refactor StatServlet

src/main/java/com/alibaba/druid/util/StringUtils.java

@@ -0,0 +1,70 @@
+package com.alibaba.druid.util;
+
+/**
+ * @author sandzhang<sandzhangtoo@gmail.com>
+ */
+public class StringUtils {
+
+    /**
+     * Example: subString("12345","1","4")=23
+     * 
+     * @param src
+     * @param start
+     * @param to
+     * @return
+     */
+    public static Integer subStringToInteger(String src, String start, String to) {
+        return stringToInteger(subString(src, start, to));
+    }
+
+    /**
+     * Example: subString("abcd","a","c")="b"
+     * 
+     * @param src
+     * @param start
+     * @param to
+     * @return
+     */
+    public static String subString(String src, String start, String to) {
+        int indexFrom = src.indexOf(start);
+        int indexTo = src.indexOf(to);
+        if (indexFrom < 0 || indexTo < 0 || indexFrom < indexTo) {
+            return null;
+        }
+        indexFrom += start.length();
+        indexTo += to.length();
+        return src.substring(indexFrom, indexTo);
+
+    }
+
+    /**
+     * @param in
+     * @return
+     */
+    public static Integer stringToInteger(String in) {
+        if (in == null) return null;
+        in = in.trim();
+        if (in.length() == 0) return null;
+        try {
+            return Integer.parseInt(in);
+        } catch (NumberFormatException e) {
+            return null;
+        }
+    }
+
+    /**
+     * @param in
+     * @return
+     */
+    public static Long stringToLong(String in) {
+        if (in == null) return null;
+        in = in.trim();
+        if (in.length() == 0) return null;
+        try {
+            return Long.parseLong(in);
+        } catch (NumberFormatException e) {
+            return null;
+        }
+    }
+
+}