我正在使用spring,jpa,hibernate,mysql,java 8 ,.在Dao中(这是接口并扩展了JpaRepository)
MyTable类
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Transient;
@Entity
@Table(name = "MY_TABLE")
public class MyTable {
@Id
@Column(name = "ID")
private long id;
@Column(name = "ITEM_NAME")
private String itemName;
@Column(name = "ITEM_PRICE")
private int itemPrice;
@Transient
private int col1;
public MyTable() {
}
public MyTable(long id, String itemName, int itemPrice, int col1) {
super();
this.id = id;
this.itemName = itemName;
this.itemPrice = itemPrice;
this.col1 = col1;
}
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
public String getItemName() {
return itemName;
}
public void setItemName(String itemName) {
this.itemName = itemName;
}
public int getItemPrice() {
return itemPrice;
}
public void setItemPrice(int itemPrice) {
this.itemPrice = itemPrice;
}
public int getCol1() {
return col1;
}
public void setCol1(int col1) {
this.col1 = col1;
}
}
MyTableDao
import java.util.List;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import com.kolip.devchain.model.MyTable;
public interface MyTableDao extends JpaRepository<MyTable , Long> {
@Query(value = "SELECT mt.*, (select count(1) from anotherTable ) as col1 from MY_TABLE mt",nativeQuery = true)
List<MyTable> getMyTableList();
}
绒球
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.0.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<!-- <dependency> -->
<!-- <groupId>org.springframework.boot</groupId> -->
<!-- <artifactId>spring-boot-starter-security</artifactId> -->
<!-- </dependency> -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.38</version>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.hibernate</groupId>
<artifactId>hibernate-entitymanager</artifactId>
</dependency>
<dependency>
<groupId>com.github.stefanbirkner</groupId>
<artifactId>system-rules</artifactId>
<version>1.16.0</version>
</dependency>
<dependency>
<groupId>org.scala-lang</groupId>
<artifactId>scala-library</artifactId>
<version>2.11.0</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.datatype</groupId>
<artifactId>jackson-datatype-hibernate5</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
MY_TABLE
CREATE TABLE `my_table` (
`ID` bigint(20) NOT NULL,
`ITEM_NAME` varchar(255) DEFAULT NULL,
`ITEM_PRICE` int(11) DEFAULT NULL,
PRIMARY KEY (`ID`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
我尝试简化我的问题。我尝试获取col1值,但我无法确定实体中的col1属性应该如何。其他值可以在实体中获得。
如果我不使用col1属性@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@来读,它将工作,但col1不是持久的(因为db上没有col1列,findAll()也不工作)。我该怎么办 ?
最佳答案
您有很多选择,但是如果您使用的是JPA 2.1,可以尝试以下步骤:
1)创建一个合适的DTO,其中应包含将采用查询结果的属性:
“ SELECT mt。*,(从anotherTable中选择count(1)作为MY_TABLE mt的col1”)
2)在MyTable实体中,使用@SqlResultSetMapping和@ConstructorResult批注将本机查询映射到您的DTO(在Google上进行简单搜索将为您提供有关其用法的许多有用信息)。(请参见http://docs.oracle.com/javaee/7/api/javax/persistence/SqlResultSetMapping.html)
3)修改MyTableDao以使用您在步骤2中创建的本机查询。
我希望这有帮助。祝好运 :)