java - 无法从元组实例化类

Question

我有两个表 Setup 和 Product，并且我创建了一个 SetupProductJoin 来表示连接两个表时的模型。 productName 是来自 Product 表的字符串 (varchar)，但我收到错误

错误

org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.QueryException: could not instantiate class [com.nano.comp.domain.io.SetupProductJoin] from tuple; nested exception is java.lang.IllegalArgumentException: org.hibernate.QueryException: could not instantiate class [com.nano.comp.domain.io.SetupProductJoin] from tuple

public interface SetupProductJoinInterface {

    String getProductName();
}

public abstract class SetupProductJoin implements SetupProductJoinInterface {
    
    private String productName = "";

    public SetupProductJoin() {

    }

    public SetupProductJoin(String productName) {
        super();
        this.productName = productName;
    }

    public String getproductName() {
        return productName;
    }

    public void setproductName(String productName) {
        this.productName = productName;
    }
}

存储库

@Query(value = " SELECT new com.nano.comp.domain.io.SetupProductJoin(p.name as productName) " +
        " FROM Setup bs " +
        "   INNER JOIN Product p ON p.id = bs.productId " +
        " WHERE bs.wgId = ?1 "
)
List<SetupProductJoin> findByWgId(Long wgId);

Controller

List<SetupProductJoin> setup = setupRepository.findByWgId(wgId);

Answer 1

正如@M所指出的。 Deinum，SetupProductJoin 不应该是抽象的。

您的查询似乎有误。尝试以下查询:

@Query(value = " SELECT new com.nano.comp.domain.io.SetupProductJoin(p.name) " +
    " FROM Setup bs " +
    "   INNER JOIN Product p ON p.id = bs.productId " +
    " WHERE bs.wgId = :wgId "
)
List<SetupProductJoin> findByWgId(@Param("wgId") Long wgId);

还要检查您的 getter/setter 方法名称，它们应该采用驼峰命名法。

public String getProductName() {
    return productName;
}

public void setProductName(String productName) {
    this.productName = productName;
}