将参数传递给 REST Web 服务

Question

我正在处理将参数传递给Web服务的问题。

我已经创建了网络服务，它适用于语言="eng"的情况

但是，当我通过 Glassfish 控制台测试服务并从语言 = "bos" 发送时，我没有得到适当的结果。

package pckgTranslator;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
@Path("/MyRestService/{wordToTranslate},{fromLanguage},{toLanguage}")
public class clsTranslate {
@GET
public String doGet(@PathParam("wordToTranslate") String wordToTranslate, 
@PathParam("fromLanguage") String fromLanguage, @PathParam("toLanguage")  String toLanguage) 
throws Exception{
Translator translator = new Translator();
return translator.getTranslation(wordToTranslate,fromLanguage, toLanguage);        
}

}

这是我尝试解析的 XML fajl：

<?xml version="1.0" encoding="utf-8" ?>
<gloss>
<word id="001">
<eng>ball</eng>
<bos>lopta</bos>
</word>
<word id="002">
<eng>house</eng>
<bos>kuca</bos>
</word>
<word id="003">
<eng>game</eng>
<bos>igra</bos>
</word>
</gloss>

这是我用来解析XML的类。

package pckgTranslator;
import java.io.IOException;
import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathExpressionException;
import javax.xml.xpath.XPathFactory;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
public class Translator {
String translation = null;
String getTranslation(String wordForTransl, String fromLanguage, String toLanguage)
throws ParserConfigurationException, SAXException, IOException, XPathExpressionException {
//fromLanguage = "eng";
//toLanguage = "bos";
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
InputStream is = Translator.class.getResourceAsStream("/resource/glossary.xml");
Document doc = builder.parse(new InputSource(is));
XPathFactory xpathfactory = XPathFactory.newInstance();
XPath xpath = xpathfactory.newXPath();
//XPathExpression expr = null; //xpath.compile("//word[eng='house']/bos/text()");
XPathExpression expr = xpath.compile("//word['" + wordForTransl + "'='" + wordForTransl + "']/bos/text()");
if (fromLanguage == "eng") {
expr = xpath.compile("//word[eng='" + wordForTransl + "']/bos/text()");
} else if (fromLanguage == "bos") {
expr = xpath.compile("//word[bos='" + wordForTransl + "']/eng/text()");
}
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
for (int i = 0; i < nodes.getLength(); i++) {
//System.out.println(nodes.item(i).getNodeValue());
translation = nodes.item(i).getNodeValue();
}
//return nodes.item(i).getNodeValue();
if (translation != null) {
return translation;
} else {
return "We are sorry, there is no translation for this word!";
}
}
}

在我看来，从语言和到语言的参数有问题，但我无法意识到究竟是什么。 提前谢谢。

Answer 1

正如我在评论中提到的，您已经硬编码了fromLanguage，并在getTranslation()方法开始时eng和bostoLanguage变量。因此，fromLanguage和'toLangugaevalues passed togetTranslation((' 方法丢失。

其次，与其通过,@PathParm来分隔它们，不如通过/来分隔它们。它将看起来像：

@Path("/MyRestService/{wordToTranslate}/{fromLanguage}/{toLanguage}")
@GET
public String doGet(@PathParam("wordToTranslate") String wordToTranslate, 
@PathParam("fromLanguage") String fromLanguage, @PathParam("toLanguage")  String toLanguage) throws Exception
Invocation: curl -X GET http://localhost:8080/MyRestService/x/y/z

或者使用@QueryParam.在这种情况下，您的路径将是：

@Path("/MyRestService")
public String doGet(@QueryParam("wordToTranslate") String wordToTranslate, 
@QueryParam("fromLanguage") String fromLanguage, @QueryParam("toLanguage")  String toLanguage) throws Exception
Invocation: curl -X GET http://localhost:8080/MyRestService?wordToTranslate=x&fromLanguage=y&toLanguage=z

getTranslation()方法中删除或注释以下行：

fromLanguage = "eng";
toLanguage = "bos";

---

注意：要解决您的问题，上述解决方案就足够了。但是，为了使您的代码更好，请参阅以下建议。 除了上述内容之外，我还看到了两个问题：

• 您将转换后的值存储在实例变量translation。如果您使用相同的 Translator 对象(单一实例(并且当前转换失败，getTranslation()将返回之前翻译的值。
• 为什么要用下面初始化expr？

XPathExpression expr = xpath.compile("//word['" + wordForTransl + "'='" + wordForTransl + "']/bos/text()");

• 最后，每次调用getTranslation()时，都会分析 XML。相反，init()方法中解析一次，然后在getTranslation()方法中使用它。

我根据以上几点修改了您的Translator类：

package org.openapex.samples.misc.parse.xml;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.xpath.*;
import java.io.IOException;
import java.io.InputStream;
public class ParseXMLAndTranslate {
public static void main(String[] args) throws Exception{
Translator translator = new Translator();
translator.init();
System.out.println(translator.getTranslation("house","eng", "bos"));
System.out.println(translator.getTranslation("igra","bos", "eng"));
}
private static class Translator {
//String translation = null;
private Document doc;
public void init() throws ParserConfigurationException, SAXException, IOException{
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
DocumentBuilder builder = factory.newDocumentBuilder();
InputStream is = Translator.class.getResourceAsStream("/resource/glossary.xml");
this.doc = builder.parse(new InputSource(is));
}
String getTranslation(String wordForTransl, String fromLanguage, String toLanguage)
throws XPathExpressionException {
//fromLanguage = "eng";
//toLanguage = "bos";
XPathFactory xpathfactory = XPathFactory.newInstance();
XPath xpath = xpathfactory.newXPath();
//XPathExpression expr = null; //xpath.compile("//word[eng='house']/bos/text()");
//XPathExpression expr = xpath.compile("//word['" + wordForTransl + "'='" + wordForTransl + "']/bos/text()");
XPathExpression expr = null;
if (fromLanguage == "eng") {
expr = xpath.compile("//word[eng='" + wordForTransl + "']/bos/text()");
} else if (fromLanguage == "bos") {
expr = xpath.compile("//word[bos='" + wordForTransl + "']/eng/text()");
}
Object result = expr.evaluate(doc, XPathConstants.NODESET);
NodeList nodes = (NodeList) result;
String translation = null;
/*for (int i = 0; i < nodes.getLength(); i++) {
//System.out.println(nodes.item(i).getNodeValue());
translation = nodes.item(i).getNodeValue();
}*/
if(nodes.getLength() > 0){
translation = nodes.item(0).getNodeValue();
}
//return nodes.item(i).getNodeValue();
if (translation != null) {
return translation;
} else {
return "We are sorry, there is no translation for this word!";
}
}
}
}

这是输出：

kuca
game