jaxb 混合内容列表包含换行符-尊龙凯时

问题描述

我希望您能帮助我解决我在 jaxb 方面遇到的问题.

i was hoping that you might be able to help me with a problem that i'm facing regarding jaxb.

我有以下 xml 文件:

i have the following xml file:

xml 下可以有其他元素(field1、field2)、文本或两者兼有.

the xml can have under prop other elements (field1, field2), text or both.

还有以下类:

@xmlaccessortype(xmlaccesstype.field)
@xmlrootelement(name = "root")
public class root {
    protected list prop;
    @xmlaccessortype(xmlaccesstype.field)
    public static class element {
        @xmlmixed
        protected list content;
        @xmlelement
        public field1 field1;
        @xmlelement
        public field2 field2;
        @xmlaccessortype(xmlaccesstype.field)
        public static class field1 {
            @xmlelement
            protected string value1;
            @xmlelement
            protected string value2;
        }
        @xmlaccessortype(xmlaccesstype.field)
        public static class field2 {
            @xmlelement
            protected string value1;
            @xmlelement
            protected string value2;
        }
    }
}

我想将 xml 解组到上述类中.我遇到的问题是，在内容列表中，除了文本之外，还有其他字符，例如换行符和制表符.更具体地说，基于上面的 xml，当我尝试解组时，我得到:

i want to unmarshal the xml in to the above classes. the issue that i'm having is that in the content list i get, besides the text, other characters like newline and tab. to be more specific, based on the above xml, when i try to unmarshal i get:

第一个属性类似于 [" ", " ", " "] - 它应该是一个空列表
第二个道具，内容如 [" text "," "] - 它应该是一个包含一个字符串的列表
第三个带有内容的道具像 [" text "] - 它应该是一个空列表

first prop with content like [" ", " ", " "] - it should be an empty list
second prop with content like [" text ", " "] - it should be a list with one string
third prop with content like [" text "] - it should be an empty list

我已经尝试创建一个 xmladapter，但它适用于列表中的每个元素，所以如果我删除和并返回 null 如果它是一个空字符串，我仍然会得到一个包含一些字符串的列表和一些空值.

i have already tried to create and a xmladapter but it is applied for every element in the list, so if i remove the and and return null if it is an empty string i still get a list with some strings and some null values.

为什么会这样

具有混合上下文的元素中的空白内容被视为重要.

why it's happening

white space content in an element that has mixed context is treated as significant.

您可以将 jaxb 与 stax 一起使用来支持此用例.使用 stax，您可以创建一个过滤的 xmlstreamreader，这样任何仅包含空格的字符串都不会被报告为事件.下面是一个如何实现它的示例.

you could use jaxb with stax to support this use case. with stax you can create a filtered xmlstreamreader so that any character strings that only contain white space are not reported as events. below is an example of how you could implement it.

import javax.xml.bind.*;
import javax.xml.stream.*;
import javax.xml.transform.stream.streamsource;
public class demo {
    public static void main(string[] args) throws exception {
        jaxbcontext jc = jaxbcontext.newinstance(root.class);
        xmlinputfactory xif = xmlinputfactory.newfactory();
        xmlstreamreader xsr = xif.createxmlstreamreader(new streamsource("src/forum22284324/input.xml"));
        xsr = xif.createfilteredreader(xsr, new streamfilter() {
            @override
            public boolean accept(xmlstreamreader reader) {
                if(reader.geteventtype() == xmlstreamreader.characters) {
                    return reader.gettext().trim().length() > 0;
                } 
                return true;
            }
        });
        unmarshaller unmarshaller = jc.createunmarshaller();
        root root = (root) unmarshaller.unmarshal(xsr);
    }
}

jaxb 混合内容列表包含换行符-尊龙凯时

问题描述

推荐答案

为什么会这样

why it's happening