本文介绍了@XmlRootElement和< T extends Serializable>抛出IllegalAnnotationExceptions的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

当我编组此类的一个实例时...

When I marshall an instance of this class ...

@XmlRootElement
public static class TestSomething<T extends Serializable> {

    T id;

    public T getId() {
        return id;
    }

    public void setId(T id) {
        this.id = id;
    }
}

...抛出以下异常...

... the following Exception is thrown ...

com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions
java.io.Serializable is an interface, and JAXB can't handle interfaces.
    this problem is related to the following location:
        at java.io.Serializable
        at public java.io.Serializable TestSomething.getId()
        at TestSomething
java.io.Serializable does not have a no-arg default constructor.
    this problem is related to the following location:
        at java.io.Serializable
        at public java.io.Serializable TestSomething.getId()
        at TestSomething

如何避免这种情况(不将类型参数更改为< T> )?

How can I avoid this (without changing the type parameter to something like <T>)?

推荐答案

您需要使用@XmlElement和@XmlSchemaType的组合:

You need to use a combination of @XmlElement and @XmlSchemaType:

import java.io.Serializable;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlSchemaType;

@XmlRootElement 
public class TestSomething<T extends Serializable> { 

    T id; 

    @XmlElement(type=Object.class)
    @XmlSchemaType(name="anySimpleType")
    public T getId() { 
        return id; 
    } 

    public void setId(T id) { 
        this.id = id; 
    } 
}

如果您运行以下内容:

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;

public class Demo {

    public static void main(String[] args) throws JAXBException {
        JAXBContext jc = JAXBContext.newInstance(TestSomething.class);

        TestSomething<Integer> foo = new TestSomething<Integer>();
        foo.setId(4);

        Marshaller marshaller = jc.createMarshaller();
        marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
        marshaller.marshal(foo, System.out);
    }
}

您将获得:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<testSomething>
    <id xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:int">4</id>
</testSomething>

这篇关于@XmlRootElement和&lt; T extends Serializable&gt;抛出IllegalAnnotationExceptions的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

10-29 20:05