Java小知识集结号

import static java.lang.System.out; 为什么要加上static关键字？

import static 是静态导入，是jdk1.5的新特征,可以不同过调用包名，直接使用包里的静态方法。
举个例子来说：
用import的情况：
public static void main(String args[]){
       System.out.println("输出内容");
}
用import static 的情况：
import static java.lang.System.out;
public static void main(String args[]){
       out.println("输出内容");
}

两者的输出情况是一样的。

Data Sink vs Processing
 Data sink stream: Acutal IO is performed
 FileReader, CharArrayReader, PipedReader, StringReader
 FileWriter, CharArrayWriter, PipedWriter, StringWriter
 FileInputStream, PipedInputStream, ByteArrayInputStream,
StringBufferInputStream
 FileOutputStream, PipedOutputStream, ByteArrayOutputStream
 Processing stream: Wrapping or connecting another stream for
processing
 BufferedReader, LineNumberReader, InputStreamReader,
FilterReader, PushbackReader
 BufferedWriter, OutputStreamWriter, FilterWriter
 FilterInputStream, LineNumberInputStream,DataInputStream,
BufferedInputStream,PushbackInputStream, ObjectInputStream
 FilterOutputStream, DataOutputStream,
BufferedOutputStream,PrintStream, ObjectOutputStream

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