內存流（數組流）：

　　把數據先臨時存在數組中，待會再從數組中獲取出來。

　　1. 字節內存流：ByteArrayInputStream/ByteArrayOutputStream

　　2. 字符內存流：CharArrayInputStream/CharArrayOutputStream

　　3. 字符串流：StringReader/StringWriter（把數據存放在數組中）

字節內存流：

public class ByteArrayDemo {
    public static void main(java.lang.String[] args) throws Exception {
        
 
//字節數組輸出流：程序到內存
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        bos.write("ABCD".getBytes());
        //使用存儲的臨時數據
        byte[] buffer = bos.toByteArray();

        //字節數組輸入流：內存到程序
        ByteArrayInputStream bis = new ByteArrayInputStream(buffer);
        byte[] bys = new byte[1024];
        
 
int len = -1;
        while ((len = bis.read(bys)) != -1) {
            System.out.print(new java.lang.String(bys,0,len));
        }
        bos.close();
        bis.close();
    }
}

字符數組流：與字節操作大致相同。

字符串流：

 1 public class StringWriterReaderDemo {
 2     public static void main(String[] args) throws
 
 IOException {
 3         //字符串的輸出流
 4         StringWriter stringWriter = new StringWriter();
 5         stringWriter.write("你多大了？");
 6         stringWriter.write("21歲！");
 7 
 8         //字符串的輸入流
 9         StringReader stringReader = new StringReader(stringWriter.toString());
10         char[] buffer = new char[1024];
11         int len = -1;
12         while((len = stringReader.read(buffer)) != -1){
13             System.out.println(new String(buffer,0,len));
14         }
15     }
16 }

Java核心類庫-IO-字節數組流/內存流