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java NIO知多少

背景

Linux系统中的IO操作内部相当复杂,下面是一张带图片的LinuxIO相关层级关系:

java NIO知多少

下面是一个简化版本Linux内部IO层级图:

java NIO知多少

对此我的理解,java程序员版本的IO理解:

java NIO知多少

java中的IO

从最早bio的只支持阻塞的bio(同步阻塞)

到默认阻塞支持非阻塞nio(同步非阻塞+同步阻塞)

再到aio(异步非阻塞)

NIO

FileChannel：从文件读取数据的
DatagramChannel：读写UDP网络协议数据
SocketChannel：读写TCP网络协议数据
ServerSocketChannel：可以监听TCP连接

示例代码: socket https://github.com/victorsheng/verification-everything/tree/master/io/src/main/java/socket/nio file https://github.com/victorsheng/verification-everything/tree/master/io/src/main/java/file/nio

AIO

示例代码: socket https://github.com/victorsheng/verification-everything/tree/master/io/src/main/java/socket/aio file https://github.com/victorsheng/verification-everything/tree/master/io/src/main/java/file/aio

NIO的应用

作为jdk的基础类库,被很多应用使用了,此处列举了几个常见的

NIO的应用例子1:tomcat

java NIO知多少

http://tomcat.apache.org/tomcat-9.0-doc/config/http.html#Connector_Comparison

NIO的应用例子2:jetty

Prior to Jetty 9, the type of the connector reflected both the protocol supported (HTTP, HTTPS, AJP, SPDY), and the nature of the implementation (NIO or BIO). From Jetty 9 onwards there is only one prime Connector type (ServerConnector), which is NIO based and uses Connection Factories to handle one or more protocols.

https://www.eclipse.org/jetty/documentation/9.4.x/quickstart-config-what.html#intro-jetty-configuration-connectors