如何使用java从资源文件中读取属性

【问题标题】：How to read properties from resource file using java如何使用java从资源文件中读取属性
【发布时间】：2014-03-04 09:33:34
【问题描述】：

当我从资源 mysqlmaven.properties 文件中读取名称 lblFathersOrGuardianName 时，使用 Java 在 JSF 页面中显示错误消息值时出现以下错误。

Mar 04, 2014 2:53:21 PM com.sun.faces.application.ActionListenerImpl processAction
SEVERE: java.lang.ExceptionInInitializerError
javax.faces.el.EvaluationException: java.lang.ExceptionInInitializerError
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
    at javax.faces.component.UICommand.broadcast(UICommand.java:311)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.ExceptionInInitializerError
    at com.uk.mysqlmaven.jsf.beans.RegistrationBean.validationRegistration(RegistrationBean.java:198)
    at com.uk.mysqlmaven.jsf.beans.RegistrationBean.submitRegistrationAction(RegistrationBean.java:189)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
    ... 24 more
Caused by: java.lang.NullPointerException
    at java.util.ResourceBundle$CacheKey.calculateHashCode(ResourceBundle.java:593)
    at java.util.ResourceBundle$CacheKey.<init>(ResourceBundle.java:522)
    at java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1259)
    at java.util.ResourceBundle.getBundle(ResourceBundle.java:721)
    at com.uk.mysqlmaven.util.ResourceKeys.<init>(ResourceKeys.java:12)
    at com.uk.mysqlmaven.util.ResourceKeys.<clinit>(ResourceKeys.java:8)
    ... 34 more
Mar 04, 2014 2:53:21 PM com.sun.faces.lifecycle.InvokeApplicationPhase execute
WARNING: #{registrationBean.submitRegistrationAction}: java.lang.ExceptionInInitializerError
javax.faces.FacesException: #{registrationBean.submitRegistrationAction}: java.lang.ExceptionInInitializerError
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:114)
    at javax.faces.component.UICommand.broadcast(UICommand.java:311)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.faces.el.EvaluationException: java.lang.ExceptionInInitializerError
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
    ... 23 more
Caused by: java.lang.ExceptionInInitializerError
    at com.uk.mysqlmaven.jsf.beans.RegistrationBean.validationRegistration(RegistrationBean.java:198)
    at com.uk.mysqlmaven.jsf.beans.RegistrationBean.submitRegistrationAction(RegistrationBean.java:189)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
    ... 24 more
Caused by: java.lang.NullPointerException
    at java.util.ResourceBundle$CacheKey.calculateHashCode(ResourceBundle.java:593)
    at java.util.ResourceBundle$CacheKey.<init>(ResourceBundle.java:522)
    at java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1259)
    at java.util.ResourceBundle.getBundle(ResourceBundle.java:721)
    at com.uk.mysqlmaven.util.ResourceKeys.<init>(ResourceKeys.java:12)
    at com.uk.mysqlmaven.util.ResourceKeys.<clinit>(ResourceKeys.java:8)
    ... 34 more
javax.faces.FacesException: #{registrationBean.submitRegistrationAction}: java.lang.ExceptionInInitializerError
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:85)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:97)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:114)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:308)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:744)
Caused by: javax.faces.FacesException: #{registrationBean.submitRegistrationAction}: java.lang.ExceptionInInitializerError
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:114)
    at javax.faces.component.UICommand.broadcast(UICommand.java:311)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:781)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1246)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:77)

