JAXB反序列化XML至列表：Error类属性值为null问题求助

你的问题核心是Error类的注解使用错误：XML中<type>和<message>是<error>的子元素，但你在代码里用了@XmlAttribute（用于绑定XML属性，比如<id version="1">里的version），这导致JAXB无法将子元素的值映射到属性上，所以type和message都是null。

修正步骤： #

1. 修改Error类的注解
   将@XmlAttribute替换为@XmlElement，因为这两个是XML子元素，不是属性：

   @XmlAccessorType(XmlAccessType.FIELD)
   @XmlType(name = "error", propOrder = {
           "type",
           "message"
   })
   public class Error implements Serializable {
   
       private final static long serialVersionUID = -1L;
       @XmlElement(required = true)
       protected String type;
       @XmlElement(required = true)
       protected String message;
   
       public String getType() {
           return type;
       }
   
       public void setType(String type) {
           this.type = type;
       }
   
       public String getMessage() {
           return message;
       }
   
       public void setMessage(String message) {
           this.message = message;
       }
   }
   

2. 优化Content类的列表绑定（可选但推荐）
   为确保JAXB正确识别多个<error>元素，建议在error列表字段上添加@XmlElement(name = "error")注解，同时初始化列表避免空指针：

   @XmlAccessorType(XmlAccessType.FIELD)
   @XmlType(name = "content", propOrder = {
           "status",
           "securitiesFinancingTrade",
           "schemaVersion",
           "error"
   })
   public class Content implements Serializable {
   
       private final static long serialVersionUID = -1L;
       protected ContentStatusEnumType status;
       protected SecuritiesFinancingTrade securitiesFinancingTrade;
       protected String schemaVersion;
       @XmlElement(name = "error", required = true)
       protected List<Error> error = new ArrayList<>();
   
       public ContentStatusEnumType getStatus() {
           return status;
       }
   
       public void setStatus(ContentStatusEnumType status) {
           this.status = status;
       }
   
       public SecuritiesFinancingTrade getSecuritiesFinancingTrade() {
           return securitiesFinancingTrade;
       }
   
       public void setSecuritiesFinancingTrade(SecuritiesFinancingTrade securitiesFinancingTrade) {
           this.securitiesFinancingTrade = securitiesFinancingTrade;
       }
   
       public String getSchemaVersion() {
           return schemaVersion;
       }
   
       public void setSchemaVersion(String schemaVersion) {
           this.schemaVersion = schemaVersion;
       }
   
       public List<Error> getError() {
           if (error == null) {
               error = new ArrayList<>();
           }
           return error;
       }
   
       public void setError(List<Error> error) {
           this.error = error;
       }
   }
   

验证说明 #

修改后重新反序列化XML，JAXB会正确将<error>下的<type>和<message>子元素的值映射到Error对象的对应属性中，同时多个<error>元素会被正确收集到列表里。

内容的提问来源于stack exchange，提问作者Jakub Znamenáček