代码下载地址
链接: https://pan.baidu.com/s/1igAPYzdkz-QTYCrsRhyqfQ?pwd=d8m6 提取码: d8m6
实体类User.java
package com.zxl.chapter51;
import lombok.Data;
import lombok.NoArgsConstructor;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
@Entity
@Data
@NoArgsConstructor
public class User {
@Id
@GeneratedValue
private Long id;
private String name;
private Integer age;
public User(String name, Integer age) {
this.name = name;
this.age = age;
}
}
JPA接口UserRepository.java
package com.zxl.chapter51;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
/**
* Created by 程序猿DD/翟永超 on 2020/7/13.
* <p>
* Blog: http://blog.didispace.com/
* Github: https://github.com/dyc87112/
*/
@CacheConfig(cacheNames = "users")
public interface UserRepository extends JpaRepository<User, Long> {
@Cacheable
User findByName(String name);
User findByNameAndAge(String name, Integer age);
@Query("from User u where u.name=:name")
User findUser(@Param("name") String name);
}
配置文件
spring.datasource.url=jdbc:mysql://localhost:3306/test?serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.show-sql=true
spring.jpa.hibernate.ddl-auto=create-drop
启动类
package com.zxl.chapter51;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
@EnableCaching
@SpringBootApplication
public class Chapter51Application {
public static void main(String[] args) {
SpringApplication.run(Chapter51Application.class, args);
}
}
测试类
package com.zxl.chapter51;
import lombok.extern.slf4j.Slf4j;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.cache.CacheManager;
import org.springframework.test.context.junit4.SpringRunner;
@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest
public class Chapter51ApplicationTests {
@Autowired
private UserRepository userRepository;
@Autowired
private CacheManager cacheManager;
@Test
public void test() throws Exception {
// 创建1条记录
userRepository.save(new User("AAA", 10));
User u1 = userRepository.findByName("AAA");
System.out.println("第一次查询:" + u1.getAge());
User u2 = userRepository.findByName("AAA");
System.out.println("第二次查询:" + u2.getAge());
}
}
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>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.zxl</groupId>
<artifactId>chapter5-1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<description>使用进程内缓存</description>
<properties>
<java.version>1.8</java.version>
</properties>
<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.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
debug观察
Hibernate: select next_val as id_val from hibernate_sequence for update
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
Hibernate: insert into user (age, name, id) values (?, ?, ?)
Hibernate: select user0_.id as id1_0_, user0_.age as age2_0_, user0_.name as name3_0_ from user user0_ where user0_.name=?
第一次查询:10
第二次查询:10