Mongodb删除_class 属性

桃扇骨 2022-04-05 05:52 262阅读 0赞

今天我做了一个查询数据典的功能,,,,,使用了mongorepository,,出现了一个很奇怪的现象

emmm 怎么说,真的是一个大坑 数据怎么查都查不出来..但是我调用 findAll(), findByParam()的时候又能查询出来

public SysDictionary selectDictionaryByType(String dType) {
            if (StringUtils.isBlank(dType)){
                ExceptionCast.cast(CommonCode.INVALIDPARAM);
            }
    
    
            List<SysDictionary> result1 = sysDictionaryRepository.findAll();
    
            List<SysDictionary> result2 = sysDictionaryRepository.findByDType(dType);
    
    
    
            ExampleMatcher matching = ExampleMatcher.matching();//匹配器
    
    
    
    //        条件封装
            SysDictionary sysDictionary = new SysDictionary();
    
            sysDictionary.setDType(dType);
    
    
            Example<SysDictionary> ex = Example.of(sysDictionary,matching);
    
            List<SysDictionary> all = sysDictionaryRepository.findAll(ex);
    
    
            if (all != null & all.size() > 0){
                return all.get(0);
            }
    
            return null;
        }

下面是我的运行结果,,,,

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzk0MjY2_size_16_color_FFFFFF_t_70][]

这个 bug 郁闷的-  -

然后我用debug 看了一下查询语句

这是result1 的查询语句

![20181211095350375.png][]

这是result2的查询语句

![20181211095429271.png][]

然后这是 all的查询语句

![20181211095530724.png][]

这属性真的是坑来着.......我网上找了挺久的,终于找到怎么删除的方法了  ,我们找到MongoConfig类

package com.xuecheng.manage_course.config;
    
    import com.mongodb.MongoClient;
    import com.mongodb.client.MongoDatabase;
    import com.mongodb.client.gridfs.GridFSBucket;
    import com.mongodb.client.gridfs.GridFSBuckets;
    import org.springframework.beans.factory.BeanFactory;
    import org.springframework.beans.factory.NoSuchBeanDefinitionException;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.data.convert.CustomConversions;
    import org.springframework.data.mongodb.MongoDbFactory;
    import org.springframework.data.mongodb.core.convert.DbRefResolver;
    import org.springframework.data.mongodb.core.convert.DefaultDbRefResolver;
    import org.springframework.data.mongodb.core.convert.DefaultMongoTypeMapper;
    import org.springframework.data.mongodb.core.convert.MappingMongoConverter;
    import org.springframework.data.mongodb.core.mapping.MongoMappingContext;
    
    @Configuration
    public class MongoConfig {
    
        String db = "sysconfig";   //数据库名 
    // 连接数据库的配置 
        @Bean
        public GridFSBucket getGridFSBucket(MongoClient mongoClient){
            MongoDatabase database = mongoClient.getDatabase(db);
            GridFSBucket bucket = GridFSBuckets.create(database);
            return bucket;
        }
    
    
    //删除_class 属性的配置 
        @Bean
        public MappingMongoConverter mappingMongoConverter(MongoDbFactory factory, MongoMappingContext context, BeanFactory beanFactory) {
            DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
            MappingMongoConverter mappingConverter = new MappingMongoConverter(dbRefResolver, context);
            try {//
                mappingConverter.setCustomConversions(beanFactory.getBean(CustomConversions.class));
            } catch (NoSuchBeanDefinitionException ignore) {
            }
    
            // Don't save _class to mongo
            mappingConverter.setTypeMapper(new DefaultMongoTypeMapper(null));
    
            return mappingConverter;
        }
    }

然后配置好后运行看结果

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzk0MjY2_size_16_color_FFFFFF_t_70 1][]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzk0MjY2_size_16_color_FFFFFF_t_70]: /images/20220405/a5b8adb45a294d8584227a55dbf1f20f.png
[20181211095350375.png]: /images/20220405/f966471691bd46f28f99e17b51f8744d.png
[20181211095429271.png]: /images/20220405/c3504e1f8cf4440490f700f7093fb21e.png
[20181211095530724.png]: /images/20220405/120df0fcd2964a06967c7d6d94ba4f26.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzk0MjY2_size_16_color_FFFFFF_t_70 1]: /images/20220405/94b888c4513140bca1d250a90e86636e.png