FastJson中文 API

在項(xiàng)目開發(fā)中經(jīng)常會(huì)遇到一些業(yè)務(wù)需要對(duì)某些數(shù)據(jù)進(jìn)行特殊的定制化處理，fastjson為我們提供了接口可以用于實(shí)現(xiàn)自定義的編解碼器來完成我們的業(yè)務(wù)要求。

ObjectSerializer和ObjectDeserializer分別是fastjson的編碼器和解碼器接口。

ObjectDeserializer接口源碼：

/*** <p>Interface representing a custom deserializer for Json. You should write a custom* deserializer, if you are not happy with the default deserialization done by Gson. You will* also need to register this deserializer through* {@link ParserConfig#putDeserializer(Type, ObjectDeserializer)}.</p>* <pre>* public static enum OrderActionEnum {* FAIL(1), SUCC(0);* * private int code;* * OrderActionEnum(int code){* this.code = code;* }* }* * public static class OrderActionEnumDeser implements ObjectDeserializer {* * public &lt;T&gt; T deserialze(DefaultJSONParser parser, Type type, Object fieldName) {* Integer intValue = parser.parseObject(int.class);* if (intValue == 1) {* return (T) OrderActionEnum.FAIL;* } else if (intValue == 0) {* return (T) OrderActionEnum.SUCC;* }* throw new IllegalStateException();* }* * * public int getFastMatchToken() {* return JSONToken.LITERAL_INT;* }* }* </pre>* * <p>You will also need to register {@code OrderActionEnumDeser} to ParserConfig:</p>* <pre>* ParserConfig.getGlobalInstance().putDeserializer(OrderActionEnum.class, new OrderActionEnumDeser());* </pre>*/ public interface ObjectDeserializer {/*** fastjson invokes this call-back method during deserialization when it encounters a field of the* specified type.* <p>In the implementation of this call-back method, you should consider invoking* {@link JSON#parseObject(String, Type, Feature[])} method to create objects* for any non-trivial field of the returned object. ** @param parser context DefaultJSONParser being deserialized* @param type The type of the Object to deserialize to* @param fieldName parent object field name* @return a deserialized object of the specified type which is a subclass of {@code T}*/<T> T deserialze(DefaultJSONParser parser, Type type, Object fieldName);int getFastMatchToken(); }

ObjectSerializer接口源碼：

/*** Interface representing a custom serializer for fastjson. You should write a custom serializer, if* you are not happy with the default serialization done by fastjson. You will also need to register* this serializer through {@link com.alibaba.fastjson.serializer.SerializeConfig#put(Type, ObjectSerializer)}.** <pre>* public static class Result {* public ResultCode code;* }* * public static enum ResultCode {* LOGIN_FAILURE(8), INVALID_ARGUMENT(0), SIGN_ERROR(17);* public final int value;* ResultCode(int value){* this.value = value;* }* }* * public static class ResultCodeSerilaizer implements ObjectSerializer {* public void write(JSONSerializer serializer, * Object object, * Object fieldName, * Type fieldType,* int features) throws IOException {* serializer.write(((ResultCode) object).value);* }* }* * SerializeConfig.getGlobalInstance().put(ResultCode.class, new ResultCodeSerilaizer());* * Result result = new Result();* result.code = ResultCode.SIGN_ERROR;* String json = JSON.toJSONString(result, config); // {"code":17}* Assert.assertEquals("{\"code\":17}", json);* </pre>* @author wenshao[szujobs@hotmail.com]*/ public interface ObjectSerializer {/*** fastjson invokes this call-back method during serialization when it encounters a field of the* specified type.* @param serializer * @param object src the object that needs to be converted to Json.* @param fieldName parent object field name* @param fieldType parent object field type* @param features parent object field serializer features* @throws IOException*/void write(JSONSerializer serializer, //Object object, //Object fieldName, //Type fieldType, //int features) throws IOException; }

自定義編解碼器實(shí)例

1、通過實(shí)現(xiàn)ObjectSerializer接口來自定義枚舉對(duì)象的序列化實(shí)現(xiàn)

