Response-響應頭、自定義重定向、文字\IO輸出、檔案下載
阿新 • • 發佈：2019-01-10
設定響應頭
package com.itheima.header;
import java.io.IOException;
import java.util.Date;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HeaderServlet extends HttpServlet 設定響應頭，重定向請求
package com.itheima.header;
import java.io.IOException;
import javax.servlet.ServletException;
import 設定響應頭，5秒跳轉
package com.itheima.header;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class RefreshServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//設定定時重新整理的頭
response.setHeader("refresh", "5;url=http://www.baidu.com");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}Response文字輸出
package com.itheima.content;
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 TextServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//設定response查詢的碼錶
//response.setCharacterEncoding("UTF-8");
//通過一個頭 Content-Type 告知客戶端使用何種碼錶
//response.setHeader("Content-Type", "text/html;charset=UTF-8");
//以下一行程式碼即可解決
response.setContentType("text/html;charset=UTF-8");
PrintWriter writer = response.getWriter();
//writer.write("hello response!!!");
writer.write("你好");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}Response IO輸出
package com.itheima.content;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ByteServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//使用response獲得位元組輸出流
ServletOutputStream out = response.getOutputStream();
//獲得伺服器上的圖片
String realPath = this.getServletContext().getRealPath("a.jpg");
InputStream in = new FileInputStream(realPath);
int len = 0;
byte[] buffer = new byte[1024];
while((len=in.read(buffer))>0){
out.write(buffer, 0, len);
}
in.close();
out.close();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}圖片a.jpg的位置如下：
Response 檔案下載
<a href="/WEB14/downloadServlet?filename=a.flv">a.flv</a><br>
<a href="/WEB14/downloadServlet?filename=a.jpg">a.jpg</a><br>
<a href="/WEB14/downloadServlet?filename=a.mp3">a.mp3</a><br>
<a href="/WEB14/downloadServlet?filename=a.mp4">a.mp4</a><br>
<a href="/WEB14/downloadServlet?filename=a.txt">a.txt</a><br>
<a href="/WEB14/downloadServlet?filename=a.zip">a.zip</a><br>
<a href="/WEB14/downLoadServlet2?filename=美女.jpg">美女.jpg</a><br>
package com.itheima.content;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URLEncoder;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import sun.misc.BASE64Encoder;
public class DownLoadServlet2 extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//*******檔名稱是中文的下載*******
//獲得要下載的檔案的名稱
String filename = request.getParameter("filename");//????.jpg
//解決獲得中文引數的亂碼----下節課講
filename = new String(filename.getBytes("ISO8859-1"),"UTF-8");//美女.jpg
//獲得請求頭中的User-Agent
String agent = request.getHeader("User-Agent");
//根據不同瀏覽器進行不同的編碼
String filenameEncoder = "";
if (agent.contains("MSIE")) {
// IE瀏覽器
filenameEncoder = URLEncoder.encode(filename, "utf-8");
filenameEncoder = filenameEncoder.replace("+", " ");
} else if (agent.contains("Firefox")) {
// 火狐瀏覽器
BASE64Encoder base64Encoder = new BASE64Encoder();
filenameEncoder = "=?utf-8?B?"
+ base64Encoder.encode(filename.getBytes("utf-8")) + "?=";
} else {
// 其它瀏覽器
filenameEncoder = URLEncoder.encode(filename, "utf-8");
}
//要下載的這個檔案的型別-----客戶端通過檔案的MIME型別去區分型別
response.setContentType(this.getServletContext().getMimeType(filename));
//告訴客戶端該檔案不是直接解析 而是以附件形式開啟(下載)----filename="+filename 客戶端預設對名字進行解碼
response.setHeader("Content-Disposition", "attachment;filename="+filenameEncoder);
//獲取檔案的絕對路徑
String path = this.getServletContext().getRealPath("download/"+filename);
//獲得該檔案的輸入流
InputStream in = new FileInputStream(path);
//獲得輸出流---通過response獲得的輸出流 用於向客戶端寫內容
ServletOutputStream out = response.getOutputStream();
//檔案拷貝的模板程式碼
int len = 0;
byte[] buffer = new byte[1024];
while((len=in.read(buffer))>0){
out.write(buffer, 0, len);
}
in.close();
//out.close();
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}