您可以通过以下方式加载属性文件:

InputStream is = new Test().getClass().getClassLoader().getResourceAsStream("app.properties");
        Properties props =  new Properties();
        props.load(is);

然后你可以使用lambda表达式遍历映射，比如:

props.stringPropertyNames().forEach(key -> {
            System.out.println("Key is :"+key + " and Value is :"+props.getProperty(key));
        });

默认情况下，Java在应用程序的工作目录中打开它(这种行为实际上取决于所使用的操作系统)。要加载一个文件，请执行:

Properties props = new java.util.Properties();
FileInputStream fis new FileInputStream("myfile.txt");
props.load(fis)

因此，任何文件扩展名都可以用于属性文件。此外，文件也可以存储在任何地方，只要您可以使用FileInputStream。

需要注意的是，如果使用现代框架，该框架可能提供打开属性文件的其他方法。例如，Spring提供了一个ClassPathResource来从JAR文件中使用包名加载属性文件。

至于遍历属性，一旦加载了属性，它们就存储在java.util.Properties对象中，该对象提供了propertyNames()方法。

这里是就绪静态类

import java.io.*;
import java.util.Properties;
public class Settings {
    public static String Get(String name,String defVal){
        File configFile = new File(Variables.SETTINGS_FILE);
        try {
            FileReader reader = new FileReader(configFile);
            Properties props = new Properties();
            props.load(reader);
            reader.close();
            return props.getProperty(name);
        } catch (FileNotFoundException ex) {
            // file does not exist
            logger.error(ex);
            return defVal;
        } catch (IOException ex) {
            // I/O error
            logger.error(ex);
            return defVal;
        } catch (Exception ex){
            logger.error(ex);
            return defVal;
        }
    }
    public static Integer Get(String name,Integer defVal){
        File configFile = new File(Variables.SETTINGS_FILE);
        try {
            FileReader reader = new FileReader(configFile);
            Properties props = new Properties();
            props.load(reader);
            reader.close();
            return Integer.valueOf(props.getProperty(name));
        } catch (FileNotFoundException ex) {
            // file does not exist
            logger.error(ex);
            return defVal;
        } catch (IOException ex) {
            // I/O error
            logger.error(ex);
            return defVal;
        } catch (Exception ex){
            logger.error(ex);
            return defVal;
        }
    }
    public static Boolean Get(String name,Boolean defVal){
        File configFile = new File(Variables.SETTINGS_FILE);
        try {
            FileReader reader = new FileReader(configFile);
            Properties props = new Properties();
            props.load(reader);
            reader.close();
            return Boolean.valueOf(props.getProperty(name));
        } catch (FileNotFoundException ex) {
            // file does not exist
            logger.error(ex);
            return defVal;
        } catch (IOException ex) {
            // I/O error
            logger.error(ex);
            return defVal;
        } catch (Exception ex){
            logger.error(ex);
            return defVal;
        }
    }
    public static void Set(String name, String value){
        File configFile = new File(Variables.SETTINGS_FILE);
        try {
            Properties props = new Properties();
            FileReader reader = new FileReader(configFile);
            props.load(reader);
            props.setProperty(name, value.toString());
            FileWriter writer = new FileWriter(configFile);
            props.store(writer, Variables.SETTINGS_COMMENT);
            writer.close();
        } catch (FileNotFoundException ex) {
            // file does not exist
            logger.error(ex);
        } catch (IOException ex) {
            // I/O error
            logger.error(ex);
        } catch (Exception ex){
            logger.error(ex);
        }
    }
    public static void Set(String name, Integer value){
        File configFile = new File(Variables.SETTINGS_FILE);
        try {
            Properties props = new Properties();
            FileReader reader = new FileReader(configFile);
            props.load(reader);
            props.setProperty(name, value.toString());
            FileWriter writer = new FileWriter(configFile);
            props.store(writer,Variables.SETTINGS_COMMENT);
            writer.close();
        } catch (FileNotFoundException ex) {
            // file does not exist
            logger.error(ex);
        } catch (IOException ex) {
            // I/O error
            logger.error(ex);
        } catch (Exception ex){
            logger.error(ex);
        }
    }
    public static void Set(String name, Boolean value){
        File configFile = new File(Variables.SETTINGS_FILE);
        try {
            Properties props = new Properties();
            FileReader reader = new FileReader(configFile);
            props.load(reader);
            props.setProperty(name, value.toString());
            FileWriter writer = new FileWriter(configFile);
            props.store(writer,Variables.SETTINGS_COMMENT);
            writer.close();
        } catch (FileNotFoundException ex) {
            // file does not exist
            logger.error(ex);
        } catch (IOException ex) {
            // I/O error
            logger.error(ex);
        } catch (Exception ex){
            logger.error(ex);
        }
    }
}

以下示例:

Settings.Set("valueName1","value");
String val1=Settings.Get("valueName1","value");
Settings.Set("valueName2",true);
Boolean val2=Settings.Get("valueName2",true);
Settings.Set("valueName3",100);
Integer val3=Settings.Get("valueName3",100);

在我看来，当我们可以非常简单地做到如下所示时，其他方法是不可取的:

@PropertySource("classpath:application.properties")
public class SomeClass{

    @Autowired
    private Environment env;

    public void readProperty() {
        env.getProperty("language");
    }

}

这很简单，但我认为这是最好的方法!! 享受

You can store the file anywhere you like. If you want to keep it in your jar file, you'll want to use Class.getResourceAsStream() or ClassLoader.getResourceAsStream() to access it. If it's on the file system it's slightly easier. Any extension is fine, although .properties is more common in my experience Load the file using Properties.load, passing in an InputStream or a StreamReader if you're using Java 6. (If you are using Java 6, I'd probably use UTF-8 and a Reader instead of the default ISO-8859-1 encoding for a stream.) Iterate through it as you'd iterate through a normal Hashtable (which Properties derives from), e.g. using keySet(). Alternatively, you can use the enumeration returned by propertyNames().

如果将属性文件放在与类Foo相同的包中，就可以轻松地加载它

new Properties().load(Foo.class.getResourceAsStream("file.properties"))

鉴于Properties扩展了哈希表，您可以以与在哈希表中相同的方式遍历值。

如果你使用*。你可以获得编辑器支持，例如Eclipse有一个属性文件编辑器。