字节流，字符流通过网络输入输出--简单例子

@Controller
public class IOController {

    @GetMapping("/getString")
    public void getString(HttpServletRequest request, HttpServletResponse response) throws IOException {
       //获取输入流中的数据
        ServletInputStream in = request.getInputStream();
        int len = 0;
        byte[] b = new byte[1024];
        in.read(b);
        String str = new String(b,0,b.length);

        //通过输出流输出数据
        PrintWriter writer = response.getWriter();
        writer.println("Hello from controller");
    }
}

使用socket通信参考：
https://blog.csdn.net/sundancer_lilong/article/details/50716536