IO流

FileOutputStream fos = new FileOutputStream("D\\b.txt");  //不存在,创建  存在,清空
fos.write();
fos.close();
FileInputStream fos = new FileInputStream("D\\b.txt");
fos.read();
fos.close();

BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("test-io\\copy.txt")); BufferedInputStream bis = new BufferedInputStream(new FileInputStream("D:\\a.txt"));

byte [] bytes = new byte[1024]; int len; while ((len = bis.read(bytes)) != -1) { 
    bos.write(bytes, 0,len);
} 
bos.close(); 
bis.close();

字符流

写出数据
FileWriter fw = new FileWriter("test-io\\a.txt");

BufferedWriter bw = new BufferedWriter(new FileWriter("test-io\\a.txt"));

BufferedReader bf = new BufferedReader(new FileReader("test-io\\a.txt"));

InputStreamReader isr = new InputStreamReader(new FileInputStream("test-io\\a.txt"),"gbk"); 

OutputStreamWriter osr = new OutputStreamWriter(new FileOutputStream("test-io\\a.txt"),"gbk");

FileReader fr = new FileReader("test-io\\a.txt", Charset.forName("gbk"));

FileWriter fw = new FileWriter("test-io\\a.txt",Charset.forName("utf-8"));

对象操作流

//实现接口Serializable,就可以被序列化 public class User implements Serializable{...}

 
// 写入对象流
ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("test-io\\b.txt")); 

User user = new User("lisi", "itheima"); 

oos.writeObject(user); 

oos.close();

// 读入对象流 ObjectInputStream ois = new ObjectInputStream(new FileInputStream("test-io\\b.txt")); User user = (User) ois.readObject(); System.out.println(user); ois.close();

Properties prop = new Properties(); 

 prop.put("张三", "李四"); // 删 prop.remove("jack");  // 修  prop.put("jack", "xiaowang");  // 查 Object o = prop.get("张三"); 

Properties prop = new Properties(); FileWriter fw = new FileWriter("test-io\\prop.properties"); prop.put("lisi","123"); prop.put("wangwu","xiaoliu"); prop.put("zhaoqi","admin"); prop.store(fw,null); fw.close();

Properties prop = new Properties(); FileReader fr = new FileReader("test-io\\prop.properties"); prop.load(fr); fr.close(); System.out.println(prop);