看这个:http://docs.oracle.com/javase/6/docs/api/java/util/Properties.html#load(java.io.Reader)

属性接受Reader对象作为参数，您可以从InputStream创建该对象。

在创建时，你可以指定Reader的编码:

InputStreamReader isr = new InputStreamReader(stream, "UTF-8");

然后将这个Reader应用到load方法:

prop.load(isr);

顺便说一句:从.properties文件中获取流:

 InputStream stream = this.class.getClassLoader().getResourceAsStream("a.properties");

顺便说一句:从InputStreamReader获取资源包:

ResourceBundle rb = new PropertyResourceBundle(isr);

希望这能帮助到你!

我们创建了一个资源。utf8文件，包含UTF-8格式的资源，并有一个规则运行如下:

native2ascii -encoding utf8 resources.utf8 resources.properties

http://sourceforge.net/projects/eclipse-rbe/

如前所述，属性文件应该用ISO 8859-1编码

您可以使用上面的eclipse IDE插件为您进行Unicode转换。

Java 9及更新版本

从Java 9开始，属性文件默认编码为UTF-8，使用ISO-8859-1以外的字符应该可以开箱即用。

Java 8及以上版本

当指定了.properties文件时，ResourceBundle#getBundle()在封面下使用PropertyResourceBundle。这反过来使用默认的Properties#load(InputStream)来加载这些属性文件。根据javadoc，它们默认读取为ISO-8859-1。

public void load(InputStream stream)抛出IOException

从输入字节流中读取属性列表(键和元素对)。输入流采用load(Reader)中指定的简单的面向行的格式，并假定使用ISO 8859-1字符编码;即每个字节是一个拉丁字符。非拉丁字符1和某些特殊字符使用Java™语言规范3.3节中定义的Unicode转义符在键和元素中表示。

So, you'd need to save them as ISO-8859-1. If you have any characters beyond ISO-8859-1 range and you can't use \uXXXX off top of head and you're thus forced to save the file as UTF-8, then you'd need to use the native2ascii tool to convert an UTF-8 saved properties file to an ISO-8859-1 saved properties file wherein all uncovered characters are converted into \uXXXX format. The below example converts a UTF-8 encoded properties file text_utf8.properties to a valid ISO-8859-1 encoded properties file text.properties.

native2ascii -encoding UTF-8 text_utf8.properties text.properties

在使用Eclipse等正常的IDE时，当您在基于Java的项目中创建.properties文件并使用Eclipse自己的编辑器时，这已经自动完成了。Eclipse将透明地将超出ISO-8859-1范围的字符转换为\uXXXX格式。另见下面的截图(注意底部的“属性”和“源”选项卡，点击放大):

或者，您也可以创建一个定制的ResourceBundle。控件实现，其中您显式读取属性文件为UTF-8使用InputStreamReader，这样您就可以将它们保存为UTF-8而不需要与native2ascii的麻烦。下面是一个开始的例子:

public class UTF8Control extends Control {
    public ResourceBundle newBundle
        (String baseName, Locale locale, String format, ClassLoader loader, boolean reload)
            throws IllegalAccessException, InstantiationException, IOException
    {
        // The below is a copy of the default implementation.
        String bundleName = toBundleName(baseName, locale);
        String resourceName = toResourceName(bundleName, "properties");
        ResourceBundle bundle = null;
        InputStream stream = null;
        if (reload) {
            URL url = loader.getResource(resourceName);
            if (url != null) {
                URLConnection connection = url.openConnection();
                if (connection != null) {
                    connection.setUseCaches(false);
                    stream = connection.getInputStream();
                }
            }
        } else {
            stream = loader.getResourceAsStream(resourceName);
        }
        if (stream != null) {
            try {
                // Only this line is changed to make it to read properties files as UTF-8.
                bundle = new PropertyResourceBundle(new InputStreamReader(stream, "UTF-8"));
            } finally {
                stream.close();
            }
        }
        return bundle;
    }
}

可以这样使用:

ResourceBundle bundle = ResourceBundle.getBundle("com.example.i18n.text", new UTF8Control());

参见:

Unicode -如何得到正确的字符?