/*** 自定義枚舉對(duì)象的序列化實(shí)現(xiàn)：在接口返回?cái)?shù)據(jù)時(shí)，將枚舉字段轉(zhuǎn)換成map格式的數(shù)據(jù)，例如{"value":1,"label":"測(cè)試"}* @author: liumengbing* @date: 2019/05/28 15:26*/ @Component public class EnumsSerializer implements ObjectSerializer {@Overridepublic void write(JSONSerializer serializer, Object object, Object o1, Type type, int i) throws IOException {if (object == null) {serializer.out.writeNull();} else {BaseEnum baseEnum = (BaseEnum) object;serializer.write(new EnumsEntity(baseEnum.getValue(), baseEnum.getLabel()));}}class EnumsEntity{private Integer value;private String label;public EnumsEntity(){}public EnumsEntity(Integer value, String label) {this.value = value;this.label = label;}public Integer getValue() {return value;}public void setValue(Integer value) {this.value = value;}public String getLabel() {return label;}public void setLabel(String label) {this.label = label;}}}

2、通過實(shí)現(xiàn)ObjectDeserializer接口來自定義枚舉對(duì)象的反序列化實(shí)現(xiàn)

/*** 自定義枚舉對(duì)象的反序列化實(shí)現(xiàn)：接口獲取枚舉的value值時(shí)，將其反序列化成枚舉對(duì)象* @author: liumengbing* @date: 2019/05/28 15:26**/ public class EnumDeserializer implements ObjectDeserializer{@Overridepublic <T> T deserialze(DefaultJSONParser parser, Type type, Object fieldName) {JSONLexer lexer = parser.lexer;Integer value = null;Object parse = parser.parse();if (parse == null)return null;String s = parse.toString();if (Pattern.matches("\\d+", s)){value = (int)parse;} else {if (s.startsWith("{")){JSONObject jo = (JSONObject) parse;value = jo.getIntValue("value");}}if (value == null)return null;if (value < -999999)return null;Class<T> clazz = (Class<T>)type;T[] enumConstants = clazz.getEnumConstants();return (T) BaseEnum.valueOfEnum1(enumConstants, value);}@Overridepublic int getFastMatchToken() {return 0;} }

3、通過實(shí)現(xiàn)ObjectDeserializer接口來自定義數(shù)字對(duì)象的反序列化

/*** 自定義數(shù)字對(duì)象的反序列化實(shí)現(xiàn)：接口在接收數(shù)字參數(shù)時(shí)，將數(shù)字轉(zhuǎn)換成BigDecimal* @author: liumengbing* @date: 2019/05/28 15:26**/ public class BigDecimalDeserializer implements ObjectDeserializer{@Overridepublic <T> T deserialze(DefaultJSONParser parser, Type type, Object fieldName) {Object parse = parser.parse();if (parse == null)return (T)(new BigDecimal(0));String s = parse.toString();if ("".equals(s))return (T)(new BigDecimal(0));if (Pattern.matches("(\\d|\\.)+", s))return (T)(new BigDecimal(s));else {throw new IllegalArgumentException();}}@Overridepublic int getFastMatchToken() {return 0;} }

