如何从字符串（Android）中拉出子字符串？

Question

I'm trying to pull out sub-string from a string using java.Util.Scan

The sub-string is between " <TD class=MoreB align=center> " and " </TD> " in the original string

This is the code:

public static String pullStringOut(String str)
{
    String stringer = null;

    Scanner scanner = new Scanner(str);
    scanner.findInLine("<TD class=MoreB align=center>");

    while (scanner.hasNext() && scanner.next() != "</TD>")
    {
        stringer+= " " + (scanner.next());
    }

    return stringer;
}

but it's not working well.

From the original string:

" <TD class=MoreB align=center>TextTextTextText</TD></TR></TABLE> } "

I get the following result:

" TextTextTextText</TD></TR></TABLE> } "

Instead of the expected

"TextTextTextText"

Answer 1

A few problems:

• scanner.next() != "</TD>" will always be true as the operands will not be the same object. Use !scanner.next().equals("</TD>") . From Reference Equality Operators == and != section of the JLS :

  The result of != is false if the operand values are both null or both refer to the same object or array; otherwise, the result is true.

• scanner.next() is being called twice on each iteration of the loop. Change to:

   String line; while (scanner.hasNext() && !(line = scanner.next()).equals("</TD>")) { stringer+= " " + line; } 

Answer 2

You can use a Regex Expresssion.

Something like :

    Pattern p = Pattern.compile("/\<TD class=MoreB align=center>(.*)\<\/td\>/"); 
Matcher m = p.matcher(str); 
while(m.find()) { 

  //do whatever you want here
 }

(not tested)

Answer 3

Here is an alternate solution:

String tvt ="<TD class=MoreB align=center>TextTextTextText</TD></TR></TABLE> }" //your original string
                String s ="<TD class=MoreB align=center>";
                String f= "</TD>";
                int sindex =tvt.indexOf(s);
                int findex =tvt.indexOf(f);
                String fs = "";
                if(sindex!=-1 && findex!=-1)
                fs=tvt.substring(sindex+s.length(), findex); // your desired substring