SpringBoot AsyncContext printWriter 推送数据到前端 观察者模式

 1 import java.util.arraylist;
 2 import java.util.list;
 3 import java.util.observable;
 4 
 5 import org.apache.commons.lang3.stringutils;
 6 
 7 import com.data2wisdom.res.dsmgr.common.stringutil;
 8 
 9 public class forginrelation extends observable {
10     private int total;
11     private int stepnum; //比对到第n个
12     private string relationid;
13     private int status = 0;  //比对状态    0：初始化    ,  1 ：正在比对,  2：比对完成 , 3:异常
14     
15     private list<forginrelationobj> ffos = new arraylist<>();
16     
17     
18     
19     //这里是通知观察者
20     public void addonefr(forginrelationobj relationobj) {
21         system.out.println("执行了添加操作");
22         this.ffos.add(relationobj);
23         setchanged();
24         notifyobservers();
25     }
26     

 2 
 3 import java.io.ioexception;
 4 import java.io.printwriter;
 5 import java.util.arraylist;
 6 import java.util.list;
 7 import java.util.observable;
 8 import java.util.observer;
 9 
10 import javax.servlet.asynccontext;
11 
12 import org.apache.log4j.logger;
13 
14 import com.google.gson.gson;
15 
16 public class findrelationobserver implements observer{
17     private static logger log = logger.getlogger(findrelationobserver.class);
18     private asynccontext  async;    
19     private int num ;
20     
21     public findrelationobserver(asynccontext  async,forginrelation forginrelation) {
22         super();
23         this.async = async;
24         forginrelation.addobserver(this);//添加被观察者
25     }
26 
27     @override
28     public void update(observable fr, object arg) {
29         try {
30             printwriter printwriter = null;
31             try {
32                 printwriter = async.getresponse().getwriter();
33             } catch (ioexception e) {
34                 e.printstacktrace();
35                 log.info("异步获取数据异常:"+e);    
36             }
37         　　//业务逻辑可以不看
38             forginrelation forginrelation = (forginrelation)fr;
39             list<forginrelationobj> ffos = forginrelation.getffos();
40             list<forginrelationobj> tempdata = new arraylist<>();
41             int temp = num;
42             num =  ffos.size();
43             for (int i = temp; i < num ; i++) {
44                 tempdata.add(ffos.get(i));
45             }
46             gson gson = new gson();
47             string json = gson.tojson(tempdata);
　　　　　　　　//这里是数据输出到前端， flush一下
48             printwriter.write("<script>  parent.datarender('"+json+"'); </script>");  //parent中打开， 看最后面的页面请求方式
49             printwriter.flush();
50             
51             if(forginrelation.getstatus() == 2 || forginrelation.getstatus() == 3) {
52                 printwriter.close();
53                 forginrelation.deleteobserver(this);//异步结束，移除观察者
54                 async.complete();//异步结束
55             }
56         } catch (exception e) {
57             
58             e.printstacktrace();
59         }
60     }
61 
62 }

 1 @requestmapping(value = "/result", method = { requestmethod.get })
 2     public void index(httpservletresponse response,httpservletrequest request,string relationid) {    
 3         response.setcontenttype("text/html;charset=utf-8");
 4         response.setcharacterencoding("utf-8");
 5         asynccontext async = null;
 6         printwriter writer = null;
 7         forginrelation relation = null;
 8         
 9         try {
10             async = request.startasync(request,response);
11             async.settimeout(0);  //超时设置
34             relation = relationmap.getforginrelationbyid(relationid);
35             async.addlistener(new forginrelationasynclistener());
36             async.start(new asyncresult(async, relation)); //这里由于数据传递需要实现runnable 所以包装了个对象asyncresult
39         }catch (exception e) {
40         
41             e.printstacktrace();
42             logger.info(e);
43         
44         }finally {
45             
46         } 

 1 import javax.servlet.asynccontext;
 2 
 3 public class asyncresult  implements runnable{
 4     private asynccontext  async;    
 5     
 6     private forginrelation relation;
 7     
 8     public asyncresult(asynccontext async,forginrelation relation){
 9         this.async = async;
10         this.relation = relation;
11     }
12 
13 
14     @override
15     public void run() {
16         new findrelationobserver(async, relation);
17     }

 1 <body>
 2 
 3     <div class="form-body layer-content">
 4 
 5         <div>
 6         
 7             <div style="padding:20px;">
 8                 <div class="form-group">
 9                 <!--     <h3 class="margin-bottom-10 sub">新增表</h3> -->
10                     <table class="layui-table" id="forginrelation"></table>
11                 </div>
12             </div>
13             
14         </div>
15         
16 
17     </div>
18 
19 
20     <div id="content" class="display_none" >
21         <form id="queryform" name="queryform" action="/rest/combing/findr/result" method="get">
22             <input type="text"  id="relationid" name="relationid" />
23         </form>
24     </div>
25 
26     <iframe id="datacometframe" src="" name="datacometframe" width="0" height="0" ></iframe>
　　　　 <script type="text/javascript">

　　　　　　$("#queryform").attr("target", "datacometframe");  //需要在iframe中打开
　　　　　　$("#relationid").val($("base").attr("relationid"))  //我的业务请求参数
　　　　　　$("#queryform").submit();　　　　//提交表单

　　　　　　function datarender(data){
　　　　　　　　console.log("datarender:");
　　　　　　　　console.log(data);
　　　　　　}

　　　　</script>

27 </body>