public class Test {
    public static void write() {
        File f = new File("d:\\test\\properties.test");
        Properties p = new Properties();
        p.setProperty("g","stu");
        /*try (FileOutputStream fos = new FileOutputStream(f,true);){
            p.store(fos,"新增信息");
        } catch (IOException e) {
            e.printStackTrace();
        }*/
        try (FileWriter fw = new FileWriter(f)){
            p.store(fw,"新增信息");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void read() {
        File f = new File("d:\\test\\properties.test");
        Properties p = new Properties();
        try (FileInputStream fis = new FileInputStream(f);){
            p.load(fis);
            Set<String> set = p.stringPropertyNames();
            for(Iterator<String> it = set.iterator();it.hasNext();) {
                String key = it.next();
                String value = p.getProperty(key);
                System.out.println(key+":"+value);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import java.io.Serializable;

public class Hero implements Serializable{//空接口，标记型接口
    private String name;
    //表示这个类当前的版本，如果有了变化，比如新设计了属性，就应该修改这个版本号，解决序列号不匹配问题
    private static final long serialVersionUID = 1L;
    private int hp;//当修改修饰词时，前后序列号不匹配，已经序列化的对象无法在读取
    //静态成员是不能被序列化的，因为静态成员是随着类的加载而加载的，
    //与类共存亡，并且静态成员都是默认初始值；
    //禁止成员变量序列化
    //transient private String sex;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getHp() {
        return hp;
    }
    public void setHp(int hp) {
        this.hp = hp;
    }
    public Hero(String name, int hp) {
        super();
        this.name = name;
        this.hp = hp;
    }
    public Hero() {
        super();
    }
    
}

public class Test {
    public static void writeHero(ArrayList<Hero> herolist) {
        File f = new File("d:\\test\\Dota2.dota");
        try (FileOutputStream fis = new FileOutputStream(f);
              ObjectOutputStream oos = new ObjectOutputStream(fis);
              ){
            oos.writeObject(herolist);
            System.out.println("写入完成！");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static ArrayList<Hero> readHero() {
        File f = new File("d:\\test\\Dota2.dota");
        ArrayList<Hero> herolist = new ArrayList<Hero>();
        try (FileInputStream fos = new FileInputStream(f);
              ObjectInputStream ois = new ObjectInputStream(fos);
              ){
             herolist = (ArrayList<Hero>)ois.readObject();
             System.out.println("读取完成！");
        } catch (Exception e) {
            e.printStackTrace();
        }
        return herolist;
    }
}

public class Test5 {
    public static void write() {
    public static void copy() {
        File f = new File("d:\\test\\LOL.txt");
        try ( BufferedReader br = new BufferedReader(new FileReader(f));
                PrintWriter pw = new PrintWriter(new FileWriter("d:\\test\\copy.txt"));
                ){
            String line =null;
            while((line=br.readLine())!=null) {
                pw.println(line);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) {
        File f = new File("d:\\test\\print.txt");
        try (PrintStream ps = new PrintStream(f);
                //PrintWriter pw = new PrintWriter(f);
                FileOutputStream fos = new FileOutputStream(f);
                PrintWriter pw = new PrintWriter(fos,true);//传入流对象，调用println、printf、format自动flush
                ){//不负责数据源，只负责数据目的
            //为其他输出流添加功能，永远不抛IO异常
            ps.println("a");
            ps.println("b");
            pw.println("c");
            pw.println("d");

        } catch (IOException e) {
            e.printStackTrace();
        }
        int[] i = {1};
        System.out.println(i);//void java.io.PrintStream.println(Object x) 打印地址
        char[] ch = {\'a\',\'b\'};
        System.out.println(ch);//void java.io.PrintStream.println(char[] x) 打印字符串
    }
}

import java.io.File;
import java.io.IOException;
import org.apache.commons.io.FileUtils;
import org.apache.commons.io.FilenameUtils;

public class Test6 {
    public static void fn() {
        FilenameUtils fnu = new FilenameUtils();
        String name = fnu.getExtension("d:\\test\\LOL.txt");//获取扩展名
        String fname = fnu.getName("d:\\test\\LOL.lol");//获取文件名
        boolean flag = fnu.isExtension("d:\\test\\LOL.txt","txt");//检查文件类型
        System.out.println(name+""+fname+""+flag);
    }
    public static void main(String[] args) throws IOException {
        fn();
        FileUtils fu = new FileUtils();
        System.out.println();
        String s =fu.readFileToString(new File("d:\\test\\LOL.txt"),"UTF-8");//读取文件内容
        fu.copyDirectory(new File("d:\\study"), new File("d:\\tocopy"));//复制文件夹
    }
}