springboot-Cacheable
Spring为我们提供了几个注解来支持Spring Cache。其核心主要是@Cacheable和@CacheEvict。使用@Cacheable标记的方法在执行后Spring Cache将缓存其返回结果，而使用@CacheEvict标记的方法会在方法执行前或者执行后移除Spring Cache中的某些元素。下面我们将来详细介绍一下Spring基于注解对Cache的支持所提供的几个注解。
@Cacheable可以标记在一个方法上，也可以标记在一个类上。当标记在一个方法上时表示该方法是支持缓存的，当标记在一个类上时则表示该类所有的方法都是支持缓存的
@Cacheable 实例
实例项目结构
1 pom.xml
?xml version="1.0" encoding="UTF-8"?>4.0.0 org.springframework.boot spring-boot-starter-parent 2.1.3.RELEASE com.example demo 0.0.1-SNAPSHOT demo Demo project for Spring Boot 1.8 org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-thymeleaf org.springframework.boot spring-boot-starter org.springframework.boot spring-boot-starter-test test org.mybatis.spring.boot mybatis-spring-boot-starter 2.0.0 org.springframework.boot spring-boot-starter-jdbc com.microsoft.sqlserver sqljdbc4 4.2 4.2 org.springframework springloaded 1.2.8.RELEASE org.springframework.boot spring-boot-devtools true org.springframework.boot spring-boot-starter-cache net.sf.ehcache ehcache 2.8.2 org.springframework.boot spring-boot-starter org.springframework.boot spring-boot-starter-logging org.springframework.boot spring-boot-starter-log4j2 org.springframework.boot spring-boot-maven-plugin 1.5.3.RELEASE true
2配至缓存ehcache.xml
UserCache" eternal="false" maxEntriesLocalHeap="0" timeToIdleSeconds="50">
3 application.properties 配至
spring.cache.type=SIMPLE #数据库连接 SQL SERVER spring.datasource.url=jdbc:sqlserver://localhost:1433;DatabaseName=Text spring.datasource.driverClassName=com.microsoft.sqlserver.jdbc.SQLServerDriver spring.datasource.username=sa spring.datasource.password=123 spring.datasource.type= org.springframework.jdbc.datasource.DriverManagerDataSource spring.cache.type=ehcache spring.cache.ehcache.config=classpath:ehcache.xml
3 User实体类User.cs
package com.example.demo.entity;
public class User {
public int ID;
public int getID() {
return ID;
}
public void setID(int ID) {
this.ID = ID;
}
public String UserName;
public String Pwd;
public String Age;
public String getUserName() {
return UserName;
}
public void setUserName(String userName) {
UserName = userName;
}
public String getPwd() {
return Pwd;
}
public void setPwd(String pwd) {
Pwd = pwd;
}
public String getAge() {
return Age;
}
public void setAge(String age) {
Age = age;
}
}
4 数据访问 接口UserDAO.cs
package com.example.demo; import com.example.demo.entity.User; import org.apache.ibatis.annotations.*; import org.springframework.cache.annotation.CacheConfig; import org.springframework.cache.annotation.Cacheable; import java.util.List; @Mapper @CacheConfig(cacheNames="UserCache") //ehcache.xml 缓存配至名称 public interface UserDAO { /** * 用户数据新增 */ @Insert("insert into Userinfo(UserName, Pwd, Age) values (#{UserName},#{Pwd},#{Age})") void addUser(User user); /** * 用户数据修改 */ @Update("update Userinfo set UserName=#{UserName},Pwd=#{Pwd} where id=#{id}") void updateUser(User user); /** * 用户数据删除 */ @Delete("delete from Userinfo where ID=#{ID}") void deleteUser(int ID); /** * 根据用户ID查询用户信息 * */ @Select("SELECT UserName, Pwd, Age FROM Userinfo where ID=#{ID}") @Cacheable User findById(@Param("ID") int ID); /** * 根据用户age查询用户信息 */ @Select("SELECT UserName, Pwd, Age FROM Userinfo") ListfindAll(); }
5 UserService.cs
package com.example.demo;
import com.example.demo.entity.User;
import org.hibernate.validator.internal.util.logging.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.SimpleTimeZone;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
@Service
public class UserService implements UserDAO {
private static final Logger logger;
static {
logger = LogManager.getLogger(UserDAO.class);
}
@Autowired
private UserDAO userDAO;
@Override
public void addUser(User user) {
}
@Override
public void updateUser(User user) {
}
@Override
public void deleteUser(int ID) {
}
@Override
@Cacheable(key = "#ID") //缓存查询数据ID
public User findById(int ID) {
logger.info("取SQL"); //验证是否取SQL
User user=this.userDAO.findById(ID);
return user;
}
@Override
public List findAll() {
return this.userDAO.findAll();
}
}
6 控制器 UserController
import com.example.demo.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
@Controller
public class UserController {
@Autowired
private UserService userService;
@RequestMapping("/User")
public String User(){
System.out.print("开始");
return "index";
}
@RequestMapping("/findById")
public String getUser(int id) {
System.out.print("开始");
User user = userService.findById(id);
System.out.print("开始"+user.Age);
return "index";
}
}
7 创建index.html
部署
测试Cacheable
8创建springboot启动器
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
@SpringBootApplication
@EnableCaching
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
运行结果：
http://127.0.0.1:8080//findById?id=5
请求2次
开始2019-04-10 16:02:38.614 INFO 7376 --- [nio-8080-exec-7] c.e.d.UserDAO : 取SQL
开始女 开始 开始女
结果只取1次SQL