对于当前(2021-2)Java版本，仍然有旧的ISO-8859-1函数utils.Properties#load。

如果您使用属性。装载时必须使用ISO-8859-1。 如果使用ResourceBundle，那么UTF-8应该没问题。

请允许我引用官方文件。

PropertyResourceBundle

PropertyResourceBundle can be constructed either from an InputStream or a Reader, which represents a property file. Constructing a PropertyResourceBundle instance from an InputStream requires that the input stream be encoded in UTF-8. By default, if a MalformedInputException or an UnmappableCharacterException occurs on reading the input stream, then the PropertyResourceBundle instance resets to the state before the exception, re-reads the input stream in ISO-8859-1, and continues reading. If the system property java.util.PropertyResourceBundle.encoding is set to either "ISO-8859-1" or "UTF-8", the input stream is solely read in that encoding, and throws the exception if it encounters an invalid sequence. If "ISO-8859-1" is specified, characters that cannot be represented in ISO-8859-1 encoding must be represented by Unicode Escapes as defined in section 3.3 of The Java™ Language Specification whereas the other constructor which takes a Reader does not have that limitation. Other encoding values are ignored for this system property. The system property is read and evaluated when initializing this class. Changing or removing the property has no effect after the initialization.

https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/util/PropertyResourceBundle.html

属性#负载

从输入字节流中读取属性列表(键和元素对)。输入流采用load(Reader)中指定的简单的面向行的格式，并假定使用ISO 8859-1字符编码;即每个字节是一个拉丁字符。非拉丁字符1和某些特殊字符使用Java™语言规范3.3节中定义的Unicode转义符在键和元素中表示。

https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/util/Properties.html加载(java.io.InputStream)

package com.varaneckas.utils;  

import java.io.UnsupportedEncodingException;  
import java.util.Enumeration;  
import java.util.PropertyResourceBundle;  
import java.util.ResourceBundle;  

/** 
 * UTF-8 friendly ResourceBundle support 
 *  
 * Utility that allows having multi-byte characters inside java .property files. 
 * It removes the need for Sun's native2ascii application, you can simply have 
 * UTF-8 encoded editable .property files. 
 *  
 * Use:  
 * ResourceBundle bundle = Utf8ResourceBundle.getBundle("bundle_name"); 
 *  
 * @author Tomas Varaneckas <tomas.varaneckas@gmail.com> 
 */  
public abstract class Utf8ResourceBundle {  

    /** 
     * Gets the unicode friendly resource bundle 
     *  
     * @param baseName 
     * @see ResourceBundle#getBundle(String) 
     * @return Unicode friendly resource bundle 
     */  
    public static final ResourceBundle getBundle(final String baseName) {  
        return createUtf8PropertyResourceBundle(  
                ResourceBundle.getBundle(baseName));  
    }  

    /** 
     * Creates unicode friendly {@link PropertyResourceBundle} if possible. 
     *  
     * @param bundle  
     * @return Unicode friendly property resource bundle 
     */  
    private static ResourceBundle createUtf8PropertyResourceBundle(  
            final ResourceBundle bundle) {  
        if (!(bundle instanceof PropertyResourceBundle)) {  
            return bundle;  
        }  
        return new Utf8PropertyResourceBundle((PropertyResourceBundle) bundle);  
    }  

    /** 
     * Resource Bundle that does the hard work 
     */  
    private static class Utf8PropertyResourceBundle extends ResourceBundle {  

        /** 
         * Bundle with unicode data 
         */  
        private final PropertyResourceBundle bundle;  

        /** 
         * Initializing constructor 
         *  
         * @param bundle 
         */  
        private Utf8PropertyResourceBundle(final PropertyResourceBundle bundle) {  
            this.bundle = bundle;  
        }  

        @Override  
        @SuppressWarnings("unchecked")  
        public Enumeration getKeys() {  
            return bundle.getKeys();  
        }  

        @Override  
        protected Object handleGetObject(final String key) {  
            final String value = bundle.getString(key);  
            if (value == null)  
                return null;  
            try {  
                return new String(value.getBytes("ISO-8859-1"), "UTF-8");  
            } catch (final UnsupportedEncodingException e) {  
                throw new RuntimeException("Encoding not supported", e);  
            }  
        }  
    }  
}