Springboot2配置Jackson Springboot2以代码的方式统一配置Jackson教程
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说明
本文主要配置Jackson对Long、Date、LocalDate、LocalDateTime的序列化和反序列化。
由于js中整数可精确表示范围小于java Long的范围,故将Long序列化为String,反序列化Jackson会自动处理String转Long,故不需要显式配置。
由于时间戳在各语言间的兼容性良好,故将Date、LocalDate、LocalDateTime序列化为Long(目前时间戳类的Long类型在js的可精确表示范围内),将Long反序列化为Date、LocalDate、LocalDateTime。将String空字符串反序列化为null。
本文除了配置Springboot整合的Jackson,还配置了功能一致的Jackson工具类,方便在代码中显示使用Jackson的序列化和反序列化功能。
7个序列化和反序列化规则
package com.xxx.config.serializers; import java.io.IOException; import java.util.Date; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.databind.JsonSerializer; import com.fasterxml.jackson.databind.SerializerProvider; public class DateSerializer extends JsonSerializer<Date> { @Override public void serialize(Date value, JsonGenerator gen, SerializerProvider serializers) throws IOException { if (value != null) { gen.writeNumber(value.getTime()); } } }
package com.xxx.config.serializers; import java.io.IOException; import java.time.LocalDate; import java.time.ZoneId; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.databind.JsonSerializer; import com.fasterxml.jackson.databind.SerializerProvider; public class LocalDateSerializer extends JsonSerializer<LocalDate> { @Override public void serialize(LocalDate value, JsonGenerator gen, SerializerProvider serializers) throws IOException { if (value != null) { long millis = value.atStartOfDay(ZoneId.of("+8")).toInstant().toEpochMilli(); gen.writeNumber(millis); } } }
package com.xxx.config.serializers; import java.io.IOException; import java.time.LocalDateTime; import java.time.ZoneId; import com.fasterxml.jackson.core.JsonGenerator; import com.fasterxml.jackson.databind.JsonSerializer; import com.fasterxml.jackson.databind.SerializerProvider; public class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> { @Override public void serialize(LocalDateTime value, JsonGenerator gen, SerializerProvider serializers) throws IOException { if (value != null) { long millis = value.atZone(ZoneId.of("+8")).toInstant().toEpochMilli(); gen.writeNumber(millis); } } }
package com.xxx.config.serializers; import java.io.IOException; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JsonDeserializer; public class StringDeserializer extends JsonDeserializer<String> { @Override public String deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException { String text = p.getText(); if ("".equals(text)) { return null; } return text; } }
package com.xxx.config.serializers; import java.io.IOException; import java.util.Date; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JsonDeserializer; public class DateDeserializer extends JsonDeserializer<Date> { @Override public Date deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException { long timestamp = p.getValueAsLong(); if (timestamp > 0){ return new Date(timestamp); }else{ return null; } } }
package com.xxx.config.serializers; import java.io.IOException; import java.time.Instant; import java.time.LocalDate; import java.time.LocalDateTime; import java.time.ZoneId; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JsonDeserializer; public class LocalDateDeserializer extends JsonDeserializer<LocalDate> { @Override public LocalDate deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException { long timestamp = p.getValueAsLong(); if (timestamp > 0){ return LocalDateTime.ofInstant(Instant.ofEpochMilli(timestamp),ZoneId.of("+8")).toLocalDate(); }else{ return null; } } }
package com.xxx.config.serializers; import java.io.IOException; import java.time.Instant; import java.time.LocalDateTime; import java.time.ZoneId; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.DeserializationContext; import com.fasterxml.jackson.databind.JsonDeserializer; public class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> { @Override public LocalDateTime deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException { long timestamp = p.getValueAsLong(); if (timestamp > 0){ return LocalDateTime.ofInstant(Instant.ofEpochMilli(timestamp),ZoneId.of("+8")); }else{ return null; } } }
Jackson统一配置类
