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112)
    at org.codehaus.jackson.map.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:72)
    at org.codehaus.jackson.map.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:23)
    at org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86)
    at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446)
    at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150)
    at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112)
    at org.codehaus.jackson.map.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:72)
    at org.codehaus.jackson.map.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:23)
    at org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86)
    at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446)
    at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150)
    at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112)
    at org.codehaus.jackson.map.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:72)
    at org.codehaus.jackson.map.ser.std.CollectionSerializer.serializeContents(CollectionSerializer.java:23)
    at org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86)
    at org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446)
    at org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150)
    at org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112)

是不是你的对象之间有相互引用，或者循环引用，导致一个死环

for 换成这个试试

if(int i = 0 ; i< schs.size() ; i++){
    System.out.println(schs.get(i).toString())
}

在你的School类上面加上这个@JsonIgnoreProperties(value={"sch"})，试试看还报错吗