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?
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。