小编Tin*_*iny的帖子

String a = "Hello\u200e";
String b = "Hello\u200f";

System.out.println("a = '" + a + "' and b = '" + b + "' are length "
                     + a.length() + " and " + b.length()
                     + ", equals() is " + a.equals(b));

上面代码段中的代码生成以下输出.

a ='Hello'和b ='Hello'的长度为6和6,equals()为false

虽然控制台上显示的值a和值b都是Hello?,但a.equals(b)返回false.怎么样？

在GlassFish(3.1.2.2b5)上运行的Java EE 6应用程序中,假设您有一个ConfigurationService,它读取一些属性文件并相应地分发属性值:

@Local
public interface ConfigurationService { ... }

@Singleton  
public class ConfigurationServiceImpl implements ConfigurationService { ... }

还有一个Eclipselink SessionCustomizer,因为应用程序中的一个持久性单元(Oracle数据库)的模式名称需要以编程方式设置,即可以从之前提到的属性文件进行配置.的SessionCustomizer是在配置persistence.xml和实施包含对一个参考ConfigurationService:

<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"...
    <persistence-unit name="myPU" transaction-type="JTA">
        <property name="eclipselink.session.customizer" value="MySessionCustomizer"/>
        ...

public class MySessionCustomizer implements SessionCustomizer {
    @EJB
    private ConfigurationService configurationService;
    @Override
    public void customize(Session session) {
        session.getLogin().setTableQualifier(configurationService.getSchemaName());
        ...

是否有可能以ConfigurationService这种方式注入,以便在SessionCustomizer实例化时可用？上述操作失败,因为ConfigurationService实例仍然为空,即注入尚未发生.此观察对应于服务器的日志条目.似乎依赖注入机制总是在持久性单元 - 因此SessionCustomizer- 被实例化之后开始.我搞砸周围的各种注释(@Startup,@DependsOn(...),...),但无济于事.我的结论是正确的还是有另一种方法让EJB更早实例化并注入？

如何转换

org.apache.poi.hssf.usermodel.HSSFWorkbook

至

org.apache.poi.xssf.usermodel.XSSFWorkbook

在Apache POI？

环境 :

• JSE1.6
• JBossAS 4.3.2
• POI 3.7

根据我几天前发布的问题,我意识到这SimpleFormController不适合处理Ajax请求.因此,我正在将我的应用程序迁移到带注释的控制器.

我正在尝试java.util.List使用Spring MVC 3.0.2和Hibernate通过Ajax使用Jackson 1.9.8(其下载页面)从Oracle数据库返回,但我还没有在任何技术中使用JSON.我已经阅读了一些教程/文章但我无法理解如何返回这样复杂的数据结构并在Spring中使用JSON解析它们.我首先尝试学习类似JSON的概念.

基本上我正在尝试的是当从国家选择框中选择国家时,应该通过Ajax从数据库填充与该国家相对应的州.我不知道如何返回java.util.ListAjax响应,如何解析它并在Java代码中再次使用它.我只达到以下水平.

JS代码.

function getStates(countryId)
{
    $.ajax({
        datatype:"json",
        type: "POST",
        url: "/wagafashion/ajax/TempAjax.htm",
        data: "countryId=" + countryId,

        success: function(response)
        {
            $('#msg').html(response);
            $('#stateList').val('');
        },
        error: function(e)
        {
            alert('Error: ' + e);
        }
    });
}

Spring控制器类中的方法,当onchange在国家/地区选择框的事件上发出Ajax请求时调用该方法.

@RequestMapping(method=RequestMethod.POST, value="ajax/TempAjax")
public @ResponseBody List<StateTable> getStateList(@ModelAttribute("tempBean") TempBean tempBean, BindingResult error, Map model, HttpServletRequest request, HttpServletResponse response)
{
    Session session=NewHibernateUtil.getSessionFactory().getCurrentSession();
    session.beginTransaction();
    List<StateTable>list=session.createQuery("from StateTable where country.countryId=:countryId order by stateId").setParameter("countryId", …

我需要根据ids提供的数组(如SELECT ... FROM table_name WHERE id IN()查询)从Oracle数据库中获取所选行.

在我试图这样做时,我试图org.hibernate.setParameterList(String name, Object[] values)在我的DAO中使用该方法如下.

