src/org/redkale/net/http/Rest.java

@@ -111,6 +111,8 @@ public final class Rest {
         if (!java.lang.reflect.Modifier.isPublic(mod)) return null;
         if (java.lang.reflect.Modifier.isAbstract(mod)) return null;
 
+        final java.lang.reflect.Type futureRestOutputType = new TypeToken<CompletableFuture<RestOutput>>() {
+        }.getType();
         final String serviceDesc = Type.getDescriptor(serviceType);
         final String webServletDesc = Type.getDescriptor(WebServlet.class);
         final String reqDesc = Type.getDescriptor(HttpRequest.class);
@@ -259,6 +261,7 @@ public final class Rest {
         for (final MappingEntry entry : entrys) {
             final Method method = entry.mappingMethod;
             final Class returnType = method.getReturnType();
+            final java.lang.reflect.Type returnGenericType = method.getGenericReturnType();
             final String methodDesc = Type.getMethodDescriptor(method);
             final Parameter[] params = method.getParameters();
 
@@ -925,6 +928,14 @@ public final class Rest {
                 mv.visitMethodInsn(INVOKEVIRTUAL, respInternalName, "finish", "(Ljava/lang/String;)V", false);
                 mv.visitInsn(RETURN);
                 maxLocals++;
+            } else if (futureRestOutputType == returnGenericType) {
+                mv.visitVarInsn(ASTORE, maxLocals);
+                mv.visitVarInsn(ALOAD, 0);
+                mv.visitVarInsn(ALOAD, 2);
+                mv.visitVarInsn(ALOAD, maxLocals);
+                mv.visitMethodInsn(INVOKEVIRTUAL, newDynName, "finishJson", "(" + respDesc + futureDesc + ")V", false);
+                mv.visitInsn(RETURN);
+                maxLocals++;
             } else if (CompletableFuture.class.isAssignableFrom(returnType)) {
                 mv.visitVarInsn(ASTORE, maxLocals);
                 mv.visitVarInsn(ALOAD, 2);//response

src/org/redkale/net/http/RestHttpServlet.java

@@ -6,7 +6,8 @@
 package org.redkale.net.http;
 
 import java.io.*;
-import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.*;
+import java.util.logging.Level;
 import jdk.internal.org.objectweb.asm.*;
 import static jdk.internal.org.objectweb.asm.Opcodes.*;
 import org.redkale.util.*;
@@ -22,6 +23,22 @@ public abstract class RestHttpServlet<T> extends HttpBaseServlet {
 
     protected abstract T currentUser(HttpRequest req) throws IOException;
 
+    protected void finishJson(final HttpResponse response, CompletableFuture<RestOutput> future) throws IOException {
+        future.whenCompleteAsync((output, e) -> {
+            if (e != null) {
+                response.getContext().getLogger().log(Level.WARNING, "Servlet occur, forece to close channel. request = " + response.getRequest(), e);
+                response.finish(500, null);
+                return;
+            }
+            try {
+                finishJson(response, output);
+            } catch (IOException ioe) {
+                response.getContext().getLogger().log(Level.WARNING, "Servlet finish RestOutput occur, forece to close channel. request = " + response.getRequest(), ioe);
+                response.finish(500, null);
+            }
+        }, response.getContext().getExecutor());
+    }
+
     protected void finishJson(final HttpResponse response, RestOutput output) throws IOException {
         if (output == null) {
             response.finishJson(output);