hadoop JsonSerDeser 源码

haddop JsonSerDeser 代码

文件路径：/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-applications/hadoop-yarn-services/hadoop-yarn-services-core/src/main/java/org/apache/hadoop/yarn/service/utils/JsonSerDeser.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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
 *
 *     http://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.apache.hadoop.yarn.service.utils;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.PropertyNamingStrategy;
import com.fasterxml.jackson.databind.SerializationFeature;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.StandardCharsets;

/**
 * Support for marshalling objects to and from JSON.
 * This class is NOT thread safe; it constructs an object mapper
 * as an instance field.
 * @param <T>
 */
public class JsonSerDeser<T> {

  private static final Logger log = LoggerFactory.getLogger(JsonSerDeser.class);

  private final Class<T> classType;
  private final ObjectMapper mapper;

  /**
   * Create an instance bound to a specific type
   * @param classType class type
   */
  @SuppressWarnings("deprecation")
  public JsonSerDeser(Class<T> classType) {
    this.classType = classType;
    this.mapper = new ObjectMapper();
    mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    mapper.configure(SerializationFeature.WRITE_NULL_MAP_VALUES, false);
  }

  public JsonSerDeser(Class<T> classType, PropertyNamingStrategy namingStrategy) {
    this(classType);
    mapper.setPropertyNamingStrategy(namingStrategy);
  }

  /**
   * Convert from JSON
   * @param json input
   * @return the parsed JSON
   * @throws IOException IO
   * @throws JsonMappingException failure to map from the JSON to this class
   */
  public T fromJson(String json)
    throws IOException, JsonParseException, JsonMappingException {
    try {
      return mapper.readValue(json, classType);
    } catch (IOException e) {
      log.error("Exception while parsing json : " + e + "\n" + json, e);
      throw e;
    }
  }

  /**
   * Convert from a JSON file
   * @param jsonFile input file
   * @return the parsed JSON
   * @throws IOException IO problems
   * @throws JsonMappingException failure to map from the JSON to this class
   */
  public T fromFile(File jsonFile)
    throws IOException, JsonParseException, JsonMappingException {
    File absoluteFile = jsonFile.getAbsoluteFile();
    try {
      return mapper.readValue(absoluteFile, classType);
    } catch (IOException e) {
      log.error("Exception while parsing json file {}", absoluteFile, e);
      throw e;
    }
  }

  /**
   * Convert from a JSON file
   * @param resource input file
   * @return the parsed JSON
   * @throws IOException IO problems
   * @throws JsonMappingException failure to map from the JSON to this class
   */
 public T fromResource(String resource)
    throws IOException, JsonParseException, JsonMappingException {
    try(InputStream resStream = this.getClass().getResourceAsStream(resource)) {
      if (resStream == null) {
        throw new FileNotFoundException(resource);
      }
      return (T) (mapper.readValue(resStream, classType));
    } catch (IOException e) {
      log.error("Exception while parsing json resource {}", resource, e);
      throw e;
    }
  }

  /**
   * Convert from an input stream, closing the stream afterwards.
   * @param stream
   * @return the parsed JSON
   * @throws IOException IO problems
   */
  public T fromStream(InputStream stream) throws IOException {
    try {
      return (T) (mapper.readValue(stream, classType));
    } catch (IOException e) {
      log.error("Exception while parsing json input stream", e);
      throw e;
    } finally {
      IOUtils.closeStream(stream);
    }
  }

  /**
   * clone by converting to JSON and back again.
   * This is much less efficient than any Java clone process.
   * @param instance instance to duplicate
   * @return a new instance
   * @throws IOException problems.
   */
  public T fromInstance(T instance) throws IOException {
    return fromJson(toJson(instance));
  }

  /**
   * Deserialize from a byte array
   * @param b
   * @return the deserialized value
   * @throws IOException parse problems
   */
  public T fromBytes(byte[] b) throws IOException {
    String json = new String(b, 0, b.length, StandardCharsets.UTF_8);
    return fromJson(json);
  }
  
  /**
   * Load from a Hadoop filesystem
   * @param fs filesystem
   * @param path path
   * @return a loaded CD
   * @throws IOException IO problems
   * @throws JsonParseException parse problems
   * @throws JsonMappingException O/J mapping problems
   */
  public T load(FileSystem fs, Path path) throws IOException {
    FSDataInputStream dataInputStream = fs.open(path);
    return fromStream(dataInputStream);
  }


  /**
   * Save to a hadoop filesystem
   * @param fs filesystem
   * @param path path
   * @param instance instance to save
   * @param overwrite should any existing file be overwritten
   * @throws IOException IO exception
   */
  public void save(FileSystem fs, Path path, T instance,
                   boolean overwrite) throws
                                      IOException {
    FSDataOutputStream dataOutputStream = fs.create(path, overwrite);
    writeJsonAsBytes(instance, dataOutputStream);
  }

  /**
   * Save an instance to a file
   * @param instance instance to save
   * @param file file
   * @throws IOException
   */
  public void save(T instance, File file) throws
      IOException {
    writeJsonAsBytes(instance, new FileOutputStream(file.getAbsoluteFile()));
  }

  /**
   * Write the json as bytes -then close the file
   * @param dataOutputStream an outout stream that will always be closed
   * @throws IOException on any failure
   */
  private void writeJsonAsBytes(T instance,
      OutputStream dataOutputStream) throws IOException {
    try {
      String json = toJson(instance);
      byte[] b = json.getBytes(StandardCharsets.UTF_8);
      dataOutputStream.write(b);
      dataOutputStream.flush();
      dataOutputStream.close();
    } finally {
      IOUtils.closeStream(dataOutputStream);
    }
  }

  /**
   * Convert an object to a JSON string
   * @param instance instance to convert
   * @return a JSON string description
   * @throws JsonProcessingException parse problems
   */
  public String toJson(T instance) throws JsonProcessingException {
    mapper.configure(SerializationFeature.INDENT_OUTPUT, true);
    return mapper.writeValueAsString(instance);
  }

}

相关信息

hadoop 源码目录

相关文章

hadoop ApplicationReportSerDeser 源码

hadoop ClientRegistryBinder 源码

hadoop Comparators 源码

hadoop ConfigHelper 源码

hadoop ConfigUtils 源码

hadoop CoreFileSystem 源码

hadoop Duration 源码

hadoop FilterUtils 源码

hadoop HttpUtil 源码

hadoop PatternValidator 源码