缓冲字符流

缓冲字符输出流

package com.mobiletrain;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;

public class BufferedWritePractice {
    public static void main(String[] args) {
        try {

            Writer writer = new FileWriter("E:\\data\\1000phone\\test\\bufferedwrite.txt");
            BufferedWriter bw = new BufferedWriter(writer);

            bw.write("1da3546fsd");

            bw.close();
            writer.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        System.out.println("200,OK");
    }
}

缓冲字符输出流

package com.mobiletrain;

import java.io.*;

public class BufferedReaderPractice {
    public static void main(String[] args) {
        try {
            //文件输入流
            Reader reader = new FileReader("E:\\data\\1000phone\\test\\bufferedwrite.txt");
            //不希望直接操作文件输入流，为了提升效率，使用缓冲输入流
            BufferedReader br = new BufferedReader(reader);

            //缓冲输入流，笔字符输入流多出一个readLine（）方法，能一次读一行
            //并且读到的时String类型，不是char[]类型
            String line=br.readLine();
            System.out.println(line);

            //关闭资源
            br.close();
            reader.close();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

File类

在这里插入图片描述

package com.mobiletrain.file;

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

public class FileFilterPractice {
    public static void main(String[] args) {
        File path = new File("E:\\data\\1000phone\\img");
        System.out.println(path.isDirectory());
        System.out.println(path.isFile());

//        System.out.println("------------------------");
//        File[] files = path.listFiles();
//        for (File file :
//                files) {
//            System.out.println(file.getName());
//        }
        FileFilter fileFilter = new FileFilter(){

            @Override
            public boolean accept(File pathname) {
                //函数名---暴露出意图
                //accept   是否同意

                //参数---

                //返回值

                //整体的含义
                //传入一个file对象，询问是否同意

                //问题：纸打印文件，不打印目录

                boolean result = pathname.isFile();
                return result;
            }
        };
        File[] files = path.listFiles(fileFilter);
        for (File file :
                files) {
            System.out.println(file.getName());
        }

    }
}

Properties对象

load(输入流)

加载输入流里面的配置，一般为properties文件

格式为key=value[换行]

package com.mobiletrain.properties;


import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class PropertiesPractice {
    public static void main(String[] args) {
        try {


        //property
        //Map
        //通过文件输入流，读properties文件
        InputStream is = new FileInputStream("E:\\data\\1000phone\\test\\user.properties");

        //创建Properties对象
        Properties properties = new Properties();

        //让properties读对象输入流
        properties.load(is);

        String username=properties.getProperty("user");
        String password = properties.getProperty("password");
        String gender = properties.getProperty("gender","unknow");
        String mobile = properties.getProperty("mobile","unknow");

            System.out.println(username);
            System.out.println(password);
            System.out.println(gender);
            System.out.println(mobile);

            is.close();


    } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}