FileOutPutStream:子类,写出数据的通道
步骤:
1.获取目标文件
2.创建通道(如果原来没有目标文件,则会自动创建一个)
3.写入数据 write()
4.释放资源
注意:
(1)如果目标文件不存在,那么会自己创建一个目标文件
(2)如果目标文件存在,先将里面的数据清空,再写入数据
(3)想在原有的数据上写入数据,则在创建通道的时候使用 构造方法:
OutPutStream(File file,Boolean append),boolean值为true则可以
(4)用 write(int a)方法写入数据,虽然接收的是int,但实际上只有一个字节的数据
(操作的是低八位的,其他的全部丢掉)
//会自动导入一些包 import java.io.File; import java.io.FileOutputStream; import java.io.IOException;
//方式一 public static void writeData() throws IOException{ //1.找目标文件 File file = new File("C:\\Users\\bigerf\\Desktop\\文件夹\\writeTest.java"); //2.创建一个通道 FileOutputStream outputStream = new FileOutputStream(file); //3.开始写入数据, int a = 10; // int 型 4个字节 outputStream.write(a); //注意这里每次只能输出一个字节 outputStream.write('b'); // char 类型 outputStream.write(5); // 0000-0000 0000-0000 0000-0001 1111-1111 == 511 int b = 511 ; //大于八位(9位) outputStream.write(b); //实际结果 255,但没有显示 int c = 63; //小于八位(6位) outputStream.write(c); //乱码 //4.关闭资源 outputStream.close(); }
//方式二 public static void writeData2() throws IOException{ //1.找目标文件 File file = new File("C:\\Users\\bigerf\\Desktop\\文件夹\\writeTest2.java"); //2.创建一个通道,(如果不存在路径中的文件,则会在这一步创建的文件) //new FileOutputStream(file,true); /true表示在原来文本的基础上写入文本(反之则会先清空再写入) FileOutputStream outputStream = new FileOutputStream(file,true); //3.创键一个字节数组 String str = "hello word"; //将字符串变为字节数组 byte[] b = str.getBytes(); //4.写入数据 outputStream.write(b); //hello word //5.关闭资源 outputStream.close(); }
陌陌说:
输入流与输出流可以实现对文件的拷贝,不妨试着实现
(先将路径文件的数据拷贝写入到字节数组,再从字节数组写出道路径文件)
更多java IO流 之 输出流 OutputString()的使用相关文章请关注PHP中文网!

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