直接使用BigDecimal类型存储数据到MongoDB里面会变成数组，最后查询的数据会报错，需要做一下转换。

报错信息：

"Cannot convert [0.00] of type class java.util.ArrayList into an instance of class java.math.BigDecimal! Implement a custom Converter<class java.util.ArrayList, class java.math.BigDecimal> and register it with the CustomConversions. Parent object was:

 解决方案：

import org.bson.types.Decimal128;
import org.springframework.core.convert.converter.Converter;
import org.springframework.data.convert.ReadingConverter;
import org.springframework.data.convert.WritingConverter;

import java.math.BigDecimal;

/**
 * BigDecimal转Decimal128
 *
 */
@ReadingConverter
@WritingConverter
public class BigDecimalToDecimal128Converter implements Converter<BigDecimal, Decimal128> {
    @Override
    public Decimal128 convert(BigDecimal source) {
        return new Decimal128(source);
    }
}

import org.bson.types.Decimal128;
import org.springframework.core.convert.converter.Converter;

import java.math.BigDecimal;

/**
 * Decimal128转BigDecimal
 *
 */
public class Decimal128ToBigDecimalConverter implements Converter<Decimal128, BigDecimal> {
    @Override
    public BigDecimal convert(Decimal128 source) {
        return source.bigDecimalValue();
    }
}

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.mongodb.MongoDatabaseFactory;
import org.springframework.data.mongodb.core.convert.*;
import org.springframework.data.mongodb.core.mapping.MongoMappingContext;

import java.util.ArrayList;
import java.util.List;


@Configuration
public class MongodbConfig {

    /**
     * 自定义转换
     *
     * @param mongoMappingContext mongoMappingContext
     * @param factory             factory
     * @return 转换
     */
    @Bean
    public MappingMongoConverter mappingMongoConverter(MongoMappingContext mongoMappingContext,
                                                       MongoDatabaseFactory factory) {
        mongoMappingContext.setAutoIndexCreation(true);
        mongoMappingContext.afterPropertiesSet();
        DbRefResolver dbRefResolver = new DefaultDbRefResolver(factory);
        MappingMongoConverter converter = new MappingMongoConverter(dbRefResolver, mongoMappingContext);
        converter.setTypeMapper(new DefaultMongoTypeMapper(null));
        List<Object> list = new ArrayList<>();
        list.add(new BigDecimalToDecimal128Converter());
        list.add(new Decimal128ToBigDecimalConverter());
        converter.setCustomConversions(new MongoCustomConversions(list));
        return converter;
    }

    /**
     * 上下文
     *
     * @return 上下文
     */
    @Bean
    public MongoMappingContext mongoMappingContext() {
        return new MongoMappingContext();
    }
}