toJSONString传入空对象如何返回null而不是字符串null

[no-trifling]

String s = JSON.toJSONString(null);
System.out.println(s instanceof String);
System.out.println(s == null);

输出

true
false

[mysmlz]

if("null".equals(s)){
    s=null;
}

完美(滑稽)

[mysmlz]

源码

public final void write(Object object) {
        if (object == null) {
            this.out.writeNull();
        } else {
...

public void writeNull() {
    this.write("null");
}