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Java MatchResult用法及代码示例


java中的接口就是用来实现抽象的。它也被认为是类的蓝图。接口只能包含抽象方法，但它可能包含也可能不包含变量。换句话说，接口只能包含抽象方法和变量。 Java 仅通过接口支持多重继承。因此，接口在 Java 中具有更广泛的范围。

本文重点介绍MatchResult 接口。

MatchResult 接口：

java中的MatchResult接口表示匹配操作的结果或结论。它包含某些查询方法的定义，可用于确定与正则表达式的匹配结果。请注意，我们无法使用 MatchResult 接口更改组/组边界和匹配边界，但可以通过该接口轻松查看它们。该接口是在 Java 1.5 版本中引入的。

可以使用以下语法声明该接口，

用法:

public interface MatchResult

MatchResult接口的方法

下面详细讨论MatchResult接口的查询方法。

1.start()方法：该方法用于返回匹配的起始索引。

用法:

int start()

返回值：

  • integer: 表示第一个匹配的字符的索引

例子：

Java 


// Java program to illustrate the working of start() method
import java.io.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class GFG {
    // Initializing regular expression string
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    // Initializing input string
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    // Main method
    public static void main(String[] args)
    {
        // Compiling the given regular expression string
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // Applying matcher operation
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // Retrieve the MatchResult Object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Printing the starting index of the match
            System.out.println(
                "Starting index of the match: "
                + myResult.start());
        }
    }
}
输出 
Start index of the match: 0

2. start(int group)：该方法返回给定组在比赛期间捕获的序列的起始索引。

用法:

int start(int index)

参数：

  • index:它表示匹配器模式中捕获组的索引。

返回值：

  • non-negative integer:它表示该组所持有的第一个字符的索引
  • -1:仅当匹配成功但组don-not匹配任何内容时

例子：

Java 


// Java program to illustrate the working 
// of start(int index) method
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class GFG {
    // Initializing the regular expression string
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    // Initializing the input string
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    // Main method
    public static void main(String[] args)
    {
        // Compiling the regular expression string
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // Applying matcher operation
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // Retrieve the MatchResult Object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Prints the start index of the sequence
            // that was held by the given group during the
            // match.
            System.out.println("Second Capturing Group: "
                               + myResult.start(1));
        }
    }
}
输出 
Second Capturing Group: 0

3.end()：该方法返回最后一个字符匹配时的偏移量。

用法:

int end()

返回类型：它返回最后一个匹配字符之后的偏移量。

例子：

Java 


// Java program to illustrate the working of end() method
import java.io.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class GFG {
    // Initializing the regular expression string
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    // Initializing the input string
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    // Main method
    public static void main(String[] args)
    {
        // Compiling the regular expression string
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // Applying the matcher operation
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // Retrieve the MatchResult object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Prints the offset following the last
            // character matched
            System.out.println("First Capturing Group: "
                               + myResult.end());
        }
    }
}
输出 
First Capturing Group: 43

4. end(int index)：该方法返回最后一个字符匹配时的偏移量。

用法:

int end(int index)

参数：

  • index:它表示匹配器模式中捕获组的索引。

返回类型：它返回最后一个匹配字符之后的偏移量。

例子：

Java 


// Java program to illustrate the working
// of end(int index) method
import java.io.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class GFG {
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    public static void main(String[] args)
    {
        // Compiling regular expression string
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // applying matcher operation
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // get the MatchResult Object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Prints the offset after the last
            // character of the sequence held by
            // the given group at the time of match.
            System.out.println("Second Capturing Group: "
                               + myResult.end(1));
        }
    }
}
输出 
Second Capturing Group: 18

5. group()：该方法返回与前一个匹配项匹配的输入序列。

用法:

String group()

返回类型：

  • 一个字符串：与上一个匹配项匹配的序列。

例子：

Java 


// Java program to illustrate the working of group() method
import java.io.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class GFG {
    // Initializing regular expression string
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    // Initializing input string
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    // Main() method
    public static void main(String[] args)
    {
        // Compiling regular expression
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // Initiating the matcher object
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // Initiating the MatchResult object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Prints the input sequence matched by the
            // previous match.
            System.out.println("First Capturing Group"
                               + myResult.group());
        }
    }
}
输出 
First Capturing GroupHello World!, 41346, these are the numbers.

6. group(int index)：该方法用于返回上一次匹配操作时指定组所持有的输入序列。

用法:

int group(int index)

参数：

  • index: 在此匹配器模式中捕获的组的索引。

返回类型：

  • 一个字符串：它代表上一场比赛时该组捕获的序列
  • null:如果该组无法匹配输入的任何部分。

例子：

Java 


// Java program to illustrate the working
// of group(int index) method
import java.io.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class GFG {
    // Initializing regular expression string
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    // Initializing input string
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    // Main method
    public static void main(String[] args)
    {
        // Compiling regular expression
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // Instantiating matcher object
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // Instantiating MatchResult object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Prints the input subsequence that was held
            // by the given group during the last match
            // occurred.
            System.out.println(
                "Second Capturing Group - Match String: "
                + myResult.group(1));
        }
    }
}
输出 
Second Capturing Group - Match String: Hello World!, 4134

7. groupCount()：该方法指定匹配结果模式中捕获组的数量。

用法:

int groupCount()

返回类型：

  • integer:它表示匹配器模式中捕获组的数量。

例子：

Java 


// Java program to illustrate the working
// of groupCount() method
import java.io.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
class GFG {
    // Regular expression
    private static final String regularExpression
        = "(.*)(\\d+)(.*)";
    // Input string
    private static final String input
        = "Hello World!, 41346, these are the numbers.";
    public static void main(String[] args)
    {
        // Compiling regular expression
        Pattern myPattern
            = Pattern.compile(regularExpression);
        // Instantiating a matcher object
        Matcher myMatcher = myPattern.matcher(input);
        if (myMatcher.find()) {
            // Instantiating a MatchResult Object
            MatchResult myResult
                = myMatcher.toMatchResult();
            // Prints the number of capturing groups in this
            // match result's pattern.
            System.out.println(
                "The number of capturing groups is equal to: "
                + myResult.groupCount());
        }
    }
}
输出 
The number of capturing groups is equal to: 3


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注：本文由纯净天空筛选整理自bhuwanesh大神的英文原创作品 MatchResult Interface in Java。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。