使用java代码读取存储在hdfs中的.properties文件

Question

我需要读取hdfs中可用的.properties文件。我使用下面的代码，但它会引发运行时错误。

FileSystem fs = FileSystem.get(config); 

    Properties conf = wc.createConfiguration(); 
    Properties prop = new Properties(); 
    String appPath = "hdfs://clusterdb05.com:8020/user/cmahajan/" + version + "/apps/apps/"; 
    conf.setProperty(OozieClient.APP_PATH,appPath); 
    FileInputStream f = new FileInputStream("hdfs://clusterdb05.com:8020/user/cmahajan/app.properties"); 
    ObjectInputStream f = new ObjectInputStream(fs.open(new Path("/user/cmahajan/app.properties"))); 

运行时间错误是：

LaunchJob.java:28: cannot find symbol 

symbol : class ObjectInputStream 
location: class LaunchJob 
    ObjectInputStream f = new ObjectInputStream(fs.open(new Path("/user/cmahajan/app.properties"))); 
    ^
LaunchJob.java:28: cannot find symbol 
symbol : class ObjectInputStream 
location: class LaunchJob 
    ObjectInputStream f = new ObjectInputStream(fs.open(new Path("/user/cmahajan/app.properties"))); 

Answer 1

要么使用类的全名：

：

java.io.ObjectInputStream 

OR

使用以下行导入类

import java.io.ObjectInputStream; 

Answer 2

对于装载属性文件形式HDFS：

1. 确保UR 核心的site.xml，HDFS现场XML文件路径
2. HDFS端口号（它会在核心提供现场.xml）

3. 替换密钥getProperty。

    String CURRENCIES_DIM1 = null; 
        String DATES_DIM2 = null; 
        Configuration conf = new Configuration(); 
        conf.addResource(new Path("/usr/local/hadoop/etc/hadoop/core-site.xml")); 
        conf.addResource(new Path("/usr/local/hadoop/etc/hadoop/hdfs-site.xml")); 
        String filePath = "hdfs://localhost:54310/user/CurrencyCache.properties"; 
        Path path = new Path(filePath); 
        FileSystem fs = path.getFileSystem(conf); 
        try (FSDataInputStream currencyInputStream = fs.open(path)) { 
         Properties currencyProp = new Properties(); 
         currencyProp.load(currencyInputStream); 
         CURRENCIES_DIM1= currencyProp.getProperty("key");//getting the 'CURRENCIES_DIM' file path from properties file 
         DATES_DIM2= currencyProp.getProperty("key");   //getting the 'DATES_DIM' file path from properties file 
   
        } catch (IOException e) { 
   
         e.printStackTrace(); 
        } 
        fs.close();