java - .length 无法解析或不是字段

Question

我已经非常努力地用以前的类似答案来解决这个问题，但我仍然无法看到我的问题，希望你能提供帮助。我的代码如下所示:

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();

我收到一个错误:

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，DataInputStream 中的方法 readLine() 已弃用。

其次，此方法返回一个 String，它没有 field length。它只有方法length()。 length 是数组的一个属性。