# 
  * [IO](#io)
    * [Java IO](#java-io)
    * [IO](#io)
    * [](#)
    * [IO](#io)
    * [Java IO](#java-io)
    * [](#)
    * [System.in, System.out, System.err](#systemin-systemout-systemerr)
    * [BufferedFilter](#bufferedfilter)
  * [JavaIO](#javaio)
    * [IO](#io)
    * [](#)
    * [Java](#java)
    * [FileInputStreamFileOutputStream](#fileinputstreamfileoutputstream)
    * [System.out.println()](#systemoutprintln)
    * [Filter](#filter)
    * [Filter](#filter)
    * [](#)
    * [(Piped Stream)](#piped-stream)
    * [File](#file)
    * [RandomAccessFile?](#randomaccessfile)
  * [](#)


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## IO

> Java IO(java.io)


****

    
    
    OutputStreamInputStreamJava IO
    
    

JavaIO
    
    
    
    
    
    System.in, System.out, System.error(Java)


![](http://ifeve.com/wp-content/uploads/2014/10/%E6%97%A0%E6%A0%87%E9%A2%981.png)

****

    Java IOJava IO()()

InputStream, OutputStream, Reader Writer
InputStreamReaderOutputStreamWriter

![](http://ifeve.com/wp-content/uploads/2014/10/%E6%97%A0%E6%A0%87%E9%A2%982.png)

InputStreamReaderOutputStreamwriter

**Java IO**

Java IOInputStreamOutputStreamReaderWriterIO
    
    
    
    
    ()
    
    
    
     (Readers / Writers)
     (long, int etc.)
    

Java IO

Java IO
Java IOJava IO

![](http://ifeve.com/wp-content/uploads/2014/10/QQ%E6%88%AA%E5%9B%BE20141020174145.png)

Java IO

![](https://images.cnblogs.com/cnblogs_com/davidgu/java_io_hierarchy.jpg)

### Java IO

Java IO

RandomAccessFile 

PushbackInputStream 
>
> Java IOstreamInputStreamOutputStreamDataInputStream DataOutputStream int, long, floatdouble
>
> ReaderWriter(Latin1Unicode)Java Readers and Writers

**InputStream**

java.io.InputStreamJava IOInputStream(FileInputStream)

****

InputStreamBufferedInputStream


    InputStream input = new BufferedInputStream(new FileInputStream("c:\\data\\input-file.txt"));
    
> OutputStream()BufferedOutputStream
>
> InputStreamPushbackInputStreamInputStreamSequenceInputStream
>
> 

### IO

JavaJava


**Java IO**

    FileInputStreamFileReader
    
    

RandomAccessFile

**Java IO**

    FileOutputStreamFileWriter
    
    

**Java IO**

RandomAccessFile
    
    
    
    RandomAccessFile


````
    @Test
        //
        public void test1() {
            try {
                FileInputStream fileInputStream = new FileInputStream(new File("a.txt"));
                FileOutputStream fileOutputStream = new FileOutputStream(new File("b.txt"));
                byte []buffer = new byte[128];
                while (fileInputStream.read(buffer) != -1) {
                    fileOutputStream.write(buffer);
                }
                //mode
                RandomAccessFile randomAccessFile = new RandomAccessFile(new File("c.txt"), "rw");
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
````
### 

Java IOReaderWriterInputStreamOutputStreamInputStreamOutputStream

Reader
ReaderJava IOReaderBufferedReaderPushbackReaderInputStreamReaderStringReaderReader

Writer
WriterJava IOWriterBufferedWriterPrintWriter

Java IO Reader
````
Reader reader = new FileReader("c:\\data\\myfile.txt");

int data = reader.read();

while(data != -1){

    char dataChar = (char) data;

    data = reader.read();

}
````
ReaderReaderReaderInputStreamReaderCharArrayReaderFileReaderJava IOReader

**ReaderInputStream**

ReaderInputStreamInputStreamInputStreamInputStreamReaderInputStreamInputStreamReader
````
Reader reader = new InputStreamReader(inputStream);
````


**Writer**

WriterJava IOWriterBufferedWriterPrintWriterJava IO Writer
````
Writer writer = new FileWriter("c:\\data\\file-output.txt"); 

writer.write("Hello World Writer"); 

writer.close();
````
WriterWriterOutputStreamWriterCharArrayWriterFileWriterWriterwrite(int c)16Writer16

**WriterOutputStream**

ReaderInputStreamWriterOutputStreamOutputStreamOutputStreamWriterOutputStreamWriterOutputStreamOutputStreamWriter
````
Writer writer = new OutputStreamWriter(outputStream);
````
### IO

