Java 使用Apache Commons配置在属性文件中使用值列表执行变量插值，即${variable}

我正在使用ApacheCommons配置来读取属性文件，我完全能够执行变量插值，并且能够以列表的形式检索多值属性。但是，我无法正确加载具有多个值的属性，其中一个值是对另一个多值属性的引用（变量插值）

下面是我的属性文件的一个示例（我还尝试使用逗号分隔的语法）：

我是如何从中读到的：

Configuration config = new PropertiesConfiguration("myFile");
final String[] mimesArray = config.getStringArray("doc.mime");
for(String mime : mimesArray) System.out.println(mime);
final List<Object> mimesList = config.getList("doc.mime");
System.out.println(mimesList);

Configuration config=新属性配置（“myFile”）；
最终字符串[]mimesArray=config.getStringArray（“doc.mime”）；
for（字符串mime:mimesArray）System.out.println（mime）；
最终列表mimesList=config.getList（“doc.mime”）；
System.out.println（模拟列表）；

这是我通过任何一种方法（

getStringArray

和

getList

）获得的内容：

[application/msword，application/vnd.openxmlformats-officedocument.wordprocessingml.document，application/x-tika-msoffice]

这与我预期的不同：doc.mime和office.mime的完整内容

---

有人知道是否可以在我的另一个列表中插入整个值列表吗？如果是这样的话，它是如何完成的？

什么是Commons配置的

public class CustomInterpolation extends StrLookup {

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.commons.lang.text.StrLookup#lookup(java.lang.String)
     */
    @Override
    public String lookup(String arg0) {

        String result = null;

        // Get the default delimiter.
        String delimiter = ""
                + PropertiesConfiguration.getDefaultListDelimiter();

        try {

            // Load the properties file.
            Configuration config = new PropertiesConfiguration(
                    "ressources/macro.properties");

            if (config.containsKey(arg0)) {

                // Get all values associated with the propertie.
                ArrayList<Object> values = (ArrayList<Object>) config
                        .getList(arg0);

                StringBuilder strBuild = new StringBuilder();
                Iterator<Object> itr = values.iterator();

                while (itr.hasNext()) {

                    // Append the property to the string.
                    strBuild.append((String) itr.next());

                    if (itr.hasNext()) {
                        // Adds the delimiter and backslash in order to retrieve
                        // all properties later.
                        strBuild.append("\\" + delimiter);
                    }

                }
                result = strBuild.toString();
            }

        } catch (ConfigurationException e) {
            // Nothing to do here...
        }
        // return null or all values concatenated
        return result;
    }

}

/**
 * The Class CustomPropertiesConfiguration.
 */
public class CustomPropertiesConfiguration extends PropertiesConfiguration {

    private String delimiter;

    /**
     * Instantiates a new custom properties configuration.
     */
    public CustomPropertiesConfiguration() {
        super();
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /**
     * Instantiates a new custom properties configuration.
     *
     * @param file the file
     * @throws ConfigurationException the configuration exception
     */
    public CustomPropertiesConfiguration (File file) throws ConfigurationException{
        super(file);
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /**
     * Instantiates a new custom properties configuration.
     *
     * @param fileName the file name
     * @throws ConfigurationException the configuration exception
     */
    public CustomPropertiesConfiguration(String fileName) throws ConfigurationException {
        super(fileName);
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /**
     * Instantiates a new custom properties configuration.
     *
     * @param url the url
     * @throws ConfigurationException the configuration exception
     */
    public CustomPropertiesConfiguration(URL url) throws ConfigurationException{
        super(url);
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /* (non-Javadoc)
     * @see org.apache.commons.configuration.AbstractConfiguration#getList(java.lang.String)
     */
    @Override
    public List<Object> getList(String key) {

        // Get the list of values associated with the property
        // Implicit call to the custom interpolation class
        List<Object> properties = super.getList(key);


        ArrayList<Object> extendedProperties = new ArrayList<Object>();

        Iterator<Object> itrProperties = properties.iterator();
        // Go through all properties and retrieve values concatenated by the custom interpolation
        while (itrProperties.hasNext()) {

            String propertie = (String) itrProperties.next();

            if (propertie.contains(delimiter)) {

                //Split concatenated values.
                String[] extendedPropertiesTab = propertie.split("\\\\"+delimiter);

                // Add the retrieved values to the list of values.
                for (int i = 0; i< extendedPropertiesTab.length; ++i){
                    extendedProperties.add(extendedPropertiesTab[i]);
                }

            } else {
                extendedProperties.add(propertie);
            }

        }
        return extendedProperties;
    }

} 

正如您所发现的：当插值多值属性时，Commons配置将只解析该属性的第一个值。请参阅上的代码

我发现了一些相关问题：

：有人想要（并且得到）与你想要的完全相反的东西：只有多值属性中的第一个值

：有关多值属性插值的更多讨论：

这个问题可能没有正确的解决方案，因为 预期结果在很大程度上取决于具体的用例

解决方法：将两个列表合并到代码中

绝对比：

List-mimesList=config.getList（“doc.mime”）；
List officeList=config.getList（“office.mime”）；
mimesList.addAll（officeList）；
System.out.println（模拟列表）；

