探讨:使用httpClient在客户端与服务器端传输对象参数的详解

昨天把httpclient的源代码下载来看了一下。 稍微跟踪了一下,最终还是使用java.net包的东西.不过封装的实在是漂亮.写程序方便多了。不过还是建议最好先熟悉net包下的东西.为了测试写了个在客户端和服务器段传对象的代码. 简单的传递了一个字符串. 如果复杂点可以传其他的对象,在参数里给出class name之类的信息.服务器端就可以使用反射来做一些实用的操作了。
客户端:

import java.io.ioexception;
import java.io.serializable;
import org.apache.commons.httpclient.httpclient;
import org.apache.commons.httpclient.methods.inputstreamrequestentity;
import org.apache.commons.httpclient.methods.postmethod;
import org.apache.commons.httpclient.methods.requestentity;
public class mytest
{
    /**
     * @param args
     * @throws ioexception
     * @throws classnotfoundexception
     */
    public static void main(string[] args) throws ioexception, classnotfoundexception
    {
        string url = "http://localhost:8084/system/linantest";
        string querystring = "test=hello";
        string inputobj = " boy!";
        serializable s = getobjfromserver(url, querystring, inputobj);
        system.out.println(s.tostring());
    }
    /**
     * @param url
     * @param querystring 类似a=b&c=d 形式的参数
     *
     * @param inputobj   发送到服务器的对象。
     *    
     * @return 服务器返回到客户端的对象。
     * @throws ioexception
     */
    public static serializable getobjfromserver(string url, string querystring, serializable inputobj) throws ioexception
    {
        httpclient client = new httpclient();
        postmethod post = new postmethod(url);
        post.setquerystring(querystring);
        post.setrequestheader("content-type", "application/octet-stream");
        java.io.bytearrayoutputstream bout = new java.io.bytearrayoutputstream(1024);
        java.io.bytearrayinputstream binput = null;
        java.io.objectoutputstream out = null;
        serializable returnobj = null;
        try
        {
            out = new java.io.objectoutputstream(bout);
            out.writeobject(inputobj);
            out.flush();
            out.close();
            out = null;
            binput = new java.io.bytearrayinputstream(bout.tobytearray());
            requestentity re = new inputstreamrequestentity(binput);
            post.setrequestentity(re);
            client.executemethod(post);
            java.io.inputstream in = post.getresponsebodyasstream();
            java.io.objectinputstream oinput = new java.io.objectinputstream(in);
            returnobj = (serializable) oinput.readobject();
            oinput.close();
            oinput = null;
        }
        catch (ioexception e)
        {
            // todo auto-generated catch block
            e.printstacktrace();
        }
        catch (classnotfoundexception e)
        {
            // todo auto-generated catch block
            e.printstacktrace();
        }
        finally
        {
            if (out != null)
            {
                out.close();
                out = null;
            }
            if (binput != null)
            {
                binput.close();
                binput = null;
            }
            //释放连接
            post.releaseconnection();
        }
        return returnobj;
    }
}

服务器端的servlet

package test.li;
import java.io.ioexception;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import org.openjweb.eai.adapter.timerdbadapter;
public class testservlet extends httpservlet
{
    public testservlet()
    {
        super();
    }
    /**
     * destruction of the servlet. <br>
     */
    public void destroy()
    {
        super.destroy(); // just puts "destroy" string in log
        // put your code here
    }
    /**
     * the doget method of the servlet. <br>
     *
     * this method is called when a form has its tag value method equals to get.
     *
     * @param request
     *            the request send by the client to the server
     * @param response
     *            the response send by the server to the client
     * @throws exception
     */
    public void doget(httpservletrequest request, httpservletresponse response)
    {
        string test = request.getparameter("test");
        java.io.objectinputstream oi = null;
        java.io.objectoutputstream ot = null;
        try
        {
            oi = new java.io.objectinputstream(request.getinputstream());
            object o = oi.readobject();
            oi.close();
            oi = null;

            string outobj = test + o.tostring();
            ot = new java.io.objectoutputstream(response.getoutputstream());
            ot.writeobject(outobj);
            ot.flush();
            ot.close();
            ot = null;
        }
        catch (ioexception e)
        {
            // todo auto-generated catch block
            e.printstacktrace();
        }
        catch (classnotfoundexception e)
        {
            // todo auto-generated catch block
            e.printstacktrace();
        }
        finally
        {
            try
            {
                if (oi != null)
                {
                    oi.close();
                    oi = null;
                }
                if (ot != null)
                {
                    ot.close();
                    ot = null;
                }
            }
            catch (ioexception e)
            {
                // todo auto-generated catch block
                e.printstacktrace();
            }
        }
        }
    /**
     * the dopost method of the servlet. <br>
     *
     * this method is called when a form has its tag value method equals to
     * post.
     *
     * @param request
     *            the request send by the client to the server
     * @param response
     *            the response send by the server to the client
     * @throws servletexception
     *             if an error occurred
     * @throws ioexception
     *             if an error occurred
     */
    public void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception
    {
        doget(request, response);
    }
    /**
     * initialization of the servlet. <br>
     *
     * @throws servletexception
     *             if an error occure
     */
    public void init() throws servletexception
    {
        // put your code here
    }
}