①手動去設置HTTP響應行中的狀態碼，這里用到了response的setStatus(int sc);這個方法

package com.itheima.line;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 StatusServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//手動去設置HTTP響應行中的狀態碼response.setStatus(1014);//這里的狀態碼設置為1014}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

建立的工程如下：

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最后的結果如下：

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②通過response設置響應頭

addHeader(String name, String value)
addIntHeader(String name, int value)
addDateHeader(String name, long date)

setHeader(String name, String value) 重點
setIntHeader(String name, int value)
setDateHeader(String name, long date)

其中，add表示添加，而set表示設置

為編輯之前的

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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 {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {Date date = new Date();//設置響應頭response.addHeader("name", "beyondyy");//若重復，則接著添加response.addHeader("name", "beyondwsq");response.addIntHeader("age", 19);response.addDateHeader("birthday", date.getTime());}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

編輯之后的結果：

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同樣的道理，add表示有相同的往后接著添加，set只保留一個，前面的會被后面的給取代。

③重定向（302）

老版

重定向：說白了就是，當你訪問servlet1時，它沒有資源，它給你說servlet2有，然后你就會再訪問servlet2。

重定向狀態碼 302

響應頭 Location （代表重定向地址）

//servlet1
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 Servlet1 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//沒有響應資源 告知客戶端去重定向到servlet2//1.設置狀態碼為302response.setStatus(302);//2.設置一個響應頭Locationresponse.setHeader("Location", "/WEB14/servlet2");}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

//servl2
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 Servlet2 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {response.getWriter().write("hello beyondsq...");}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

web.xml里面url分別設置為servlet1和servlet2

由于重定向的方法每次都那么寫麻煩，javaEE進行封裝成一個叫重定向的方法sendRedirect（url）；

封裝之后的servlet1

新版

//servlet1
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 Servlet1 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//沒有響應資源 告知客戶端去重定向到servlet2//封裝成一個重定向的方法sendRedirect(url);response.sendRedirect("/WEB14/servlet2");}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

④定時刷新（跟重定向一樣，就是多了一個時間延遲而已）

//refresh
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 {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//設置定時刷新的頭response.setHeader("refresh", "5;url=//www.baidu.com");//5s之后再跳轉到url為百度的地址}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

⑤js完成頁面的定時跳轉

案例：5秒后自動跳轉到百度

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">window.onload = function(){var time = 5;var secondEle = document.getElementById("second");var timer = setInterval(function(){secondEle.innerHTML = time;time--;if(time==0){clearInterval(timer);	location.href="http://www.baidu.com";}},1000);//1000ms表示1s變一次}
</script>
</head>
<body>恭喜你，注冊成功，<span style="color:red" id="second">5</span>秒后跳轉。如不跳轉，請點擊<a href="http://www.baidu.com">這里</a>
</body>
</html>

⑥通過response設置響應體

舊

//text
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 {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//設置response查詢的碼表response.setCharacterEncoding("UTF-8");//通過一個頭Content-Type告知客戶端使用何種碼表進行解碼response.setHeader("Context-Type", "text/html;charset=UTF-8");//文本為HTML類型，編碼為UTF-8 PrintWriter writer = response.getWriter();writer.write("原諒我這一生不羈放縱愛自由wsq");}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

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工程創建

新（進行代碼封裝之后）

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 {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//進行方法封裝之后	response.setContentType("text/html;charset=UTF-8");PrintWriter writer = response.getWriter();writer.write("原諒我這一生不羈放縱愛自由wsq");}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}

牢記這行代碼即可：

response.setContentType(“text/html;charset=UTF-8”);

⑦response的outputstream來獲得服務器上的圖片

響應頭設置字節

ServletOutputStream getOutputStream()
獲得字節流，通過該字節流的write(byte[] bytes)可以向response緩沖區中寫入字節，在由Tomcat服務器將字節內容組成Http響應返回給瀏覽器。

//byte
package com.itheima.content;import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;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 {public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//使用response獲得字節輸出流ServletOutputStream out = response.getOutputStream();//獲得服務器上的圖片String realPath = this.getServletContext().getRealPath("a.jpg");//相對地址，相對web應用的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();	}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}
}