java查询WFS服务

在我们访问wfs服务时候，有时候会遇到前台访问时候的跨域问题。这里给出java访问的一个小例子。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.StringRequestEntity;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.QName;

public class WFSUtil
{
    
    /**
     * 得到过滤结果。名字默认是Poi
     * 
     * @param keyWords
     * @param wfsUrl
     * @return
     * @throws HttpException
     * @throws IOException
     */
    public String findPointsXmlByKeywords(String[] keyWords, String wfsUrl,
            String wfsTitle, String layerName) throws HttpException,
            IOException
    {
        if (keyWords.length==0)
        {
            return "<root/>";
        }

        if (wfsTitle == null)
        {
            wfsTitle = "ST";
        }
        if (layerName == null)
        {
            layerName = "POI";
        }
        StringBuffer buffer = new StringBuffer(
                "<?xml version='1.0' encoding='UTF-8'?>"
                        + "<wfs:GetFeature maxFeatures='100' service='WFS' version='1.1.0' "
                        + "xmlns:wfs='http://www.opengis.net/wfs' "
                        + "xmlns:gml='http://www.opengis.net/gml' "
                        + "xmlns:ogc='http://www.opengis.net/ogc' "
                        + "xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' "
                        + "xsi:schemaLocation='http://www.opengis.net/wfs http://schemas.opengis.net/wfs/1.1.0/wfs.xsd'>"
                        + "<wfs:Query typeName='" + layerName
                        + "' srsName='EPSG:4326'>"
                        + "<ogc:Filter xmlns:ogc='http://www.opengis.net/ogc'>");

        if (keyWords.length > 1)
        {
            buffer.append("<ogc:Or>");
            for (int i = 0; i < keyWords.length; i++)
            {
                buffer.append(addPropertyIsLike(keyWords[i]));
            }
            buffer.append("</ogc:Or>");
        }
        else if (keyWords.length == 1)
        {
            buffer.append(addPropertyIsLike(keyWords[0]));
        }
        else
        {
            return null;
        }

        buffer.append("</ogc:Filter></wfs:Query></wfs:GetFeature>");
        PostMethod post = new PostMethod(wfsUrl);
        post.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET,
                "utf-8");
        post.setRequestEntity(new StringRequestEntity(buffer.toString(),
                "application/xml", "UTF-8"));
        HttpClient httpclient = new HttpClient();

        httpclient.executeMethod(post);

        InputStream xmlis = post.getResponseBodyAsStream();
        //确定读取编码为utf-8，不设置的话会用系统默认编码，例如在tomcat容器中，就可能乱码。
        BufferedReader br = new BufferedReader(new InputStreamReader(xmlis,"utf-8"));

        String tempbf;
        StringBuffer html = new StringBuffer(100);
        while ((tempbf = br.readLine()) != null)
        {
            html.append(tempbf);
        }
        // System.out.println(html.toString());
        return formatPoint(html.toString(),keyWords[0]);
    }

    private String addPropertyIsLike(String word)
    {
        String result = "";
        if (word != null && (!word.trim().isEmpty()))
        {
            result += "<ogc:PropertyIsLike wildCard='*' singleChar='.' escape='!'><ogc:PropertyName>POI_NAME</ogc:PropertyName><ogc:Literal>*"
                    + word + "*</ogc:Literal></ogc:PropertyIsLike>";
        }
        return result;
    }

    private String formatPoint(String xml,String keyWord)
    {
        try
        {
            Document doc = DocumentHelper.parseText(xml);
            
            Element root = doc.getRootElement();
            
            Element newRoot = DocumentHelper.createElement("root");
            newRoot.addAttribute("keyword", keyWord);
        
            List<Element> list = root.elements("featureMember");
            
            for (Element e : list)
            {
                Element point = newRoot.addElement("point");
                Element xs = e.element("Poi").element("X");
                Element ys = e.element("Poi").element("Y");
                if (xs != null&&ys!=null)
                {
                    String text=xs.getText()+","+ys.getText();
                    point.addElement("xys").setText(text);
                    point.addElement("type").setText("point");
                    //point.addElement("x").setText(xs.getText());
                    //point.addElement("y").setText(ys.getText());
                }
                point.addElement("name").setText(
                        e.element("Poi").element("POI_NAME").getText());
                point.addElement("address").setText(
                        e.element("Poi").element("ADDRESS").getText());
            }
            return newRoot.asXML();
            // throw new Exception("formatPoint is fail");
        }
        catch (DocumentException e)
        {
            // TODO Auto-generated catch block
            System.out.println("格式化失败！");
            e.printStackTrace();
        }

        return null;
    }

    
}

这里面用到了commons.HttpClientj-3.1.jar和dom4j这两个jar包,如果是不同版本的jar包，写法可能略有不同。

欢迎交流：http://www.cnblogs.com/shizhongtao/p/3468664.html

有时间再整理下……