扫描仪类的next()方法 (Scanner Class next() method)

Syntax:

句法：

public String next();    public String next(Pattern patt);    public String next(String patt);

• next() method is available in java.util package.

  next()方法在java.util包中可用。

• next() method is used to search & get the next complete token from this Scanner and a token is preceded & followed by the input that meets the pattern.

  next()方法用于搜索并从此扫描器中获取下一个完整令牌，令牌之前和之后是符合模式的输入。

• next(Pattern patt) method is used to retrieve the next token when it meets the given Pattern (patt).

  next(Pattern patt)方法用于在遇到给定Pattern(patt)时检索下一个标记。

• next(String patt) method is used to retrieve the next token when it meets the pattern formed from the given String (patt).

  next(String patt)方法用于在下一个令牌遇到由给定String(patt)形成的模式时检索下一个令牌。

• These methods may throw an exception at the time of representing a token as a pattern.

  这些方法在将令牌表示为模式时可能会引发异常。

  • NoSuchElementException: This exception may throw when no more token exists.NoSuchElementException ：如果不再存在令牌，则可能引发此异常。
  • IllegalStateException: This exception may throw when this Scanner is not opened.IllegalStateException ：如果未打开此扫描器，则可能引发此异常。

• These are non-static methods, it is accessible with class object & if we try to access these methods with the class name then we will get an error.

  这些是非静态方法，可通过类对象访问；如果尝试使用类名称访问这些方法，则会收到错误消息。

Parameter(s):

参数：

• In the first case, next(),

  在第一种情况下， next() ，

  • It does not accept any parameter.

• In the first case, next(Pattern patt),

  在第一种情况下， next(Pattern patt) ，

  • Pattern patt – represents the pattern (patt) to read.
  • 模式patt –表示要读取的模式(patt)。

• In the second case, next(String patt),

  在第二种情况下， next(String patt) ，

  • String patt – represents the string to define the pattern (patt) to read.
  • 字符串patt –表示用于定义要读取的图案(图案)的字符串。

Return value:

返回值：

In all the cases, the return type of the method is String, it retrieves the next token

在所有情况下，方法的返回类型为String ，它检索下一个标记

Example 1:

范例1：

// Java program is to demonstrate the example // of next() method of Scannerimport java.util.*;import java.util.regex.*;public class Next {
    public static void main(String[] args) {
     String str = "Java Programming! 3 * 8= 24";  // Instantiates Scanner  Scanner sc = new Scanner(str);  // By using next() method is to  // display the next complete   // token  String next = sc.next();  System.out.println("sc.next(): " + next);  // Scanner closed  sc.close(); }}

Output

输出量

sc.next(): Java

Example 2:

范例2：

import java.util.*;import java.util.regex.*;public class Next {
    public static void main(String[] args) {
     String str = "Java Programming! 3 * 8= 24";  // Instantiates Scanner  Scanner sc = new Scanner(str);  // By using net(Pattern) method is  // to return the next token when it meets  // the given pattern  String next_p = sc.next(Pattern.compile("J..a"));  System.out.println("sc.next(Pattern.compile(J..a)): " + next_p);  // Scanner closed  sc.close(); }}

Output

输出量

sc.next(Pattern.compile(J..a)): Java

Example 3:

范例3：

import java.util.*;import java.util.regex.*;public class Next {
    public static void main(String[] args) {
     String str = "Java Programming! 3 * 8= 24";  // Instantiates Scanner  Scanner sc = new Scanner(str);  // By using net(String) method is  // to return the next token when it meets  // the given pattern formed from the given  // string  String next_s = sc.next("Java");  System.out.println("sc.next(Java)): " + next_s);  // Scanner closed  sc.close(); }}

Output

输出量

sc.next(Java)): Java

翻译自: