Amending function parseInt

src/main/java/org/leolo/nrdatad/util/JSONUtil.java

@@ -8,8 +8,23 @@ public class JSONUtil {
     static Logger log = LogManager.getLogger();
 
     public static int parseInt(String val){
+        //Throw exception for empty string, or just a plus sign to maintenance backward
+        //compatibility with previous version.
+        if(val.length()==0 || "+".equals(val)){
+            throw new NumberFormatException();
+        }
         if (val.startsWith("+")) {
-            return Integer.parseInt(val.substring(1));
+            return _parseInt(val.substring(1));
+        }
+        return _parseInt(val);
+    }
+
+    private static int _parseInt(String val) {
+        if(val.length()==0){
+            return 0;
+        }
+        if (val.startsWith("0")) {
+            return _parseInt(val.substring(1));
         }
         return Integer.parseInt(val);
     }

src/test/java/org/leolo/nrdatad/util/JSONUtilTest.java

@@ -8,10 +8,24 @@ public class JSONUtilTest {
 
     @Test public void testJSONUtilParseIntNormal(){
         assertEquals(10, JSONUtil.parseInt("10"));
+        assertEquals(0, JSONUtil.parseInt("0"));
         assertEquals(10, JSONUtil.parseInt("+10"));
         assertEquals(-10, JSONUtil.parseInt("-10"));
     }
 
+    @Test public void testZeroPrefix(){
+        assertEquals(75, JSONUtil.parseInt("075"));
+        assertEquals(5, JSONUtil.parseInt("005"));
+        assertEquals(75, JSONUtil.parseInt("+075"));
+        assertEquals(5, JSONUtil.parseInt("+005"));
+        assertEquals(-75, JSONUtil.parseInt("-075"));
+        assertEquals(-5, JSONUtil.parseInt("-005"));
+    }
+
+    @Test public void testAllZero(){
+        assertEquals(0, JSONUtil.parseInt("00000000"));
+    }
+
     @Test(expected = NumberFormatException.class) public void testJSONUtilParseIntError1(){
         JSONUtil.parseInt("abcd");
     }