小编yod*_*uhe的帖子

弹簧配置

 <bean id="jmsQueueConnectionFactory" class="org.apache.qpid.client.AMQConnectionFactory">
    <constructor-arg index="0"
        value="amqp://guest:guest@localhost/test?brokerlist='tcp://localhost:5672'" />
</bean>

<bean id="cachingConnectionFactory" class="org.springframework.jms.connection.CachingConnectionFactory">
    <property name="targetConnectionFactory" ref="jmsQueueConnectionFactory" />
    <property name="sessionCacheSize" value="1" />
    <property name="reconnectOnException" value="true" />
</bean>

<bean id="myDestination" class="org.apache.qpid.client.AMQAnyDestination">
    <constructor-arg index="0" value="ADDR:myqueue; {create: always}" />
</bean>

<bean id="myServiceBean" class="com.test.MyService" />

<bean id="myContainer"
    class="org.springframework.jms.listener.DefaultMessageListenerContainer">
    <property name="connectionFactory" ref="cachingConnectionFactory" />
    <property name="exceptionListener" ref="cachingConnectionFactory" /> 
    <property name="messageListener" ref="myServiceBean" />
    <property name="concurrentConsumers" value="1" />
    <property name="autoStartup" value="true" />
    <property name="destination" ref="myDestination" />
    <property name="recoveryInterval" value="10000" />      
</bean>

MyService.java

public class MyService implements MessageListener {
    public void …

我正在使用Flex/Bison/C++来评估表达式这是一个示例bison文件

string res; 
yy_scan_string(expression.c_str());               

yyparse();
cout<<"Result:"<<res<<"\n";
....
expr: expr PLUS expr { 
          $$=evaluate("+",$1,$3);
          res=$$;
          } 
     |expr MINUS expr { 
          $$=evaluate("-",$1,$3);
          res=$$;
          } 

而不是使用变量res并将值存储在每个动作中,是否有一种标准(如yylval)方式来访问yyparse()之后的最终结果？

我们升级了我们的项目，主要是 springboot 1.4.3，java 7 到 java 8。

之后，在应用程序启动过程中，需要超过 8 分钟才能通过 'Initializing ExecutorService 'taskScheduler' '

我们也有活动依赖

下面是日志

2017-01-24 14:56:15 INFO  o.activiti.engine.impl.ProcessEngineImpl:82 - ProcessEngine default created
2017-01-24 14:56:15 INFO  o.a.e.i.a.DefaultAsyncJobExecutor:86 - Starting up the default async job executor [org.activiti.engine.impl.asyncexecutor.DefaultAsyncJobExecutor].
2017-01-24 14:56:15 INFO  o.a.e.i.a.DefaultAsyncJobExecutor:121 - Creating thread pool queue of size 100
2017-01-24 14:56:15 INFO  o.a.e.i.a.DefaultAsyncJobExecutor:126 - Creating executor service with corePoolSize 2, maxPoolSize 10 and keepAliveTime 5000
2017-01-24 14:56:15 INFO  o.a.e.i.a.AcquireTimerJobsRunnable:45 - {} starting to acquire async jobs due
2017-01-24 14:56:16 INFO …

如何处理primefaces文件下载的错误

<p:fileDownload value="#{testBean.file}" /> 

测试Bean.java

    public StreamedContent getFile() {  
    if(selectedReport ==null){
        FacesContext.getCurrentInstance().addMessage(.."Please select a file");
        return null;//What to do here
    }
    InputStream inps =  ReportGenerator.getPDF(selectedReport);
    return new DefaultStreamedContent(inps, "application/pdf", "report.pdf"); 
    }

我正在使用 JSF 2、myfaces、hibernate-validator-4.1.0.Final.jar。

我使用 hibernate-validator 来验证表单中输入的值。

public class Client {
   @Persistent
   @Pattern(regexp = "|.+@.+\\.[a-z]+", message = "Email format is invalid.")
   private String email;
   //getter
}

我正在开发批量上传模块，我在其中解析 csv 数据并创建数据库记录。

...
try{
  Client cl=new Client();
  cl.setEmail("from_csv_data");
}catch( //validation failed

我如何在这里重用相同的验证器？

SEVERE: Received 'java.lang.NoSuchMethodError' when invoking action listener '#{clientBean.bulkUpload}' for component 'j_idt86'

2011 年 1 月 28 日上午 8:35:39 javax.faces.event.MethodExpressionActionListener processAction
严重：java.lang.NoSuchMethodError：javax.persistence.Persistence.getPersistenceUtil()Ljavax/persistence/PersistenceUtil; 在 org.hibernate.validator.engine.resolver.JPATraversableResolver.isReachable(JPATraversableResolver.java:62)

我试过这个解决方案链接
我有 hibernate-jpa-2.0-api-1.0.0.Final.jar,hibernate-validator-4.1.0.Final.jar
我需要任何其他 jar 来完成这项工作吗？

有没有办法配置(xml)tomcat(6.x)来生成唯一的SessionId.(不扩展ManagerBase/StandardManager).

可能重复:
浮点精度

        double a=0.000001,b=50000;
        b=a*b;
        System.out.println("double:"+b); // -> double:0.049999999999999996

        float a=0.000001f,b=50000;
        b=a*b;
        System.out.println("float"+b);  // -> float0.05

我在代码的大部分时间里使用了double,今天我发现了这个问题.我该怎么处理？

语境:

        double []refValues= {100,75,50,25,15,5,1};

        double bInMilliGram=b*1000;
        double pickedVal=0;
        for(double ref:refValues)
            if(ref<=bInMilliGram) {
                pickedVal=ref;
                break;
            }
        System.out.println("bInMilliGram:"+bInMilliGram+", pickedVal:"+pickedVal);

o/p: - > bInMilliGram:49.99999999999999,pickedVal:25.0

@Entity
@Table
public class Book {

    @Id @GeneratedValue @Column private Long bookId;

    @Column private String name;

    @OneToMany(cascade=CascadeType.ALL,fetch=FetchType.EAGER)
    @JoinColumn(name="bookId")
    private List<Chapter> chapters=new ArrayList<Chapter>();
.....

@Entity
@Table
public class Chapter {

    @Id @Column @GeneratedValue
    private Long cid;

    @Column private String name;

    @Column private Long bookId;
....

我应该在Chapter.bookId中使用什么注释来引用Book.bookId,这样chapter.bookid将在插入新书时获取Book.bookId的生成值.

    Book bk=new Book();
    bk.setName("b1");

    Chapter ch=new Chapter();
    ch.setName("b1c1");
    bk.getChapters().add(ch);

我得到这个错误Hibernate:插入Book(名称)值(？)Hibernate:插入章节(bookId,name)值(？,？)19:56:59,094 ERROR JDBCExceptionReporter:234 - 列'bookId'不能为null