java_IO write and read content to file code instance
- 2021-07-09 08:22:01
- OfStack
Write content to a file using OutStream () in java
package Stream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
public class OutStreamDemo01 {
public static void main(String[] args) {
// Define the file path, without which the file will be created automatically. If the path has folders, 1 Do have, folders will not be created automatically
String filename = "e:"+File.separator+"a"+File.separator+"b.txt";
File file = new File(filename);
String str = " These will all be written to the file ";
byte[] b = str.getBytes(); // Convert a string to a number of bytes
OutputStream out = null;
try {
out = new FileOutputStream(file); // Instantiation OutpurStream
}catch(FileNotFoundException e){
e.printStackTrace();
}
// Write
try {
out.write(b); // Write
out.close(); // Shut down
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Use InputStream () to read the contents of the file:
package Stream;
import java.io.*;;
public class InputStreamDemo01 {
public static void main(String[] args) {
File file = new File("e:"+File.separator+"a"+File.separator+"b.txt");
byte[] b = new byte[(int)file.length()];// Definition byte Length of bytes
InputStream in = null;
int len = 0;
try { // Handle exceptions
in = new FileInputStream(file); // Instantiation FileInputstream Class
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace(); // Output exception
}
try {
len = in.read(b); // Read the contents of the specified file
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(new String(b,0,len));// Converts a byte array to a string output from the specified file 0 Begin to len Byte end
}
}