我可以SELECT COUNT(*) from tableName在C程序中使用吗?
如果是这样,我如何获取结果?我不想使用循环,因为我只想要行数,而不是数据。
我想比较两个Java8流终端操作reduce()以及collect()它们的并行性能.
我们来看看下面的Java8并行流示例:
import java.math.BigInteger;
import java.util.function.BiConsumer;
import java.util.function.Function;
import java.util.function.Supplier;
import java.util.stream.Stream;
import static java.math.BigInteger.ONE;
public class StartMe {
static Function<Long, BigInteger> fac;
static {
fac = x -> x==0? ONE : BigInteger.valueOf(x).multiply(fac.apply(x - 1));
}
static long N = 2000;
static Supplier<BigInteger[]> one() {
BigInteger[] result = new BigInteger[1];
result[0] = ONE;
return () -> result;
}
static BiConsumer<BigInteger[], ? super BigInteger> accumulator() {
return (BigInteger[] ba, BigInteger b) -> {
synchronized (fac) {
ba[0] …Run Code Online (Sandbox Code Playgroud) 我有以下代码在我的spring.xml中正常工作...
<beans:bean id="sessionFactory"
class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<beans:property name="annotatedClasses">
<beans:list>
<beans:value>org.assessme.com.entity.User</beans:value>
</beans:list>
</beans:property>
<beans:property name="dataSource" ref="dataSource" />
<beans:property name="packagesToScan"
value="org.assessme.com.entity.*" />
<beans:property name="hibernateProperties">
<beans:props>
<beans:prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect
</beans:prop>
<beans:prop key="hibernate.transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory
</beans:prop>
<beans:prop key="hibernate.show_sql">true</beans:prop>
<beans:prop key="hibernate.hbm2ddl.auto">update</beans:prop>
</beans:props>
</beans:property>
</beans:bean>
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我只能让User对象首先工作,你可以从beans:list中看到.
我的所有实体都在同一个文件夹中,如下所示

问题是,当我在这个列表中添加另一个类时,例如......
org.assessme.com.entity.Campaign
当我启动Tomcat时,我得到以下异常...
Caused by: org.hibernate.AnnotationException: No identifier specified for entity: org.assessme.com.entity.Campaign
at org.hibernate.cfg.InheritanceState.determineDefaultAccessType(InheritanceState.java:272)
at org.hibernate.cfg.InheritanceState.getElementsToProcess(InheritanceState.java:227)
at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:712)
at org.hibernate.cfg.AnnotationConfiguration.processArtifactsOfType(AnnotationConfiguration.java:636)
at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:359)
at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1206)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:717)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1514)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1452)
... 132 more
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如果需要,下面的实体代码......
Campaign.java
package org.assessme.com.entity;
import javax.persistence.Column;
import javax.persistence.Entity;
import …Run Code Online (Sandbox Code Playgroud) 我有一个调用第三方Web服务的Web服务.
现在我想对我的网络服务进行单元测试.为此,我应该模拟第三方Web服务还是在测试期间调用它?
是否有关于单元测试的标准文件?
我正在使用此代码:
StringTokenizer tokenizer=new StringTokenizer(line, "::");
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拆分以下字符串:
hi my name is visghal:: what is yor name name:: being thw simple my::: what is yor name name.
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现在我想使用::as分隔符拆分字符串.它工作正常.但它也在:::考虑中.
换句话说,我想:
hi my name is visghal
what is yor name name
being thw simple my
: what is yor name name
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相反,它给了我以下内容:
being thw simple my
what is yor name name
hi my name is visghal
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它正在采取::和:::相同.有没有办法避免这种情况?
我使用java从文件中读取数据,将数据复制到较小的数组并将这些数组放在Hashtables中.我注意到Hashmap比原始文件消耗更多内存(大约两倍)!知道为什么吗?
这是我的代码:
public static void main(final String[] args) throws IOException {
final PrintWriter writer = new PrintWriter(new FileWriter("test.txt",
true));
for(int i = 0; i < 1000000; i++)
writer.println("This is just a dummy text!");
writer.close();
final BufferedReader reader = new BufferedReader(new FileReader(
"test.txt"));
final HashMap<Integer, String> testMap = new HashMap<Integer, String>();
String line = reader.readLine();
int k = 0;
while(line != null) {
testMap.put(k, line);
k++;
line = reader.readLine();
}
}
Run Code Online (Sandbox Code Playgroud) 我正在使用Ivy将我们的构建系统从Ant转换为Ant,并遇到了一个指定我们需要的特定jar的问题.
