Python工程师Java之路（q）Properties

Properties是啥？

import java.util.Properties;

public class Hello {
    public static void main(String[] args) {
        // 创建对象
        Properties p = new Properties();
        // 加入键值对
        p.put("key1", "value1");
        p.setProperty("key2", "value2");
        // 获取键值对
        String v2 = p.getProperty("key2");
        System.out.println(v2); //打印结果：value2
        String v3 = p.getProperty("key3", "value3");
        System.out.println(v3); //打印结果：value3
    }
}

Properties应用场景

properties文件是Java中的一种配置文件，文件后缀为.properties，内容格式为key=value，用#注释

获取.properties文件的配置信息

package utils;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

public class MyPropertiesUtil {
    public static void main(String[] args) {
        Properties p = MyPropertiesUtil.load(
                "src/main/resources/a.properties");
        System.out.println(p.getProperty("name"));
        System.out.println(p.getProperty("level"));
    }

    public static Properties load(String propertiesPath) {
        Properties p = new Properties();
        try {
            p.load(new FileInputStream(new File(propertiesPath)));
        } catch (IOException e) {
            e.printStackTrace();
        }
        return p;
    }
}

补充一个Scala版

package utils

import java.io.InputStreamReader
import java.util.Properties

object MyPropertiesUtil {
  def main(args: Array[String]): Unit = {
    val properties: Properties = MyPropertiesUtil.load("log4j.properties")
    println(properties.getProperty("log4j.rootCategory"))
  }

  def load(propertiesName: String): Properties = {
    val prop = new Properties();
    prop.load(new InputStreamReader(
      Thread.currentThread().getContextClassLoader.getResourceAsStream(propertiesName),
      "UTF-8"))
    prop
  }
}

补充一个Python版

def read_file(file):
    with open(file, encoding='utf-8') as f:
        return f.read()

def properties2dict(properties):
    dt = dict()
    for r in properties.strip().split('\n'):
        # 过滤properties注释
        if r.startswith('#'):
            continue
        # 获取键值对
        if r.find('=') > 0:
            k, v = r.split('=', 1)
            dt[k.strip()] = v.strip()
    return dt

def get_properties(file):
    properties = read_file(file)
    dt = properties2dict(properties)
    return dt

print(get_properties('a.properties'))