java – XStream序列化空值
发布时间:2020-12-15 03:03:03 所属栏目:Java 来源:网络整理
导读:假设我有 class Student{String name;int age;String teacher;} 然后 : public class App1{ public static void main(String[] args) { Student st = new Student(); st.setName("toto"); XStream xs = new XStream(); xs.alias("student",Student.class);
假设我有
class Student { String name; int age; String teacher; } 然后 : public class App1 { public static void main(String[] args) { Student st = new Student(); st.setName("toto"); XStream xs = new XStream(); xs.alias("student",Student.class); System.out.println(xs.toXML(st)); } } 给我 : <student> <name>toto</name> <age>0</age> </student> 有没有办法处理空值?我的意思是 : <student> <name>toto</name> <age>0</age> <teacher></teacher> </student> 如果我这样做可能 st.setTeacher(""); 但如果老师是空的,那就没有. 我尝试使用自定义转换器,但似乎空值不会发送到转换器. 解决方法
我正在使用XStream 1.4.7,@ XStreamAlias注释用于自定义字段名称,@ XStreamConverter用于自定义转换器(用于表示日期和其他自定义bean).但是,甚至没有调用空值的自定义转换器.
我的目标是序列化对象的所有字段,包括null字段,我不需要解组XML. 我设法通过创建自定义ReflectionConverter来做到这一点. new Object() { { for (Iterator fieldIter = fields.iterator(); fieldIter.hasNext();) { FieldInfo info = (FieldInfo) fieldIter.next(); if (info.value != null) { //leave the code unchanged ... } else { //add this to write null info.value to xml Log.info("MyCustomReflectionConverter -> serialize null field: " + info.fieldName); writeField(info.fieldName,null,info.type,info.definedIn,info.value); } } //... leave the rest of the code unchanged } }; 之后,我创建了类似的xStream实例(以非常低的优先级注册转换器非常重要): StaxDriver driver = new StaxDriver(new NoNameCoder()) { @Override public StaxWriter createStaxWriter(XMLStreamWriter out) throws XMLStreamException { // the boolean parameter controls the production of XML declaration return createStaxWriter(out,false); } }; XStream xStream = new XStream(driver); xStream.autodetectAnnotations(true);//needed to process aliases //register MyCustomReflectionConverter MyCustomReflectionConverter reflectionConverter = new MyCustomReflectionConverter (xStream.getMapper(),new SunUnsafeReflectionProvider()); xStream.registerConverter(reflectionConverter,XStream.PRIORITY_VERY_LOW); 感谢Mark Nabours的解决方案here 希望能帮助到你.有人找到了更好的解决方案吗? (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |