Mybatis中怎么样操作mysql8的Json字段类型

这篇文章主要介绍Mybatis中怎么样操作mysql8的Json字段类型，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！

Json字段是从mysql 5.7起加进来的全新的字段类型，现在我们看看在什么情况下使用该字段类型，以及用mybatis如何操作该字段类型

一般来说，在不知道字段的具体数量的时候，使用该字段是非常合适的，比如说--商品的无限属性。

现在我们来假设这么一个场景，在商品的二级分类中给商品定义足够多的属性，我们先设计属性的类

/** * 商品自定义属性 */@NoArgsConstructor@AllArgsConstructorpublic class OtherProperty implements Serializable {@Getter    @Setter    private Long id; //属性id    @Getter    @Setter    private FormType formType; //前端使用的表单类型    @Getter    @Setter    private String name; //属性名称    @Getter    @Setter    private String unit; //单位    @Getter    @Setter    private String values; //可选值以@分隔，如配件@车品    @Getter    private List valueList = new ArrayList<>(); //对可选值的取值列表    @Getter    @Setter    private String defaultValue; //可选值中的默认值    @Getter    @Setter    private boolean search; //是否可搜索    @Getter    @Setter    private boolean mustWrite; //是否必录    @Getter    @Setter    private Boolean used = false; //是否已经在商品中使用，已使用该属性则不允许修改    public OtherProperty changeValuesToList() {        String[] split = this.values.split("@");        for (String value : split) {this.valueList.add(value);        }this.values = null;        return this;    }@Override    public boolean equals(Object o) {if (this == o) return true;        if (o == null || getClass() != o.getClass()) return false;        OtherProperty that = (OtherProperty) o;        if (!id.equals(that.id)) return false;        if (search != that.search) return false;        if (mustWrite != that.mustWrite) return false;        if (formType != that.formType) return false;        if (!name.equals(that.name)) return false;        if (unit != null ? !unit.equals(that.unit) : that.unit != null) return false;        if (values != null ? !values.equals(that.values) : that.values != null) return false;        return defaultValue != null ? defaultValue.equals(that.defaultValue) : that.defaultValue == null;    }@Override    public int hashCode() {int result = id.hashCode() + formType.hashCode() + name.hashCode();        result = result + (unit != null ? unit.hashCode() : 0);        result = result + (values != null ? values.hashCode() : 0);        result = result + (defaultValue != null ? defaultValue.hashCode() : 0);        result = result + (search ? 1 : 0);        result = result + (mustWrite ? 1 : 0);        return result;    }}

其中formType为枚举类型

public enum FormType implements Localisable {TYPE1("文本框"),    TYPE2("下拉框"),    TYPE3("单选框"),    TYPE4("复选框"),    TYPE5("多行文本框");    private String value;    private FormType(String value) {this.value = value;    }@Override    public String getValue() {return this.value;    }}

我们来看一下商品分类的部分代码

@AllArgsConstructor@NoArgsConstructorpublic class ProviderProductLevel implements Provider,Serializable

其中包含一个商品属性对象的列表

@Getter@Setterprivate List otherProperties;

部分操作源码如下

/** * 通过二级配件分类id查找其包含的所有其他属性 * @param * @return */public List findOtherProperties() {if (this.level == 2) {        LevelDao levelDao = SpringBootUtil.getBean(LevelDao.class);        String ids = levelDao.findIdsByLevel2Id(this.id);        return levelDao.findOtherProperties(ids);    }return null;}/** * 在二级配件分类中删除其他属性的id * @param paramIds * @return */public boolean deletePropertyIdfromLevel(String paramIds) {if (this.level == 2) {        LevelDao levelDao = SpringBootUtil.getBean(LevelDao.class);        String ids = levelDao.findIdsByLevel2Id(this.id);        String[] idsArray = ids.split(",");        List idsList = Arrays.asList(idsArray);        List contentIdsList = new ArrayList<>();        contentIdsList.addAll(idsList);        String[] paramArray = paramIds.split(",");        List paramList = Arrays.asList(paramArray);        if (contentIdsList.containsAll(paramList)) {            contentIdsList.removeAll(paramList);        }if (contentIdsList.size() > 0) {            StringBuilder builder = new StringBuilder();            contentIdsList.stream().forEach(eachId -> builder.append(eachId + ","));            String newIds = builder.toString().substring(0, builder.toString().length() - 1);            levelDao.addOtherPropertiesToLevel(new ParamOtherPropertiesId(newIds, this.id));        }else {            levelDao.addOtherPropertiesToLevel(new ParamOtherPropertiesId("",this.id));        }return true;    }return false;}

/** * 展示某二级配件分类的所有其他属性 * @param id * @return */@SuppressWarnings("unchecked")@Transactional@GetMapping("/productprovider-anon/showproperties")public Result> showOtherProperties(@RequestParam("id") Long id) {    Provider level2 = levelDao.findLevel2(id);    return Result.success(((ProviderProductLevel)level2).findOtherProperties());}/** * 修改某二级配件分类的其他属性 * @param id * @param otherProperties * @return */@SuppressWarnings("unchecked")@Transactional@PostMapping("/productprovider-anon/changeother")public Result changeOtherProperties(@RequestParam("id") Long id,@RequestBody List otherProperties) {//获取配件二级分类对象    Provider level2 = levelDao.findLevel2(id);    //获取未使用的配件二级分类的其他属性(没有任何商品使用过该属性)    List unUsedList = Optional.ofNullable(((ProviderProductLevel) level2).getOtherProperties()).map(otherProperties1 -> otherProperties1.stream())            .orElse(new ArrayList().stream())            .filter(otherProperty -> !otherProperty.getUsed())            .collect(Collectors.toList());    //获取已使用的配件二级分类的其他属性    List usedIdList = Optional.ofNullable(((ProviderProductLevel) level2).getOtherProperties()).map(otherProperties1 -> otherProperties1.stream())            .orElse(new ArrayList().stream())            .filter(otherProperty -> otherProperty.getUsed())            .map(OtherProperty::getId)            .collect(Collectors.toList());    //在传递回来的配件二级分类其他属性中校对没有修改过的，没有使用过的其他属性，只对修改过的，没有使用过的其他属性进行    //存储，否则不处理    List changeList = otherProperties.stream().filter(otherProperty -> Optional.ofNullable(otherProperty.getId()).isPresent())            .filter(otherProperty -> !unUsedList.contains(otherProperty))            .filter(otherProperty -> !usedIdList.contains(otherProperty.getId()))            .peek(otherProperty -> otherPropertyDao.deleteOtherPropertiesById(otherProperty.getId()))            .collect(Collectors.toList());    if (changeList.size() > 0) {        StringBuilder builder = new StringBuilder();        changeList.stream().map(OtherProperty::getId).forEach(eachId -> builder.append(eachId + ","));        String newIds = builder.toString().substring(0, builder.toString().length() - 1);        ((ProviderProductLevel) level2).deletePropertyIdfromLevel(newIds);        ((ProviderProductLevel) level2).addOtherProperties(changeList);    }//获取新增的其他属性进行追加到配件二级分类的其他属性中    List newList = otherProperties.stream().filter(otherProperty -> !Optional.ofNullable(otherProperty.getId()).isPresent())            .peek(otherProperty -> otherProperty.setId(idService.genId()))            .collect(Collectors.toList());    ((ProviderProductLevel) level2).addOtherProperties(newList);    return Result.success("修改成功");}

在进行一番增删改查后，数据库中的数据大致如下

我们查高级项链的所有属性的结果如下

现在我们要在属于该商品分类中添加商品，商品类定义大致如下

@Data@NoArgsConstructorpublic class ProviderProduct implements Provider {    private Product product; //配件元信息对象    private String code; //配件编码    private Brand brand; //品牌    private String details; //配件图文说明    private String levelName; //二级配件分类名称    private DefaultProvider provider; //配件商    private ExtBeanWrapper otherValues; //其他属性集合}

其中对应于属性列表的字段为otherValues，这个值正是我们要存入数据库的Json字段类型映射。

商品的数据库表结构如下

要使用mybatis的数据对Json字段类型的转换，可以先引用一个网上写好的转换器，当然也可以自己写

pom

   com.github.jeffreyning   extcol   0.0.1-RELEASE

配置文件中添加 type-handlers-package: com.nh.micro.ext.th

mybatis:  type-aliases-package: com.cloud.model.productprovider  type-handlers-package: com.nh.micro.ext.th  mapper-locations: classpath:/mybatis-mappers/*  configuration:    mapUnderscoreToCamelCase: true

在mapper文件中写入一段插入语句

    insert into product (id,name,code,model,normal_price,price_begin,product_imgs,details,brand_id,other_property_value)    values (#{product.id},#{product.name},#{code},#{product.model},#{product.price.normalPrice},                    1                    0    ,    #{product.productImgs},    #{details},    #{brand.id},    #{otherValues,jdbcType=VARCHAR}    )

对应商品分类的每一个自定义属性，我们可以先拿到该自定义属性的id,然后以该id，取值为键值对进行插入

{
"product":{
"name":"AAAA",
"model":"AAAAA",
"price":{
"normalPrice":199,
"begin":false
},
"productImgs":"http://123.433.567.988"
},
"code":"0001",
"details":"",
"brand":{
"id":1,
"name":"飞利浦"
},
"otherValues":{
"innerMap":{
"2459623566996408120":"10",
"2459623566996409144":"呼和浩特",
"2459623566996410168":"飞利浦",
"2459623566996411192":"国际",
"2459623566996412216":"包邮"
}
}
}

执行之后，数据库的数据如下

该插件的数据类和转换器的源码如下，其实也是很简单的

public class ExtBeanWrapper {   public ExtBeanWrapper() {   };   public ExtBeanWrapper(Object entity) {      this.setObj(entity);   }   private Map innerMap = new HashMap();   public Map getInnerMap() {      return innerMap;   }   public void setInnerMap(Map innerMap) {      this.innerMap = innerMap;   }   public void setObj(Object entity) {      if (entity == null) {         innerMap = null;      }      JSON jobj = (JSON) JSON.toJSON(entity);      innerMap = JSON.toJavaObject(jobj, Map.class);   }   public Object getObj() {      if (innerMap == null) {         return null;      }      JSON jobj = (JSON) JSON.toJSON(innerMap);      Map entity = JSON.toJavaObject(jobj, Map.class);      return entity;   }   public Object getObj(Class targetClass) {      if (innerMap == null) {         return null;      }      JSON jobj = (JSON) JSON.toJSON(innerMap);      Object entity = JSON.toJavaObject(jobj, targetClass);      return entity;   }}

MappedTypes(com.nh.micro.ext.ExtBeanWrapper.class)@MappedJdbcTypes(JdbcType.VARCHAR)public class TagToJsonTypeHandler extends BaseTypeHandler {   private Map jsonToMap(String value) {      if (value == null || "".equals(value)) {         return Collections.emptyMap();      } else {         return JSON.parseObject(value, new TypeReference>() {         });      }   }   @Override   public void setNonNullParameter(PreparedStatement ps, int i, ExtBeanWrapper parameter, JdbcType jdbcType)         throws SQLException {         ps.setString(i, JSON.toJSONString(parameter.getInnerMap()));   }   public boolean isJson(String value){      if(value==null || "".equals(value)){         return false;      }else{         if(value.startsWith("{")){return true;         }      }      return false;   }   @Override   public ExtBeanWrapper getNullableResult(ResultSet rs, String columnName) throws SQLException {      String value=rs.getString(columnName);      Map innerMap=jsonToMap(value);      ExtBeanWrapper extBeanTag=new ExtBeanWrapper();      extBeanTag.setInnerMap(innerMap);      return extBeanTag;   }   @Override   public ExtBeanWrapper getNullableResult(ResultSet rs, int columnIndex) throws SQLException {      String value=rs.getString(columnIndex);      Map innerMap=jsonToMap(value);      ExtBeanWrapper extBeanTag=new ExtBeanWrapper();      extBeanTag.setInnerMap(innerMap);      return extBeanTag;   }   @Override   public ExtBeanWrapper getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {      String value=cs.getString(columnIndex);      Map innerMap=jsonToMap(value);      ExtBeanWrapper extBeanTag=new ExtBeanWrapper();      extBeanTag.setInnerMap(innerMap);      return extBeanTag;   }}

现在我们来看一下如何将该Json字段从数据库取出，还是以上面的案例为例，先在mapper文件中定义一组resultMap

这里稍微解释一下，price里的begin是boolean类型，price_begin在数据库中是整形，有一个转换器，代码如下

public class BoolIntTypeHandler extends BaseTypeHandler {@Override    public void setNonNullParameter(PreparedStatement ps, int i, Boolean parameter, JdbcType jdbcType) throws SQLException {        ps.setBoolean(i,parameter);    }@Override    public Boolean getNullableResult(ResultSet rs, String columnName) throws SQLException {int value = rs.getInt(columnName);        if (rs.wasNull()) {return false;        }else {if (value == 0) {return false;            }else if (value == 1) {return true;            }        }return false;    }@Override    public Boolean getNullableResult(ResultSet rs, int columnIndex) throws SQLException {int value = rs.getInt(columnIndex);        if (rs.wasNull()) {return false;        }else {if (value == 0) {return false;            }else if (value == 1) {return true;            }        }return false;    }@Override    public Boolean getNullableResult(CallableStatement cs, int columnIndex) throws SQLException {int value = cs.getInt(columnIndex);        if (cs.wasNull()) {return false;        }else {if (value == 0) {return false;            }else if (value == 1) {return true;            }        }return false;    }}

品牌这里有一个查找

    select id,code,name,sort,log_url logoUrl from brand        id=#{brand_id}

配件二级分类名称

    select name from product_level        id=#{level_id}

配件商信息

    select a.id,a.name,b.code from product_provider a    inner join default_provider b on a.id=b.id        a.id=#{default_provider_id}

当然我们的重点还是otherValues这里

获取数据的全部select代码如下

    select id,code,name,model,brand_id,normal_price,level_id,default_provider_id,other_property_value    from product        id=#{id}

获取出来的数据如下

{     "code": 200,     "data": {         "brand": {             "code": "001",             "id": 1,             "logoUrl": "http://123.456.789",             "name": "飞利浦",             "sort": 1         },         "code": "0001",         "levelName": "高级项链",         "otherValues": {             "innerMap": {                 "2459623566996411192": "国际",                 "2459623566996408120": "10",                 "2459623566996409144": "呼和浩特",                 "2459623566996410168": "飞利浦",                 "2459623566996412216": "包邮"             },             "obj": {                 "2459623566996410168": "飞利浦",                 "2459623566996411192": "国际",                 "2459623566996408120": "10",                 "2459623566996409144": "呼和浩特",                 "2459623566996412216": "包邮"             }         },         "product": {             "id": 2459722970793247544,             "model": "AAAAA",             "name": "AAAA",             "onShelf": false,             "price": {                 "begin": false,                 "normalPrice": 199             }         },         "provider": {             "code": "0001",             "productProvider": {                 "id": 2459698718186668856,                 "name": "大众4S店",                 "productList": []             },             "status": false         }     },     "msg": "操作成功" }

当然我们这里要把其他属性的id替换成用户能看懂的其他属性的名称

@Overridepublic Provider findProduct(Long id) {    ProductDao productDao = SpringBootUtil.getBean(ProductDao.class);    OtherPropertyDao otherPropertyDao = SpringBootUtil.getBean(OtherPropertyDao.class);    Provider product = productDao.findProductById(id);    Map map = ((ProviderProduct) product).getOtherValues().getInnerMap();    Map insteadMap = new HashMap<>();    for (Object key : map.keySet()) {log.info("键名为：" + String.valueOf(key));        String name = otherPropertyDao.findNameById(Long.parseLong(String.valueOf(key)));        insteadMap.put(name,(String) map.get(key));    }    ((ProviderProduct) product).getOtherValues().setObj(insteadMap);    return product;}

最后我们获取的结果为

{     "code": 200,     "data": {         "brand": {             "code": "001",             "id": 1,             "logoUrl": "http://123.456.789",             "name": "飞利浦",             "sort": 1         },         "code": "0001",         "levelName": "高级项链",         "otherValues": {             "innerMap": {                 "商品等级": "国际",                 "运费设置": "包邮",                 "生产厂家": "飞利浦",                 "包装规格": "10",                 "商品产地": "呼和浩特"             },             "obj": {                 "$ref": "$.data.otherValues.innerMap"             }         },         "product": {             "id": 2459722970793247544,             "model": "AAAAA",             "name": "AAAA",             "onShelf": false,             "price": {                 "begin": false,                 "normalPrice": 199             }         },         "provider": {             "code": "0001",             "productProvider": {                 "id": 2459698718186668856,                 "name": "大众4S店",                 "productList": []             },             "status": false         }     },     "msg": "操作成功" }

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