In my java project, I'm passing FileInputStream to a function, I need to convert (typecast FileInputStream to string), How to do it.??
public static void checkfor(FileInputStream fis) {
String a=new String;
a=fis //how to do convert fileInputStream into string
print string here
}
6 Answers
You can't directly convert it to string. You should implement something like this Add this code to your method
//Commented this out because this is not the efficient way to achieve that
//StringBuilder builder = new StringBuilder();
//int ch;
//while((ch = fis.read()) != -1){
// builder.append((char)ch);
//}
//
//System.out.println(builder.toString());
Use Aubin's solution:
public static String getFileContent(
FileInputStream fis,
String encoding ) throws IOException
{
try( BufferedReader br =
new BufferedReader( new InputStreamReader(fis, encoding )))
{
StringBuilder sb = new StringBuilder();
String line;
while(( line = br.readLine()) != null ) {
sb.append( line );
sb.append( '\n' );
}
return sb.toString();
}
}
public static String getFileContent(
FileInputStream fis,
String encoding ) throws IOException
{
try( BufferedReader br =
new BufferedReader( new InputStreamReader(fis, encoding )))
{
StringBuilder sb = new StringBuilder();
String line;
while(( line = br.readLine()) != null ) {
sb.append( line );
sb.append( '\n' );
}
return sb.toString();
}
}
Using Apache commons IOUtils function
import org.apache.commons.io.IOUtils;
InputStream inStream = new FileInputStream("filename.txt");
String body = IOUtils.toString(inStream, StandardCharsets.UTF_8.name());
Don't make the mistake of relying upon or needlessly converting/losing endline characters. Do it character by character. Don't forget to use the proper character encoding to interpres the stream.
public String getFileContent( FileInputStream fis ) {
StringBuilder sb = new StringBuilder();
Reader r = new InputStreamReader(fis, "UTF-8"); //or whatever encoding
int ch = r.read();
while(ch >= 0) {
sb.append(ch);
ch = r.read();
}
return sb.toString();
}
If you want to make this a little more efficient, you can use arrays of characters instead, but to be honest, looping over the characters can be still quite fast.
public String getFileContent( FileInputStream fis ) {
StringBuilder sb = new StringBuilder();
Reader r = new InputStreamReader(fis, "UTF-8"); //or whatever encoding
char[] buf = new char[1024];
int amt = r.read(buf);
while(amt > 0) {
sb.append(buf, 0, amt);
amt = r.read(buf);
}
return sb.toString();
}
From an answer I edited here:
static String convertStreamToString(java.io.InputStream is) {
if (is == null) {
return "";
}
java.util.Scanner s = new java.util.Scanner(is);
s.useDelimiter("\\A");
String streamString = s.hasNext() ? s.next() : "";
s.close();
return streamString;
}
This avoids all errors and works well.
Use following code ---->
try {
FileInputStream fis=new FileInputStream("filename.txt");
int i=0;
while((i = fis.read()) !=-1 ) { // to reach until the laste bytecode -1
System.out.print((char)i); /* For converting each bytecode into character */
}
fis.close();
} catch(Exception ex) {
System.out.println(ex);
}
