达梦数据库+mybatis返回字段转小写

1、开启mybatis驼峰命名规则

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   mybatis:
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   configuration:
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   #使用mybatis驼峰功能将达梦返回字段转小写
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   map-underscore-to-camel-case: true

2、继承MapWrapper

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   import org.apache.ibatis.reflection.MetaObject;
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   import org.apache.ibatis.reflection.wrapper.MapWrapper;
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   import java.util.Map;
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   public class SqlFieldToLowerCase extends MapWrapper {
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   public SqlFieldToLowerCase(MetaObject metaObject, Map<String, Object> map) {
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    super(metaObject, map);
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    }
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    @Override
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    public String findProperty(String name, boolean useCamelCaseMapping) {
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    if (useCamelCaseMapping) {
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    //查询字段转小写
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    return name == null ? null : name.toLowerCase();
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    }
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    return name;
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    }
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    }

3、实现ObjectWrapperFactory

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   import com.alibaba.fastjson.JSONObject;
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   import org.apache.ibatis.reflection.MetaObject;
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   import org.apache.ibatis.reflection.wrapper.ObjectWrapper;
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   import org.apache.ibatis.reflection.wrapper.ObjectWrapperFactory;
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   import org.apache.ibatis.session.Configuration;
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   import org.mybatis.spring.boot.autoconfigure.ConfigurationCustomizer;
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   import org.springframework.context.annotation.Bean;
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   import org.springframework.stereotype.Component;
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    import java.util.Map;
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    @Component
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    public class SqlFieldToLowerCaeFactory implements ObjectWrapperFactory {
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    @Override
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    public boolean hasWrapperFor(Object o) {
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    return o instanceof Map;
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    }
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    @Override
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    public ObjectWrapper getWrapperFor(MetaObject metaObject, Object o) {
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    return new SqlFieldToLowerCase(metaObject, (Map) o);
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    }
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    /**
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    * 使用该方式object-wrapper-factory: com.demo.config.SqlFieldToLowerCaeFactory
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    * 会报类型转换异常所以使用下面这种方式
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    * @return
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    */
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    @Bean
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    public ConfigurationCustomizer mybatisConfigurationCustomizer() {
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    return new ConfigurationCustomizer() {
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    @Override
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    public void customize(Configuration configuration) {
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    configuration.setObjectWrapperFactory(new SqlFieldToLowerCaeFactory());
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    }
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    };
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    }
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    }

注意事项：mybatis返回结果为fastjson:JSONObject类型时，使用该方式将返回字段转小写可能会在遇见达梦数据库字段类型为CLOB、TEXT等类型字段报JSON解析内存溢出

可以尝试在数据库链接上拼接clobAsString=1 或者将字段类型改为varchar

jdbc:dm://127.0.0.1:5236/DEMO?clobAsString=1

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