    ... 19 more
Caused by: javax.faces.el.EvaluationException: java.lang.ExceptionInInitializerError
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:98)
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:98)
    ... 23 more
Caused by: java.lang.ExceptionInInitializerError
    at com.uk.mysqlmaven.jsf.beans.RegistrationBean.validationRegistration(RegistrationBean.java:198)
    at com.uk.mysqlmaven.jsf.beans.RegistrationBean.submitRegistrationAction(RegistrationBean.java:189)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
    at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:274)
    at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:102)
    at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:84)
    ... 24 more
Caused by: java.lang.NullPointerException
    at java.util.ResourceBundle$CacheKey.calculateHashCode(ResourceBundle.java:593)
    at java.util.ResourceBundle$CacheKey.<init>(ResourceBundle.java:522)
    at java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:1259)
    at java.util.ResourceBundle.getBundle(ResourceBundle.java:721)
    at com.uk.mysqlmaven.util.ResourceKeys.<init>(ResourceKeys.java:12)
    at com.uk.mysqlmaven.util.ResourceKeys.<clinit>(ResourceKeys.java:8)
    ... 34 more

mysqlmaven.properties

#registration.xhtml
lblFirstName=First Name
lblMiddleName=Middle Name
lblLastName=Last Name
lblDateOfBirth=Date Of Birth
lblFathersOrGuardianName=Father's / Guardian Name

RegistrationBean.java

package com.uk.mysqlmaven.jsf.beans;

import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionEvent;

import com.uk.mysqlmaven.util.ResourceKeys;

public class RegistrationBean {

    private String fathersOrGuardianName;

    public String getFathersOrGuardianName() {
        return fathersOrGuardianName;
    }

    public void setFathersOrGuardianName(String fathersOrGuardianName) {
        this.fathersOrGuardianName = fathersOrGuardianName;
    }

    public String submitRegistrationAction() {
        if (validationRegistration()) {
            return "views/home.faces?faces-redirect=true&param=98";
        } else {
            return "";
        }
    }

    public Boolean validationRegistration() {
        if (this.fathersOrGuardianName.length() == 0) {
            FacesContext.getCurrentInstance().addMessage(fathersOrGuardianName, new FacesMessage(FacesMessage.SEVERITY_ERROR, ResourceKeys.getInstance().get("lblFathersOrGuardianName"), "Fathers/GurdianName can't be empty."));
        }
        return Boolean.FALSE;
    }

    public void clearRegistrationAction(ActionEvent event) {
        this.fathersOrGuardianName = "";
    }

}

ResourceKeys.java

package com.uk.mysqlmaven.util;


import java.util.ResourceBundle;

public class ResourceKeys {

private static ResourceKeys instance = new ResourceKeys();
private final ResourceBundle resourceBundle;

private ResourceKeys() { 
    resourceBundle = ResourceBundle.getBundle(BUNDLE_NAME);
}

/**
 * Return singleton instance of this class
 * @return singleton instance
 */
public synchronized static ResourceKeys  getInstance() {
    return instance;
}

private static String BUNDLE_NAME = "/MySqlMavenJSF/com/uk/mysqlmaven/resources/mysqlmaven";

/**
 * Return value of the key
 * @param key
 * @return value
 */
public String get(String key) {
    return resourceBundle.getString(key);
}

}

如何从java中的资源文件中获取名称。 mysqlmaven.properties 文件放在我的项目中，如下图所示。

【问题讨论】：

  • 你必须用另一个单引号转义单引号。 lblFathersOrGuardianName=父亲/监护人姓名。试试这个，让我知道。

标签： java jsf jsf-2 primefaces resourcebundle


【解决方案1】：

mysqlmaven.properties 文件路径未在 ResourceKeys.java 文件中访问。 为了在java中从package访问properties文件，我在Constants.java中使用了下面的路径。

Constants.java

package com.uk.mysqlmaven.util;

public class Constants {

public class Resources {
    public static final String BUNDLENAME_MYSQLMAVEN = "com.uk.mysqlmaven.resources.mysqlmaven";
}
}

ResourceKeys.java

package com.uk.mysqlmaven.util;


import java.util.Locale;
import java.util.ResourceBundle;

import javax.faces.context.FacesContext;

public class ResourceKeys {

private static ResourceKeys instance = new ResourceKeys();
private ResourceBundle resourceBundle;

private ResourceKeys() {

}

/**
 * Return singleton instance of this class
 * @return singleton instance
 */
public synchronized static ResourceKeys  getInstance() {
    return instance;
}

