filter类里写代码
包装类思想
1 package cn.itcast.filter;
2
3 import java.io.IOException;
4 import java.io.UnsupportedEncodingException;
5
6 import javax.servlet.Filter;
7 import javax.servlet.FilterChain;
8 import javax.servlet.FilterConfig;
9 import javax.servlet.ServletException;
10 import javax.servlet.ServletRequest;
11 import javax.servlet.ServletResponse;
12 import javax.servlet.http.HttpServletRequest;
13 import javax.servlet.http.HttpServletRequestWrapper;
14 import javax.servlet.http.HttpServletResponse;
15
16 public class AllCharacterEncodingFilter implements Filter {
17 private FilterConfig filterConfig;
18
19 public void init(FilterConfig filterConfig) throws ServletException {
20 this.filterConfig = filterConfig;
21 }
22 public void doFilter(ServletRequest req, ServletResponse resp,
23 FilterChain chain) throws IOException, ServletException {
24 HttpServletRequest request = (HttpServletRequest)req;
25 HttpServletResponse response = (HttpServletResponse)resp;
26 //获取配置的过滤器参数encoding的值：如果没有，给定一个默认值
27 String encoding = filterConfig.getInitParameter("encoding");
28 if(encoding==null)
29 encoding = "UTF-8";
30 //设置POST请求方式的中文请求参数的编码
31 request.setCharacterEncoding(encoding);
32 //设置响应输出时的编码：字符流和字节流
33 response.setCharacterEncoding(encoding);//字节流输出时通知客户端的解码码表
34 response.setContentType("text/html;charset="+encoding);//字节流输出时通知客户端的解码码表；字符流：字符流输出时使用的码表及通知客户端解码用的码表
35
36 MyHttpServletRequest mrequest = new MyHttpServletRequest(request);
37 //放行
38 chain.doFilter(mrequest, response);
39 }
40
41
42 public void destroy() {
43
44 }
45 }
46
47 //HttpServletRequestWrapper内部的代码与连接池原理中那个默认适配器一样
48 class MyHttpServletRequest extends HttpServletRequestWrapper{
49 public MyHttpServletRequest(HttpServletRequest request){
50 super(request);
51 }
52 //只对get请求方式进行改写
53 public String getParameter(String name) {
54 String value = super.getParameter(name);
55 if(value==null)
56 return value;
57 //得到请求方式
58 String method = super.getMethod();
59 if("get".equalsIgnoreCase(method)){
60 try {
61 value = new String(value.getBytes("ISO-8859-1"),super.getCharacterEncoding());
62 } catch (UnsupportedEncodingException e) {
63 e.printStackTrace();
64 }
65 }
66 return value;
67 }
68
69 }
70 class MyHttpServletRequest1 extends HttpServletRequestWrapper{
71 private HttpServletRequest request;
72 public MyHttpServletRequest1(HttpServletRequest request){
73 super(request);
74 this.request = request;
75 }
76 //只对get请求方式进行改写
77 public String getParameter(String name) {
78 String value = request.getParameter(name);
79 if(value==null)
80 return value;
81 //得到请求方式
82 String method = request.getMethod();
83 if("get".equalsIgnoreCase(method)){
84 try {
85 value = new String(value.getBytes("ISO-8859-1"),"UTF-8");
86 } catch (UnsupportedEncodingException e) {
87 e.printStackTrace();
88 }
89 }
90 return value;
91 }
92
93 }
动态代理类思想
1 package cn.itcast.web.bbs.mvc.filter;
2
3 import java.io.IOException;
4 import java.lang.reflect.InvocationHandler;
5 import java.lang.reflect.Method;
6 import java.lang.reflect.Proxy;
7
8 import javax.servlet.Filter;
9 import javax.servlet.FilterChain;
10 import javax.servlet.FilterConfig;
11 import javax.servlet.ServletException;
12 import javax.servlet.ServletRequest;
13 import javax.servlet.ServletResponse;
14 import javax.servlet.annotation.WebFilter;
15 import javax.servlet.http.HttpServletRequest;
16 import javax.servlet.http.HttpServletResponse;
17
18 public class EncodingFilter implements Filter {
19
20 public EncodingFilter() {
21 }
22
23 public void destroy() {
24 }
25
26 /**
27 * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
28 */
29 public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
30
31 HttpServletRequest req=(HttpServletRequest) request;
32 HttpServletResponse res=(HttpServletResponse) response;
33 RequestProxy requestProxy=new RequestProxy(req);
34 HttpServletRequest xx=requestProxy.getRequestProxy();
35 chain.doFilter(xx, response);
36 }
37
38 public void init(FilterConfig fConfig) throws ServletException {
39 }
40 }
41 class RequestProxy
42 {
43 private HttpServletRequest request;
44 public RequestProxy(HttpServletRequest request) {
45 super();
46 this.request = request;
47 }
48 //产生动态代理对象
49 public HttpServletRequest getRequestProxy()
50 {
51 return (HttpServletRequest) Proxy.newProxyInstance(RequestProxy.class
52 .getClassLoader(), request.getClass().getInterfaces(),
53 new InvocationHandler() {
54 @Override
55 public Object invoke(Object proxy, Method method,
56 Object[] args) throws Throwable {
57 Object returnValue="";
58 String methodName=method.getName();
59 if(methodName.equals("getParameter"))
60 {
61 String methodType=request.getMethod();
62 if("GET".equalsIgnoreCase((methodType)))
63 {//乱码
64 String temp = (String) method.invoke(request,args);
65 //还原
66 byte[] buf = temp.getBytes("ISO8859-1");
67 //正码
68 returnValue = new String(buf,"UTF-8");
69 }
70 else if("POST".equalsIgnoreCase(methodType))
71 {
72 request.setCharacterEncoding("UTF-8");
73 returnValue = method.invoke(request,args);
74 }
75 }
76 else
77 {
78 returnValue=method.invoke(request, args);
79 }
80 return returnValue;
81 }
82 });
83 }
84
85 }
时间： 2024-10-22 19:58:42