fix doesObjectExist bug.

Author: huiguangjun

src/main/java/com/aliyun/oss/internal/OSSObjectOperation.java

@@ -963,7 +963,7 @@ public boolean doesObjectExistWithRedirect(GenericRequest genericRequest) throws
             ossObject = this.getObject(getObjectRequest);
             return true;
         } catch (OSSException e) {
-            if (e.getErrorCode() == OSSErrorCode.NO_SUCH_BUCKET || e.getErrorCode() == OSSErrorCode.NO_SUCH_KEY) {
+            if (e.getErrorCode().equals(OSSErrorCode.NO_SUCH_BUCKET) || e.getErrorCode().equals(OSSErrorCode.NO_SUCH_KEY)) {
                 return false;
             }
             throw e;

src/test/java/com/aliyun/oss/integrationtests/DoesObjectExistTest.java

@@ -90,6 +90,13 @@ public void testExistingBucketAndNonExistentObject() {
         } catch (Exception e) {
             Assert.fail(e.getMessage());
         }
+
+        try {
+            boolean exist = ossClient.doesObjectExist(bucketName, nonexistentKey, false);
+            Assert.assertFalse(exist);
+        } catch (Exception e) {
+            Assert.fail(e.getMessage());
+        }
     }
 
     @Test