Spring Boot设置并使用缓存的步骤

2024-07-14 08:43:34

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几个缓存注解的作用：

@Cacheable：将方法的返回结果根据key指定的键保存在缓存中，以后要获取相同的数据直接从缓存中共获取

cacheNames/value：指定Cache组件名称
key：指定缓存时使用的key，默认使用方法参数值，可以使用#a0、#p0、#参数名等，支持SpEL表达式，root可省略
keyGenerator：指定key的生成器的组件id，如自定义的KeyGenerator
cacheManager：指定缓存管理器
cacheResolver：指定缓存解析器
condition：指定在哪种条件下缓存，如condition = “#id>=1”在参数>=1时缓存
unless：指定该条件为真时不缓存
sync：指定是否使用异步模式

@CachePut：不管缓存中是否有需要的数据，都会执行该注解标注的方法，并将结果更新到缓存，属性见上

@CacheEvit：执行方法后，清除key指定的缓存

allEntries：默认为false，值为true，删除所有缓存
beforeInvocation：默认为false，值为true，在方法调用之前清除缓存

@CacheConfig：定义一些通用或公共的规则，如cacheNames、keyGenerator等

可使用的SpEL表达式：

Spring,Boot,缓存

使用缓存的步骤：

（1）创建一个Spring Boot应用，勾选Cache、Web、MySQL、Mybatis模块,在主程序类上添加注解，开启基于注解的缓存

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

（2）创建JavaBean，和数据库中的表对应，并配置数据源

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#开启驼峰命名法mybatis: configuration:  map-underscore-to-camel-case: truelogging: level:  com.youngpain.cache.mapper: debug

（3）创建mapper接口进行增删改查操作

/** * 部门表的增删改查操作 */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）创建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）创建controller

@Controllerpublic 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）测试结果：