Mybatis Plus通过lambda获取数据库对应的列名

灰太狼 2023-10-09 23:19 16阅读 0赞

## 项目场景： ##

`Mybatis Plus通过lambda获取数据库对应的列名`

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## 解决方案： ##

> 通过baomidou自带的LambdaUtils工具类获取数据库对应的列名

#### 1.引入maven依赖 ####

<dependency>
    	<groupId>cn.hutool</groupId>
    	<artifactId>hutool-all</artifactId>
    	<version>5.8.0</version>
    </dependency>
    
    <dependency>
    	<groupId>com.baomidou</groupId>
    	<artifactId>mybatis-plus-boot-starter</artifactId>
    	<version>3.5.1</version>
    </dependency>

#### 2.创建实体 ####

@Data
    @TableName("test")
    public class TestEntity {
    
        @ApiModelProperty(value = "主键id")
    	@TableId
        private String id;
    
        @ApiModelProperty(value = "完整姓名")
        @TableField("pull_name")
        private String pullName;
    }

#### 3.测试 ####

import cn.hutool.core.lang.func.LambdaUtil;
    import com.baomidou.mybatisplus.core.toolkit.LambdaUtils;
    import com.baomidou.mybatisplus.core.toolkit.support.ColumnCache;
    import org.junit.Test;
    
    @Test
    public void test() {
        //获取实体所有对应的列
    	Map<String, ColumnCache> testMap = LambdaUtils.getColumnMap(TestEntity.class);
        //hutool包，获取实体属性名称
    	String fieldName = LambdaUtil.getFieldName(TestEntity::getPullName);
        //通过属性名获取对应的列名
        String column = testMap.get(LambdaUtils.formatKey(fieldName)).getColumn();
        System.out.println(column);
    }

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这里如果不想引用hutool的包，可以自己写个方法获取属性名

package test;
    
    import java.beans.Introspector;
    import java.io.Serializable;
    import java.lang.invoke.SerializedLambda;
    import java.lang.reflect.Method;
    import java.util.function.Function;
     
     
    @FunctionalInterface
    public interface TypeFunction<T, R> extends Serializable, Function<T, R> {
     
        /**
         * 获取列名称
         * @param lambda
         * @return String
         */
        static String getLambdaColumnName(Serializable lambda) {
            try {
                Method method = lambda.getClass().getDeclaredMethod("writeReplace");
                method.setAccessible(Boolean.TRUE);
                SerializedLambda serializedLambda = (SerializedLambda) method.invoke(lambda);
                String getter = serializedLambda.getImplMethodName();
                String fieldName = Introspector.decapitalize(getter.replace("get", ""));
                return fieldName;
            } catch (ReflectiveOperationException e) {
                throw new RuntimeException(e);
            }
        }
        
        static <T, R> String getFieldName(TypeFunction<T, R> name){
        	return getLambdaColumnName(name);
        }
    }

测试，改了获取属性名的方式

@Test
    public void test() {
        //获取实体所有对应的列
    	Map<String, ColumnCache> testMap = LambdaUtils.getColumnMap(TestEntity.class);
        //自定义方法，获取实体属性名称
    	String fieldName = TypeFunction.getFieldName(TestEntity::getPullName);
        //通过属性名获取对应的列名
        String column = testMap.get(LambdaUtils.formatKey(fieldName)).getColumn();
        System.out.println(column);
    }