向Commons配置项目提出此问题

---

改变整个变量插值系统可能很困难。但他们至少可以澄清文档。

好吧，我确实需要这个功能：将几个值与属性关联起来，甚至可以通过插值来检索它们

因此，我编写了一个自定义插值类和一个自定义属性配置。即使使用带有反斜杠和默认分隔符的值，也可以正常工作

这里是自定义插值类：

自定义插值类

public class CustomInterpolation extends StrLookup {

    /*
     * (non-Javadoc)
     * 
     * @see org.apache.commons.lang.text.StrLookup#lookup(java.lang.String)
     */
    @Override
    public String lookup(String arg0) {

        String result = null;

        // Get the default delimiter.
        String delimiter = ""
                + PropertiesConfiguration.getDefaultListDelimiter();

        try {

            // Load the properties file.
            Configuration config = new PropertiesConfiguration(
                    "ressources/macro.properties");

            if (config.containsKey(arg0)) {

                // Get all values associated with the propertie.
                ArrayList<Object> values = (ArrayList<Object>) config
                        .getList(arg0);

                StringBuilder strBuild = new StringBuilder();
                Iterator<Object> itr = values.iterator();

                while (itr.hasNext()) {

                    // Append the property to the string.
                    strBuild.append((String) itr.next());

                    if (itr.hasNext()) {
                        // Adds the delimiter and backslash in order to retrieve
                        // all properties later.
                        strBuild.append("\\" + delimiter);
                    }

                }
                result = strBuild.toString();
            }

        } catch (ConfigurationException e) {
            // Nothing to do here...
        }
        // return null or all values concatenated
        return result;
    }

}

/**
 * The Class CustomPropertiesConfiguration.
 */
public class CustomPropertiesConfiguration extends PropertiesConfiguration {

    private String delimiter;

    /**
     * Instantiates a new custom properties configuration.
     */
    public CustomPropertiesConfiguration() {
        super();
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /**
     * Instantiates a new custom properties configuration.
     *
     * @param file the file
     * @throws ConfigurationException the configuration exception
     */
    public CustomPropertiesConfiguration (File file) throws ConfigurationException{
        super(file);
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /**
     * Instantiates a new custom properties configuration.
     *
     * @param fileName the file name
     * @throws ConfigurationException the configuration exception
     */
    public CustomPropertiesConfiguration(String fileName) throws ConfigurationException {
        super(fileName);
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /**
     * Instantiates a new custom properties configuration.
     *
     * @param url the url
     * @throws ConfigurationException the configuration exception
     */
    public CustomPropertiesConfiguration(URL url) throws ConfigurationException{
        super(url);
        delimiter = PropertiesConfiguration.getDefaultListDelimiter()
                + "";
    }

    /* (non-Javadoc)
     * @see org.apache.commons.configuration.AbstractConfiguration#getList(java.lang.String)
     */
    @Override
    public List<Object> getList(String key) {

        // Get the list of values associated with the property
        // Implicit call to the custom interpolation class
        List<Object> properties = super.getList(key);


        ArrayList<Object> extendedProperties = new ArrayList<Object>();

        Iterator<Object> itrProperties = properties.iterator();
        // Go through all properties and retrieve values concatenated by the custom interpolation
        while (itrProperties.hasNext()) {

            String propertie = (String) itrProperties.next();

            if (propertie.contains(delimiter)) {

                //Split concatenated values.
                String[] extendedPropertiesTab = propertie.split("\\\\"+delimiter);

                // Add the retrieved values to the list of values.
                for (int i = 0; i< extendedPropertiesTab.length; ++i){
                    extendedProperties.add(extendedPropertiesTab[i]);
                }

            } else {
                extendedProperties.add(propertie);
            }

        }
        return extendedProperties;
    }

} 

我得到以下输出：

base.prop=>
[0]/base
[1]/root\\
[2]t,t,t,t,

first.prop=>
[0]/base
[1]/root\\
[2]t,t,t,t,
[3]/first,/base

second.prop=>
[0]/base
[1]/root\\
[2]t,t,t,t,
[3]/first,/base
[4]/second

---

如您所见，该解决方案能够使用反斜杠和默认分隔符“，”处理属性值。包含这两个元素的某些模式可能无法正确处理，但此解决方案应处理基本值。

这是一个有点特殊的问题，可能只有熟悉commons配置（如开发或调试commons配置）的人才能回答。你查过了吗，也许吧？

base.prop = /base, /root\\\\\\\\, t\\,t\\,t\\,t\\,
first.prop = ${custom:base.prop}, /first\\,/base
second.prop = ${custom:first.prop}, /second

base.prop=>
[0]/base
[1]/root\\
[2]t,t,t,t,

first.prop=>
[0]/base
[1]/root\\
[2]t,t,t,t,
[3]/first,/base

second.prop=>
[0]/base
[1]/root\\
[2]t,t,t,t,
[3]/first,/base
[4]/second