小编tit*_*geo的帖子

我从缓存中获取价值时遇到问题.

java.lang.RuntimeException: java.lang.ClassCastException: com.mycom.admin.domain.User cannot be cast to com.mycom.admin.domain.User

缓存配置

@Configuration
@EnableCaching
@AutoConfigureAfter(value = { MetricsConfiguration.class, DatabaseConfiguration.class })
@Profile("!" + Constants.SPRING_PROFILE_FAST)
public class MemcachedCacheConfiguration extends CachingConfigurerSupport {

    private final Logger log = LoggerFactory.getLogger(MemcachedCacheConfiguration.class);

    @Override
    @Bean
    public CacheManager cacheManager() {
        ExtendedSSMCacheManager cacheManager = new ExtendedSSMCacheManager();
        try {
            List<SSMCache> list = new ArrayList<>();
            list.add(new SSMCache(defaultCache("apiCache"), 86400, false));
            cacheManager.setCaches(list);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return cacheManager;
    }


    @Override
    public CacheResolver cacheResolver() {
        return null;
    }

    @Override
    public CacheErrorHandler errorHandler() {
        return …

在下面的查询中

{ $group : {
        _id :  { success:'$success', responseCode:'$responseCode', label:'$label'},
        max_timeStamp : { $timeStamp : 1 },
        count_responseCode : { $sum : 1 },
        avg_value : { $sum : "$value" },
        count_success : { $sum : 1 }
    }}

如何 _id : { success:'$success', responseCode:'$responseCode', label:'$label'},在java mongodb驱动程序中翻译使用.

我试过了

BasicDBList list = new BasicDBList();
list.add(new BasicDBObject("success", "$success"));
list.add(new BasicDBObject("responseCode", "$responseCode"));
list.add(new BasicDBObject("label", "$label"));
AggregationOutput output = collection.aggregate(match, project, group); 

和

多维数组

String [][] muitiGroupBy = {{"success", "$success"},{"responseCode", "$responseCode"},{"label", "$label"}}; …

尝试了以下语法,它们都没有帮助将字符串类型列转换为日期

select INVC_,APIDT,APDDT from APAPP100 limit 10
select current_date, APIDT,APDDT from APAPP100 limit 10
select date_format( b.APIDT, '%Y-%m-%d') from APAPP100 b
select CAST( b.APIDT AS date) from APAPP100 b
select date(b.APIDT) from APAPP100 b
select convert(datetime, b.APIDT) from APAPP100 b
select date_parse(b.APIDT, '%Y-%m-%d') from APAPP100 b
select str_to_date(b.APIDT) from APAPP100 b

我正在使用以下代码来同步 goroutine。最近在调查一个错误时，我发现下面的代码并不总是有效。大约五分之一的失败。频道quit在我之前收到消息out频道。我能够在我的本地（不是在 go-playground）和 k8s 环境中一致地重现这个问题。作为一种解决方法，我现在使用sync.Map同步。

有没有办法修复下面的代码？

package main

import (
    "fmt"
    "io/ioutil"
    "log"
    "os"
    "path"
    "sync"
    "sync/atomic"
    "time"
)

func main() {
    //test setup
    filePaths := []string{
        path.Join(os.TempDir(), fmt.Sprint("f1-", time.Now().Nanosecond())),
        path.Join(os.TempDir(), fmt.Sprint("f2-", time.Now().Nanosecond())),
        path.Join(os.TempDir(), fmt.Sprint("f3-", time.Now().Nanosecond())),
        path.Join(os.TempDir(), fmt.Sprint("f4-", time.Now().Nanosecond())),
        path.Join(os.TempDir(), fmt.Sprint("f5-", time.Now().Nanosecond())),
        path.Join(os.TempDir(), fmt.Sprint("f6-", time.Now().Nanosecond())),
    }
    for _, filePath := range filePaths {
        f, err := os.OpenFile(filePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0600)
        if err != nil {
            log.Fatal(err)
        }
        _, err = f.WriteString("There are many variations of …

有没有办法使用spring-data mongo @Query注释来表示下面的查询.

db.users.find({userName: "titogeo"}, {requests: 1, _id:0})

控制台中的上述查询输出是

请求":[{"who":"blahblahblah1","who":"blahblahblah2",
"
what":"REQUEST",
"when":ISODate("2012-09-05T17:52:14.339Z")}] }

我尝试了以下但没有奏效.

@Query("{userName: ?0}, {requests:1, _id:0}")
public Page<AddRequest> getAllFriendRequests(String userName, Pageable pageable);

集合用户拥有User对象和请求是其中包含AddRequest对象的列表.

当我执行上面的方法时,我得到一个空白列表.任何帮助表示赞赏.

还有什么好的参考网站或书籍spring-data-mongo apis？

int equal = 0;
for (int i = 0; i < a.length(); i++) {
   equal |= a.charAt(i) ^ b.charAt(i);
}
return equal == 0;

我理解管道和XOR运算符但是在|=做什么？