JAVA一个注解实现数据字典功能_java 数据字典开发

注解序列化方式实现数据字典功能

为什么要写这篇文章？

一个项目开发从无到有得考虑很多东西，做到从架构层去思考问题，需要从代码的通用性、易读性等多个方面去考虑，网上看了很多文章都是通过反射去实现，会影响性能，结合实战代码发一篇文章给广大码友做一个参考

引入依赖

除了springboot的起步依赖，还需要引入jackson-databind依赖

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.13.2.1</version>
</dependency>
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数据库设计

CREATE TABLE `sys_dict`  (
  `id` bigint NOT NULL COMMENT '主键id',
  `code` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '编码',
  `name` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '名称',
  `describe` varchar(64) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '描述',
  `status` tinyint(1) NOT NULL DEFAULT 0 COMMENT '状态（0--正常1--冻结）',
  `is_delete` tinyint(1) NULL DEFAULT 0 COMMENT '删除状态（0，正常，1已删除）',
  `remark` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '备注',
  `create_by` varchar(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '创建者',
  `create_time` datetime NULL DEFAULT NULL COMMENT '创建时间',
  `update_by` varchar(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '修改者',
  `update_time` datetime NULL DEFAULT NULL COMMENT '修改时间',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

CREATE TABLE `sys_dict_detail`  (
  `id` bigint NOT NULL COMMENT '主键id',
  `dict_id` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '字典ID',
  `code` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '编码',
  `name` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT '名称',
  `sort` tinyint NOT NULL DEFAULT 0 COMMENT '排序',
  `create_by` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '创建人登录名称',
  `create_time` datetime NULL DEFAULT NULL COMMENT '创建日期',
  `update_by` varchar(32) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '更新人登录名称',
  `update_time` datetime NULL DEFAULT NULL COMMENT '更新日期',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;


INSERT INTO `cloud`.`sys_dict` (`id`, `code`, `name`, `describe`, `status`, `is_delete`, `remark`, `create_by`, `create_time`, `update_by`, `update_time`) VALUES (1, 'sex', '性别', NULL, 0, 0, NULL, NULL, NULL, NULL, NULL);
INSERT INTO `cloud`.`sys_dict_detail` (`id`, `dict_id`, `code`, `name`, `sort`, `create_by`, `create_time`, `update_by`, `update_time`) VALUES (1, '1', '0', '男', 0, NULL, NULL, NULL, NULL);
INSERT INTO `cloud`.`sys_dict_detail` (`id`, `dict_id`, `code`, `name`, `sort`, `create_by`, `create_time`, `update_by`, `update_time`) VALUES (2, '1', '1', '女', 1, NULL, NULL, NULL, NULL);

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代码实现

定义@Dict注解

import cn.hutool.core.annotation.AliasFor;
import com.fasterxml.jackson.annotation.JacksonAnnotation;
import com.fasterxml.jackson.annotation.JacksonAnnotationsInside;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.annotation.JsonSerialize;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
@JsonSerialize(using = DictSerializer.class)
@JacksonAnnotationsInside
@JacksonAnnotation
public @interface Dict {

    /**
     * 字典code
     */
    String value();

    @AliasFor(
            annotation = JsonSerialize.class,
            attribute = "using"
    )
    Class<? extends JsonSerializer> using() default DictSerializer.class;
}
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序列化器

import cn.hutool.extra.spring.SpringUtil;
import com.ayu.sx.system.vo.DictVO;
import com.ayu.sx.system.bo.DictRedisBO;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.BeanProperty;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.ser.ContextualSerializer;
import com.fasterxml.jackson.databind.ser.std.StdSerializer;
import lombok.SneakyThrows;

import java.util.List;
import java.util.stream.Collectors;

public class DictSerializer extends StdSerializer<Object> implements ContextualSerializer {

    private static final long serialVersionUID = -6157558261755426448L;

    private String dictCode;

    public DictSerializer() {
        super(Object.class);
    }

    public DictSerializer(String dictCode) {
        super(Object.class);
        this.dictCode = dictCode;
    }

    @Override
    public JsonSerializer<?> createContextual(SerializerProvider prov, BeanProperty property) {
        Dict annotation = property.getAnnotation(Dict.class);
        return new DictSerializer(annotation.value());
    }

    @SneakyThrows
    @Override
    public void serialize(Object code, JsonGenerator gen, SerializerProvider provider) {
        // 我这里是从redis获取数据字典，项目启动时查询数据库加载到redis
        List<Object> objects = redisTemplate.opsForList().range("dict_info:", 0, -1);
        List<DictVO> dictVOList = objects.stream().filter(item -> {
            DictVO dictRedis = (DictVO) item;
            boolean bool1 = dictRedis.getDictCode().equals(this.dictCode);
            boolean bool2 = dictRedis.getCode().equals(String.valueOf(code));
            return bool1 && bool2;
        }).map(item -> (DictVO) item).collect(Collectors.toList());
        DictVO dictVO = new DictVO();
        if (dictVOList.size() > 0) {
            dictVO = dictVOList.get(0);
        }
        gen.writeObject(dictVO);
    }
}
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DictVO

@Data
public class DictVO {

    private String dictCode;

    private String code;

    private String name;

}
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测试类

controller

@RestController
@RequestMapping("/test")
@Api(tags = "测试")
public class TestController {

    @RequestMapping(value = "/query", method = RequestMethod.GET)
    public Test1Entity query() {
        Test1Entity testEntity = new Test1Entity();
        testEntity.setSex(1);
        return testEntity;
    }

}
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entity

import com.ayu.sx.dict.Dict;
import lombok.Data;

@Data
public class Test1Entity {

    @Dict(value = "sex")
    private Integer sex;

}
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测试结果