使用HttpServletResponse对象获取请求行信息

目录

• HttpServletResponse对象获取请求行信息
• 方法列表
• 实例
• HttpServletResponse和HttpServletRequest解析
• HttpServletResponse和HttpServletRequest
• HttpServletResponse

HttpServletResponse对象获取请求行信息

方法列表

String reqMethod = request.getMethod()
String reqURI=request.getRequestURI();
String reqURI=request.getRequestURI();
StringBuffer reqURL=request.getRequestURL();
String reqPath=request.getContextPath();
String queryString=request.getQueryString();
String reqClient=request.getRemoteAddr();

实例

HTML

	
	

 

	

		姓名：

		年龄：

		
	

java

package servlet; 
import java.io.IOException;
import java.io.PrintWriter; 
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
public class LineServlet extends HttpServlet { 
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 
		// 设置编码方式
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html; charset=UTF-8");
 
		// 获得PrintWriter输出对象
		PrintWriter writer = response.getWriter();		
 
		// 1、获取请求方式
		String reqMethod = request.getMethod();
		writer.write("请求方式method: " + reqMethod);
		writer.print("
");
		
		//2、获得请求的资源相关的内容
		String reqURI=request.getRequestURI();
		StringBuffer reqURL=request.getRequestURL();
		writer.write("请求内容URI: " + reqURI);
		writer.print("
");
		writer.write("请求内容URL: " + reqURL);
		writer.print("
");
		
		//获得web应用的名称
		String reqPath=request.getContextPath();
		writer.write("web应用contextPath: " + reqPath);
		writer.print("
");
		
		//地址后的参数的字符串
		String queryString=request.getQueryString();
		writer.write("参数的字符串queryString: " + queryString);
		writer.print("
");
		
		//3、获得客户机的信息---获得访问者IP地址
		String reqClient=request.getRemoteAddr();
		writer.write("客户机的信息RemoteAddr: " + reqClient); 
	}
 
	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doGet(request, response);
	} 
}

HttpServletResponse和HttpServletRequest解析

最近有这么一个诉求，我在A服务器中的java调用执行一个python文件，并将其返回值返回给B服务器的客户端。当时在想A服务器暴露一个接口，然后使用runtime API调用即可，但是返回值这块我却有点苦恼。我的本意是直接返回IO流，因为生成的数据可大可小，无规律，但是我发现这样是不可以的。

[org.springframework.http.converter.HttpMessageNotWritableException: No converter found for return value of type: class org.springframework.boot.loader.jar.JarURLConnection$2]

后来兜兜转转发现了HttpServletResponse 可以来解决这个问题。

HttpServletResponse和HttpServletRequest

Web服务器收到客户端的http请求，会针对每一次请求，分别创建一个用于代表请求的request对象、和代表响应的response对象。request和response对象即然代表请求和响应，那我们要获取客户机提交过来的数据，只需要找request对象就行了。要向客户机输出数据，只需要找response对象就行了。

本文主讲HttpServletResponse，HttpServletRequest碰到合适的场景我会将他补全。

HttpServletResponse

HttpServletResponse对象代表服务器的响应。这个对象中封装了向客户端发送数据、发送响应头，发送响应状态码的方法。

他的作用如下

1、保存流对象

使用HttpServletResponse 我们可以将IO流读出来在写入HttpServletResponse中的OutputStream中。然后别的客户端访问的时候方便获取

相关代码

   @RequestMapping(value = "/testHdf")
    @ResponseBody
    public void testHdfs(String csv, String sql, HttpServletResponse response) {
        BufferedInputStream bis = null;
        try {
            Process process = Runtime.getRuntime().exec("python  /blazingsql/testData/zgh/aaa.py");
            process.waitFor();
            bis = new BufferedInputStream(process.getInputStream());
            OutputStream os = null;
            byte[] buff = new byte[1024];
            os = response.getOutputStream();
            int i = bis.read(buff);
            while (i != -1) {
                os.write(buff, 0, buff.length);
                os.flush();
                i = bis.read(buff);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
        } finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

2、下载文件

使用HttpServletResponse可以下载文件，很方便

下载文件是，设置这些参数很重要

response.setHeader(“Content-Disposition”, “attachment;filename=”+ URLEncoder.encode(“demo.csv”, “UTF-8”));
response.setHeader(“Connection”, “close”);
response.setHeader(“Content-Type”, “application/octet-stream”);

相关代码

  @RequestMapping(value = "/download")
    @ResponseBody
    public void download(String path,HttpServletResponse response) throws UnsupportedEncodingException {
        response.reset();
        response.setHeader("Content-Disposition", "attachment;filename="+ URLEncoder.encode("demo.csv", "UTF-8"));
        response.setHeader("Connection", "close");
        response.setHeader("Content-Type", "application/octet-stream");
        OutputStream ops = null;
        FileInputStream fis =null;
        byte[] buffer = new byte[8192];
        int bytesRead = 0;
        try {
            ops = response.getOutputStream();
            fis = new FileInputStream(path);
            while((bytesRead = fis.read(buffer, 0, 8192)) != -1){
                ops.write(buffer, 0, bytesRead);
            }
            ops.flush();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if(fis != null){
                    fis.close();
                }
                if(ops != null){
                    ops.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。