1、StringBuffer中append方法有错误

原因分析：是project默认的JRE系统库和配置的jre不匹配。

解决方法：项目属性->Add Libray->JRE System Library->Alternate JRE(选择Sun JDK 1.6.0_13)

2、文件上传问题

mySmartUpload.setAllowedFilesList("txt");  //设置上传文件类型只能是txt格式

文件上传处理过程

• jsp文件：

  <div id="input" align="center" style="width:900px;">    <p>Please select file    <input type="file" name="uploadFile" id="file">    &nbsp;&nbsp;</div>

   

• servlet文件：

  PrintWriter out=response.getWriter();                String wrongmessage = "success!";        SmartUpload mySmartUpload=new SmartUpload();        mySmartUpload.initialize(config, request, response);        mySmartUpload.setMaxFileSize(1024*2048);        //mySmartUpload.setAllowedFilesList("txt");                //bebug        int j = 0;        try        {            mySmartUpload.upload();            for (int i = 0; i < mySmartUpload.getFiles().getCount(); i++)             {                ++j;                com.jspsmart.upload.File file = mySmartUpload.getFiles().getFile(i);                if (file.isMissing())                     continue;            }        }catch(Exception err)        {            wrongmessage="error in upload " + err.getMessage() + " File:"+j+" in line 251";            //out.println("error in upload"+err.getMessage());            //allright=false;            //return;        }        out.print(wrongmessage+" num: " + j);    }

  3、提示错误，serialVersionUID冲突。

java.io.InvalidClassException: message.RegisterMessage; local class incompatible: stream classdesc serialVersionUID = 5540404719929042644, local class serialVersionUID = -8915824483106432775

serialVersionUID的详细介绍：http://www.cnblogs.com/guanghuiqq/archive/2012/07/18/2597036.html

解决方法：

如果不想定义它，在Eclipse的设置中也可以把它关掉的，设置如下：        

Window ==> Preferences ==> Java ==> Compiler ==> Error/Warnings ==>Potential programming problems        

将Serializable class without serialVersionUID的warning改成ignore即可。

2014-09-20

web server（protein protection ）搭建过程中遇到的问题