Java-IO流

public class OutputStreamWriterDemo {
    public static void main(String[]args)throws IOException {
　　　　　//从文件中读取字符
        BufferedReader br=new BufferedReader(new FileReader("test.txt"));
        OutputStream os=System.out;
        String line;
        while ((line=br.readLine())!=null) {
            os.write(line.getBytes());
            os.write("\r\n".getBytes());
        }
        os.close();
        br.close();
    }
}

public class InputStreamReaderDemo {
    public static void main(String[]args) throws IOException{
　　　　　//创建字节流对象
        InputStream is =System.in;
        //转换成字符流
        Reader r=new InputStreamReader(is);
        //将字符流写入文件
        FileWriter fw=new FileWriter("a.txt");
        char[]chs=new char[1024];
        int len;
        while((len=r.read(chs))!=-1) {
            fw.write(new String(chs,0,len));
            fw.flush();
        }
        //释放资源
        fw.close();
        is.close();
    }
}

public class PrintWriteDemo {
    public static void main(String[] args) throws IOException {
        /**
        * PrintStream
* 只能输出，不能输入
* PrintWrite用println实现换行，能够自动刷新。
        * PW支持两个直接对文件写操作的构造方法：
        * PrintWriter(File f)传文件名
        * PrintWriter(String s)传路径
        * PrintWriter给人一种可以直接对文件进行操作的假象
        * PW是一个高级流
        * 实际上PW包装了字节流、字符流和字符缓冲流。
        * PW负责自动行刷新
        * bw负责提高效率
        * osw负责读字符
        * fos负责写字节
        * 最后PW能够按行很快地把一个字符串变成字节写在文件中
* new PrintWriter(new FileWriter("c.txt"),true)启动了自动刷新，
        * 即不用.close()方法，直接释放资源
        */
        PrintWriter pw = new PrintWriter(new FileWriter("c.txt"),true);
        
        pw.println("飞雪连天射白鹿");
        pw.println("金庸小说我都爱看");
        
        //pw.close();
        
        PrintWriter s=new PrintWriter("d.txt");
        s.println("hello");
        s.println("world");
        s.close();
        System.out.println("写出完毕！");
        }
}

public class PropertiesDemo {
    public static void main(String []args) {
        Properties pro=new Properties();
        pro.put("1", "zhangsan");
        pro.put("2", "lisi");
        Set<Object>keys=pro.keySet();
        for (Object key:keys) {
            String value=(String) pro.get(key);
            System.out.println(key+"="+value);
        }
        System.out.println("---------------");
        Set<Map.Entry<Object,Object>>entrys=pro.entrySet();
        for (Map.Entry<Object,Object>entry:entrys) {
            Object key=entry.getKey();
            Object value=entry.getValue();
            System.out.println(key+":"+value);
        }
    }
}

public class PropertiesDemo1 {
    public static void main(String[]args) throws IOException {
        //method();
        //method1();
        method2();
    }

    private static void method2() throws IOException {
        //创建属性流对象
        Properties pro=new Properties();
        pro.put("1", "zhangsan");
        pro.put("2", "lisi");
        //创建输出流对象
        BufferedWriter wr=new BufferedWriter(new FileWriter("h.txt"));
        //void store(wruter,writer,String comments)
        pro.store(wr, "hello world");
        //释放资源
        wr.close();
    }

    private static void method1() throws FileNotFoundException, IOException {
        Properties pro=new Properties();
        //创建输入流
        FileReader fr=new FileReader("g.txt");
        pro.load(fr);
        System.out.println(pro);
        fr.close();
    }

    private static void method() throws FileNotFoundException {
        Properties pro=new Properties();
        //映射关系
        pro.put("1", "zhangsan"); 
        pro.put("2", "lisi");
        
        //映射关系
        //pro.setProperty("1", "zhangsan");
        //pro.setProperty("2","lisi");
        
        PrintWriter out =new PrintWriter("g.txt");
        pro.list(out);
        out.close();
    }
}

public class Student implements Serializable{
    private static final long serialVersionUID = 5021773103026564312L;
    
    String name;
    int age;
    String gender;
    public Student(String name,int age) {
        this.name=name;
        this.age=age;
    }
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }
    @Override
    public String toString() {
        return "Student [name=" + name + ", age=" + age + ", gender=" + gender + "]";
    }
    
}

/*对象操作流：
 * 可以用于读写任意类型的对象
 * ObjectOutputStream
 *         writeObject
 *         ObjectOutputStream(OutStream out)
 * ObjectInputStream
 *         readObject
 *         ObjectInputStream(InputStream in)
 *问题：存在 java.io.InvalidClassException,已解决
 *        原因：该类的序列版本号与读出的类的描述版本不同；
 *            该类包含未知的数据类型
 *            该类没有可访问的无参数构造方法
 * */
public class ObjectOutputStreamDemo {
    public static void main(String[]args) throws IOException, ClassNotFoundException{
        method2()； 
    }private static void method2() throws IOException{
        //创建字节输出流对象
        FileOutputStream fos=new FileOutputStream("newFile.txt");
        //创建对象输出流对象，字节输出流作为参数传入
        ObjectOutputStream oos=new ObjectOutputStream(fos);
        //FileOutputStream fos=new FileOutputStream(new FileOutputStream("newFile.txt"));
        //创建学生对象
        Student s=new Student("zhangsan",18);
        Student s1=new Student("wangwu",19);
        //写学生对象
        oos.writeObject(s);
        oos.writeObject(s1);
        oos.close();
    }

}