package com.xxx.config; import java.time.LocalDate; import java.time.LocalDateTime; import java.util.Date; import org.springframework.boot.autoconfigure.jackson.Jackson2ObjectMapperBuilderCustomizer; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder; import com.xxx.config.serializers.DateDeserializer; import com.xxx.config.serializers.DateSerializer; import com.xxx.config.serializers.LocalDateDeserializer; import com.xxx.config.serializers.LocalDateSerializer; import com.xxx.config.serializers.LocalDateTimeDeserializer; import com.xxx.config.serializers.LocalDateTimeSerializer; import com.xxx.config.serializers.StringDeserializer; import com.fasterxml.jackson.databind.ser.std.ToStringSerializer; @Configuration public class JacksonConfig { @Bean public Jackson2ObjectMapperBuilderCustomizer jackson2ObjectMapperBuilderCustomizer() { Jackson2ObjectMapperBuilderCustomizer customizer = new Jackson2ObjectMapperBuilderCustomizer() { @Override public void customize(Jackson2ObjectMapperBuilder jacksonObjectMapperBuilder) { jacksonObjectMapperBuilder .serializerByType(Long.TYPE, ToStringSerializer.instance) .serializerByType(Long.class, ToStringSerializer.instance) .serializerByType(Date.class, new DateSerializer()) .serializerByType(LocalDate.class, new LocalDateSerializer()) .serializerByType(LocalDateTime.class, new LocalDateTimeSerializer()) .deserializerByType(String.class, new StringDeserializer()) .deserializerByType(Date.class, new DateDeserializer()) .deserializerByType(LocalDate.class, new LocalDateDeserializer()) .deserializerByType(LocalDateTime.class, new LocalDateTimeDeserializer()) .failOnEmptyBeans(false) .failOnUnknownProperties(false); } }; return customizer; } }
Jackson工具类
package com.xxx.util; import java.io.IOException; import java.time.LocalDate; import java.time.LocalDateTime; import java.util.Date; import java.util.TimeZone; import com.xxx.config.serializers.StringDeserializer; import com.xxx.config.serializers.DateDeserializer; import com.xxx.config.serializers.DateSerializer; import com.xxx.config.serializers.LocalDateDeserializer; import com.xxx.config.serializers.LocalDateSerializer; import com.xxx.config.serializers.LocalDateTimeDeserializer; import com.xxx.config.serializers.LocalDateTimeSerializer; import com.fasterxml.jackson.core.JsonParser.Feature; import com.fasterxml.jackson.core.type.TypeReference; import com.fasterxml.jackson.databind.DeserializationFeature; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializationFeature; import com.fasterxml.jackson.databind.ser.std.ToStringSerializer; import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule; public class JsonUtils { private static final ObjectMapper objectMapper; static { objectMapper = new ObjectMapper(); // 去掉默认的时间戳格式 objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false); // 设置为中国北京时区 objectMapper.setTimeZone(TimeZone.getTimeZone("GMT+8")); // 空值不序列化 // objectMapper.setSerializationInclusion(Include.NON_NULL);//已过时 // objectMapper.setDefaultPropertyInclusion(Include.NON_NULL);//新API // 反序列化时,属性不存在的兼容处理 objectMapper.getDeserializationConfig().withoutFeatures(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES); objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false); objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); // 单引号处理 objectMapper.configure(Feature.ALLOW_SINGLE_QUOTES, true); JavaTimeModule javaTimeModule = new JavaTimeModule(); javaTimeModule.addSerializer(Long.TYPE, ToStringSerializer.instance); javaTimeModule.addSerializer(Long.class, ToStringSerializer.instance); javaTimeModule.addSerializer(Date.class, new DateSerializer()); javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer()); javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer()); javaTimeModule.addDeserializer(String.class, new StringDeserializer()); javaTimeModule.addDeserializer(Date.class, new DateDeserializer()); javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer()); javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer()); objectMapper.registerModule(javaTimeModule); } /** * json 转换成 Object * * @param json * @param clazz * @return */ public static <T> T json2Object(String json, Class<T> clazz) { try { return objectMapper.readValue(json, clazz); } catch (IOException e) { throw new RuntimeException("解析json错误"); } } @SuppressWarnings("unchecked") public static <T> T json2Object(String json, TypeReference<T> tr) { try { return (T)objectMapper.readValue(json, tr); } catch (IOException e) { throw new RuntimeException("解析json错误", e); } } /** * obj 转换成json * * @param entity * @return */ public static <T> String object2Json(T entity) { try { return objectMapper.writeValueAsString(entity); } catch (IOException e) { throw new RuntimeException("转换json错误"); } } /** * obj对象 转换成树型JSON * * @param obj * @return */ public static JsonNode object2TreeJson(Object obj) { try { return objectMapper.valueToTree(obj); } catch (Exception e) { throw new RuntimeException("转换json错误"); } } /** * 解码json串成对象 * * @param <T> * @param json * @param valueType * @return T */ @SuppressWarnings("unchecked") public static <T> T decode(String json, Class<?> valueType) { try { return (T) objectMapper.readValue(json, valueType); } catch (Exception e) { throw new RuntimeException(json, e); } } /** * 解码json串成JsonNode * @param json * @return */ public static JsonNode readTree(String json) { try { return objectMapper.readTree(json); } catch (Exception e) { throw new RuntimeException(json, e); } } }
总结
以上为个人经验,希望能给大家一个参考,也希望大家多多支持。
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