我正在使用CSVReader类,它将本地文件作为输入.但现在,我需要能够读取本地文件以及具有URL路径的文件(如
http://example.com/example.txt).为此,我想从CSVReader派生一个类,用于标识文件是本地文件还是URL,然后使用构造函数第一行中的super()将InputStream传递给父文件.这样做的优雅方式是什么？
public class FileReader extends CsvReader{
public FileReader(){
if (fileName != null) {
if (fileName.trim().startsWith("http:")) {
// it is URL
URL url = new URL(fileName);
inputStream = new BufferedReader(new InputStreamReader(
url.openStream(),charset),StaticSettings.MAX_FILE_BUFFER_SIZE);
}else{
//it is a local file
inputStream = new BufferedReader(new InputStreamReader(
new FileInputStream(fileName),StaticSettings.MAX_FILE_BUFFER_SIZE);
}
}
//Now pass the input stream to CsvReader
super(inputStream,delimiter,charset); //error - super has to be first line of constructor
}
}
解决方法
你可以编写辅助方法：
super(createReader(createInputStream(resouce),"UTF-8"),";");
您的辅助方法可能如下所示：
public static InputStream createInputStream(String resource)
{
resource = resource.trim();
if (resource.startsWith("http:"))
{
return new URL(resource).openStream();
} else
{
return new FileInputStream(new File(resource));
}
}
public static BufferedReader createReader(InputStream is,String charset)
{
return new BufferedReader(new InputStreamReader(is,charset));
}