spring-batch JacksonJsonObjectReader 源码
spring-batch JacksonJsonObjectReader 代码
文件路径：/spring-batch-infrastructure/src/main/java/org/springframework/batch/item/json/JacksonJsonObjectReader.java
/*
* Copyright 2018-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.batch.item.json;
import java.io.IOException;
import java.io.InputStream;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.batch.item.ParseException;
import org.springframework.core.io.Resource;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
/**
* Implementation of {@link JsonObjectReader} based on
* <a href="https://github.com/FasterXML/jackson">Jackson</a>.
*
* @param <T> type of the target object
* @author Mahmoud Ben Hassine
* @since 4.1
*/
public class JacksonJsonObjectReader<T> implements JsonObjectReader<T> {
private final Class<? extends T> itemType;
private JsonParser jsonParser;
private ObjectMapper mapper;
private InputStream inputStream;
/**
* Create a new {@link JacksonJsonObjectReader} instance.
* @param itemType the target item type
*/
public JacksonJsonObjectReader(Class<? extends T> itemType) {
this(new ObjectMapper(), itemType);
}
public JacksonJsonObjectReader(ObjectMapper mapper, Class<? extends T> itemType) {
this.mapper = mapper;
this.itemType = itemType;
}
/**
* Set the object mapper to use to map Json objects to domain objects.
* @param mapper the object mapper to use
* @see #JacksonJsonObjectReader(ObjectMapper, Class)
*/
public void setMapper(ObjectMapper mapper) {
Assert.notNull(mapper, "The mapper must not be null");
this.mapper = mapper;
}
@Override
public void open(Resource resource) throws Exception {
Assert.notNull(resource, "The resource must not be null");
this.inputStream = resource.getInputStream();
this.jsonParser = this.mapper.getFactory().createParser(this.inputStream);
Assert.state(this.jsonParser.nextToken() == JsonToken.START_ARRAY,
"The Json input stream must start with an array of Json objects");
}
@Nullable
@Override
public T read() throws Exception {
try {
if (this.jsonParser.nextToken() == JsonToken.START_OBJECT) {
return this.mapper.readValue(this.jsonParser, this.itemType);
}
}
catch (IOException e) {
throw new ParseException("Unable to read next JSON object", e);
}
return null;
}
@Override
public void close() throws Exception {
this.inputStream.close();
this.jsonParser.close();
}
}
相关信息
相关文章
spring-batch GsonJsonObjectMarshaller 源码
spring-batch GsonJsonObjectReader 源码
spring-batch JacksonJsonObjectMarshaller 源码
spring-batch JsonFileItemWriter 源码
spring-batch JsonItemReader 源码
spring-batch JsonObjectMarshaller 源码
0
赞
热门推荐
-
2、 - 优质文章
-
3、 gate.io
-
8、 golang
-
9、 openharmony
-
10、 Vue中input框自动聚焦