我在常春藤中指定它:
<dependency org="net.sf.json-lib" artifact="json-lib"
rev="2.3" conf="compile->default"/>
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并得到以下错误:
[ivy:retrieve] ==== public: tried
[ivy:retrieve] http://buildl01.tcprod.local/artifactory/libs-release/net/sf/json-lib/json-lib/2.3/json-lib-2.3.jar
[ivy:retrieve] ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:retrieve] :: FAILED DOWNLOADS ::
[ivy:retrieve] :: ^ see resolution messages for details ^ ::
[ivy:retrieve] ::::::::::::::::::::::::::::::::::::::::::::::
[ivy:retrieve] :: net.sf.json-lib#json-lib;2.3!json-lib.jar
[ivy:retrieve] ::::::::::::::::::::::::::::::::::::::::::::::
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注意Ivy试图json-lib-2.3.jar从存储库下载文件.
我做的一个搜索中央Maven仓库,发现神器不叫json-lib-2.3.jar,但无论是json-lib-2.3-jdk-13.jar或json-lib-2.3-jdk-15.jar.
问题是指定工件名称的方式.版本号出现在jar名称的中间.如果工件是`json-lib-jdk-15-2.4.jar,我可以这样做:
<dependency org="net.sf.json-lib" artifact="json-lib"
rev="2.3" conf="compile->default">
<artifact name="json-lib-jdk-15"/>
</dependency>
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如何指定此jar用于下载?
嗨我已经为iOS 6应用程序集成了Facebook SDK.Facebook身份验证和共享工作完美,但没有关闭FB Dialogue box.ie的条款.当FB Dialogue框打开时,它将在认证成功后关闭.没有提供关闭或导航回来.如何创建一个关闭按钮.我正在使用的代码片段如下所示.谢谢提前.
-(NSDictionary *)shareFacebook
{
NSDictionary *userInfo;
if (FBSession.activeSession.isOpen)
{
if (FBSession.activeSession.isOpen)
{
[self.closeButton setHidden:NO];
[FBRequestConnection startForMeWithCompletionHandler:^(FBRequestConnection *connection, id<FBGraphUser> user, NSError *error) {
NSUserDefaults *standardUserDefaults=[NSUserDefaults standardUserDefaults];
[standardUserDefaults setObject:user forKey:@"fbUserInfo"];
[self.manager authenticateUserUsingFB:[user objectForKey:@"email"]];
}];
}
}
else{
NSLog(@"fb session not active.");
[self openSessionWithAllowLoginUI:YES];
}
return userInfo;
}
- (void)openSessionWithAllowLoginUI:(BOOL)allowLoginUI {
NSArray *permissions = [[NSArray alloc] initWithObjects:
@"user_photos",
@"publish_actions",
@"read_stream",
@"friends_photos",
@"email" ,nil];
[FBSession setActiveSession:[[FBSession alloc] initWithPermissions:permissions]];
[[FBSession activeSession] openWithBehavior:FBSessionLoginBehaviorForcingWebView
completionHandler:^(FBSession *session,
FBSessionState state,
NSError *error) {
NSLog(@" …Run Code Online (Sandbox Code Playgroud) 我想使用Soot对Java程序进行静态分析,包括例如控制流程图.
各种教程都说使用Soot的"标准方法"是创建一个main方法,其中一个将自定义转换添加到Soot管道,然后调用soot.Main.main(...):
public static void main(String[] args) {
PackManager.v().getPack("jtp").add(
new Transform("jtp.gotoinstrumenter", GotoInstrumenter.v()));
soot.Main.main(args);
}
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当然,如果你想在命令行工具之外使用Soot,这有一些严重的限制.例如,我不清楚在程序中多次调用Soot的主要方法是否合法.
那么有没有人知道有可能通过一个更复杂的API直接使用Soot分析工具?
我有两个类:User和Video:
@Entity
class User{
@Id
int id;
String name;
}
@Entity
class Video{
@Id
int id;
String url;
User user;
}
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当我使用它时,我收到以下错误:
无法确定类型:用户,在表:视频
我正在通过 Tapestry 使用 Hibernate。有什么建议?
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