response讀取圖片+下載圖片

讀取圖片

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.URLEncoder;

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


public class OutServlet extends HttpServlet {


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

                  String url = this.getContext().getRealPath("test.jpg");
                  InputStream in = new FileInputStream(url);
                  OutputStream out = response.getOutputStream();
		  byte [] by = new by[1024];
                  int i = 0;
                  while((i=in.read(by))!=-1)
                 {
                      
                         out.write(by,0,i);

                  }
                   in.close();
	
	}


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

		doGet(request,response);
	}

}
                      

　下載圖片

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.URLEncoder;

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


public class OutServlet extends HttpServlet {


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

//寫入請求頭下載圖片文件
            
 responst.setHeader("Content-Disposition","attachment;filename=test.jpg");

   
    
		
	}


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

		doGet(request,response);
	}

}

　

可以使用

URLEncoder.encode("String","utf-8");   把一個String轉成UTF-8

URLDecoder.decode("String","utf-8");   把一個String 解析成UTF-8

可以使用上面方法來給圖片文件設置名稱，

response.setHeader("Content-Dispostion","attachment;filename="+URLEncoder.encoder("測試.jpg","utf-8"));

 

常用的幾種response輸出數據格式(不亂碼)

　　　①

　　　　　　response.setContentType("text/html;charset=utf-8");    // 告訴用UTF-8解析

　　　　　　response.setCharacterEncoding("utf-8");    // 告訴服務器用UTF-8 解析

　　　　　　response.getWriter().write("中國");

　　　

　　　②

　　　　　　response.setContenType("text/html;charset=utf-8");  // 告訴用UTF-8解析

　　　　　　response.getOutputStream().write("中國".getBytes("UTF-8"));  // 瀏覽器用UTF-8解析

　　　

　　　③

　　　　　  response.getOutputStream().write("中國".getBytes());     //按照瀏覽器默認的編碼解析

 

　　　　　　　　　　日期:2018/05/21