Java无法读取文本文件中的其他行

Question

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I am unable to make the program read more than the first line of text in s.dat in this case.

Is there anything that I am missing? Any help is greatly appreciated.

Answer 1

Try something like this:

    //get the file location
    String filePath = "somefilepath.txt";

    //catch file IO errors
    try {
        //return the contents of the file
        String[] lines = Files.readAllLines(Paths.get(filePath))
    }

It will assign to the variable lines an array of all the string lines in the file. Then you can index into that array to get what you need or loop through it.

EDIT: to do it without arrays see this link:

http://www.programcreek.com/2011/03/java-read-a-file-line-by-line-code-example/

Answer 2

您正在做 if ..else 语句错误 在这两种情况下，您都将返回函数或中断循环，您将在第一次执行后终止循环，这就是发生这种情况的原因。

Answer 3

Your while loop reads (approximately):

while ( more lines ) {
     if ( match ) {
          return;
     } else {
          break;
     }
 }

Your loop will never execute more than once.

Remove the else clause, and put the println("Not found"); after the loop finishes.

Answer 4

Your code will only read the first line as you have placed return in if block and break in else block. It will come out of loop in both the cases.

Remove the return statement from the if block.

Answer 5

your else clause is wrong, if the first loop doesn't match, it's immediately exit while and doesn't do anything else. you should print the statement "Not found .... " after while loop end.