io系统

一、浅谈io系统

　　io系统的结构化思想是：输入-转换流-装饰器-输出。

　　对于字节流来说，常见的结构类为：

　　

　　

package com.handchina.yunmart.middleware.service;

import org.elasticsearch.common.inject.Inject;
import org.junit.Test;

import java.io.*;

/**
 * Created by yq on 2016/11/18.
 */
public class IOTestServiceTest {
    @Inject
    private IOTestService ioTestService;

    @Test
    public void testFile() {
        FileReader br = null;
        FileWriter bw = null;
        try {
            String in = "file/fileDemoIn.txt";
            String out = "file/fileDemoOut.txt";
            br = new FileReader(in);int s;
            Long start1 = System.currentTimeMillis();
            bw = new FileWriter(out);
            while ((s = br.read()) != -1) {
                bw.write(s);
            }
            System.out.println("===========================复制时间：" + (System.currentTimeMillis() - start1) + "毫秒");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bw != null) {
                try {
                    bw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Test
    public void testFileDemo() {
        BufferedReader br = null;
        BufferedWriter bw = null;
        try {
            String in = "file/fileDemoIn.txt";
            String out = "file/fileDemoOut.txt";
            br = new BufferedReader(new FileReader(in));
            StringBuilder sb = new StringBuilder();
            String s = null;
            Long start1 = System.currentTimeMillis();
            while ((s = br.readLine()) != null) {
                sb.append(s);
                sb.append("\r\n");
            }
            System.out.println("===========================读取时间：" + (System.currentTimeMillis() - start1) + "毫秒");

            bw = new BufferedWriter(new FileWriter(out));
            Long start2 = System.currentTimeMillis();
            bw.write(sb.toString());
            bw.flush();
            System.out.println("===========================写入时间：" + (System.currentTimeMillis() - start2) + "毫秒");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bw != null) {
                try {
                    bw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Test
    public void testByte() {
        FileInputStream bi = null;
        FileOutputStream bo = null;
        try {
            String in = "file/fileStreamIn.avi";
            String out = "file/fileStreamOut.avi";
            bi = new FileInputStream(in);
            bo = new FileOutputStream(out);
            byte[] buf = new byte[1024];
            Long start1 = System.currentTimeMillis();
            int temp = 0;
            while ((temp = bi.read(buf)) != -1) {
                bo.write(buf, 0, temp);
            }
            System.out.println("===========================复制时间：" + (System.currentTimeMillis() - start1) + "毫秒");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (bi != null) {
                try {
                    bi.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bo != null) {
                try {
                    bo.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    @Test
    public void testByteDemo() {
        BufferedInputStream bi = null;
        BufferedOutputStream bo = null;
        try {
            String in = "file/fileStreamIn.avi";
            String out = "file/fileStreamOut.avi";
            bi = new BufferedInputStream(new FileInputStream(in));
            bo = new BufferedOutputStream(new FileOutputStream(out));
            byte[] buf = new byte[1024];
            Long start1 = System.currentTimeMillis();
            int temp = 0;
            while ((temp = bi.read(buf)) != -1) {
                bo.write(buf, 0, temp);
            }
            System.out.println("===========================复制时间：" + (System.currentTimeMillis() - start1) + "毫秒");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (bi != null) {
                try {
                    bi.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bo != null) {
                try {
                    bo.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}