InputStream.read(byte[] b)

从输入流中读取一定数量的字节，并将其存储在缓冲区数组 b 中。

OutputStream.write(byte[] b)

将 b.length 个字节从指定的 byte 数组写入此输出流。

PrintWriter(Writer out)

创建不带自动行刷新的新 PrintWriter。

String urlPath="";URL url=new URL(urlPath);

HttpURLConnectioncoon=

(HttpURLConnection)url.openConnection();

字符流->字节流：

String s=”asasaa”;

printWriter pw=new printWrite(conn.getoutputStream);

Pw.print(s);           pw.flush();

byte[] s= str.getBytes();

字节流->字符流：

bufferedReader br=new bufferedRead(new inputStreamReader(conn.getinputStream);

String result=””;

While(String line=br.readLine()!=null){result+=line;}

InputStreamReader(new inputstream())

通常 Writer 将其输出立即发送到底层字符或字节流。除非要求提示输出，否则建议用 BufferedWriter 包装所有其 write() 操作可能开销很高的 Writer(如 FileWriters 和 OutputStreamWriters)。例如，

PrintWriter out

= new PrintWriter(new BufferedWriter(new FileWriter("foo.out")));

同理：BufferedReader in

= new BufferedReader(new FileReader("foo.in"));

1.字节流和字符流之间的转换

字节流转换成字符流可以用InputSteamReader/OutputStreamWriter相互转换.

输出字符流

OutputStream out = System.out;//打印到控制台。

OutputStream out = new FileOutputStream("D:\\demo.txt");//打印到文件。

OutputStreamWriter osr = new OutputStreamWriter(out);//输出

BufferedWriter bufw = new BufferedWriter(osr);//缓冲

String str = "你好吗？\r\n我很好！";//你好吗？

bufw.write(str);

bufw.flush();

bufw.close();

读取字节流

InputStream in = System.in;//读取键盘的输入。

InputStream in = new FileInputStream("D:\\demo.txt");//读取文件的数据。

//将字节流向字符流的转换。要启用从字节到字符的有效转换，可以提前从底层流读取更多的字节.

InputStreamReader isr = new InputStreamReader(in);//读取

char []cha = new char[1024];

int len = isr.read(cha);

System.out.println(new String(cha,0,len));

isr.close();

2.怎么把字符串转为流. 下面的程序可以理解把字符串line 转为流输出到aaa.txt中去

FileOutputStream fos = null;

fos = new FileOutputStream("C:\\aaa.txt");

String line="This is 1 line";

fos.write(line.getBytes());

fos.close();

字符串与字节流转换

static String src = "今天的天气真的不好";

public static void main(String[] args) throws IOException {

StringBuilder sb = new StringBuilder();

byte[] buff = new byte[1024];

//从字符串获取字节写入流

InputStream is = new ByteArrayInputStream(src.getBytes("utf-8"));

int len = -1;

while(-1 != (len = is.read(buff))) {

//将字节数组转换为字符串

String res = new String(buff, 0, len);

Sb.append(res);}

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作者：ChampionDragon

来源：CSDN

原文：https://blog.csdn.net/xxdw1992/article/details/81168917

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