java - 发现 java 中 Matcher 的 find() 方法出现意外行为

Question

public class Test2 {

    public static void main(String[] args) 
    {
        String country="india";
        String arry[]={"indians are great","i am india","govt","dhoomindian","prashindiahim","i jdsdindi a","i n d i a"};
        Pattern p = Pattern.compile(".*" + country + ".*");
        for (String stringVal : arry) 
        {
            Matcher m = p.matcher(stringVal);
            System.out.println("test1..."+" -->"+stringVal+"  "+m.find());
            System.out.println("test2..."+" -->"+stringVal+"  "+m.find());
        }
    }
}


OUTPUT::

*test1... -->indians are great  true*   ----1
**test2... -->indians are great  false**-----2
*test1... -->i am india  true*   ----3
**test2... -->i am india  false** ---4
test1... -->govt  false
test2... -->govt  false
test1... -->dhoomindian  true----5
test2... -->dhoomindian  false----6
test1... -->prashindiahim  true----7
test2... -->prashindiahim  false----8
test1... -->i jdsdindi a  false
test2... -->i jdsdindi a  false
test1... -->i n d i a  false
test2... -->i n d i a  false

您可以看到相同的 find() 方法在第一行中给出 true，在前面的第二行中给出 false。您可以从第 1-8 行看到行为。谁能告诉我为什么我会遇到 find() 方法的这种行为。

Answer 1

来自docs

public boolean find() Attempts to find the next subsequence of the input sequence that matches the pattern. This method starts at the beginning of this matcher's region, or, if a previous invocation of the method was successful and the matcher has not since been reset, at the first character not matched by the previous match.