[+] LeetCode 28:前缀表（不减一）Java实现

problems/0028.实现strStr.md

@@ -649,6 +649,41 @@ class Solution {
 }
 ```
 
+```Java
+class Solution {
+    //前缀表（不减一）Java实现
+    public int strStr(String haystack, String needle) {
+        if (needle.length() == 0) return 0;
+        int[] next = new int[needle.length()];
+        getNext(next, needle);
+
+        int j = 0;
+        for (int i = 0; i < haystack.length(); i++) {
+            while (j > 0 && needle.charAt(j) != haystack.charAt(i)) 
+                j = next[j - 1];
+            if (needle.charAt(j) == haystack.charAt(i)) 
+                j++;
+            if (j == needle.length()) 
+                return i - needle.length() + 1;
+        }
+        return -1;
+
+    }
+    
+    private void getNext(int[] next, String s) {
+        int j = 0;
+        next[0] = 0;
+        for (int i = 1; i < s.length(); i++) {
+            while (j > 0 && s.charAt(j) != s.charAt(i)) 
+                j = next[j - 1];
+            if (s.charAt(j) == s.charAt(i)) 
+                j++;
+            next[i] = j; 
+        }
+    }
+}
+```
+
 Python3：
 
 ```python