/**
 * Return value of the key
 * @param key
 * @param bundleName 
 * @return value
 */
public String get(String key, String bundleName) {
    Locale locale = FacesContext.getCurrentInstance().getViewRoot().getLocale();
    resourceBundle = ResourceBundle.getBundle(bundleName, locale);
    return resourceBundle.getString(key);
}

}

RegistrationBean.java

package com.uk.mysqlmaven.jsf.beans;

import javax.faces.application.FacesMessage;
import javax.faces.context.FacesContext;
import javax.faces.event.ActionEvent;

import com.uk.mysqlmaven.util.Constants;
import com.uk.mysqlmaven.util.ResourceKeys;

public class RegistrationBean {

private String fathersOrGuardianName;

public String getFathersOrGuardianName() {
    return fathersOrGuardianName;
}

public void setFathersOrGuardianName(String fathersOrGuardianName) {
    this.fathersOrGuardianName = fathersOrGuardianName;
}

public String submitRegistrationAction() {
    if (validationRegistration()) {
        return "views/home.faces?faces-redirect=true&param=98";
    } else {
        return "";
    }
}

public Boolean validationRegistration() {
    if (this.fathersOrGuardianName.length() == 0) {
        String commonName = ResourceKeys.getInstance().get("lblPleaseEnter", Constants.Resources.BUNDLENAME_MYSQLMAVEN);
        String displayName = ResourceKeys.getInstance().get("lblFathersOrGuardianName", Constants.Resources.BUNDLENAME_MYSQLMAVEN);
        FacesContext.getCurrentInstance().addMessage(fathersOrGuardianName, new FacesMessage(FacesMessage.SEVERITY_ERROR, commonName +" "+ displayName , "Fathers/GurdianName can't be empty."));
    }
    return Boolean.FALSE;
}

public void clearRegistrationAction(ActionEvent event) {
    this.fathersOrGuardianName = "";
}

}

Registration.xhtml

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:ui="http://java.sun.com/jsf/facelets" xmlns:h="http://java.sun.com/jsf/html" xmlns:f="http://java.sun.com/jsf/core" xmlns:p="http://primefaces.org/ui">

<f:view>
    <h:head>
        <title>Registration</title>
        <f:loadBundle var="mysqlmaven" basename="com.uk.mysqlmaven.resources.mysqlmaven" />
        <h:outputStylesheet name="style/mysqlmaven.css"></h:outputStylesheet>
    </h:head>
    <h:form id="registrationForm">
        <table align="center">
            <tr>
                <td><h:panelGrid>
                        <h:messages id="registrationMessageId" errorClass="lblRed" warnClass="lblWarning" infoClass="lblGreen"></h:messages>
                        <h:message for="registrationMessageId"></h:message>
                    </h:panelGrid> <h:panelGrid columns="1" cellpadding="2" frame="hsides" border="0">
                        <h:panelGrid columns="2">
                            <h:panelGroup>
                                <p:outputLabel value="*" styleClass="lblRed"></p:outputLabel>
                                <p:outputLabel value="#{mysqlmaven.lblFathersOrGuardianName}"></p:outputLabel>
                                <p:inputText id="fathersOrGuardianNameId" label="#{mysqlmaven.lblFathersOrGuardianName}" value="#{registrationBean.fathersOrGuardianName}"></p:inputText>
                            </h:panelGroup>
                        </h:panelGrid>
                    </h:panelGrid> <h:panelGrid columns="2">
                        <p:commandButton id="submitId" value="Submit" title="Submit" actionListener="#{registrationBean.submitRegistrationAction}" update="registrationMessageId"></p:commandButton>
                        <p:commandButton id="clearId" value="Clear" actionListener="#{registrationBean.clearRegistrationAction}"></p:commandButton>
                    </h:panelGrid>
                </td>
            </tr>
        </table>
    </h:form>
</f:view>

</html>

【讨论】：

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