逐行将文本文件读取为字符串

Question

How do I read the contents of a text file line by line into String without using a BufferedReader ?

For example, I have a text file that looks like this inside:

Purlplemonkeys
greenGorilla

I would want to create two strings , then use something like this

File file = new File(System.getProperty("user.dir") + "\Textfile.txt");
String str = new String(file.nextLine());
String str2 = new String(file.nextLine());

That way it assigns str the value of "Purlplemonkeys" , and str2 the value of "greenGorilla" .

Answer 1

You can read text file to list:

List<String> lst = Files.readAllLines(Paths.get("C:\\test.txt"));

and then access each line as you want

PS Files - java.nio.file.Files

Answer 2

You should use an ArrayList .

File file = new File(fileName);
Scanner input = new Scanner(file);
List<String> list = new ArrayList<String>();

while (input.hasNextLine()) {
    list.add(input.nextLine());
}

Then you can access to one specific element of your list from its index as next:

System.out.println(list.get(0));

which will give you the first line (ie: Purlplemonkeys)

Answer 3

If you use Java 7 or later

List<String> lines = Files.readAllLines(new File(fileName));

for(String line : lines){
   // Do whatever you want
   System.out.println(line);
}

Answer 4

Sinse JDK 7 is quite easy to read a file into lines:

List<String> lines = Files.readAllLines(new File("text.txt").toPath())

String p1 = lines.get(0);
String p2 = lines.get(1);

Answer 5

How about using commons-io :

List<String> lines = org.apache.commons.io.IOUtils.readLines(new FileReader(file));

//Direct access if enough lines read
if(lines.size() > 2) {
  String line1 = lines.get(0);
  String line2 = lines.get(1);
}

//Iterate over all lines
for(String line : lines) {
  //Do something with lines
}

//Using Lambdas
list.forEach(line -> {
  //Do something with line
});

Answer 6

You can use apache.commons.io.LineIterator

LineIterator it = FileUtils.lineIterator(file, "UTF-8");
 try {
   while (it.hasNext()) {
     String line = it.nextLine();
     // do something with line
   }
 } finally {
   it.close();
 }

One can also validate line by overriding boolean isValidLine(String line) method. refer doc

Answer 7

File file = new File(fileName);
Scanner input = new Scanner(file);
while (input.hasNextLine()) {
  System.out.println(input.nextLine());
}