Fix for issue influxdata#117.

Author: antjori

src/main/java/org/influxdb/dto/Point.java

@@ -286,9 +286,13 @@ private StringBuilder concatenateFields() {
 		numberFormat.setMinimumFractionDigits(1);
 
 		for (Entry<String, Object> field : this.fields.entrySet()) {
-			sb.append(KEY_ESCAPER.escape(field.getKey())).append("=");
 			loops++;
 			Object value = field.getValue();
+			if (value == null) {
+				continue;
+			}
+
+			sb.append(KEY_ESCAPER.escape(field.getKey())).append("=");
 			if (value instanceof String) {
 				String stringValue = (String) value;
 				sb.append("\"").append(FIELD_ESCAPER.escape(stringValue)).append("\"");
@@ -304,6 +308,7 @@ private StringBuilder concatenateFields() {
 				sb.append(",");
 			}
 		}
+
 		return sb;
 	}
 

src/test/java/org/influxdb/dto/PointTest.java

@@ -1,14 +1,15 @@
 package org.influxdb.dto;
 
-import org.testng.annotations.Test;
-import static org.assertj.core.api.Assertions.*;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicLong;
 
+import org.testng.annotations.Test;
+
 /**
  * Test for the Point DTO.
  *
@@ -156,4 +157,20 @@ public void testEscapingOfKeysAndValues() {
 		assertThat(point.lineProtocol()).asString().isEqualTo("test,foo=bar\\=baz a=1.0 1");
 	}
 
+	/**
+	 * Test for issue #117.
+	 */
+	@Test
+	public void testIgnoreNullPointerValue() {
+		// Test omission of null values
+		Point.Builder pointBuilder = Point.measurement("nulltest").time(1, TimeUnit.NANOSECONDS).tag("foo", "bar");
+
+		pointBuilder.field("field1", "value1");
+		pointBuilder.field("field2", null);
+		pointBuilder.field("field3", (Integer) 1);
+
+		Point point = pointBuilder.build();
+
+		assertThat(point.lineProtocol()).asString().isEqualTo("nulltest,foo=bar field1=\"value1\",field3=1.0 1");
+	}
 }