一个简单的实现跨域的 servlet

淡淡的烟草味﹌ 2022-03-18 05:48 257阅读 0赞

先看一下整体的目录结构：  
![在这里插入图片描述][2019021916360242.]

//ConnServer.java
    package oa.com.cn;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /** * 短链接，判断复印机和服务器是否在线。mfp请求 * * @author admin * */
    public class ConnServer extends HttpServlet { 
    
    	/** * */
    	private static final long serialVersionUID = 2987369059483122344L;
    
    	/** * Constructor of the object. */
    	public ConnServer() { 
    		super();
    	}
    
    	/** * Destruction of the servlet. <br> */
    	public void destroy() { 
    		super.destroy(); // Just puts "destroy" string in log
    		// Put your code here
    	}
    
    	/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    		this.doPost(request, response);
    	}
    
    	/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    		System.out.println("ok servlet 接受请求");
    		String str = "";
    		// response.addHeader("Access-Control-Allow-Origin", "*");
    		response.getWriter().println(str);
    	}
    
    	/** * Initialization of the servlet. <br> * * @throws ServletException * if an error occurs */
    	public void init() throws ServletException { 
    		// Put your code here
    	}
    
    }

//HttpServer.java
    package oa.com.cn;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /** * mfp请求 获取跳转界面 * * @author admin * */
    public class HttpServer extends HttpServlet { 
    
    	/** * */
    	private static final long serialVersionUID = 137052495915525281L;
    
    	/** * Constructor of the object. */
    	public HttpServer() { 
    		super();
    	}
    
    	/** * Destruction of the servlet. <br> */
    	public void destroy() { 
    		super.destroy(); // Just puts "destroy" string in log
    		// Put your code here
    	}
    
    	/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    
    		this.doPost(request, response);
    	}
    
    	/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    		// if (true) { 
    
    		StringBuffer sb = new StringBuffer();
    		String line;
    		String string2 = request.getParameter("status");
    		System.out.println("string2:" + string2);
    		BufferedReader reader = request.getReader();
    		while ((line = reader.readLine()) != null)
    			sb.append(line);
    		String jbstring = sb.toString();
    		System.out.println("jbstring:" + jbstring);
    		String status = "0";
    		String[] arr = jbstring.split("&");
    		for (String str : arr) { 
    			String[] arr2 = str.split("=");
    			if (arr2[0] == "status" || "status".equals(arr2[0])) { 
    				status = arr2[1];
    			}
    
    		}
    		if ("0".equals(status)) { 
    			System.out.println("conn servlet 接受请求");
    			String str = "{\"result\":\"OK\",\"url\":\"http://192.168.xx.xx:8090/xeroxmfp/index5.html\"}";
    			// String str = "{\"result\":\"OK\",\"url\":\"http://baidu.com\"}";
    			System.out.println(str);
    			response.setHeader("Connection", "keep-alive");
    			response.getWriter().println(str);
    		} else { 
    			response.getWriter().println("{\"result\":\"OK\"}");
    		}
    
    		// }
    	}
    
    	/** * Initialization of the servlet. <br> * * @throws ServletException * if an error occurs */
    	public void init() throws ServletException { 
    		// Put your code here
    	}
    
    }

//LicenseServer.java
    package oa.com.cn;
    
    import java.io.IOException;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    /** * mfp请求获取授权码 * * @author admin * */
    public class LicenseServer extends HttpServlet { 
    
    	/** * */
    	private static final long serialVersionUID = -2877799836073284638L;
    
    	/** * Constructor of the object. */
    	public LicenseServer() { 
    		super();
    	}
    
    	/** * Destruction of the servlet. <br> */
    	public void destroy() { 
    		super.destroy(); // Just puts "destroy" string in log
    		// Put your code here
    	}
    
    	/** * The doGet method of the servlet. <br> * * This method is called when a form has its tag value method equals to get. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */
    	public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    		this.doPost(request, response);
    	}
    
    	/** * The doPost method of the servlet. <br> * * This method is called when a form has its tag value method equals to post. * * @param request * the request send by the client to the server * @param response * the response send by the server to the client * @throws ServletException * if an error occurred * @throws IOException * if an error occurred */
    	public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    		System.out.println("license servlet 接受请求");
    		String str = "{\"result\":\"OK\",\"license\":\"8DD5-716D-15C3-xxxx\"}";
    		response.getWriter().println(str);
    	}
    
    	/** * Initialization of the servlet. <br> * * @throws ServletException * if an error occurs */
    	public void init() throws ServletException { 
    		// Put your code here
    	}
    
    }

//CorsFilter.java
    package oa.com.filter;
    
    import java.io.IOException;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletResponse;
    
    public class CorsFilter implements Filter { 
    
    	public void init(FilterConfig filterConfig) throws ServletException { 
    
    	}
    
    	public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
    			throws IOException, ServletException { 
    		HttpServletResponse httpResponse = (HttpServletResponse) servletResponse;
    		httpResponse.addHeader("Access-Control-Allow-Origin", "*");
    		httpResponse.addHeader("Access-Control-Allow-Headers", "*");
    		httpResponse.addHeader("Access-Control-Request-Headers", "*");
    		filterChain.doFilter(servletRequest, servletResponse);
    	}
    
    	public void destroy() { 
    
    	}
    }

<?xml version="1.0" encoding="UTF-8"?>
    <web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
      <display-name></display-name>
      <servlet>
        <description>This is the description of my J2EE component</description>
        <display-name>This is the display name of my J2EE component</display-name>
        <servlet-name>HttpServer</servlet-name>
        <servlet-class>oa.com.cn.HttpServer</servlet-class>
      </servlet>
      <servlet>
        <description>This is the description of my J2EE component</description>
        <display-name>This is the display name of my J2EE component</display-name>
        <servlet-name>LicenseServer</servlet-name>
        <servlet-class>oa.com.cn.LicenseServer</servlet-class>
      </servlet>
      <servlet>
        <description>This is the description of my J2EE component</description>
        <display-name>This is the display name of my J2EE component</display-name>
        <servlet-name>ConnServer</servlet-name>
        <servlet-class>oa.com.cn.ConnServer</servlet-class>
      </servlet>
    
    	<filter>
    	    <filter-name>CorsFilter</filter-name>
    	    <filter-class>oa.com.filter.CorsFilter</filter-class>
    	</filter>
    	
    	<filter-mapping>
    	    <filter-name>CorsFilter</filter-name>
    	    <url-pattern>/*</url-pattern>
    	</filter-mapping>
    
      <servlet-mapping>
        <servlet-name>HttpServer</servlet-name>
        <url-pattern>/conn</url-pattern>
      </servlet-mapping>
      <servlet-mapping>
        <servlet-name>LicenseServer</servlet-name>
        <url-pattern>/license</url-pattern>
      </servlet-mapping>
      <servlet-mapping>
        <servlet-name>ConnServer</servlet-name>
        <url-pattern>/ok</url-pattern>
      </servlet-mapping>	
      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
      </welcome-file-list>
    </web-app>

//index.html
    
    <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
    <html>
    <head>
    
    <title>My JSP 'index.jsp' starting page</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
    
    </head>
    
    <body>
    	<h1>
    		This is my JSP page. <br>
    	</h1>
    </body>
    <script type="text/javascript"> window.onload = function() { window.document.onclick = function() { window.parent.postMessage("", "*"); }; }; </script>
    </html>

可以打成war包运行。

[2019021916360242.]: /images/20220318/00b06b0e3f39487abc279098c2006f50.png