Spring Boot設置並使用緩存的步驟

今天小編就爲大家分享一篇關於Spring Boot設置並使用緩存的步驟，小編覺得內容挺不錯的，現在分享給大家，具有很好的參考價值，需要的朋友一起跟隨小編來看看吧

幾個緩存註解的作用：

@Cacheable：將方法的返回結果根據key指定的鍵保存在緩存中，以後要獲取相同的數據直接從緩存中共獲取

• cacheNames/value：指定Cache組件名稱
• key：指定緩存時使用的key，默認使用方法參數值，可以使用#a0、#p0、#參數名等，支持SpEL表達式，root可省略
• keyGenerator：指定key的生成器的組件id，如自定義的KeyGenerator
• cacheManager：指定緩存管理器
• cacheResolver：指定緩存解析器
• condition：指定在哪種條件下緩存，如condition = “#id>=1”在參數>=1時緩存
• unless：指定該條件爲真時不緩存
• sync：指定是否使用異步模式

@CachePut：不管緩存中是否有需要的數據，都會執行該註解標註的方法，並將結果更新到緩存，屬性見上

@CacheEvit：執行方法後，清除key指定的緩存

• allEntries：默認爲false，值爲true，刪除所有緩存
• beforeInvocation：默認爲false，值爲true，在方法調用之前清除緩存

@CacheConfig：定義一些通用或公共的規則，如cacheNames、keyGenerator等

可使用的SpEL表達式：

使用緩存的步驟：

（1）創建一個Spring Boot應用，勾選Cache、Web、MySQL、Mybatis模塊,在主程序類上添加註解，開啓基於註解的緩存

@MapperScan(basePackages = "com.youngpain.cache.mapper")
@SpringBootApplication
@EnableCaching

（2）創建JavaBean，和數據庫中的表對應，並配置數據源

spring:
 datasource:
  url: jdbc:mysql://localhost:3306/mybatis_database
  username: root
  password: 1741248769
  driver-class-name: com.mysql.jdbc.Driver
 redis:
  host: 39.108.114.57
#開啓駝峯命名法
mybatis:
 configuration:
  map-underscore-to-camel-case: true
logging:
 level:
  com.youngpain.cache.mapper: debug

（3）創建mapper接口進行增刪改查操作

/**
 * 部門表的增刪改查操作
 */
public interface DepartmentMapper {
  @Insert("insert into department(id,depart_name,depart_build) values(#{id},#{depart_name},#{depart_build})")
  void insertDepartment(Department department);
  @Delete("delete from department where id=#{id}")
  void deleteDepartment(Integer id);
  @Update("update department set depart_name=#{departName},depart_build=#{departBuild} where id=#{id}")
  void updateDepartment(Department department);
  @Select("select * from department where id=#{id}")
  Department getDepartmentById(Integer id);
}

（4）創建service

@Service
@CacheConfig(cacheNames = {"departs"})
public class DepartmentService {
  @Autowired
  DepartmentMapper departmentMapper;
  @Cacheable(key = "#a0.id")
  public void insertDepartment(Department department) {
    departmentMapper.insertDepartment(department);
  }
  @CacheEvict(key = "#p0")
  public void deleteDepartment(Integer id) {
    departmentMapper.deleteDepartment(id);
  }
  @CachePut(key = "#a0.id")
  public Department updateDepartment(Department department) {
    departmentMapper.updateDepartment(department);
    return department;
  }
  @Cacheable(key = "#id", condition = "#p0>=1")
  public Department getDepartmentById(Integer id) {
    return departmentMapper.getDepartmentById(id);
  }
}

（5）創建controller

@Controller
public class DepartmentController {
  @Autowired
  DepartmentService departmentService;
  @GetMapping("/index")
  public String index() {
    return "index";
  }
  @GetMapping("/deleteDepart/{id}")
  public String deleteDepart(@PathVariable("id") Integer id, Model model) {
    model.addAttribute("condition", "delete");
    Department delete = departmentService.getDepartmentById(id);
    model.addAttribute("department", delete);
    departmentService.deleteDepartment(id);
    return "success";
  }
  @PostMapping("/updateDepart")
  public String updateDepart(Department department, Model model) {
    model.addAttribute("condition", "update");
    Department update = departmentService.updateDepartment(department);
    model.addAttribute("department", update);
    return "success";
  }
  @GetMapping("/getDepart/{id}")
  public String getDepartmentById(@PathVariable("id") Integer id, Model model) {
    model.addAttribute("condition", "delete");
    Department get = departmentService.getDepartmentById(id);
    model.addAttribute("department", get);
    return "success";
  }
}

（6）測試結果：

@Cacheable：第一次查詢數據，控制檯發出sql語句，之後再查詢直接從緩存中獲取
@CachePut：調用方法修改某個數據後，再次查詢該數據是從緩存中獲取的更新後的數據
@CacheEvict：調用該方法後，再次查詢某個數據需要重新發出sql語句查詢

ps：之前只是用markdown記筆記，今天第一次用markdown寫文章，寫起來好舒服啊QAQ

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