Java 中的 StringTokenizer

以下文章提供了 Java 中 StringTokenizer 的概述。 java 中的字串分詞器允許應用程式根據某些分隔符號將給定字串分解為標記。字串的每個分割部分稱為一個標記。字串標記產生器在內部使用 String 類別的 substring 方法來建立標記。字串分詞器在內部維護最後一個分詞的索引，並根據該索引計算下一個分詞。

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在本文中，我們將看到字串分詞器類別中可用的不同建構子的詳細描述。此外，還會有 Java 程式碼範例，展示字串分詞器實例的建立以及其中可用的不同方法的用法。

這是java字串分詞器的宣告：

public class StringTokenizer extends Object
implements Enumeration<Object>

字串分詞器建構子

字串分詞器是舊框架的一部分。

以下是字串分詞器類別的主要建構子。

• StringTokenizer (String str): 這會為指定的字串建立字串標記產生器。設定預設分隔符，可以是空格、製表符、換行符、回車符和換頁符。
• StringTokenizer (String str, String delim): 這會為指定的字串建立字串分詞器，並且將根據指定的分隔符號產生標記。
• StringTokenizer (String str, String delim, boolean returndelims): 這會為指定的字串建立字串分詞器，並且將根據指定的分隔符號產生標記。第三個參數是一個布林值，指定是否需要分隔符號作為標記。

可以根據需要使用上面指定的建構子。

Java 中字串分詞器的重要方法

Method Name	Description
boolean hasMoreTokens()	This method checks whether there are more tokens available.
String nextToken()	This method returns the value of the next available token.
String nextToken(String delim)	This method returns the value of the next available token based on provided delimiter.
boolean hasMoreElements()	This works similarly to hasMoreTokens.
Object nextElement()	This method is the same as nextToken but returns an object.
int countTokens()	This method returns a number of tokens.

方法名稱 描述 布林值 hasMoreTokens() 此方法檢查是否有更多可用令牌。 字串 nextToken() 此方法傳回下一個可用令牌的值。 字串 nextToken（字串 delim） 此方法根據提供的分隔符號傳回下一個可用標記的值。 布林值 hasMoreElements() 這與 hasMoreTokens 類似。 物件 nextElement() 此方法與 nextToken 相同，但傳回一個物件。 int countTokens() 此方法傳回多個標記。 表>

Examples

Given below are the examples:

Example #1

Let us see an example of a string tokenizer class showing the use of the first constructor.

Code:

package com.edubca.stringtokenizerdemo;
import java.util.*;
public class StringTokenizerDemo{
public static void main(String args[]){
//create string tokenizer instance
StringTokenizer st1 =
new StringTokenizer("This is Edubca Java Training");
System.out.println("Tokens separated by space are : ");
while (st1.hasMoreTokens())
System.out.println(st1.nextToken());
}
} <strong> Output:</strong>

Example #2

 In this example, we will see the use of the second constructor of a string tokenizer class that accepts a string and delimiter.

Code:

package com.edubca.stringtokenizerdemo;
import java.util.*;
public class StringTokenizerDemo{
public static void main(String args[]){
//create string tokenizer instance
StringTokenizer st1 =
new StringTokenizer("This,is,Edubca,Java,Training", ",");
System.out.println("Tokens separated by comma are : ");
while (st1.hasMoreTokens())
System.out.println(st1.nextToken());
}
}

Output:

In the above example, we have seen how to create tokens based on a given delimiter in the string tokenizer.

 

Example #3

In this example, we will see the use of the third constructor of a string tokenizer class that accepts a string, delimiter and boolean value.

Code:

package com.edubca.stringtokenizerdemo;
import java.util.*;
public class StringTokenizerDemo{
public static void main(String args[]){
//create string tokenizer instance
StringTokenizer st1 =
new StringTokenizer("This,is,Edubca,Java,Training", ",",true);
System.out.println("Tokens separated by comma are : ");
while (st1.hasMoreTokens())
System.out.println(st1.nextToken());
}
}

Output:

 

As we can see in the above output delimiter is also considered as a token.

Example #4

In this example, we will how to handle multiple delimiters in java string tokenizer.

Code:

package com.edubca.stringtokenizerdemo;
import java.util.*;
public class StringTokenizerDemo{
public static void main(String args[]){
String stringvalue = "http://127.0.0.1:8080/";
//create string tokenizer instance with multiple delimiters
StringTokenizer st1=new StringTokenizer (stringvalue,"://.");
System.out.println("Tokens generated are : ");
while (st1.hasMoreTokens())
System.out.println(st1.nextToken());
}
}

Here is the output produced after running the above code:

The above tokens are generated by tokenizing strings based on multiple tokens (://.).

Example #5

In this example, we will see the use of the count tokens method in the string tokenizer.

Code:

package com.edubca.stringtokenizerdemo;
import java.util.*;
public class StringTokenizerDemo{
public static void main(String args[]){
//create string tokenizer instance
StringTokenizer st1 = new StringTokenizer("This,is,Edubca,Java,Training", ",",true);
System.out.println("Number of available tokens are : " + st1.countTokens());
System.out.println("Tokens separated by comma are : ");
while (st1.hasMoreTokens())
System.out.println(st1.nextToken());
}
}

Output:

Conclusion – StringTokenizer in Java

From the above discussion, we have a clear understanding of what is string tokenizer in java, how it’s created, and what are the different methods available in the string tokenizer class.

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