This Java code defines a BufferTest class that uses buffered streams to read lines from a source text file, convert the text to uppercase, and write it to a target file. It opens file readers and writers, creates buffered readers and writers, reads the source file line by line, converts to uppercase, writes to the target file, and closes the streams.

1. import java.io.*;
class BufferTest {
public static void main(String args[]){
//creat stream
FileReader fileReader = null;
BufferedReader bufferedReader = null;
FileWriter fileWriter = null;
BufferedWriter bufferedWriter = null;
String line = null;
try{
//acquire origin file address
fileReader = new FileReader("f:/excise/Stream/zzz.txt");
//output path of generated file
fileWriter = new FileWriter("f:/excise/Stream/aaa.txt");
//write buffer stream
bufferedReader = new BufferedReader(fileReader);
//write buffer stream
bufferedWriter = new BufferedWriter(fileWriter);
//read data iteratively
while(true){
//read one line data
line = bufferedReader.readLine();
if(line == null){
break;
}
String str = line.toUpperCase();//to uppercase
//String str = line.toLowerCase(); to lowercase
//output buffer stream
bufferedWriter.write(str);
//change line
bufferedWriter.newLine();
}
}
catch(Exception e){
System.out.println(e);
}finally{
try{
//close stream
fileReader.close();
bufferedReader.close();
bufferedWriter.close();
fileWriter.close();
}
catch(Exception e){
System.out.println(e);
}
}
}
}