1.中文乱码过滤器。
get和set中文字体的设置
public class AllCharacterEncodingFilter implements Filter {
private FilterConfig filterConfig;
public void init(FilterConfig filterConfig) throws ServletException {
this.filterConfig = filterConfig;
}
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)req;
HttpServletResponse response = (HttpServletResponse)resp;
//获取配置的过滤器參数encoding的值：假设没有。给定一个默认值
String encoding = filterConfig.getInitParameter("encoding");
if(encoding==null)
encoding = "UTF-8";
//设置POST请求方式的中文请求參数的编码
request.setCharacterEncoding(encoding);
//设置响应输出时的编码：字符流和字节流
response.setCharacterEncoding(encoding);//字节流输出时通知client的解码码表
response.setContentType("text/html;charset="+encoding);//字节流输出时通知client的解码码表；字符流：字符流输出时使用的码表及通知client解码用的码表
MyHttpServletRequest mrequest = new MyHttpServletRequest(request);
//放行
chain.doFilter(mrequest, response);
}
public void destroy() {
}
}
//使用包装类设计模式
//HttpServletRequestWrapper内部的代码与连接池原理中那个默认适配器一样
class MyHttpServletRequest extends HttpServletRequestWrapper{
public MyHttpServletRequest(HttpServletRequest request){
super(request);
}
//仅仅对get请求方式进行改写
public String getParameter(String name) {
String value = super.getParameter(name);
if(value==null)
return value;
//得到请求方式
String method = super.getMethod();
if("get".equalsIgnoreCase(method)){
try {
value = new String(value.getBytes("ISO-8859-1"),super.getCharacterEncoding());
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
return value;
}
}2.脏话过滤器
public class DirtyWordsFilter implements Filter {
public void destroy() {
}
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)req;
HttpServletResponse response = (HttpServletResponse)resp;
DirtyWordsHttpServletRequest drequest = new DirtyWordsHttpServletRequest(request);
chain.doFilter(drequest, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
}
}
class DirtyWordsHttpServletRequest extends HttpServletRequestWrapper{
private String words[] = {"傻B","畜生","禽兽"};
public DirtyWordsHttpServletRequest(HttpServletRequest request){
super(request);
}
@Override
public String getParameter(String name) {
String value = super.getParameter(name);
if(value==null)
return "木有";
for(String dword:words){
if(value.contains(dword)){//推断用户输入的内容中包括脏话
value = value.replace(dword, "**");
}
}
return value;
}
}3. HTML特殊标记过滤器
//HTML标记过滤器：< <
public class HtmlFilter implements Filter {
public void destroy() {
}
public void doFilter(ServletRequest req, ServletResponse resp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request = (HttpServletRequest)req;
HttpServletResponse response = (HttpServletResponse)resp;
HtmlHttpServletRequest hrequest = new HtmlHttpServletRequest(request);
chain.doFilter(hrequest, response);
}
public void init(FilterConfig filterConfig) throws ServletException {
}
}
class HtmlHttpServletRequest extends HttpServletRequestWrapper{
public HtmlHttpServletRequest(HttpServletRequest request){
super(request);
}
@Override
public String getParameter(String name) {
String value = super.getParameter(name);
if(value==null)
return value;
value = htmlFilter(value);//完毕标记过滤
return value;
}
private String htmlFilter(String message) {
if (message == null)
return (null);
char content[] = new char[message.length()];
message.getChars(0, message.length(), content, 0);
StringBuffer result = new StringBuffer(content.length + 50);
for (int i = 0; i < content.length; i++) {
switch (content[i]) {
case '<':
result.append("<");
break;
case '>':
result.append(">");
break;
case '&':
result.append("&");
break;
case '"':
result.append(""");
break;
default:
result.append(content[i]);
}
}
return (result.toString());
}
}
web.xml中配置
<filter> <filter-name>AllCharacterEncodingFilter</filter-name> <filter-class>cn.itcast.filter.AllCharacterEncodingFilter</filter-class> <init-param> <param-name>encoding</param-name> <param-value>GBK</param-value> </init-param> </filter> <filter-mapping> <filter-name>AllCharacterEncodingFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter> <filter-name>DirtyWordsFilter</filter-name> <filter-class>cn.itcast.filter.DirtyWordsFilter</filter-class> </filter> <filter-mapping> <filter-name>DirtyWordsFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter> <filter-name>HtmlFilter</filter-name> <filter-class>cn.itcast.filter.HtmlFilter</filter-class> </filter> <filter-mapping> <filter-name>HtmlFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter>