我有一个配置值的键/值对列表,我想将其存储为Java属性文件,然后进行加载和遍历。

问题:

我是否需要将文件存储在与装入它们的类相同的包中,或者它应该放置在任何特定的位置? 文件是否需要以任何特定的扩展名结束,或者。txt OK? 如何在代码中加载文件 我如何遍历里面的值?


当前回答

在Java 8中获取所有属性

public static Map<String, String> readPropertiesFile(String location) throws Exception {

    Map<String, String> properties = new HashMap<>();

    Properties props = new Properties();
    props.load(new FileInputStream(new File(location)));

    props.forEach((key, value) -> {
        properties.put(key.toString(), value.toString());
    });

    return properties;
}

其他回答

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);

读取属性文件并将其内容加载到properties

String filename = "sample.properties";
Properties properties = new Properties();

input = this.getClass().getClassLoader().getResourceAsStream(filename);
properties.load(input);

下面是遍历Properties的有效方法

    for (Entry<Object, Object> entry : properties.entrySet()) {

        System.out.println(entry.getKey() + " => " + entry.getValue());
    }

你可以将一个InputStream传递给属性,所以你的文件几乎可以在任何地方,并被称为任何东西。

Properties properties = new Properties();
try {
  properties.load(new FileInputStream("path/filename"));
} catch (IOException e) {
  ...
}

迭代:

for(String key : properties.stringPropertyNames()) {
  String value = properties.getProperty(key);
  System.out.println(key + " => " + value);
}

1)在类路径中有你的属性文件是很好的,但你可以把它放在项目的任何地方。

下面是如何从类路径加载属性文件并读取所有属性。

Properties prop = new Properties();
InputStream input = null;

try {

    String filename = "path to property file";
    input = getClass().getClassLoader().getResourceAsStream(filename);
    if (input == null) {
        System.out.println("Sorry, unable to find " + filename);
        return;
    }

    prop.load(input);

    Enumeration<?> e = prop.propertyNames();
    while (e.hasMoreElements()) {
        String key = (String) e.nextElement();
        String value = prop.getProperty(key);
        System.out.println("Key : " + key + ", Value : " + value);
    }

} catch (IOException ex) {
    ex.printStackTrace();
} finally {
    if (input != null) {
        try {
            input.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2)属性文件的扩展名为.properties

在顺序:

您可以将文件存储在几乎任何地方。 不需要延期。 Montecristo已经说明了如何加载这个。这应该没问题。 propertyNames()提供了一个用于迭代的枚举。