@Service
@Transactional(readOnly = true, propagation=Propagation.REQUIRES_NEW)
public final class ProductImageDAO implements ProductImageService {

    @SuppressWarnings("unchecked")
    public List<Object[]> getFileName(String[] list) {
        return sessionFactory
                .getCurrentSession()
                .createQuery("SELECT prodImageId, prodImage FROM ProductImage WHERE prodImageId=:list")
                .setParameterList("list", list).list();
    }
}

String[]给定方法中的类型参数由相应的Spring控制器类提供.

它会导致抛出以下异常.

org.hibernate.hql.ast.QuerySyntaxException:意外的令牌:,在第1行第78列附近[从model.ProductImage中选择prodImageId,prodImage,其中prodImageId =:id0_,:id1_,:id2_,:id3_,:id4_,:id5_]

根据ids使用Hibernate的列表检索所选行的方法是什么？

我用,

• Spring Framework 4.0.0 RELEASE(GA)
• Spring Security 3.2.0 RELEASE(GA)
• Struts 2.3.16

其中,我使用内置安全令牌来防范CSRF攻击.

<s:form namespace="/admin_side"
        action="Category"
        enctype="multipart/form-data"
        method="POST"
        validate="true"
        id="dataForm"
        name="dataForm">

    <s:hidden name="%{#attr._csrf.parameterName}"
              value="%{#attr._csrf.token}"/>
</s:form>

它是其中CSRF令牌是不可用的,除非春季安全多部分请求MultipartFilter连同MultipartResolver被适当地配置成使得所述多请求由弹簧处理.

MultipartFilterin web.xml配置如下.

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
         xmlns="http://java.sun.com/xml/ns/javaee" 
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
         http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/applicationContext.xml
            /WEB-INF/spring-security.xml
        </param-value>
    </context-param>

    <filter>
        <filter-name>MultipartFilter</filter-name>
        <filter-class>org.springframework.web.multipart.support.MultipartFilter</filter-class>
    </filter>

    <filter>
        <filter-name>springSecurityFilterChain</filter-name>
        <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>MultipartFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter-mapping>
        <filter-name>springSecurityFilterChain</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>AdminLoginNocacheFilter</filter-name>
        <filter-class>filter.AdminLoginNocacheFilter</filter-class>
    </filter>

    <filter-mapping>
        <filter-name>AdminLoginNocacheFilter</filter-name>
        <url-pattern>/admin_login/*</url-pattern>
    </filter-mapping>

    <filter>
        <filter-name>NoCacheFilter</filter-name>
        <filter-class>filter.NoCacheFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>NoCacheFilter</filter-name>
        <url-pattern>/admin_side/*</url-pattern> …

我只需要使用JPA标准执行以下MySQL查询(state_table根据给定的国家名称(in country)获取状态列表(from )).

SELECT state_id, 
       state_name, 
       country_id
FROM   state_table 
WHERE  country_id IN(SELECT country_id 
                     FROM   country 
                     WHERE  country_name = ?)

我编写了以下JPA条件查询.

CriteriaBuilder criteriaBuilder=entityManager.getCriteriaBuilder();
CriteriaQuery<StateTable>criteriaQuery=criteriaBuilder.createQuery(StateTable.class);
Root<StateTable> root = criteriaQuery.from(entityManager.getMetamodel().entity(StateTable.class));

Subquery<Long> subquery = criteriaQuery.subquery(Long.class);
Root<Country> subRoot = subquery.from(Country.class);
subquery.select(subRoot.get(Country_.countryId));

ParameterExpression<String>parameterExpression=criteriaBuilder.parameter(String.class);
subquery.where(criteriaBuilder.equal(subRoot.get(Country_.countryName), parameterExpression));
criteriaQuery.where(criteriaBuilder.in(root.get(StateTable_.country).get(Country_.countryId)).value(subquery));
List<StateTable> list = entityManager.createQuery(criteriaQuery).setParameter(parameterExpression, "India").getResultList();

此条件查询不必要地在生成的SQL查询中生成冗余连接,如下所示.

SELECT t1.state_id, 
       t1.state_name, 
       t1.country_id 
FROM   projectdb.country t0, 
       projectdb.state_table t1 
WHERE  (t0.country_id IN (SELECT t2.country_id 
                           FROM   projectdb.country t2 
                           WHERE  (t2.country_name = ? )) 
         AND (t0.country_id = t1.country_id )) 

可以注意到,存在冗余连接AND (t0.country_id = …

为了utf8mb4在MySQL(5.6.11)中使用4字节,我在my.ini文件中设置了以下变量(my.cnf未找到).此文件位于Windows XP上名为Application Data(C:\Documents and Settings\All Users\Application Data\MySQL\MySQL Server 5.6)的隐藏文件夹中.它在安装目录下不可用.

