struts的include标签的修改，使支持http形式

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本文需要读者对struts的标签源码比较熟悉。

由于公司的web应用根据不同的业务形式采用的独立部署。使各个业务的耦合度降低。使业务更加的灵活。
但是面临的是业务WEB_A应用需要调用业务WEB_B应用的页面。

1:ajax的形式。

2:action中用java拿到页面的IO流。输出到页面上。
3:代码、页面写在WEB_A上。但是这样的话，就使的开发需要维护两个业务工程。
4:如有其他方案请联系我：）

后来在研究struts的s:include标签的时候，感觉也可以用自定义标签来解决类似问题。
附上代码：
中间的标签的配置省略了。

/**
 * 获取http请求内容
 *
 * @author shanzhu
 * @version 1.0 2011-9-15
 */
package org.apache.struts2.views.jsp;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.components.Component;
import org.apache.struts2.components.IncludeHttp;

import com.opensymphony.xwork2.util.ValueStack;

public class IncludeHttpTag extends ComponentTagSupport{

    /**
     * 
     */
    private static final long serialVersionUID = 4811111257523224901L;
    protected String value;
    protected String charset;   //编码
    protected int conntimeout;
    protected int requtimeout;
    

    public Component getBean(ValueStack stack, HttpServletRequest req, HttpServletResponse res) {
        return new IncludeHttp(stack, req, res);
    }

    protected void populateParams() {
        super.populateParams();

        ((IncludeHttp) component).setValue(value);
        ((IncludeHttp) component).setCharset(charset);
        ((IncludeHttp) component).setConntimeout(conntimeout);
        ((IncludeHttp) component).setRequtimeout(requtimeout);
    }
    

    public void setValue(String value) {
        this.value = value;
    }

    public void setCharset(String charset) {
        this.charset = charset;
    }

    public void setConntimeout(int conntimeout) {
        this.conntimeout = conntimeout;
    }

    public void setRequtimeout(int requtimeout) {
        this.requtimeout = requtimeout;
    }
}

/**
 * includehttp的时候。处理value是http开头。
 * 当使用这个标签的时候，会根据标签内的值取得url的io，写在页面上
 *
 * @author shanzhu
 * @version 1.0 2011-9-15
 */
package org.apache.struts2.components;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.Writer;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts2.StrutsConstants;
import org.apache.struts2.components.Component;
import org.apache.struts2.views.annotations.StrutsTag;
import org.apache.struts2.views.annotations.StrutsTagAttribute;

import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.ValueStack;


@StrutsTag(name="IncludeHttp", tldTagClass="org.apache.struts2.components.IncludeHttp", description="Include a servlet's output " +
                "(result of http context)")
public class IncludeHttp extends Component {

    private final String URL_AND = "&";
    private final String URL_DENGYU = "=";
    private final String URL_WENHAO = "?";
    private final String STR_KONG = "";
    private static final Log _log = LogFactory.getLog(IncludeHttp.class);

    protected String value;     //url
    protected String charset;   //以charset编码去取得远程的io
    protected int conntimeout;  //超时时间
    protected int requtimeout;  //超时时间
    private String wenhao  ;
    private String strParmaeters = "";
    private HttpServletRequest req;
    private HttpServletResponse res;
    private static String defaultEncoding;
    
    
    public IncludeHttp(ValueStack stack, HttpServletRequest req, HttpServletResponse res) {
        super(stack);
        this.req = req;
        this.res = res;
    }

    @Inject(StrutsConstants.STRUTS_I18N_ENCODING)
    public static void setDefaultEncoding(String encoding) {
        defaultEncoding = encoding;
    }

    public boolean end(Writer writer, String body) { 
        checkURL();
        value = value + this.wenhao + strParmaeters;
        String webContext = GetWebContent(value,charset,conntimeout,requtimeout); 
        return super.end(writer, webContext);
    }
    /**
     * 对url进行检查拼装
     */
    private void checkURL(){
        checkUrlSameStatus();
        checkParmater();
    }

