The I/O data flow tools in the Java function library mainly include: InputStream: abstract input stream OutputStream: abstract output stream FileInputStream: read bytes from the file FileOutputStream: write bytes to the file ByteArrayInputStream: read from the byte array Get bytes ByteArrayOutputStream: Write bytes to byte array BufferedInputStream: Input stream with buffer, improve performance BufferedOutputStream: Output stream with buffer, improve performance DataInputStream: Read basic data types from input stream DataOutputStream: To output stream Writing basic data types

Introduction
Data flow tools are used in Java to process binary data and are very useful in input/output (I/O) operations. The Java function library provides multiple I/O data flow tools. This article will introduce the most commonly used tools and provide practical cases.
Commonly used data flow tools
| Tool | Description |
|---|---|
InputStream |
Abstract input stream |
OutputStream |
Abstract output Stream |
FileInputStream |
Read bytes from file |
FileOutputStream |
Write bytes to file |
##ByteArrayInputStream
| Read bytes from byte array|
ByteArrayOutputStream
| Write bytes to byte array|
BufferedInputStream
| Buffered input stream to improve performance|
BufferedOutputStream
| Buffered output stream to improve performance|
DataInputStream
| Read basic data types from the input stream|
DataOutputStream
| Write basic data types to the output stream
Practical case
Read text file
import java.io.FileInputStream;
import java.io.IOException;
public class ReadTextFile {
public static void main(String[] args) {
try (FileInputStream fis = new FileInputStream("myfile.txt")) {
// 逐字节读取文件
int c;
while ((c = fis.read()) != -1) {
System.out.print((char) c);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}Write to text file
import java.io.FileOutputStream;
import java.io.IOException;
public class WriteTextFile {
public static void main(String[] args) {
try (FileOutputStream fos = new FileOutputStream("myfile.txt")) {
// 写入文本
String text = "Hello, world!";
fos.write(text.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
}Read basic data types from byte array
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
public class ReadBasicTypesFromBytes {
public static void main(String[] args) {
// 定义字节数组并写入基本数据类型
byte[] bytes = {1, 2, 3, 4};
ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
DataInputStream dis = new DataInputStream(bis);
try {
// 读取基本数据类型
int i = dis.readInt();
System.out.println("Int: " + i);
} catch (IOException e) {
e.printStackTrace();
}
}
}Write basic data types to byte array
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.IOException;
public class WriteBasicTypesToBytes {
public static void main(String[] args) {
// 创建字节数组输出流
ByteArrayOutputStream bos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(bos);
try {
// 写入基本数据类型
dos.writeInt(12345);
dos.flush();
// 获取字节数组
byte[] bytes = bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
}
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