public class JavaBeanTest {
    private int anInt;
    private State state;
    private String string;
    private JavaBean2 javaBean2;
}

public class JavaBean2 {
    private int anInt;
    private State state;
    private String string;
}

测试JSON.toJSON(javaBeanTest, new SerializeConfig(true))

结果：{"string":"hello json","anInt":15,"state":"LOGIN","javaBean2":{}}