IO流总结

//InputStream（字节流、输入流）Reader（字符流、输入流）OutputStream（字节流、输出流）Writer（字符流、输出流）
//InputStream-FilterInputStream(BufferedInputStream(缓冲字节输入流)、DataInputStream、LineNumberInputStream(过时)、PushbackInputStream)、
//ByteArrayInputStream(字节数组输入流)、FileInputStream(文件输入流)、ObjectInputStream(对象输入流)、PipedInputStream、SequenceInputStream、StringBufferInputStream(过时)

//OutputStream-FilterOutputStream(BufferedOutputStream(缓冲字节输出流)、DataOutputStream、PrintStream)、
//ByteArrayOutputStream(字节数组输出流)、FileOutputStream(文件输出流)、ObjectOutputStream(对象输出流)、PipedOutputStream

//Reader-BufferedReader(缓冲字符输入流)(LineNumberReader)、CharArrayReader、InputStreamReader(字符输入流)(FileReader)、FilterReader(PushbackReader)、PipedReader、StringReader
//Writer-BufferedWriter、CharArrayWriter、OutputStreamWriter(字符输出流)(FileWriter)、FilterWriter、PipedWriter、PrintWriter(缓冲字符输出流)、StringWriter

//文件操作
File file = new File("."+File.separator+"test.txt");//文件、目录（"demo"、"a"+File.separator+"b"）
boolean hasFile = file.exists();//判断当前File表示的文件或目录是否真实存在
boolean isFile = file.isFile();//判断当前File表示的是否为一个文件
boolean isDirectory = file.isDirectory();//判断当前File表示的是否为一个目录
File[] subs = file.listFiles();//获取当前目录中的所有子项
file.createNewFile();//创建该文件
file.delete();//删除文件或目录
file.mkdir();//创建目录
file.mkdirs();//创建多级目录
String name = file.getName();
long length = file.length();
boolean canRead =file.canRead();//可读
boolean canWrite =file.canWrite();//可写
boolean isHidden = file.isHidden();//是否为隐藏文件

RandomAccessFile raf = new RandomAccessFile("raf.dat","rw");//rw读写，r读
raf.write(1);//单字节、多字节write(data,0,len)
int rafInt = raf.read();//若返回值为-1表示读取到了文件末尾
raf.close();

//输入流
FileInputStream fis = new FileInputStream("osw.txt");//文件输入流
byte[] data = new byte[300];
int len = fis.read(data);
String fisStr = new String(data,0,len,"utf-8");
fis.close();
InputStreamReader isr = new InputStreamReader(fis,"utf-8");//字符输入流
int isrInt = isr.read();//-1表示不存在，用StringBuilder拼接(append((char)d))转为String
isr.close();
ObjectInputStream ois = new ObjectInputStream(fis);//对象输入流-对象必须实现Serializable接口
ois.readObject();
ois.close();
BufferedInputStream bis = new BufferedInputStream(fis);//缓冲字节输入流，提高读取效率
int bisInt = bis.read();//-1表示不存在
bis.close();
BufferedReader br = new BufferedReader(isr);//缓冲字符输入流
br.readLine();//读取一行数据
br.close();

//输出流
FileOutputStream fos = new FileOutputStream("osw.txt");//文件输出流(覆盖写模式、追加写模式-"fos.txt",true)
fos.close();
fos.write("hello".getBytes("utf-8"));
OutputStreamWriter osw = new OutputStreamWriter(fos,"utf-8");//字符输出流
osw.write("hello");
osw.close();
ObjectOutputStream oos = new ObjectOutputStream(fos);//对象输出流-对象必须实现Serializable接口
oos.writeObject("hello");
oos.close();
BufferedOutputStream bos = new BufferedOutputStream(fos);//缓冲字节输出流
bos.write(1);
bos.flush();
bos.close();
PrintWriter pw = new PrintWriter(osw);//缓冲字符输出流
pw.println("hello");
pw.close();
ByteArrayOutputStream baos = new ByteArrayOutputStream();//字节数组输出流
baos.write(data, 0, len);
byte[] buffer = baos.toByteArray();