java.util.regex.Matcher.start(int group)方法返回在上一次匹配操作期间给定组捕获的子序列的起始索引。
int start(int group) - 声明
以下是 java.util.regex.Matcher.start(int group)方法的声明。
public int start(int group)
group - 该匹配器模式中捕获组的索引。
int start(int group) - 返回值
该组捕获的第一个字符的索引；如果匹配成功，但组本身不匹配任何内容，则为-1。
int start(int group) - 异常
IllegalStateException - 如果尚未尝试匹配，或者先前的匹配操作失败。
IndexOutOfBoundsException - 如果模式中没有具有给定索引的捕获组。
int start(int group) - 示例
下面的示例显示java.util.regex.Matcher.start(int group)方法的用法。
package com.learnfk;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class MatcherDemo {
private static String REGEX = "(a*b)(foo)";
private static String INPUT = "aabfooaabfooabfoob";
private static String REPLACE = "-";
public static void main(String[] args) {
Pattern pattern = Pattern.compile(REGEX);
</span><span class="com">//获取匹配器对象</span><span class="pln">
</span><span class="typ">Matcher</span><span class="pln"> matcher </span><span class="pun">=</span><span class="pln"> pattern</span><span class="pun">.</span><span class="pln">matcher</span><span class="pun">(</span><span class="pln">INPUT</span><span class="pun">);</span><span class="pln">
</span><span class="kwd">while</span><span class="pun">(</span><span class="pln">matcher</span><span class="pun">.</span><span class="pln">find</span><span class="pun">())</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
</span><span class="com">//打印给定组捕获的子序列的开始索引。</span><span class="pln">
</span><span class="typ">System</span><span class="pun">.</span><span class="kwd">out</span><span class="pun">.</span><span class="pln">println</span><span class="pun">(</span><span class="str">"Second Capturing Group, (foo) Match String start():
"</span><span class="pun">+</span><span class="pln">matcher</span><span class="pun">.</span><span class="pln">start</span><span class="pun">(</span><span class="lit">1</span><span class="pun">));</span><span class="pln">
</span><span class="pun">}</span><span class="pln">
}
}
让无涯教程编译并运行以上程序，这将产生以下输出-
Second Capturing Group, (foo) Match String start(): 0 Second Capturing Group, (foo) Match String start(): 6 Second Capturing Group, (foo) Match String start(): 12