Java IOJVM

JVM()JavaUnix/LinuxUnix/LinuxJava

Java IO

    Java IOPipedOutputStreamPipedInputStreamPipedInputStreamPipedOutputStream
    
    PipedOutputStreamPipedInputStream

Java IO
PipedInputStreamPipedOutputStream
````
//
    @Test
    public void test2() throws IOException {
        PipedInputStream pipedInputStream = new PipedInputStream();
        PipedOutputStream pipedOutputStream = new PipedOutputStream(pipedInputStream);
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    pipedOutputStream.write("hello input".getBytes());
                    pipedOutputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    byte []arr = new byte[128];
                    while (pipedInputStream.read(arr) != -1) {
                        System.out.println(Arrays.toString(arr));
                    }
                    pipedInputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
````


read()write()


JVMJava IO

### Java IO

JavaJava IOJavaJavaJava IOAPI


InputStreamOutputStreamJavaAPIJava IO

OutputStreamFileOutputStreamFileOutputStreamOuputStream
````
    //OutputStream
    public void test3() {
        //
        OutputStream outputStream = new OutputStream() {
            @Override
            public void write(int b) throws IOException {
            }
        };
    }
    public void process(OutputStream ouput) throws IOException {
        //
        //do something with the OutputStream
    }
````
### 


InputStreamReader

OutputStreamWriter

java



````
    //io
        public void test4() {
            //arrbrr
            char []arr = {'a','c','d'};
            CharArrayReader charArrayReader = new CharArrayReader(arr);
            byte []brr = {1,2,3,4,5};
            ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(brr);
        }
````
### System.in, System.out, System.err    

System.in, System.out, System.err3System.out

JVMJava3()


    System.in
    System.inInputStreamJavaSystem.inJava IO
    
    System.out
    System.outPrintStreamSystem.outSystem.outSystem.out()
    
    System.err
    System.errPrintStreamSystem.errSystem.outEclipseSystem.err

System.outSystem.err
System.outSystem.err
````
     //System.in, System.out, System.err    
        public static void main(String[] args) {
            int in = new Scanner(System.in).nextInt();
            System.out.println(in);
            System.out.println("out");
            System.err.println("err");
            //10
    //        err
    //        10
    //        out
        }
````

### BufferedFilter

BufferedReaderIOIO

BufferedReaderBufferedInputStreamBufferedReaderBufferedInputStreamReaderBufferedReaderReader(81928KB)

    Reader input = new BufferedReader(new FileReader("c:\\data\\input-file.txt"));



    Reader input = new BufferedReader(new FileReader("c:\\data\\input-file.txt"), 8 * 1024);

8KB1024

BufferedReaderReaderBufferedReaderreadLine()

**BufferedWriter**

BufferedReaderBufferedWriterBufferedWriter(8 * 1024B)

    Writer writer = new BufferedWriter(new FileWriter("c:\\data\\output-file.txt"));



    Writer writer = new BufferedWriter(new FileWriter("c:\\data\\output-file.txt"), 8 * 1024);

1024BufferedWriterWriterBufferedWriterwriteLine()


**flush()**

**FilterReader**

FilterInputStreamFilterReaderReader

ReaderFilterReaderReaderFilterReaderReader

## JavaIO

### IO
(process)

### 
JDK1.0ASCIIJAVAUnicodeUnicodeJAVAJDK1.1ASCIIUnicode

### Java

java.io.InputStream
java.io.OutputStream
java.io.Reader
java.io.Writer

### FileInputStreamFileOutputStream
BufferedInputStream ( BufferedReader)  BufferedOutputStream ( BufferedWriter)

### System.out.println()
printlnPrintStreamoutPrintStreamSystemjava.lang

### Filter
Filter StreamIO

### Filter

java.io4filter Streamfilter streamfilter stream. FilterInputStream, FilterOutputStream, FilterReader and FilterWriter.

### 
BufferedInputStreamBufferedOutputStream
BufferedReader  BufferedWriter

### (Piped Stream)
 PipedInputStream, PipedOutputStream, PipedReader  PipedWriter.

### File
 IO

### RandomAccessFile?
java.ioObjectRandomAccessFile DataInputStream  DataOutStreamRandomAccessFile

## 

https://www.imooc.com/article/24305
https://www.cnblogs.com/UncleWang001/articles/10454685.html
https://www.cnblogs.com/Jixiangwei/p/Java.html
https://blog.csdn.net/baidu_37107022/article/details/76890019