001/* 002 * Copyright 2002-2020 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.http.codec.json; 018 019import java.nio.charset.Charset; 020import java.nio.charset.StandardCharsets; 021import java.util.Arrays; 022import java.util.Map; 023 024import com.fasterxml.jackson.databind.ObjectMapper; 025import org.reactivestreams.Publisher; 026import reactor.core.publisher.Flux; 027 028import org.springframework.core.ResolvableType; 029import org.springframework.core.codec.StringDecoder; 030import org.springframework.core.io.buffer.DataBuffer; 031import org.springframework.core.io.buffer.DataBufferFactory; 032import org.springframework.core.io.buffer.DefaultDataBufferFactory; 033import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder; 034import org.springframework.lang.Nullable; 035import org.springframework.util.MimeType; 036import org.springframework.util.MimeTypeUtils; 037 038/** 039 * Decode a byte stream into JSON and convert to Object's with Jackson 2.9, 040 * leveraging non-blocking parsing. 041 * 042 * @author Sebastien Deleuze 043 * @author Rossen Stoyanchev 044 * @since 5.0 045 * @see Jackson2JsonEncoder 046 */ 047public class Jackson2JsonDecoder extends AbstractJackson2Decoder { 048 049 private static final StringDecoder STRING_DECODER = StringDecoder.textPlainOnly(Arrays.asList(",", "\n"), false); 050 051 private static final ResolvableType STRING_TYPE = ResolvableType.forClass(String.class); 052 053 054 public Jackson2JsonDecoder() { 055 super(Jackson2ObjectMapperBuilder.json().build()); 056 } 057 058 public Jackson2JsonDecoder(ObjectMapper mapper, MimeType... mimeTypes) { 059 super(mapper, mimeTypes); 060 } 061 062 @Override 063 protected Flux<DataBuffer> processInput(Publisher<DataBuffer> input, ResolvableType elementType, 064 @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) { 065 066 Flux<DataBuffer> flux = Flux.from(input); 067 if (mimeType == null) { 068 return flux; 069 } 070 071 // Jackson asynchronous parser only supports UTF-8 072 Charset charset = mimeType.getCharset(); 073 if (charset == null || StandardCharsets.UTF_8.equals(charset) || StandardCharsets.US_ASCII.equals(charset)) { 074 return flux; 075 } 076 077 // Potentially, the memory consumption of this conversion could be improved by using CharBuffers instead 078 // of allocating Strings, but that would require refactoring the buffer tokenization code from StringDecoder 079 080 MimeType textMimeType = new MimeType(MimeTypeUtils.TEXT_PLAIN, charset); 081 Flux<String> decoded = STRING_DECODER.decode(input, STRING_TYPE, textMimeType, null); 082 DataBufferFactory factory = new DefaultDataBufferFactory(); 083 return decoded.map(s -> factory.wrap(s.getBytes(StandardCharsets.UTF_8))); 084 } 085 086}