分布式服务架构学习（五）：实现自己的序列化工具引擎（四）-序列化JSON实现

╰半夏微凉° 2022-05-18 07:15 178阅读 0赞

JSON(JavaScript Object Notation)是一种轻量级的数据交换格式。相比XML，JSON码流更小，而且保留了XML可读性好的优势。

JSON序列化常用的开元工具有如下几个：

*  Jackson
 *  阿里开源的fastjson
 *  Google开发的GSON

相比较而言，Jackson与fastjson比GSON的性能要好。Jackson、GSON相对fastjson稳定性更好，fastjson的优势在于非常易用的API操作及高性能。但fastjson对序列化对象本身有一些额外的要求，比如序列化对象的属性必须实现get/set方法才能完成对属性的序列化。

本人采用的Jackson方式进行的序列化，序列化代码如下：

package ares.remoting.framework.serialization.serializer.impl;
    
    import ares.remoting.framework.serialization.common.FDateJsonDeserializer;
    import ares.remoting.framework.serialization.common.FDateJsonSerializer;
    import ares.remoting.framework.serialization.serializer.ISerializer;
    import com.fasterxml.jackson.core.JsonParser;
    import com.fasterxml.jackson.core.Version;
    import com.fasterxml.jackson.databind.DeserializationFeature;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import com.fasterxml.jackson.databind.SerializationFeature;
    import com.fasterxml.jackson.databind.module.SimpleModule;
    
    import java.util.Date;
    
    /**
     * @author fuss created on 18/7/23.
     * @version $Id$
     */
    public class JSONSerializer implements ISerializer {
    
    
        private static final ObjectMapper objectMapper = new ObjectMapper();
    
        static {
            objectMapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);
            objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
            objectMapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
            objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_CONTROL_CHARS, true);
            objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
            objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
    
            SimpleModule module = new SimpleModule("DateTimeModule", Version.unknownVersion());
            module.addSerializer(Date.class, new FDateJsonSerializer());
            module.addDeserializer(Date.class, new FDateJsonDeserializer());
    
            objectMapper.registerModule(module);
    
        }
    
        private static ObjectMapper getObjectMapperInstance() {
            return objectMapper;
        }
    
        public <T> byte[] serialize(T obj) {
            if (obj == null) {
                return new byte[0];
            }
    
            try {
                String json = objectMapper.writeValueAsString(obj);
                return json.getBytes();
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    
        public <T> T deserialize(byte[] data, Class<T> clazz) {
            String json = new String(data);
            try {
                return (T) objectMapper.readValue(json, clazz);
            } catch (Exception e) {
                throw new RuntimeException(e);
            }
        }
    
    }

在上面的代码中：

SimpleModule module = new SimpleModule("DateTimeModule", Version.unknownVersion());
            module.addSerializer(Date.class, new FDateJsonSerializer());
            module.addDeserializer(Date.class, new FDateJsonDeserializer());

是用来对java.util.Date类进行格式化的定制化输出的。

其中，FDateJsonSerializer.java代码如下：

package ares.remoting.framework.serialization.common;
    
    import com.fasterxml.jackson.core.JsonGenerator;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.JsonSerializer;
    import com.fasterxml.jackson.databind.SerializerProvider;
    import org.apache.commons.lang3.time.FastDateFormat;
    
    import java.io.IOException;
    import java.util.Date;
    
    /**
     * @author fuss created on 18/7/31.
     * @version $Id$
     */
    public class FDateJsonSerializer extends JsonSerializer<Date> {
    
        private static final FastDateFormat DATE_FORMAT = FastDateFormat.getInstance("yyyy-MM-dd HH:mm:ss");
    
        @Override public void serialize(Date date, JsonGenerator jsonGenerator, SerializerProvider serializers) throws IOException, JsonProcessingException {
            jsonGenerator.writeString(date != null ? DATE_FORMAT.format(date) : "null");
        }
    
    }

FDateJsonDeserializer.java代码如下：

package ares.remoting.framework.serialization.common;
    
    import com.fasterxml.jackson.core.JsonParser;
    import com.fasterxml.jackson.core.JsonProcessingException;
    import com.fasterxml.jackson.databind.DeserializationContext;
    import com.fasterxml.jackson.databind.JsonDeserializer;
    import org.apache.commons.lang3.StringUtils;
    import org.joda.time.DateTime;
    import org.joda.time.format.DateTimeFormat;
    import org.joda.time.format.DateTimeFormatter;
    
    import java.io.IOException;
    import java.util.Date;
    
    /**
     * @author fuss created on 18/7/31.
     * @version $Id$
     */
    public class FDateJsonDeserializer extends JsonDeserializer<Date> {
    
        static final String PATTERN = "yyyy-MM-dd HH:mm:ss";
        static final DateTimeFormatter fmt = DateTimeFormat.forPattern(PATTERN);
    
    
        @Override
        public Date deserialize(JsonParser gen, DeserializationContext ctxt) throws IOException, JsonProcessingException {
            String date = gen.getText();
    
            if (StringUtils.isEmpty(date)) {
                return null;
            }
    
            if (StringUtils.isNumeric(date)) {
                return new Date(Long.valueOf(date));
            }
            try {
                DateTime dt = fmt.parseDateTime(date);
                return dt.toDate();
            } catch (Exception e) {
                throw new IOException(e);
            }
        }
    }

另外，maven中需要引入jackson包，代码如下：

<dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-core</artifactId>
                <version>2.8.6</version>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-databind</artifactId>
                <version>2.8.6</version>
            </dependency>
            <dependency>
                <groupId>com.fasterxml.jackson.core</groupId>
                <artifactId>jackson-annotations</artifactId>
                <version>2.8.6</version>
            </dependency>