springboot缓存的使用

spring针对各种缓存实现，抽象出了CacheManager接口，用户使用该接口处理缓存，而无需关心底层实现。并且也可以方便的更改缓存的具体实现，而不用修改业务代码。下面对于在springboot中使用缓存做一简单介绍：

1.添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>

 

2.在需要使用缓存的方法上加上注解，如下：

@Override
    //@CachePut 该注解会将方法的返回值缓存起来,其中缓存名字是 people,数据的key是person的id
    @CachePut(value = "people", key = "#person.id")
    public Person save(Person person) {
        Person p = personRepository.save(person);
        System.out.println("为id、key为:"+p.getId()+"数据做了缓存");
        return p;
    }

 

@Override
    //@CacheEvict 该注解会删除people缓存中key为id 的数据
    @CacheEvict(value = "people", key = "#id")
    public void remove(Long id) {
        System.out.println("删除了id、key为"+id+"的数据缓存");
        //这里不做实际删除操作
    }

 

@Override
    //@Cacheable 该注解会在方法执行时，判断缓存people中key为#person.id
   //的缓存是否存在,如果存在，则直接返回缓存中的数据。如果不存在，则会查数据库，然后将返回结果缓存起来。
    @Cacheable(value = "people", key = "#person.id")
    public Person findOne(Person person) {
        Person p = personRepository.findOne(person.getId());
        System.out.println("为id、key为:"+p.getId()+"数据做了缓存");
        return p;
    }

 

以上几部就完成了缓存，但是现在的缓存是默认的基于内存的，没有实现持久化。下面以redis作为缓存的具体实现，如下

 

1.添加依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-redis</artifactId>
</dependency>

 

2.在配置文件里添加redis配置

redis.hostname=localhost
redis.port=6379

 

3.在spring容器中配置redis

@Configuration
public class RedisConfig extends CachingConfigurerSupport{
    private static final Logger logger = LoggerFactory.getLogger(RedisConfig.class);
 
    @Autowired
    private Environment env;
 
    @Bean
    public JedisConnectionFactory redisConnectionFactory() {
        JedisConnectionFactory redisConnectionFactory = new JedisConnectionFactory();
        redisConnectionFactory.setHostName(env.getProperty("redis.hostname"));
        redisConnectionFactory.setPort(Integer.parseInt(env.getProperty("redis.port")));
        return redisConnectionFactory;
    }
 
    @Bean
    public RedisTemplate<String, String> redisTemplate(RedisConnectionFactory cf) {
        RedisTemplate<String, String> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(cf);
        return redisTemplate;
    }
 
    @Bean
    public CacheManager cacheManager(RedisTemplate<?, ?> redisTemplate) {
        RedisCacheManager cacheManager = new RedisCacheManager(redisTemplate);
        cacheManager.setDefaultExpiration(600);
        return cacheManager;
    }
    
}

 

4.从缓存中取到的数据有时为JsonArray 需要转换成对象类型输出到页面时

js

 var optionsPerson = "";
                $.ajax({
                    url: "/personing/getPerson", //所需要的列表接口地址
                    type: "get",
                    dataType: "json",
                    success: function (data) {
                        var Data = data;
                        for (var key in Data) {
                            if (key == 'personList') {
                                var pList = Data[key];
                                for (var i = 0; i < pList.length; i++) {
                                    optionsPerson += "<option value=\'" + pList[i].Id + "'\>" + pList[i].name + "</option>";
                                }
                            }
                        }
                        $("#person").html(optionsPerson);
                    }
                });

 

controller

    @ApiOperation(value = "获取人",notes = "获取人")
    @GetMapping("/getPerson")
    public Map<String, List<Object>> findPersons(){
        Map<String, List<Object>> map = new HashMap<String, List<Object>>();
        List<Person> pList=PersonService.findAll();

        List<Object> personList=new ArrayList<>(pList);
       
        /*  for (Person p:pList){
            personList.add(p);
        } 不可用*/
        map.put("personList",personList);

        return map;
    }

serviceImpl

@Cacheable(value="person_list",keyGenerator = "wiselyKeyGenerator") //开启缓存
    @Override
    public List<Person> findAllPerson(){

        List<Person> list=personRepository.findAll();

        return list;
    }

 

注：要缓存的类必须序列化。