使用Redis Hash结构来存储对象,更改有限字段;

Redis的hash结构特别适合 用来存储对象; 比如我们有吧问题的回答根据id存储到Redis中,

key为 "siye_answerId:"+answer.getId();

然后把对象转换成map直接存储进去, hashkey为对象的field,hashvalue为对象的值;

当有人对回答进行浏览,评论,点赞,踩,收藏等操作的时候直接更新这1个字段,

然后获取对象的时候可以直接转换为对象;

下面为 实例代码: 和转换的工具类(注意只能转换基本数据类型,String,Date等里面有2级对象的不能转换;)

@Testpublic void test2() throws Exception {    Date date = new Date();    UserInfo user = new UserInfo(25L, "嬴政", 2000, date);    String key = "test_UserInfoId:" + user.getId();    Map<String, String> stringMap = EntityUtils.objectToHash(user);//对象转换map    hashOps.putAll(key, stringMap);    hashOps.put(key, "name", "姜子牙");    Map<String, Object> map4 = hashOps.entries(key);// 返回map集合    UserInfo user2 = EntityUtils.hashToObject2(map4, UserInfo.class);    Long age = hashOps.increment(key, "age", 500L);// 指定字段的值增加,可用来点赞等操作;    Map<String, Object> map5 = hashOps.entries(key);// 返回map集合    UserInfo user3 = EntityUtils.hashToObject2(map5, UserInfo.class);    System.out.println(user3);}

下面为转换器

public class EntityUtils {    static {        ConvertUtils.register(new LongConverter(null), Long.class);        ConvertUtils.register(new ByteConverter(null), Byte.class);        ConvertUtils.register(new IntegerConverter(null), Integer.class);        ConvertUtils.register(new DoubleConverter(null), Double.class);        ConvertUtils.register(new ShortConverter(null), Short.class);        ConvertUtils.register(new FloatConverter(null), Float.class);        ConvertUtils.register(new Converter() {            public Object convert(Class type, Object value) {                if (value == null) {                    return null;                }                return new Date(Long.valueOf((String) value));            }        }, Date.class);    }    public static Map<String, String> objectToHash(Object obj) {        try {            Map<String, String> map = Maps.newHashMap();            BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());            PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();            for (PropertyDescriptor property : propertyDescriptors) {                if (!property.getName().equals("class")) {                    if (property.getReadMethod().invoke(obj) != null) {                        // 时间类型会错乱所以吧时间手动转换成long;                        if (property.getReadMethod().invoke(obj) != null) {                            if ("java.util.Date".equals(property.getPropertyType().getTypeName())) {                                Date invoke = (Date) property.getReadMethod().invoke(obj);                                long time = invoke.getTime();                                map.put(property.getName(), String.valueOf(time));                            } else {                                map.put(property.getName(), "" + property.getReadMethod().invoke(obj));                            }                        }                    }                }            }            return map;        } catch (IntrospectionException | InvocationTargetException | IllegalAccessException e) {            throw new RuntimeException(e);        }    }    public static <T> T hashToObject2(Map<?, ?> map, Class t) {        try {            Object o = t.newInstance();            BeanUtils.populate(o, (Map) map);            return (T) o;        } catch (IllegalAccessException | InvocationTargetException e) {            throw new RuntimeException(e);        } catch (InstantiationException e) {            e.printStackTrace();        }        return null;    }}