[client]
port=3306
default-character-set=utf8mb4

[mysql]
default-character-set=utf8mb4

[mysqld]
init-connect='SET NAMES utf8mb4'
collation_server=utf8mb4_unicode_ci
character_set_server=utf8mb4

然后发出以下命令,

SHOW VARIABLES
WHERE Variable_name
LIKE 'character\_set\_%'
OR Variable_name LIKE 'collation%';

仍显示以下列表.

从图片本身可以看出,几个变量仍然使用3字节utf8.

在执行此操作之前,已发出以下命令以对数据库本身进行相应的更改.

ALTER DATABASE database_name
CHARACTER SET utf8mb4
COLLATE utf8mb4_unicode_ci;

并且还在所述数据库中的每个表上发出以下命令.

ALTER TABLE table_name
CONVERT TO CHARACTER SET utf8mb4
COLLATE utf8mb4_unicode_ci;

然而,为什么有些变量尚未设置为所述字符集以及整理？缺什么？

在执行上面指定的每个任务之后,系统(操作系统)本身重新启动.

我正在使用GlassFish Server 4.1/Java EE 7.在我的web.xml文件中,我提到了以下安全约束.

<security-constraint>
    <display-name>UserConstraint</display-name>
    <web-resource-collection>
        <web-resource-name>Provide a Name</web-resource-name>
        <description/>
        <url-pattern>/admin_side/*</url-pattern>
        <http-method>GET</http-method>
        <http-method>POST</http-method>
    </web-resource-collection>
    <auth-constraint>
        <description/>
        <role-name>ROLE_ADMIN</role-name>
    </auth-constraint>
    <user-data-constraint>
        <description/>
        <transport-guarantee>CONFIDENTIAL</transport-guarantee>
    </user-data-constraint>
</security-constraint>

其他当局也是如此.

由于transport-guarantee设置为CONFIDENTIAL,与指定的URL模式匹配的网页/admin_side/*通过安全通道(HTTPS)运行.

使用WebSockets时如下(JavaScript),

var ws = new WebSocket("ws://localhost:8181/Context/Push");

它无法建立初始握手.浏览器在浏览器控制台上显示以下警告.

[blocked] The page at 'https://localhost:8181/Context/admin_side/Category' was loaded over HTTPS, but ran insecure content from 'ws://localhost:8080/Context/Push': this content should also be loaded over HTTPS.

Uncaught SecurityError: Failed to construct 'WebSocket': An insecure WebSocket connection may not be initiated from …

我已将PrimeFaces从5.1决赛升级到5.2决赛(社区发布).我有一个<p:dataTable>懒惰加载如下(一个最小的例子来重现问题仅用于纯测试目​​的).

<p:dataTable  var="row"
              value="#{testManagedBean}"
              lazy="true"
              editable="true"
              rowKey="#{row.fruitId}"
              selection="#{testManagedBean.selectedValues}"
              rows="50">

    <p:column selectionMode="multiple"/>

    <p:ajax event="rowEdit" listener="#{testManagedBean.onRowEdit}"/>

    <p:column headerText="Id">
        <h:outputText value="#{row.fruitId}"/>
    </p:column>

    <p:column headerText="Fruit Name">
        <p:cellEditor>
            <f:facet name="output">
                <h:outputText value="#{row.fruitName}"/>
            </f:facet>
            <f:facet name="input">
                <p:inputText value="#{row.fruitName}"/>
            </f:facet>
        </p:cellEditor>
    </p:column>

    <p:column headerText="Price">
        <p:cellEditor>
            <f:facet name="output">
                <h:outputText value="#{row.price}"/>
            </f:facet>
            <f:facet name="input">
                <p:inputText value="#{row.price}"/>
            </f:facet>
        </p:cellEditor>
    </p:column>

    <p:column headerText="Edit">
        <p:rowEditor/>
    </p:column>
</p:dataTable>

相应的托管bean:

@Named
@ViewScoped
public class TestManagedBean extends LazyDataModel<Fruit>  implements Serializable {

    private List<Fruit> selectedValues; // Getter & setter.
    private static final long serialVersionUID …