Cannot Determine Value Type From String 'Xxxxxx'

在使用MyBatis的时候，若实体类上使用了lombok的@Builder注解，那么在查询数据做映射的时候会出现Cannot determine value type from string 'xxxxxx'错误，产生这个错误的原因是当使用了@Builder注解之后会默认把无参构造方法忽略掉，创建一个全参的构造方法，比如

import java.io.Serializable;

import lombok.Builder;
import lombok.Data;

@Data
@Builder
public class DemoBean implements Serializable {

    private Long   id;

    private String name;

}

被编译之后再反编译，变成了：

import java.io.Serializable;

public class DemoBean implements Serializable {
    private Long id;
    private String name;

    DemoBean(Long id, String name) {
        this.id = id;
        this.name = name;
    }

    public static DemoBean.DemoBeanBuilder builder() {
        return new DemoBean.DemoBeanBuilder();
    }
  	
  	// ...忽略setter、getter方法

    public static class DemoBeanBuilder {
        private Long id;
        private String name;

        DemoBeanBuilder() {
        }

        public DemoBean.DemoBeanBuilder id(Long id) {
            this.id = id;
            return this;
        }

        public DemoBean.DemoBeanBuilder name(String name) {
            this.name = name;
            return this;
        }

        public DemoBean build() {
            return new DemoBean(this.id, this.name);
        }

        public String toString() {
            return "DemoBean.DemoBeanBuilder(id=" + this.id + ", name=" + this.name + ")";
        }
    }
}

从代码看到是没有默认构造方法，而MyBatis进行映射的时候会需要无参构造方法实例化一个类，所以我们再使用@Builder的时候，即使使用@NoArgsConstructor注解也无济于事，那我们该怎么办？

---

在lombok中有一个@Tolerate注解，我们看下它的定义

/**
 * Put on any method or constructor to make lombok pretend it doesn't exist,
 * i.e., to generate a method which would otherwise be skipped due to possible conflicts.
 */
@Target({ElementType.METHOD, ElementType.CONSTRUCTOR})
@Retention(RetentionPolicy.SOURCE)
public @interface Tolerate {
}

注释上的意思就是让lombok在扫描的时候假装被@Tolerate修饰的方法不存在，也就是会原封不动的被编译到字节码中，不会覆盖它，那么这样的话我们就可以进行骚操作了，修改原代码为：

import java.io.Serializable;

import lombok.Builder;
import lombok.Data;

@Data
@Builder
public class DemoBean implements Serializable {

    private Long   id;

    private String name;
  
  	@Tolerate
    public DemoBean() {
    }

}