.length無法解析或不是字段

Question

我已經盡力用以前的類似答案來解決這個問題，但是仍然無法看到我的問題，希望能對您有所幫助。 我的代碼如下所示：

String MyContent =" ";
String nextline = " ";

InputStream in = new FileInputStream(f);

BufferedInputStream bin = new BufferedInputStream(in);

DataInputStream din = new DataInputStream(bin);

    while(din.available()>1)
    {
    nextline = din.readLine();

    //Filter out XML headers which are not browser compliant
    if (nextline.length > 4)
        {
        if (nextline.substring(1,5) != "<?xml")
            {
            MyContent=MyContent+ nextline;
            }
        }   
    }

    out.print (MyContent);

in.close();
bin.close();
din.close();

我收到一個錯誤：

An error occurred at line: 25 in the jsp file: /MaxiSunReports/DisplayXMLFile.jsp
nextline.length cannot be resolved or is not a field
22:     nextline = din.readLine();
23:     nextline = "THISISATEST";
24:     //Filter out XML headers which are not browser compliant
25:     if (nextline.length > 4)
26:         {
27:         if (nextline.substring(1,5) != "<?xml")

Answer 1

首先，不贊成使用DataInputStream readLine()方法。

其次，此方法返回一個String ，它沒有field length 。 它只有方法length() 。 length是數組的屬性。

Answer 2

length不是字段。 這是一個函數，因此您必須調用nextline.length() > 4

Answer 3

長度不是屬性，而是方法。

采用

while(din.available()>1)
{
nextline = din.readLine();

//Filter out XML headers which are not browser compliant
if (nextline.length() > 4)
    {
    if (nextline.substring(1,5) != "<?xml")
        {
        MyContent=MyContent+ nextline;
        }
    }   
}