spring boot + jpa学习笔记

约定不等于承诺〃 2022-09-25 02:23 172阅读 0赞

pom.xml:

<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/maven-v4_0_0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.my.app</groupId>
      <artifactId>spring-boot-jpa-demo</artifactId>
      <packaging>war</packaging>
      <version>1.0-SNAPSHOT</version>
      <name>spring-boot-jpa-demo Maven Webapp</name>
      <url>http://maven.apache.org</url>
      <properties>
            <java.version>1.8</java.version>
        </properties>
    
        
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>1.4.1.BUILD-SNAPSHOT</version>
        </parent>
    
        <dependencies>
            <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>
            <dependency>
                <groupId>org.hsqldb</groupId>
                <artifactId>hsqldb</artifactId>
                <scope>runtime</scope>
            </dependency>
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
            <dependency>
                <groupId>org.apache.tomcat</groupId>
                <artifactId>tomcat-jdbc</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>spring-jdbc</artifactId>
            </dependency>
        </dependencies>
    
        <build>
            <finalName>spring-boot-jpa-demo</finalName>
            <plugins>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                    <dependencies>
                        <dependency>
                            <groupId>org.springframework</groupId>
                            <artifactId>springloaded</artifactId>
                            <version>1.2.6.RELEASE</version>
                        </dependency>
                    </dependencies>
                </plugin>
            </plugins>
        </build>
    
        
        
        <repositories>
            <repository>
                <id>spring-snapshots</id>
                <url>http://repo.spring.io/snapshot</url>
                <snapshots><enabled>true</enabled></snapshots>
            </repository>
            <repository>
                <id>spring-milestones</id>
                <url>http://repo.spring.io/milestone</url>
            </repository>
        </repositories>
        <pluginRepositories>
            <pluginRepository>
                <id>spring-snapshots</id>
                <url>http://repo.spring.io/snapshot</url>
            </pluginRepository>
            <pluginRepository>
                <id>spring-milestones</id>
                <url>http://repo.spring.io/milestone</url>
            </pluginRepository>
        </pluginRepositories>
    </project>

我们需要一个starter：spring-boot-starter-data-jpa  
因为我们使用的是mysql，所以需要：mysql-connector-java  
需要配置数据库文件：application.properties:

spring.datasource.url=jdbc:mysql://localhost:3306/spring_boot_test
    spring.datasource.username=root
    spring.datasource.password=123456
    spring.datasource.driver-class-name=com.mysql.jdbc.Driver

dao：

import java.util.List;
    
    import org.springframework.data.jpa.repository.Query;
    import org.springframework.data.repository.CrudRepository;
    import org.springframework.data.repository.query.Param;
    import org.springframework.stereotype.Repository;
    
    import com.my.app.domain.Student;
    
    @Repository
    public interface StudentRepository extends CrudRepository<Student, Integer>{
    
        @Query(value = "select s from Student s where s.name = ?1")
        List<Student> findByName(@Param("name") String name);
    
    }

serviceImpl:

@Service
    public class StudentServiceImpl implements StudentService { 
    
        @Autowired
        private StudentRepository studentRepository;
    
        @Override
        public Student findByName(String name) {
            List<Student> students = studentRepository.findByName(name);
            return students != null && !students.isEmpty() ? students.get(0) : null;
        }
    
    }

这里我们使用了CrudRepository来做一系列增删改查的操作。

代码地址，git:  
[https://github.com/sunhuwh/spring-boot-jpa-demo][https_github.com_sunhuwh_spring-boot-jpa-demo]

[https_github.com_sunhuwh_spring-boot-jpa-demo]: https://github.com/sunhuwh/spring-boot-jpa-demo