优化ByteArray

src/main/java/org/redkale/net/http/HttpResponse.java

@@ -1300,7 +1300,9 @@ public class HttpResponse extends Response<HttpContext, HttpRequest> {
                 addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8"));
             }
         }
-        this.contentType = MimeType.getByFilename(filename == null || filename.isEmpty() ? file.getName() : filename);
+        if (this.contentType == null) {
+            this.contentType = MimeType.getByFilename(filename == null || filename.isEmpty() ? file.getName() : filename);
+        }
         if (this.contentType == null) {
             this.contentType = "application/octet-stream";
         }

src/main/java/org/redkale/util/ByteArray.java

@@ -7,8 +7,10 @@ package org.redkale.util;
 
 import java.io.*;
 import java.nio.ByteBuffer;
+import java.nio.channels.ReadableByteChannel;
 import java.nio.charset.*;
 import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicInteger;
 
 /**
  * 简单的byte[]操作类。
@@ -60,6 +62,33 @@ public final class ByteArray implements ByteTuple {
         return true;
     }
 
+    public ReadableByteChannel toChannel() {
+        final byte[] bytes = getBytes();
+        final AtomicInteger offset = new AtomicInteger();
+
+        return new ReadableByteChannel() {
+            @Override
+            public int read(ByteBuffer dst) throws IOException {
+                if (offset.get() >= bytes.length) {
+                    return -1;
+                }
+                int len = Math.min(bytes.length - offset.get(), dst.remaining());
+                dst.put(bytes, offset.get(), len);
+                offset.addAndGet(len);
+                return len;
+            }
+
+            @Override
+            public boolean isOpen() {
+                return true;
+            }
+
+            @Override
+            public void close() throws IOException {
+            }
+        };
+    }
+
     /**
      * 设置count的新位置
      *