枚舉基類：

package com.example.springboottest;import org.springframework.util.ReflectionUtils;import java.lang.reflect.Field;/*** 枚舉基類接口* @author: liumengbing* @date: 2019/04/10 10:40**/ public interface BaseEnum {String DEFAULT_VALUE_NAME = "value";String DEFAULT_LABEL_NAME = "label";default Integer getValue() {Field field = ReflectionUtils.findField(this.getClass(), DEFAULT_VALUE_NAME);if (field == null)return null;try {field.setAccessible(true);return Integer.parseInt(field.get(this).toString());} catch (IllegalAccessException e) {throw new RuntimeException(e);}}default String getLabel() {Field field = ReflectionUtils.findField(this.getClass(), DEFAULT_LABEL_NAME);if (field == null)return null;try {field.setAccessible(true);return field.get(this).toString();} catch (IllegalAccessException e) {throw new RuntimeException(e);}}static <T extends Enum<T>> T valueOfEnum(Class<T> enumClass, Integer value) {if (value == null)throw new IllegalArgumentException("DisplayedEnum value should not be null");if (enumClass.isAssignableFrom(BaseEnum.class))throw new IllegalArgumentException("illegal DisplayedEnum type");T[] enums = enumClass.getEnumConstants();for (T t: enums) {BaseEnum displayedEnum = (BaseEnum)t;if (displayedEnum.getValue().equals(value))return (T) displayedEnum;}throw new IllegalArgumentException("cannot parse integer: " + value + " to " + enumClass.getName());}static <T> T valueOfEnum1(T[] enums, Integer value) {for (T t: enums) {BaseEnum displayedEnum = (BaseEnum)t;if (displayedEnum.getValue().equals(value))return (T) displayedEnum;}throw new IllegalArgumentException("cannot parse integer: " + value + " to " );} }

實(shí)現(xiàn)了自定義的編解碼器之后就該考慮如何使用了，上面我們提到過，實(shí)現(xiàn)自定義的編解碼器的目的是完成業(yè)務(wù)要求中對(duì)一些數(shù)據(jù)的定制化處理，這些數(shù)據(jù)可能是單獨(dú)一個(gè)屬性字段，也可能是某種類，那么針對(duì)不同的情況，自定義編解碼器有兩種使用方式：

1、通過 @JsonField的serializeUsing和deserializeUsing屬性指定編解碼過程中使用的編解碼器來對(duì)類的某個(gè)屬性進(jìn)行定制序列化

public class TestEnum {@JSONField(serializeUsing = EnumsSerializer.class)public Enum status; }public class TestBigDecimalSerializer {@JSONField(serializeUsing = BigDecimalSerializerSerializer.class)public BigDecimal money; }

2、通過SerializeConfig來配置某一個(gè)類的序列化

private static SerializeConfig mapping = new SerializeConfig(); private static String dateFormat; static { dateFormat = "yyyy-MM-dd HH:mm:ss"; mapping.put(Date.class, new SimpleDateFormatSerializer(dateFormat)); }

3、結(jié)合之前的文章還有一種用法-通過添加配置類來注入Bean（使用HttpMessageConverter來實(shí)現(xiàn)HTTP的序列化和反序列化）

import com.alibaba.fastjson.serializer.SerializerFeature; import com.alibaba.fastjson.support.config.FastJsonConfig; import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.autoconfigure.http.HttpMessageConverters; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.http.MediaType; import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;import java.math.BigDecimal; import java.util.ArrayList; import java.util.List;/*** @author: liumengbing* @date: 2019/04/09 17:35**/ @Configuration//將一個(gè)物理類變成一個(gè)配置文件 public class MassageConverConfiguration {@Autowiredprivate BigDecimalSerializer bigDecimalSerializer;@Beanpublic HttpMessageConverters fastJsonHttpMessageConverters() {//1.構(gòu)建了一個(gè)HttpMessageConverter FastJson 消息轉(zhuǎn)換器FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();//2.定義一個(gè)配置，設(shè)置編碼方式，和格式化的形式FastJsonConfig fastJsonConfig = new FastJsonConfig();//3.設(shè)置成了PrettyFormat格式fastJsonConfig.setSerializerFeatures(SerializerFeature.PrettyFormat);//使用SerializeConfig配置自定義編解碼器fastJsonConfig.getSerializeConfig().put(BigDecimal.class,bigDecimalSerializer);//4.處理中文亂碼問題List<MediaType> fastMediaTypes = new ArrayList<>();fastMediaTypes.add(MediaType.APPLICATION_JSON_UTF8);fastConverter.setSupportedMediaTypes(fastMediaTypes);//5.將fastJsonConfig加到消息轉(zhuǎn)換器中fastConverter.setFastJsonConfig(fastJsonConfig);return new HttpMessageConverters(fastConverter);}} 超強(qiáng)干貨來襲 云風(fēng)專訪：近40年碼齡，通宵達(dá)旦的技術(shù)人生

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