Jackson 实现 JSON 字段类型处理器

1.处理过程

1.1 实体类设为autoResultMap = true

@TableName(value = "table1", autoResultMap = true)

1.2 字段 typeHandler = JacksonTypeHandler.class

 @ApiModelProperty(value = "明细")
 @TableField(value = "detail", typeHandler = JacksonTypeHandler.class)
 private Object detail;

2.Json字段类型处理器

@Slf4j
@MappedTypes({Object.class})
@MappedJdbcTypes(JdbcType.VARCHAR)
public class JacksonTypeHandler extends AbstractJsonTypeHandler<Object> {
    private static ObjectMapper OBJECT_MAPPER;
    private final Class<?> type;

    private static final DateTimeFormatter DATE_TIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    private static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    private static final DateTimeFormatter TIME_FORMATTER = DateTimeFormatter.ofPattern("HH:mm:ss");
    public JacksonTypeHandler(Class<?> type) {
        if (log.isTraceEnabled()) {
            log.trace("JacksonTypeHandler(" + type + ")");
        }
        Assert.notNull(type, "Type argument cannot be null");
        this.type = type;
    }

    @Override
    protected Object parse(String json) {
        try {
            return getObjectMapper().readValue(json, type);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    protected String toJson(Object obj) {
        try {
            return getObjectMapper().writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            throw new RuntimeException(e);
        }
    }

    public static ObjectMapper getObjectMapper() {
        if (null == OBJECT_MAPPER) {
            OBJECT_MAPPER = new ObjectMapper();
            //取消时间的转化格式，默认是时间戳,同时需要设置要表现的时间格式
            OBJECT_MAPPER.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
            OBJECT_MAPPER.configure(SerializationFeature.WRITE_DURATIONS_AS_TIMESTAMPS, false);
            OBJECT_MAPPER.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
            // 默认序列化没有实现，反序列化有实现
            JavaTimeModule javaTimeModule = new JavaTimeModule();
            javaTimeModule.addSerializer(LocalDateTime.class, new LocalDateTimeSerializer(DATE_TIME_FORMATTER));
            javaTimeModule.addSerializer(LocalDate.class, new LocalDateSerializer(DATE_FORMATTER));
            javaTimeModule.addSerializer(LocalTime.class, new LocalTimeSerializer(TIME_FORMATTER));
            javaTimeModule.addSerializer(Date.class, new DateSerializer(false, new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")));
            javaTimeModule.addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer(DATE_TIME_FORMATTER));
            javaTimeModule.addDeserializer(LocalDate.class, new LocalDateDeserializer(DATE_TIME_FORMATTER));
            javaTimeModule.addDeserializer(LocalTime.class, new LocalTimeDeserializer(DATE_TIME_FORMATTER));
            javaTimeModule.addDeserializer(Date.class, new DateDeserializers.DateDeserializer(new DateDeserializers.DateDeserializer(), new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"), "yyyy-MM-dd HH:mm:ss"));
            OBJECT_MAPPER.registerModule(javaTimeModule);
            // 设置时区
            OBJECT_MAPPER.setTimeZone(TimeZone.getDefault());
            // 设置格式化输出
            //  OBJECT_MAPPER.enable(SerializationFeature.INDENT_OUTPUT);
            // 属性为空为null都不参与序列化
            OBJECT_MAPPER.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);

        }
        return OBJECT_MAPPER;
    }

    public static void setObjectMapper(ObjectMapper objectMapper) {
        Assert.notNull(objectMapper, "ObjectMapper should not be null");
        JacksonTypeHandler.OBJECT_MAPPER = objectMapper;
    }
}