اسکنر جاوا — به زبان ساده

1@Test
2public void whenReadFileWithScanner_thenCorrect() throws IOException{
3    Scanner scanner = new Scanner(new File("test.txt"));
4 
5    assertTrue(scanner.hasNext());
6    assertEquals("Hello", scanner.next());
7    assertEquals("world", scanner.next());
8 
9    scanner.close();
10}

1@Test
2public void whenConvertInputStreamToString_thenConverted()
3  throws IOException {
4    String expectedValue = "Hello world";
5    FileInputStream inputStream 
6      = new FileInputStream("test.txt");
7     
8    Scanner scanner = new Scanner(inputStream);
9    scanner.useDelimiter("A");
10 
11    String result = scanner.next();
12    assertEquals(expectedValue, result);
13 
14    scanner.close();
15}

1@Test
2public void whenReadUsingBufferedReader_thenCorrect() 
3  throws IOException {
4    String firstLine = "Hello world";
5    String secondLine = "Hi, John";
6    BufferedReader reader 
7      = new BufferedReader(new FileReader("test.txt"));
8 
9    String result = reader.readLine();
10    assertEquals(firstLine, result);
11 
12    result = reader.readLine();
13    assertEquals(secondLine, result);
14 
15    reader.close();
16}

1@Test
2public void whenReadUsingScanner_thenCorrect() 
3  throws IOException {
4    String firstLine = "Hello world";
5    FileInputStream inputStream 
6      = new FileInputStream("test.txt");
7    Scanner scanner = new Scanner(inputStream);
8 
9    String result = scanner.nextLine();
10    assertEquals(firstLine, result);
11 
12    scanner.useDelimiter(", ");
13    assertEquals("Hi", scanner.next());
14    assertEquals("John", scanner.next());
15 
16    scanner.close();
17}

1@Test
2public void whenReadingInputFromConsole_thenCorrect() {
3    String input = "Hello";
4    InputStream stdin = System.in;
5    System.setIn(new ByteArrayInputStream(input.getBytes()));
6 
7    Scanner scanner = new Scanner(System.in);
8 
9    String result = scanner.next();
10    assertEquals(input, result);
11 
12    System.setIn(stdin);
13    scanner.close();
14}

1scanner.nextLine();

1scanner.nextInt();

1@Test
2public void whenValidateInputUsingScanner_thenValidated() 
3  throws IOException {
4    String input = "2000";
5    InputStream stdin = System.in;
6    System.setIn(new ByteArrayInputStream(input.getBytes()));
7 
8    Scanner scanner = new Scanner(System.in);
9 
10    boolean isIntInput = scanner.hasNextInt();
11    assertTrue(isIntInput);
12 
13    System.setIn(stdin);
14    scanner.close();
15}

1@Test
2public void whenScanString_thenCorrect() 
3  throws IOException {
4    String input = "Hello 1 F 3.5";
5    Scanner scanner = new Scanner(input);
6 
7    assertEquals("Hello", scanner.next());
8    assertEquals(1, scanner.nextInt());
9    assertEquals(15, scanner.nextInt(16));
10    assertEquals(3.5, scanner.nextDouble(), 0.00000001);
11 
12    scanner.close();
13}

1@Test
2public void whenFindPatternUsingScanner_thenFound() throws IOException {
3    String expectedValue = "world";
4    FileInputStream inputStream = new FileInputStream("test.txt");
5    Scanner scanner = new Scanner(inputStream);
6 
7    String result = scanner.findInLine("wo..d");
8    assertEquals(expectedValue, result);
9 
10    scanner.close();
11}

1@Test
2public void whenFindPatternInHorizon_thenFound() 
3  throws IOException {
4    String expectedValue = "world";
5    FileInputStream inputStream = new FileInputStream("test.txt");
6    Scanner scanner = new Scanner(inputStream);
7 
8    String result = scanner.findWithinHorizon("wo..d", 5);
9    assertNull(result);
10 
11    result = scanner.findWithinHorizon("wo..d", 100);
12    assertEquals(expectedValue, result);
13 
14    scanner.close();
15}

1@Test
2public void whenSkipPatternUsingScanner_thenSkipped() 
3  throws IOException {
4    FileInputStream inputStream = new FileInputStream("test.txt");
5    Scanner scanner = new Scanner(inputStream);
6 
7    scanner.skip(".e.lo");
8 
9    assertEquals("world", scanner.next());
10 
11    scanner.close();
12}

1@Test
2public void whenChangeScannerDelimiter_thenChanged() 
3  throws IOException {
4    String expectedValue = "Hello world";
5    String[] splited = expectedValue.split("o");
6 
7    FileInputStream inputStream = new FileInputStream("test.txt");
8    Scanner scanner = new Scanner(inputStream);
9    scanner.useDelimiter("o");
10 
11    assertEquals(splited[0], scanner.next());
12    assertEquals(splited[1], scanner.next());
13    assertEquals(splited[2], scanner.next());
14 
15    scanner.close();
16}

1@Test
2public void whenReadWithScannerTwoDelimiters_thenCorrect() 
3  throws IOException {
4    Scanner scanner = new Scanner(new File("test.txt"));
5    scanner.useDelimiter(",|-");
6 
7    assertEquals("John", scanner.next());
8    assertEquals("Adam", scanner.next());
9    assertEquals("Tom", scanner.next());
10 
11    scanner.close();
12}