    /**
     * 对？进行检查
     */
    private void checkUrlSameStatus(){
        if (this.value.indexOf(this.URL_WENHAO)>-1) {
            wenhao = STR_KONG;
        }else {
            wenhao = this.URL_WENHAO;
        }
    }
    /**
     * 对参数进行检查
     */
    private void checkParmater(){
        if (this.parameters==null || this.parameters.size()<=0) {
            strParmaeters = STR_KONG;
        }else {
            Iterator<?> it = parameters.entrySet().iterator();  
                while (it.hasNext()) {  
                    Map.Entry entry = (Map.Entry) it.next();  
                    if (strParmaeters.indexOf("&")>-1) {
                        strParmaeters = strParmaeters + this.URL_AND+entry.getKey() + this.URL_DENGYU + ((List)entry.getValue()).get(0);  
                    }else {
                        strParmaeters = strParmaeters +entry.getKey() + this.URL_DENGYU + ((List)entry.getValue()).get(0);
                    }
                    
            }  
        }
    }
    
    
    
    
    @StrutsTagAttribute(description="The jsp/servlet output to include", required=true)
    public void setValue(String value) {
        this.value = value;
    }

    /**
     * 取得includehttp标签内使用的parameter标签的值
     */
    @SuppressWarnings("unchecked")
    public void addParameter(String key, Object value) {
        // don't use the default implementation of addParameter,
        // instead, include tag requires that each parameter be a list of objects,
        // just like the HTTP servlet interfaces are (String[])
        if (value != null) {
            List currentValues = (List) parameters.get(key);

            if (currentValues == null) {
                currentValues = new ArrayList();
                parameters.put(key, currentValues);
            }
            currentValues.add(value);
        }
    }

    public void setCharset(String charset) {
        if (isEmpty(charset)) {
            charset = "utf-8";
        }
        this.charset = charset;
    }

    public void setConntimeout(int conntimeout) {
        if (conntimeout<=0) {
            conntimeout = 3000;
        }
        this.conntimeout = conntimeout;
    }

    public void setRequtimeout(int requtimeout) {
        if (requtimeout<=0) {
            requtimeout = 3000;
        }
        this.requtimeout = requtimeout;
    }
    
    boolean isEmpty(String str){
        if (str == null || "".equals(str)) {
            return true;
        }
        return false;
    }
    
    
    
    /*
     * 取得指定URL的Web内容
     */
    public static String GetWebContent(final String theURL,final String charset,final int connTimeout,final int requTimeout) {
        String sTotalString = "";
        URL l_url = null;
        HttpURLConnection l_connection = null;
        java.io.InputStream l_urlStream = null;
        BufferedReader l_reader = null;
        try {
            l_url = new URL(theURL);
            l_connection = (HttpURLConnection) l_url.openConnection();
            l_connection.setConnectTimeout(connTimeout);
            // 加入取内容超时处理
            l_connection.setReadTimeout(requTimeout);
            l_connection.connect();
            l_urlStream = l_connection.getInputStream();
            l_reader = new BufferedReader(new InputStreamReader(l_urlStream,charset));
            int buffer_size = 1024;
            char[] buffer = new char[buffer_size];
            StringBuffer sb = new StringBuffer();
            int readcount = 0;
            while ((readcount = l_reader.read(buffer, 0, buffer_size)) > 0) {
                sb.append(buffer, 0, readcount);
            }
            sTotalString = sb.toString();
            l_reader.close();
            l_urlStream.close();
            l_connection.disconnect();
        } catch (Exception e) {
            System.out.println("error: exception in WebUtil: " + e.toString()
                    + ":" + theURL);
        } finally {
            if (l_reader != null) {
                try {
                    l_reader.close();
                } catch (Exception e) {
                }
            }
            if (l_urlStream != null) {
                try {
                    l_urlStream.close();
                } catch (Exception e) {
                }
            }
            if (l_connection != null) {
                try {
                    l_connection.disconnect();
                } catch (Exception e) {
                }
            }
        }
        
        if (sTotalString==null) {
            sTotalString = "";   
        }
        return sTotalString;
    }

   
}

这个时候。调用方仅仅需要使用标签即可。
举个例子：
<s:includehttp value="http://www.aaa.html?a=1">
<s:param name="b" value="'b'"></s:param>
</s:includehttp>

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