Spring Boot Data JPA @NamedQuery 教程

来源：这里教程网时间：2026-02-17 21:33:07 作者：

Spring Boot Data JPA @NamedQuery 教程展示了如何使用 JPA @NamedQuery 创建自定义查询。

Spring 是用于创建企业应用的流行 Java 应用框架。 Spring Boot 是 Spring 框架的演进，可帮助您轻松创建独立的，生产级的基于 Spring 的应用。

Spring Data JPA

Spring Data JPA 有助于实现基于 JPA 的存储库。它增强了对基于 JPA 的数据访问层的支持。它使构建使用数据访问技术的 Spring 支持的应用变得更加容易。 Spring Data JPA 是较大的 Spring Data 系列的一部分。

JPA @NamedQuery

@NamedQuery注解是我们创建的预定义查询，并与容器管理的实体相关联。 @Query注解是类似的注解，它直接在存储库方法上声明查找程序查询。在域类上使用@NamedQuery时，在 Repository 接口上使用 Spring Data JPA @Query 注解。这样可以将域类从持久性特定的信息中解放出来，这是一件好事。

Spring Boot Data JPA @NamedQuery 示例

以下应用是一个简单的 Spring Boot Web 应用，它使用 JPA @NamedQuery 创建一个自定义查询。该示例的数据存储在基于内存的 H2 数据库中。数据库在应用启动时初始化。

pom.xmlsrc├───main│   ├───java│   │   └───com│   │       └───zetcode│   │           │   Application.java│   │           ├───controller│   │           │       MyController.java│   │           ├───model│   │           │       City.java│   │           ├───repository│   │           │       CityRepository.java│   │           └───service│   │                   CityService.java│   │                   ICityService.java│   └───resources│       │   application.properties│       │   data-h2.sql│       │   schema-h2.sql│       ├───static│       │       index.html│       └───templates│               showCities.ftl└───test    └───java

这是项目结构。

pom.xml

<?xml version="1.0" encoding="UTF-8"?><project xmlns="http://maven.apache.org/POM/4.0.0"         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0         http://maven.apache.org/xsd/maven-4.0.0.xsd">    <modelVersion>4.0.0</modelVersion>    <groupId>com.zetcode</groupId>    <artifactId>springbootdatajpanamedquery</artifactId>    <version>1.0-SNAPSHOT</version>    <packaging>jar</packaging>    <properties>        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>        <maven.compiler.source>11</maven.compiler.source>        <maven.compiler.target>11</maven.compiler.target>    </properties>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>2.1.1.RELEASE</version>    </parent>    <dependencies>        <dependency>            <groupId>com.h2database</groupId>            <artifactId>h2</artifactId>            <scope>runtime</scope>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-freemarker</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-data-jpa</artifactId>        </dependency>    </dependencies>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build></project>

Maven POM 文件包含 H2 数据库，Freemarker 和 Spring Boot Data JPA 的依赖项。

resources/application.properties

spring.main.banner-mode=offspring.datasource.platform=h2logging.level.org.hibernate.SQL=DEBUGspring.jpa.show-sql=truespring.jpa.hibernate.ddl-auto=none

在application.properties文件中，我们有各种配置设置。使用spring.main.banner-mode属性，我们可以关闭 Spring 标语。

spring.datasource.platform设置数据库的供应商名称。在初始化脚本中使用它。 spring.jpa.show-sql允许记录 SQL 语句。最后，spring.jpa.hibernate.ddl-auto禁止从实体自动创建模式。

com/zetcode/model/City.java

package com.zetcode.model;import java.util.Objects;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.GenerationType;import javax.persistence.Id;import javax.persistence.NamedQuery;import javax.persistence.Table;@Entity@Table(name = "cities")@NamedQuery(name = "City.findAllOrderedByNameDescending",        query = "SELECT c FROM City c ORDER BY c.name DESC")public class City {    @Id    @GeneratedValue(strategy = GenerationType.AUTO)    private Long id;    private String name;    private int population;    public City() {    }    public City(String name, int population) {        this.name = name;        this.population = population;    }    public Long getId() {        return id;    }    public void setId(Long id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public int getPopulation() {        return population;    }    public void setPopulation(int population) {        this.population = population;    }    @Override    public int hashCode() {        int hash = 7;        hash = 79 * hash + Objects.hashCode(this.id);        hash = 79 * hash + Objects.hashCode(this.name);        hash = 79 * hash + this.population;        return hash;    }    @Override    public boolean equals(Object obj) {        if (this == obj) {            return true;        }        if (obj == null) {            return false;        }        if (getClass() != obj.getClass()) {            return false;        }        final City other = (City) obj;        if (this.population != other.population) {            return false;        }        if (!Objects.equals(this.name, other.name)) {            return false;        }        return Objects.equals(this.id, other.id);    }    @Override    public String toString() {        var builder = new StringBuilder();        builder.append("City{id=").append(id).append(", name=")                .append(name).append(", population=")                .append(population).append("}");        return builder.toString();    }}

