java标签笔记

package cn.bestwiz.jhf.register.iphone.common.taglibs;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.tagext.SimpleTagSupport;

import org.apache.commons.logging.Log;
import org.apache.commons.validator.GenericValidator;

import cn.bestwiz.jhf.core.util.LogUtil;

/**
 * 指定网络URL读取内容
 * 
 * @author fangyp <[e-mail]>

 * @copyright 2006-2010, emcom(Dalian) Co.,Ltd
 */
public class ReadOnlineContentTag extends SimpleTagSupport {

    protected transient final Log log = LogUtil.getLog(getClass());

    private String url;

    private String charset;

    public String getCharset() {

        return charset;
    }
    public void setCharset(String charset) {

        this.charset = charset;
    }
    public String getUrl() {

        return url;
    }
    public void setUrl(String url) {

        this.url = url;
    }

    /**
     * (non-Javadoc)
     * 
     * @return
     * @throws JspException
     * @see javax.servlet.jsp.tagext.TagSupport#doEndTag()
     * @author fangyp <[e-mail]>
     * @throws IOException
     */
    @Override
    public void doTag() throws JspException, IOException {

        StringBuilder output = new StringBuilder();
        
        if (GenericValidator.isBlankOrNull(url)) {
            return;
        }
        if (GenericValidator.isBlankOrNull(charset)) {
            charset="utf-8";
        }
        try {

            URL httpurl = new URL(url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) httpurl.openConnection();
            httpURLConnection.setDoInput(true);
            BufferedReader reader = new BufferedReader(new InputStreamReader(httpURLConnection.getInputStream(),
                    charset));
            String line = null;
            while ((line = reader.readLine()) != null) {
                output.append(line + "\r\n");
            }
            JspWriter jspWriter = getJspContext().getOut();
            jspWriter.print(output.toString());
        } catch (Exception e) {
            log.info("can not find the URL file...filename=" + url);
        }
    }
}