【java】JSON.toJSONString 空对象也可以转化为JSON字符串

　　　　　　　　<dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.23</version>
            </dependency>

 Student item = new Student();
        System.out.println(
                JSON.toJSONString(
                        item,
                        SerializerFeature.WriteMapNullValue,
                        SerializerFeature.WriteNullNumberAsZero,
                        SerializerFeature.WriteNullListAsEmpty,
                        SerializerFeature.WriteNullStringAsEmpty,
                        SerializerFeature.WriteNullBooleanAsFalse
                )
        );

QuoteFieldNames———-输出key时是否使用双引号,默认为true

WriteMapNullValue——–是否输出值为null的字段,默认为false

WriteNullNumberAsZero—-数值字段如果为null,输出为0,而非null

WriteNullListAsEmpty—–List字段如果为null,输出为[],而非null

WriteNullStringAsEmpty—字符类型字段如果为null,输出为”“,而非null

WriteNullBooleanAsFalse–Boolean字段如果为null,输出为false,而非nul