自己做了一个上传的bean，出了点问题，各位帮忙看看！

//部分代码

public class upload {
public HttpServletRequest request;

private byte[] b = new byte[4096];//字节流存放数组

private int FileCount=0;//
public void setRequest(HttpServletRequest Request)
{
this.request=Request;
}

public upload(){

}
//获取text框内容
public String getText(String FieldName) throws java.io.IOException
{
ServletInputStream sis ;

sis = request.getInputStream();
System.out.println(FieldName);
String ReturnValues="";
String SplitStr="";
int a = 0;
int k=0;
String s = "";

boolean isend=false;
System.out.println("-----start---------");
while ((a = sis.readLine(b, 0, b.length)) != -1&&!isend) {
//while start
s=new String(b,0,a);
System.out.println(s);
if(s.indexOf("Content-Disposition: form-data; name=\""+FieldName+"\"")!=-1)//获得指定字段名的value值
{//if start
System.out.println("ok");
a = sis.readLine(b,0,b.length);
s = new String(b,0,a);
while(true)
{//while start

a=sis.readLine(b,0,b.length);
s=new String(b,0,a);
if((b[0]==45)&&(b[1]==45)&&(b[2]==45)&&(b[3]==45)&&(b[4]==45))
{

isend = true;
break;
}

else
ReturnValues=ReturnValues+s;
}//while end


}//if end

}//while end

sis.close();
return ReturnValues;


}

====================
调用时：
out.println(ddy.getText("t1"));

out.println(ddy.getText("t2"));

在读t2得值的时候，数据流总是从读t1停止的地方开始，不知道怎么解决