Merge pull request networknt#174 from networknt/feature/util_file_to_bytebuffer

feat(util): Add toByteBuffer overload util method to convert files.

Author: stevehu

utility/pom.xml

@@ -54,6 +54,10 @@
             <groupId>org.owasp.encoder</groupId>
             <artifactId>encoder</artifactId>
         </dependency>
+        <dependency>
+            <groupId>commons-io</groupId>
+            <artifactId>commons-io</artifactId>
+        </dependency>
 
         <dependency>
             <groupId>ch.qos.logback</groupId>

utility/src/main/java/com/networknt/utility/NioUtils.java

@@ -1,5 +1,6 @@
 package com.networknt.utility;
 
+import org.apache.commons.io.IOUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -238,6 +239,22 @@ public static ByteBuffer toByteBuffer(String s) {
         return buffer;
     }
 
+    /**
+     * Convert a File into a ByteBuffer
+     * @param file File to be converted
+     * @return ByteBuffer containing the file
+     */
+    public static ByteBuffer toByteBuffer(File file) {
+        ByteBuffer buffer = ByteBuffer.allocateDirect((int) file.length());
+        try {
+            buffer.put(IOUtils.toByteArray(new FileInputStream(file)));
+        } catch (IOException e) {
+            logger.error("Failed to write file to byte array: " + e.getMessage());
+        }
+        buffer.flip();
+        return buffer;
+    }
+
     /**
      * get temp dir from OS.
      *