解決 i18n properties檔案中文必須是unicode的問題

目前產品需要做國際化，但 java 的 I18N 資原始檔中中文必須轉換成 unicode 才行。雖然並不會有問題，但實在是不方便，通過檢視 ResourceBundler 類的原始碼，發現其內部類 Control 在讀取資原始檔時，使用的是位元組流而非字元流。

問題找到了，我們只要重寫 Control 類即可，使用 UTF-8 的 Reader 去讀取資原始檔即可。

詳細程式碼實現如下：

package com.feshfans.spring;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import
 
 java.util.Locale;
import java.util.PropertyResourceBundle;
import java.util.ResourceBundle;

/**
 * DESC:
 * CleanUser com.feshfans.spring
 * feshfans 2018/5/11 18:46
 * email: [email protected]
 **/
public class UTF8Control extends ResourceBundle.Control {
    @Override
    public ResourceBundle newBundle
 
(String baseName, Locale locale, String format,
                                    ClassLoader loader, boolean reload)
            throws IllegalAccessException, InstantiationException, IOException {
        String bundleName = toBundleName(baseName, locale);
        ResourceBundle bundle = null;
        if (format.equals("java.class")) {
            try {
                @SuppressWarnings("unchecked")
                Class<? extends ResourceBundle> bundleClass
                        = (Class<? extends ResourceBundle>)loader.loadClass(bundleName);

                // If the class isn't a ResourceBundle subclass, throw a
                // ClassCastException.
                if (ResourceBundle.class.isAssignableFrom(bundleClass)) {
                    bundle = bundleClass.newInstance();
                } else {
                    throw new ClassCastException(bundleClass.getName()
                            + " cannot be cast to ResourceBundle");
                }
            } catch (ClassNotFoundException e) {
            }
        } else if (format.equals("java.properties")) {
            final String resourceName = toResourceName0(bundleName, "properties");
            if (resourceName == null) {
                return bundle;
            }
            final ClassLoader classLoader = loader;
            final boolean reloadFlag = reload;
            InputStream stream = null;
            try {
                stream = AccessController.doPrivileged(
                        new PrivilegedExceptionAction<InputStream>() {
                            public InputStream run() throws IOException {
                                InputStream is = null;
                                if (reloadFlag) {
                                    URL url = classLoader.getResource(resourceName);
                                    if (url != null) {
                                        URLConnection connection = url.openConnection();
                                        if (connection != null) {
                                            // Disable caches to get fresh data for
                                            // reloading.
                                            connection.setUseCaches(false);
                                            is = connection.getInputStream();
                                        }
                                    }
                                } else {
                                    is = classLoader.getResourceAsStream(resourceName);
                                }
                                return is;
                            }
                        });
            } catch (PrivilegedActionException e) {
                throw (IOException) e.getException();
            }
            if (stream != null) {
                try {
                    bundle = new PropertyResourceBundle(new InputStreamReader(stream,"UTF-8"));
                } finally {
                    stream.close();
                }
            }
        } else {
            throw new IllegalArgumentException("unknown format: " + format);
        }
        return bundle;
    }

    private String toResourceName0(String bundleName, String suffix) {
        // application protocol check
        if (bundleName.contains("://")) {
            return null;
        } else {
            return toResourceName(bundleName, suffix);
        }
    }

    public static void main(String[] args) {
        ResourceBundle.getBundle("baseName",new UTF8Control());
    }

}

然後，在構建 ResourceBundler 時，使用以下方法即可:

ResourceBundle.getBundle("baseName",new UTF8Control());