java_IO_3

Reader和Writer针对字符文件  对图片类文件可能就显得无能为力了  会损坏文件

package ioStudy;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;

/*
1.创建源
2.选择流
3.操作
4.释放资源
*/
public class IOstudy5 {
    public static void main(String[] args) {
        File file = new File("test.txt");
        //针对字符文件
        Reader reader = null;
        try {
            reader = new FileReader(file);
            char[] buffer = new char[1024];
            int len;
            while ((len = reader.read(buffer)) != -1) {    //一次读取多个
                String s = new String(buffer,0,len);
                System.out.print(s);
            }
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }finally {
            if(reader!=null) {
                try {
                    reader.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}

package ioStudy;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.io.IOException;
import java.io.Writer;

/*
1.创建源
2.选择流
3.操作
4.释放资源
*/
public class IOstudy6 {
    public static void main(String[] args) {
        File file = new File("output.txt"); // 不存在会自动创建
        Writer writer = null;

        try {
            writer = new FileWriter(file,true);  //开启向后追加  不然每次都删掉原来的 再写  默认的是false
            String temp = "hello world!
哈哈哈哈，测试中文可以用嘛";
//            byte[] b = temp.getBytes();
            writer.write(temp);
            writer.flush();   //刷新内存
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            if (writer != null) {
                try {
                    writer.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}