不带锚点的Java中不区分大小写的字符串匹配

Question

注意:这不是关于不区分大小写匹配的问题.这是关于regex锚点的问题.

我在Java中进行基本的不区分大小写的匹配时遇到了很多麻烦:

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class match {
    public static void main(String[] args) {
        String prompt="das101.lo1>";
        String str="automate@DAS101.LO1>";

        Pattern ignore = Pattern.compile(prompt.toUpperCase(), Pattern.CASE_INSENSITIVE);
        Matcher mIgn  = ignore.matcher(str);
        if(mIgn.matches())
            System.out.println(str+" Matches " + prompt.toUpperCase());
        else
            System.out.println(str+" Doesn't Match " + prompt.toUpperCase());

        char[] cStr = str.toCharArray();
        char[] cPrompt = prompt.toUpperCase().toCharArray();

        /* Verify that strings match */
        for(int i=cPrompt.length-1, j=cStr.length-1; i>=0 && j>=0 ; --i,--j) {
            if (cPrompt[i]==cStr[j])
                System.out.println("Same: "+ cPrompt[i]+":" + cStr[j]);
            else
                System.out.println("Different: "+ cPrompt[i]+":" + cStr[j]);
        }
    }
}

输出:

samveen@javadev-tahr:/tmp$ javac match.java
samveen@javadev-tahr:/tmp$ java match
automate@DAS101.LO1> Doesn't Match DAS101.LO1>
Same: >:>
Same: 1:1
Same: O:O
Same: L:L
Same: .:.
Same: 1:1
Same: 0:0
Same: 1:1
Same: S:S
Same: A:A
Same: D:D

如果我if(mIgn.matches())改为if(mIgn.find()),我会得到这个简单的字符串模式匹配工作:

samveen@javadev-tahr:/tmp$ javac match.java
samveen@javadev-tahr:/tmp$ java match
automate@DAS101.LO1> Matches DAS101.LO1>
Same: >:>
Same: 1:1
Same: O:O
Same: L:L
Same: .:.
Same: 1:1
Same: 0:0
Same: 1:1
Same: S:S
Same: A:A
Same: D:D

我哪里错了？

我提到了Java RegEx中的Case-Insensitive Matching和Pattern Class的方法

Answer 1

String.matches要求整个字符串与模式匹配.好像模式有隐含的"^ ... $".

Pattern ignore = Pattern.compile(".*" + Pattern.quote(prompt) + ".*",
    Pattern.CASE_INSENSITIVE);

是为了寻找匹配.

这可以使用原始模式完成:

if (mIgn.find()) {
    System.out.println("Found at position " + mIgn.start());
}