这是City实体。它包含一个命名查询。

@Entity@Table(name = "cities")@NamedQuery(name = "City.findAllOrderedDescending",        query = "SELECT c FROM City c ORDER BY c.name DESC")public class City {

@Entity注解指定该类是一个实体，并映射到数据库表。 @Table注解指定要用于映射的数据库表的名称。 @NamedQuery定义了一个命名查询，该查询返回按名称降序排列的所有城市。

resources/schema-h2.sql

CREATE TABLE cities(id INT PRIMARY KEY AUTO_INCREMENT,    name VARCHAR(255), population INT);

启动应用时，将执行schema-h2.sql脚本。它创建一个新的数据库表。

resources/data-h2.sql

INSERT INTO cities(name, population) VALUES('Bratislava', 432000);INSERT INTO cities(name, population) VALUES('Budapest', 1759000);INSERT INTO cities(name, population) VALUES('Prague', 1280000);INSERT INTO cities(name, population) VALUES('Warsaw', 1748000);INSERT INTO cities(name, population) VALUES('Los Angeles', 3971000);INSERT INTO cities(name, population) VALUES('New York', 8550000);INSERT INTO cities(name, population) VALUES('Edinburgh', 464000);INSERT INTO cities(name, population) VALUES('Suzhou', 4327066);INSERT INTO cities(name, population) VALUES('Zhengzhou', 4122087);INSERT INTO cities(name, population) VALUES('Berlin', 3671000);

之后，执行data-h2.sql文件。它用数据填充表。

com/zetcode/CityRepository.java

package com.zetcode.repository;import com.zetcode.model.City;import java.util.List;import org.springframework.data.repository.CrudRepository;import org.springframework.stereotype.Repository;@Repositorypublic interface CityRepository extends CrudRepository<City, Long> {    List<City> findAllOrderedByNameDescending();}

我们将findAllOrderedByNameDescending()的声明添加到存储库接口中。

com/zetcode/service/ICityService.java

package com.zetcode.service;import com.zetcode.model.City;import java.util.List;public interface ICityService {    List<City> findAllOrderedByNameDescending();}

ICityService包含一种合同方法，用于按名称降序排列所有城市。

com/zetcode/service/CityService.java

package com.zetcode.service;import com.zetcode.model.City;import com.zetcode.repository.CityRepository;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;@Servicepublic class CityService implements ICityService {    @Autowired    private CityRepository repository;    @Override    public List<City> findAllOrderedByNameDescending() {        var cities = (List<City>) repository.findAllOrderedByNameDescending();        return cities;    }}

CityService包含findAllOrderedByNameDescending()方法的实现。我们使用存储库从数据库检索数据。

com/zetcode/controller/MyController.java

package com.zetcode.controller;import com.zetcode.model.City;import com.zetcode.service.ICityService;import java.util.List;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.GetMapping;@Controllerpublic class MyController {    @Autowired    private ICityService cityService;    @GetMapping("/showCities")    public String findAllOrderedByNameDescending(Model model) {        var cities = (List<City>) cityService.findAllOrderedByNameDescending();        model.addAttribute("cities", cities);        return "showCities";    }}

MyController类用@Controller注解。

@Autowiredprivate ICityService cityService;

我们在countryService字段中插入ICityService。

@GetMapping("/showCities")public String findAllOrderedByNameDescending(Model model) {    var cities = (List<City>) cityService.findAllOrderedByNameDescending();    System.out.println(cities);    model.addAttribute("cities", cities);    return "showCities";}

我们将带有showCities路径的请求映射到控制器的findAllOrderedByNameDescending()方法。该模型将获得按名称降序排列的城市列表，并将处理发送到showCities.ftl Freemarker 模板文件。

resources/templates/showCities.ftl

<!DOCTYPE html><html>    <head>        <title>Cities</title>        <meta charset="UTF-8">        <meta name="viewport" content="width=device-width, initial-scale=1.0">        </head>    <body>        <h2>List of cities ordered by name in descending order</h2>        <table>            <tr>                <th>Id</th>                <th>Name</th>                <th>Population</th>            </tr>            <#list cities as city>                <tr>                    <td> ${city.id}</td> <td>$ {city.name}</td>                    <td>${city.population}</td>                </tr>            </#list>        </table>    </body></html>

在showCities.ftl模板文件中，我们在 HTML 表中显示数据。

resources/static/index.html

<!DOCTYPE html><html>    <head>        <title>Home page</title>        <meta charset="UTF-8"/>        <meta name="viewport" content="width=device-width, initial-scale=1.0"/>    </head>    <body>        <a href="showCities">Show ordered cities by name in descending order</a>    </body></html>

在index.html中有一个链接，显示订购的城市。

com/zetcode/Application.java

package com.zetcode;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplicationpublic class Application {    public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

Application设置 Spring Boot 应用。 @SpringBootApplication启用自动配置和组件扫描。