版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/cheidou123/article/details/82962456
一、处理流的原理
处理流使用的是装饰器设计模式，对节点流进行增强。
处理流四个重点特征：
1.性能提升
2.底层都是节点流
3.释放处理流时会自动释放内部的节点流，如果手动释放，从里到外依次释放
4.缓冲流嵌套一次就行,多次嵌套没用
二、常用缓冲流
1.IO字节缓冲流
⑴BufferedInputStream
public static void main(String[] args) {
File src = new File("/Users/caibin/IOstudy/caibin.txt");
InputStream is = null;
try {
//这里直接套上就可以
is = new BufferedInputStream(new FileInputStream(src));
//这里的byte一般指定1024*某个数，这里为了效果搞成3
byte[] cache = new byte[3];
int len;
//当读到-1时就到文件末尾了
while ((len = is.read(cache)) != -1) {
String str = new String(cache,0,len);
System.out.println(str);
}
} catch (FileNotFoundException ex) {
} catch (IOException ex) {
} finally {
try {
if (is != null) {
is.close();
}
} catch (IOException ex) {
}
}
}
⑵BufferedOutputStream
public class No51_BufferedOutputStream {
public static void main(String[] args) {
//文件不需要存在，不存在的话就创建
File src = new File("out.txt");
OutputStream os = null;
try {
//这里构造函数有一个是追加的,下面这种默认会覆盖以前的
os = new BufferedOutputStream(new FileOutputStream(src));
String msg = "caibin is handsome";
byte[] cache = msg.getBytes();
os.write(cache, 0, cache.length);
//输出流flush一下，保证一个好习惯
os.flush();
} catch (FileNotFoundException ex) {
} catch (IOException ex) {
} finally {
try {
if (os != null) {
os.close();
}
} catch (IOException ex) {
}
}
}
}
2.IO字符缓冲流
不要发生多态~~
⑴BufferedReader
public static void main(String[] args) {
// 1.创建源
File src = new File("caibin.txt");
// 2.选择流
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(src));
String line = null;
// 3.操作流，分段读
while ((line = reader.readLine()) != null) {
System.out.println(line);
}
} catch (FileNotFoundException ex) {
} catch (IOException ex) {
} finally {
//先打开后关闭
try {
if (reader != null) {
reader.close();
}
} catch (IOException ex) {
}
}
}
⑵BufferedWriter
public static void main(String[] args) {
File dest = new File("dest.txt");
BufferedWriter writer = null;
try {
writer = new BufferedWriter(new FileWriter(dest));
writer.write("handsome");
writer.newLine();
writer.write("heidouzi");
writer.flush();
} catch (FileNotFoundException ex) {
} catch (IOException ex) {
} finally {
//先打开后关闭
try {
if (writer != null) {
writer.close();
}
} catch (IOException ex) {
}
}
}
3.IO转换流
⑴作用
字节流转字符流，前提是这个字节流是操作纯文本的
处理过程中可以指定字符集
⑵实例
public class No54_Convert {
public static void main(String[] args) {
try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(System.out));) {
String msg = "";
while (!msg.equals("quit")) {
msg = reader.readLine();
writer.write(msg);
writer.newLine();
writer.flush();
}
} catch (Exception ex) {
}
}
}
4.IO数据流
方便处理基本类型和string，这里要保证先写先读，不用也要读出来
⑴DataInputStream
⑵DataOutputStream
public class No55_DataStream {
public static void main(String[] args) throws Exception {
DataOutputStream dos = null;
DataInputStream ios = null;
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
dos = new DataOutputStream(new BufferedOutputStream(out));
dos.writeInt(123);
dos.writeUTF("黑豆");
dos.flush();
byte[] data = out.toByteArray();
ios = new DataInputStream(new BufferedInputStream(new ByteArrayInputStream(data)));
int a = ios.readInt();
String b = ios.readUTF();
System.out.println(a + b);
} finally {
try {
if (ios != null) {
ios.close();
}
} catch (IOException ex) {
}
try {
if (dos != null) {
dos.close();
}
} catch (IOException ex) {
}
}
}
}
5.IO对象流
对象流可以操作
先写出后读取，保证先写先读，不用也要读出来，对象要实现序列化接口
⑴ObjectInputStream(反序列化)
⑵ObjectOutputStream(序列化)
public class No56_ObjectStream {
public static void main(String[] args) throws Exception {
ObjectOutputStream dos = null;
ObjectInputStream ios = null;
try {
ByteArrayOutputStream out = new ByteArrayOutputStream();
dos = new ObjectOutputStream(new BufferedOutputStream(out));
dos.writeObject(123);
dos.flush();
byte[] data = out.toByteArray();
ios = new ObjectInputStream(new BufferedInputStream(new ByteArrayInputStream(data)));
Object a = ios.readObject();
if (a instanceof Integer) {
System.out.println(a);
}
} catch (Exception ex) {
try {
if (ios != null) {
ios.close();
}
} catch (IOException e) {
}
try {
if (dos != null) {
dos.close();
}
} catch (IOException e) {
}
}
}
}