代码二些

1.封装

 

 

2.捕获异常 (try catch finally)  (Ctrl+Alt+T快捷键)

 

 

3.抛出异常(throw throws)

 

4.IO文件字节流(文本,图片,影音)

package com.io;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public class FileCopyTools {
    public static void main(String[] args) {
        copyFile("d:/999.jpg","d:/333.jpg");
    }
    public static void copyFile(String src,String des){
        FileInputStream fis = null;
        BufferedInputStream bis = null;
        FileOutputStream fos = null;
        BufferedOutputStream bos = null;
        try{
            bis = new BufferedInputStream(new FileInputStream(src));
            bos = new BufferedOutputStream(new FileOutputStream(des));
            int temp = 0;
            while ((temp = bis.read())!=-1){
                bos.write(temp);
            }
            bos.flush();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                if (bis!=null){
                    bis.close();
                }
                if (fis!=null){
                    fis.close();
                }
                if (bos!=null){
                    bos.close();
                }
                if (fos!=null){
                    fos.close();
                }

            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}



5.IO转换流 实现键盘输入屏幕输出

import java.io.*;

public class ConvertStream {
    public static void main(String[] args) {
        BufferedReader br = null;
        BufferedWriter bw = null;

        try {
            br = new BufferedReader(new InputStreamReader(System.in));

            bw = new BufferedWriter(new OutputStreamWriter(System.out));

            while (true){
                bw.write("请输入:");
                bw.flush();
                String input = br.readLine();
                if ("exit".equals(input)){
                    break ;
                }
                bw.write("您输入的是:"+input);
                bw.newLine();
                bw.flush();

            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                if (bw!=null){
                    bw.close();
                }
                if (br!=null){
                    br.close();
                }


            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

6. IO流 通过字节流读取文本文件并添加行号

package com.io;


import java.io.*;

public class LineNumberDemo02 {
    public static void main(String[] args) {
        BufferedReader br = null;
        BufferedWriter bw = null;
        try {
            br = new BufferedReader(new InputStreamReader(new FileInputStream("d:/a.txt")));
            bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("d:/g.txt")));
            String temp = "";
            int i = 1;
            while ((temp = br.readLine())!=null){
                bw.write(i+"."+temp);
                bw.newLine();
                i++;
            }bw.flush();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try{
                if (bw!=null){
                    bw.close();
                }
                if (br!=null){
                    br.close();
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}



7.IO流 PrintWriter实现字符换行输出

package com.io;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class LineNumberDemo03 {
    public static void main(String[] args) {
        BufferedReader br = null;
        PrintWriter pw = null;
        try {
            br = new BufferedReader(new InputStreamReader(new FileInputStream("d:/a.txt")));
            pw = new PrintWriter("d:/h.txt");
            String temp = "";
            int i = 1;
            while ((temp=br.readLine())!=null){
                pw.println(i+"."+temp);
                i++;
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                if (br!=null){
                    br.close();
                }
                if (pw!=null){
                    pw.close();
                }

            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

 
8.IO流ObjectOutputStream将对象序列化到文件,再反序列化回内存

一.创建一个对象(被序列化的对象必须要实现Seriliazable序列化接口)

package com.io;

import java.io.Serializable;

public class Users implements Serializable {
    private int userid;
    private String username;
    private String userage;

    public Users(int userid, String username, String userage) {
        this.userid = userid;
        this.username = username;
        this.userage = userage;
    }

    public Users() {
    }

    public int getUserid() {
        return userid;
    }

    public void setUserid(int userid) {
        this.userid = userid;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getUserage() {
        return userage;
    }

    public void setUserage(String userage) {
        this.userage = userage;
    }
}

二.将对象序列化到文件

package com.io;

import java.io.BufferedOutputStream;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;

public class ObjectOutputStreamObjectTypeDemo {
    public static void main(String[] args) {
        ObjectOutputStream oos = null;
        try {
            oos = new ObjectOutputStream(new FileOutputStream("d:/ccl6.txt"));
            Users users = new Users(1,"ccl","18");
            oos.writeObject(users);
            oos.flush();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try {
                if (oos != null){
                    oos.close();
                }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

三.将对象反序列化回内存

package com.io;

import java.io.FileInputStream;
import java.io.ObjectInputStream;

public class ObjectInputStreamObjectTypeDemo {
    public static void main(String[] args) {
        ObjectInputStream ois = null;
        try {
            ois = new ObjectInputStream(new FileInputStream("d:/ccl6.txt"));
            Users users = (Users) ois.readObject();
            System.out.println(users.getUserid()+"\t"+users.getUsername()+"\t"+users.getUserage());
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            try{
               if (ois != null){
                   ois.close();
               }
            }catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

9.FileUtils 文件过滤后拷贝

package com.io;

import org.apache.commons.io.FileUtils;

import java.io.File;
import java.io.FileFilter;

public class FileUtilsDemo02 {
    public static void main(String[] args)throws Exception {
        FileUtils.copyDirectory(new File("d:/a"), new File("e:/a"), new FileFilter() {
            //在文件拷贝时的过滤条件
            @Override
            public boolean accept(File pathname) {
                if (pathname.isDirectory()||pathname.getName().endsWith("html")){
                    return true;
                }
                return false;
            }
        });
    }
}