从 Java Rest 服务响应解析 XML

Question

我正在从 Java Rest Service 获得以下 XML 响应。有人知道如何获取 status 标记信息吗？

<operation name="EDIT_REQUEST">
<result>
<status>Failed</status>
<message>Error when editing request details - Request Closing Rule Violation. Request cannot be Resolved</message>
</result>
</operation>

Answer 1

XPath 是一种非常健壮且直观的快速查询 XML 文档的方法。您可以通过以下步骤达到status标签的值。

   DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
   documentBuilderFactory.setNamespaceAware(true);
   DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
   Document doc = builder.parse(stream); //input stream of response.

   XPathFactory xPathFactory = XPathFactory.newInstance();
   XPath xpath = xPathFactory.newXPath();

   XPathExpression expr = xpath.compile("//status"); // Look for status tag value.
   String status =  expr.evaluate(doc);
   System.out.println(status);

Answer 2

这里有一个粗略的代码

    ByteArrayInputStream input =  new ByteArrayInputStream(
            response.getBytes("UTF-8"));

    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    DocumentBuilder builder = factory.newDocumentBuilder();
    Document doc = builder.parse(input);

    // first get root tag and than result tag and childs of result tag
    NodeList childNodes = doc.getDocumentElement().getChildNodes().item(0).getChildNodes();
    for(int i = 0 ; i < childNodes.getLength(); i++){
        if("status".equals(childNodes.item(i).getNodeName())){
            System.out.println(childNodes.item(i).getTextContent());
        }
    } 

Answer 3

如果您只关心状态文本，那么使用一个简单的正则表达式与组怎么样？

例如

String responseXml = 'xml response from service....'

Pattern p = Pattern.compile("<status>(.+?)</status>");
Matcher m = p.matcher(responseXml);

if(m.find())
{
   System.out.println(m.group(1)); //Should print 'Failed'
}

Answer 4

一种选择是使用joox 库，使用gradle 导入，例如：

compile 'org.jooq:joox:1.3.0'

并像这样使用它：

import org.xml.sax.SAXException;
import java.io.File;
import java.io.IOException;
import static org.joox.JOOX.$;

public class Main {

    public static void main(String[] args) throws IOException, SAXException {
        System.out.println(
                $(new File(args[0])).xpath("/operation/result/status").text()
        );
    }
}

它产生：

Failed