【HTTP协议】HTTP请求、请求头、HTTP响应、状态吗、响应头、使用响应头编程

1、HTTP请求：

除了表单请求可以设置为post请求请求方式，其余全是get请求方式

2、HTTP请求头

3、HTTP响应

4、HTTP状态码

5、HTTP响应头

6、使用响应头编写程序

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.zip.GZIPOutputStream;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class MyServlet extends HttpServlet
{

	public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException
	{
		test5(response);
	}

	public void test5(HttpServletResponse response) throws IOException
	{
		//使用响应头设置浏览器以下载的方式打开
		response.setHeader("content-disposition","attachment:filename=mm.png");
		
		InputStream inputStream= this.getServletContext().getResourceAsStream("/mm.png");
		int len=0;
		byte[] buffer=new byte[1024];
		
		OutputStream outputStream=response.getOutputStream();
		while((len=inputStream.read(buffer))!=-1){
			outputStream.write(buffer, 0, len);
		}
		
		inputStream.close();
	}

	public void test4(HttpServletResponse response) throws IOException
	{
		//每隔3秒钟刷新
//		response.setHeader("refresh","3");
		//3秒钟跳往百度
		response.setHeader("refresh","3;url='http://www.baidu.com'");
		test3(response);
	}

	public void test3(HttpServletResponse response) throws IOException
	{
		//使用响应头设置浏览器打开方式，查conf目录下的web.xml文件,不同的格式打开方式不同
		response.setHeader("content-type","image/png");
		
		InputStream inputStream= this.getServletContext().getResourceAsStream("/mm.png");
		int len=0;
		byte[] buffer=new byte[1024];
		
		OutputStream outputStream=response.getOutputStream();
		while((len=inputStream.read(buffer))!=-1){
			outputStream.write(buffer, 0, len);
		}
		
		inputStream.close();
	}

	public void test2(HttpServletResponse response) throws IOException
	{
		String data="aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa";
		System.out.println(data.getBytes().length);
		
		ByteArrayOutputStream arrayOutputStream=new ByteArrayOutputStream();
		
		GZIPOutputStream gzipOutputStream=new GZIPOutputStream(arrayOutputStream);
		gzipOutputStream.write(data.getBytes());
		gzipOutputStream.flush();
		gzipOutputStream.close();
		
		byte[] gzip=arrayOutputStream.toByteArray();
		System.out.println(gzip.length);
		
		//使用响应头压缩
		response.setHeader("Content-Encoding","gzip");
		response.setHeader("Content-Length",gzip.length+"");
		response.getOutputStream().write(gzip);
	}

	public void test1(HttpServletResponse response)
	{
		//使用响应头实现重定向
		response.setStatus(302);
		response.setHeader("location","/HelloJavaWeb/index.jsp");
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException
	{

	}

}