自定义Jackson序列化 @JsonSerialize
自定义json序列化需要实现StdSerializer<T>或者JsonSerializer<T>。
我要序列化House这个类，加上注解，指定用于序列化的类
package com.xhx.json.entity;
import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;
import com.xhx.json.serializers.HourseSerializer;
import java.util.Date;
@JsonSerialize(using = HourseSerializer.class)
public class Hourse {
private String location;
private Date buildDate;
public String getLocation() {
return location;
}
public void setLocation(String location) {
this.location = location;
}
public Date getBuildDate() {
return buildDate;
}
public void setBuildDate(Date buildDate) {
this.buildDate = buildDate;
}
}
package com.xhx.json.serializers;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;
import com.xhx.json.entity.Hourse;
import java.io.IOException;
public class HourseSerializer extends StdSerializer<Hourse> {
public HourseSerializer(){
super(Hourse.class);
}
protected HourseSerializer(Class<Hourse> t) {
super(t);
}
@Override
public void serialize(Hourse hourse, JsonGenerator generator, SerializerProvider provider) throws IOException {
generator.writeStartObject();
generator.writeFieldName("id");
generator.writeString("自定义");
generator.writeFieldName("location");
generator.writeString(hourse.getLocation());
generator.writeObjectField("buildDate",hourse.getBuildDate());
generator.writeEndObject();
}
}测试：
jackson自定义全局序列化、反序列化
需要自定义Jackson序列化和反序列化有两种方式，一种是全局定义，一种是非全局定义。先来看看全局定义。全局定义的步骤如下，以定义一个localDateTime的序列化和反序列化为例：
创建序列化类
创建一个序列化类然后继承JsonSerializer，重写serialize序列化方法。其中第一个参数localDateTime为JsonSerializer的泛型，表示的是被序列化的类型的值，第二个参数jsonGenerator表示的是用于输出生成的Json内容，第三个参数暂时没明白什么应用场景。重写方法一般是将想要序列化的字符串传入 jsonGenerator.writeString。
public final class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {
public static final LocalDateTimeSerializer INSTANCE = new LocalDateTimeSerializer();
public LocalDateTimeSerializer() {
}
@Override
public void serialize(LocalDateTime localDateTime, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException, JsonProcessingException {
jsonGenerator.writeString(DateUtil.format(localDateTime, DateUtil.DateTimeFormatEnum.DATE_TIME_FORMAT_4));
}
}创建反序列化类
创建两个类，一个类继承JsonDeserializer，一个类继承KeyDeserializer,重写deserialize反序列化方法。参数jsonParser用于读取json内容的解析，deserializationContext可用于访问此有关反序列化的上下文（暂时也不知道怎么用），返回值则是JsonDeserializer的泛型对象，表示要反序列化的对象。一般用法是通过jsonParser.getText().trim()获取该字段json字符串，然后将该字符串转换为对象返回。
public final class LocalTimeDeserializer extends JsonDeserializer<LocalTime> {
public static final LocalTimeDeserializer INSTANCE = new LocalTimeDeserializer();
public LocalTimeDeserializer() {
}
@Override
public LocalTime deserialize(JsonParser jsonParser, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
String text = jsonParser.getText().trim();
return LocalTime.parse(text, DateUtil.DATE_TIME_FORMATTER_6);
}
}
public final class LocalDateTimeKeyDeserializer extends KeyDeserializer {
public static final LocalDateTimeKeyDeserializer INSTANCE = new LocalDateTimeKeyDeserializer();
public LocalDateTimeKeyDeserializer() {
}
@Override
public Object deserializeKey(String s, DeserializationContext deserializationContext) throws IOException, JsonProcessingException {
return StringUtils.isBlank(s) ? null : LocalDateTime.parse(s, DateUtil.DATE_TIME_FORMATTER_4);
}
}将两个类注册进入jackson核心对象objectMapper
@Bean
public ObjectMapper objectMapper(){
ObjectMapper objectMapper = new ObjectMapper();
objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
//不注释,会导致swagger报错
//objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
//关闭日期序列化为时间戳的功能
objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
//关闭序列化的时候没有为属性找到getter方法,报错
objectMapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
//关闭反序列化的时候，没有找到属性的setter报错
objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
//序列化的时候序列对象的所有属性
objectMapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);
//反序列化的时候如果多了其他属性,不抛出异常
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
//如果是空对象的时候,不抛异常
objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
SimpleModule simpleModule = new SimpleModule();
//json值序列化
simpleModule.addSerializer(LocalDateTime.class, LocalDateTimeSerializer.INSTANCE);
//json值反序列化
simpleModule.addDeserializer(LocalDateTime.class, LocalDateTimeDeserializer.INSTANCE);
//json键序列化
simpleModule.addKeySerializer(LocalDateTime.class,LocalDateTimeSerializer.INSTANCE);
//json键反序列化
simpleModule.addKeyDeserializer(LocalDateTime.class, LocalDateTimeKeyDeserializer.INSTANCE);
objectMapper.registerModule(simpleModule);
return objectMapper;
}小结一下
以上，通过objectMapper的配置，完成了全局序列化、反序列化的配置，如果不需要全局则通过@jsonserialize或 @JsonDeserialize指定使用的序列化、反序列化类。仅为个人经验，希望能给大家一个参考，也希望大家多多支持编程网
