redis缓存

1. 通过MyBatis使用redis缓存

1. 在 *Mapper.xml 内添加 cache 标签，type的值为自定义的redisCache类的全路径

2. 定义RedisCache类，继承自Cache，如下:
public class RedisCache implements Cache {

    private RedisTemplate redisTemplate;

    private final String id;

    public RedisCache(String id){
        this.id = id;
    }

    @Override
    public String getId() {
        return id;
    }

    @Override
    public void putObject(Object o, Object o1) {
        if(o == null)   return ;
        if(redisTemplate == null)
            redisTemplate = ((RedisTemplate) ApplicationContextUtil.getBean("redisTemplate"));
        redisTemplate.opsForHash().put(id,o.toString(),o1);
    }

    @Override
    public Object getObject(Object o) {
        if(o == null)   return null;
        if(redisTemplate == null)
            redisTemplate = ((RedisTemplate) ApplicationContextUtil.getBean("redisTemplate"));
        return redisTemplate.opsForHash().get(id,o.toString());
    }

    // 为mybatis的保留方法，基本不使用
    @Override
    public Object removeObject(Object o) {
        return null;
    }

    //delete,save,update都会调用这个方法
    @Override
    public void clear() {
        if(redisTemplate == null)
            redisTemplate = ((RedisTemplate) ApplicationContextUtil.getBean("redisTemplate"));
        redisTemplate.delete(id);
    }

    @Override
    public int getSize() {
        if(redisTemplate == null)
            redisTemplate = ((RedisTemplate) ApplicationContextUtil.getBean("redisTemplate"));
        return redisTemplate.opsForHash().size(id).intValue();
    }
}