Java 使用属性文件中的条目填充 HashMap
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Populating a HashMap with entries from a properties file
提问by OneMoreError
I want to populate a HashMapusing the Propertiesclass.
I want to load the entries in the .propetiesfile and then copy it into the HashMap.
我想HashMap使用Properties该类填充 a 。
我想加载.propeties文件中的条目，然后将其复制到HashMap.
Earlier, I used to just initialize the HashMapwith the properties file, but now I have already defined the HashMapand want to initialize it in the constructor only.
之前，我曾经只是HashMap用属性文件初始化，但现在我已经定义了HashMap并且只想在构造函数中初始化它。
Earlier approach:
较早的做法：
Properties properties = new Properties();
try {
properties.load(ClassName.class.getResourceAsStream("resume.properties"));
} catch (Exception e) {
}
HashMap<String, String> mymap= new HashMap<String, String>((Map) properties);
But now, I have this
但是现在，我有了这个
public class ClassName {
HashMap<String,Integer> mymap = new HashMap<String, Integer>();
public ClassName(){
Properties properties = new Properties();
try {
properties.load(ClassName.class.getResourceAsStream("resume.properties"));
} catch (Exception e) {
}
mymap = properties;
//The above line gives error
}
}
How do I assign the properties object to a HashMaphere?
如何将属性对象分配给HashMap此处？
采纳答案by JB Nizet
If I understand correctly, each value in the properties is a String which represents an Integer. So the code would look like this:
如果我理解正确，属性中的每个值都是一个代表整数的字符串。所以代码看起来像这样：
for (String key : properties.stringPropertyNames()) {
String value = properties.getProperty(key);
mymap.put(key, Integer.valueOf(value));
}
回答by cahen
Use .entrySet()
用 .entrySet()
for (Entry<Object, Object> entry : properties.entrySet()) {
map.put((String) entry.getKey(), (String) entry.getValue());
}
回答by Rupesh Patil
public static Map<String,String> getProperty()
{
Properties prop = new Properties();
Map<String,String>map = new HashMap<String,String>();
try
{
FileInputStream inputStream = new FileInputStream(Constants.PROPERTIESPATH);
prop.load(inputStream);
}
catch (Exception e) {
e.printStackTrace();
System.out.println("Some issue finding or loading file....!!! " + e.getMessage());
}
for (final Entry<Object, Object> entry : prop.entrySet()) {
map.put((String) entry.getKey(), (String) entry.getValue());
}
return map;
}
回答by aprodan
Java 8 Style:
Java 8 风格：
Properties properties = new Properties();
// add some properties here
Map<String, String> map = new HashMap();
map.putAll(properties.entrySet()
.stream()
.collect(Collectors.toMap(e -> e.getKey().toString(),
e -> e.getValue().toString())));
