一、目标
1.用Filter模拟处理Request、Response
2.思路细节技巧：
(1)Filter的doFilter方法改为doFilter(Request,Resopnse,FilterChain),有FilterChain引用，为利用FilterChain调用下一个Filter做准备
(2)FilterChain继承Filter,这样，FilterChain既是FilterChain又是Filter,那么FilterChain就可以调用Filter的方法doFilter(Request,Resopnse,FilterChain)
(3)FilterChain的doFilter(Request,Resopnse,FilterChain)中，有index标记了执行到第几个Filter,当所有Filter执行完后request处理后，就会return,以倒序继续执行response处理
二、代码
1.Filter.java
2.HTMLFilter.java
3.SensitiveFilter.java
4.FilterChian.java
5.Request.java
6.Response.java
7.Test.java
1.Filter.java
1 public interface Filter {
2 public void doFilter(Request request, Response response, FilterChain filterChain);
3 }
2.HTMLFilter.java
1 public class HTMLFilter implements Filter {
2
3 @Override
4 public void doFilter(Request request, Response response,
5 FilterChain filterChain) {
6 request.setRequestStr(request.getRequestStr().replace(‘<‘, ‘[‘).replace(">", "]")+"---HTMLFilter()");
7 filterChain.doFilter(request, response, filterChain);
8 response.setResponseStr(response.getResponseStr()+"---HTMLFilter()");
9 }
10
11 }
3.SensitiveFilter.java
1 public class SensitiveFilter implements Filter {
2
3 @Override
4 public void doFilter(Request request, Response response,
5 FilterChain filterChain) {
6 request.setRequestStr(request.getRequestStr().replace("敏感", "幸福")+"---SensitiveFilter()");
7 filterChain.doFilter(request, response, filterChain);
8 response.setResponseStr(response.getResponseStr()+"---SensitiveFilter()");
9 }
10
11 }
4.FilterChian.java
1 public class FilterChain implements Filter {
2
3 private List<Filter> filters = new ArrayList<Filter>();
4 int index = 0; //标记执行到第几个filter
5
6 //把函数的返回值设为FilterChain，返回this,就能方便链式编写代码
7 public FilterChain addFilter(Filter filter) {
8 filters.add(filter);
9 return this;
10 }
11
12 public void doFilter(Request request, Response response, FilterChain fc) {
13 if(index == filters.size()) return ;
14 Filter f = filters.get(index);
15 index++;
16 f.doFilter(request, response, fc);
17 }
18
19 }
5.Request.java
1 public class Request {
2
3 private String requestStr;
4
5 public String getRequestStr() {
6 return requestStr;
7 }
8
9 public void setRequestStr(String requestStr) {
10 this.requestStr = requestStr;
11 }
12
13 }
6.Response.java
1 public class Response {
2
3 private String responseStr;
4
5 public String getResponseStr() {
6 return responseStr;
7 }
8
9 public void setResponseStr(String responseStr) {
10 this.responseStr = responseStr;
11 }
12
13 }
7.Test.java
1 public class Test {
2
3 @org.junit.Test
4 public void testFilter(){
5
6 String msg = "<html>敏感字眼</html>";
7
8 Request request = new Request();
9 request.setRequestStr(msg);
10 Response response = new Response();
11 response.setResponseStr("response------------");
12
13 FilterChain fc = new FilterChain();
14 fc.addFilter(new HTMLFilter()).addFilter(new SensitiveFilter());
15
16 fc.doFilter(request, response, fc);
17 System.out.println(request.getRequestStr());
18 System.out.println(response.getResponseStr());
19
20 }
21
22 }
三、执行结果
时间： 2024-05-11 13:04:08