Java file and stream read

In the Java language IO programming, reading a file is two steps: 1, the data in the file is converted to a stream, 2, the data inside the stream is read. The first step is completed by the system, only need to create the corresponding stream object, the object is created after the completion of Step 1, the second step is implemented using the Read method in the input stream object.

When programming with an input stream, the code is generally divided into 3 parts: 1, creating a Stream object, 2, reading the data inside the stream object, 3, closing the stream object. The following code example reads a file:

Import java.io.*;

/**

* Read files using FileInputStream

*/

public class ReadFile1 {

public static void Main (string[] args) {

FileInputStream FIS = null; Declaring a Stream object

try{

FIS = new FileInputStream ("E:\\a.txt"); Creating a Stream object

Reads the data and stores the read data in an array

byte[] data = new byte[1024]; Array of data stores

int i = 0; Current subscript

Reads the first byte of data in a stream

int n = fis.read ();

Read the subsequent data sequentially

while (n! =-1) {//does not reach the end of the stream

To store valid data in an array

Data[i] = (byte) n;

Subscript Increase

i++;

Read the next byte of data

n = fis.read ();

}

Parsing data

string s = new string (data,0,i);

Output string

System.out.println (s);

}catch (Exception e) {

E.printstacktrace ();

}finally{

try{

Close the stream and release the resource

Fis.close ();

}catch (Exception e) {}

}

}

}

The following example code is code that reads with another read method:

Import Java.io.FileInputStream;

/**

* Read files using FileInputStream

*/

public class ReadFile2 {

public static void Main (string[] args) {

Declaring a Stream object

FileInputStream FIS = null;

try{

Creating a Stream object

FIS = new FileInputStream ("E:\\a.txt");

Reads the data and stores the read data in an array

byte[] data = new byte[1024]; Array of data stores

int i = fis.read (data);

Parsing data

string s = new string (data,0,i);

Output string

System.out.println (s);

}catch (Exception e) {

E.printstacktrace ();

}finally{

try{

Close the stream and release the resource

Fis.close ();

}catch (Exception e) {}

}

}

}

The steps for programming with the output stream are:

1. Set up the output stream

The corresponding output stream object is established, that is, the conversion between the stream object and the external data source is completed.

2. Write data to the stream

The data that needs to be output is called, and the corresponding write method is written to the stream object.

3. Turn off the output stream

After the write is completed, the Close method of the call flow object closes the output stream and frees the resource.

The use of the output stream is illustrated below with FileOutputStream as an example. The sample code is as follows:

Import java.io.*;

/**

* Example of using FileOutputStream to write files

*/

public class WriteFile1 {

public static void Main (string[] args) {

String s = "Java language";

int n = 100;

Declaring a Stream object

FileOutputStream fos = null;

try{

Creating a Stream object

FOS = new FileOutputStream ("E:\\out.txt");

Convert to byte array

Byte[] B1 = S.getbytes ();

Line break

byte[] B2 = "\ r \ n". GetBytes ();

byte[] B3 = string.valueof (n). GetBytes ();

Write to file in sequence

Fos.write (B1);

Fos.write (B2);

Fos.write (B3);

} catch (Exception e) {

E.printstacktrace ();

}finally{

try{

Fos.close ();

}catch (Exception e) {}

}

}

}

Java file and stream read