java oop第12章_IO、序列化和反序列化

        InputStream inputStream = null;
    OutputStream outputStream = null;

    /**
     * 案例1：通过字节流完成文件的复制，文件可以是任何类型。
     * 
     * @throws IOException
     * @throws Exception
     */
    @Test
    public void testCopyWithStream() throws IOException {
        // 创建一个输入的字节流，通过输入字节流读取文件
        inputStream = new FileInputStream("G:/Javatest/桌面壁纸.jpg");
        // 创建一个输出的字节流：将文件写出到目标位置
        outputStream = new FileOutputStream("G:/image.jpg");

        /**
         * 通过输入字节流，一边读取数据，再通过输出字节流一边写数据 read(byte []
         * b):表示可以读取输入字节流中的数据，并返回读取到的字节数，若返回-1则表示读取完成。
         * 为了提高读取效率，可以传入一个byte数组作为缓冲区，否则一次只能读取一个字节，效率太低
         */
        // 创建一个缓冲区
        byte[] buffer = new byte[2048];
        
        try {
            while (inputStream.read(buffer) != -1) {
                outputStream.write(buffer);
                System.out.println(buffer);
            }
            System.out.println("复制成功");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                inputStream.close();
            }
            if (outputStream != null) {
                outputStream.close();
            }

        }
    }    

        InputStream inputStream = null;
    OutputStream outputStream = null;   

    /**
     * 案例2：通过字符流完成文件复制，只能是文本操作。
     */
    @Test
    public void testCopyWithChar() {
        Reader reader = null;
        BufferedReader bufferedReader = null;
        
        Writer writer = null;
        BufferedWriter bufferedWriter = null; 
        
        
        try {
            /**
             * 在Java中不管是文件名、路径、路径加文件名，通通都是用File类型表示
             */
            
            /*
             * //判断以上的路径是否不存在就把他创建出来
             * File file = File("G:/Javatest");
            if (!file.exists()) {
                file.mkdirs();
            }*/
            
            File file =  new File("G:/Javatest/java代码.txt");
            reader = new FileReader(file);
            bufferedReader = new BufferedReader(reader);
            writer = new FileWriter("G:/java.txt");
            bufferedWriter = new BufferedWriter(writer);
            /**
             * readLine():返回值是String，即读取到一行字符串
             * 若读取完成则返回null
             */
            String str;
            while((str = bufferedReader.readLine()) != null) {
                bufferedWriter.write(str + "\r\n");
                System.out.println(str);
            }
            System.out.println("复制完成");
            
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (bufferedWriter != null) {
                    bufferedWriter.close();
                }
                if (writer != null) {
                    writer.close();
                }
                if (bufferedReader != null) {
                    bufferedReader.close();
                }
                if (reader != null) {
                    reader.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    } 

package com.oop.ch12;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;

import org.junit.Test;

import com.oop.entity.Grade;


/**
 * 练习序列化和反序列化的两个过程
 * @author zhangzimu
 *
 *Java中有4中创建对象的方式
 *
 */
public class SerializableTest {
    Grade grade = null;
    OutputStream outputStream = null;
    ObjectOutputStream objectOutputStream  = null;
    /**
     * 序列化：将该类的“对象”保存到外存的过程，若属性使用transient（瞬时、临时的）关键字修饰，表示该属性不需要序列化（持久化）。
     * 前提是类必须实现Serializable接口
     * @throws IOException 
     */
    
    @Test
    public void test1(){
        
        try {
            grade = new Grade();
            grade.setGradeId(6);
            grade.setGradeName("六年级");
            
            outputStream = new FileOutputStream("G:/Javatest/grade.txt");
            objectOutputStream = new ObjectOutputStream(outputStream);
            objectOutputStream.writeObject(grade);
            System.out.println("序列化完成");
            
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (objectOutputStream != null) {
                    objectOutputStream.close();
                }
                if (outputStream != null) {
                    outputStream.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
    
    /**
     * 反序列化：将保存了某个类的数据读取出来创建对象的过程。
     */
    @Test
    public void test2() {
        InputStream inputStream = null;
        ObjectInputStream objectInputStream = null;
        try {
            inputStream = new FileInputStream("G:/Javatest/grade.txt");
            objectInputStream = new ObjectInputStream(inputStream);
            Grade grade =  (Grade) objectInputStream.readObject();
            System.out.println("反序列化完成:" + grade);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                if (objectInputStream != null) {
                    objectInputStream.close();
                }
                if (inputStream != null) {
                    inputStream.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
    }
}