Servlet 3.0过滤器Filter

Servlet：

其中：

filterName：即以前web.xml中的filter-name。

urlPatterns：访问路径，即web.xml中的filter-mapping->url-pattern

initParams :初始化参数，等价于web.xml的init-param节点。name=>param-name>,value=>param-value

[code=language-java]/**
* 字符过滤
*/
@WebFilter(filterName = "/WordFilter", urlPatterns = "/*", initParams = {
@WebInitParam(name = "encoding", value = "UTF-8"), @WebInitParam(name = "words", value = "日,次奥,靠,艹,尼玛,呵呵") })
public class WordFilter implements Filter {

private String Encoding;
private String[] words;

/**
* Default constructor.
*/
public WordFilter() {
}

/**
* @see Filter#destroy()
*/
public void destroy() {
}

/**
* @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain)
*/
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws IOException, ServletException {
if (null != this.Encoding && this.Encoding != "") {
request.setCharacterEncoding(Encoding);
request = new MyWordsRequest((HttpServletRequest) request);
response.setContentType("text/html;" + Encoding);
}
chain.doFilter(request, response);
}

/**
* 文字过滤
*
* @param value
*            原始文字
* @return 返回过滤后的文字
*/
private String filter(String value) {
try {
if (null != this.words && this.words.length > 0) {
for (int i = 0; i < words.length; i++) {
if (value.contains(this.words[i])) {
value = value.replaceAll(this.words[i], "**");
}
}
}

} catch (Exception err) {
err.printStackTrace();
}
return value;
}

/**
* 初始化
*/
public void init(FilterConfig fConfig) throws ServletException {
System.out.println("WordFilter..");
Encoding = fConfig.getInitParameter("encoding");
String wordStr = fConfig.getInitParameter("words");
if (null != wordStr && wordStr != "") {
this.words = wordStr.split(",");
}
System.out.println(this.Encoding + "--" + this.words);
}

class MyWordsRequest extends HttpServletRequestWrapper {

public MyWordsRequest(HttpServletRequest request) {
super(request);
}

@Override
public String getParameter(String name) {
return filter(super.getRequest().getParameter(name));
}

@Override
public String[] getParameterValues(String name) {
String[] values = super.getRequest().getParameterValues(name);
if (null != values && values.length > 0) {
for (int i = 0; i < values.length; i++) {
values[i] = filter(values[i]);
}
}
return values;
}

}

}

JSP：

[code=language-html]<form action="MessageServlet" method="post">
<table border="0" width="500" align="center">
<tr>
<td align="right">内 容：</td>
<td><textarea rows="5" cols="40" name="content"></textarea></td>
</tr>
<tr>
<td align="center" colspan="2"><input type="submit"
value="提 交"></td>
</tr>
</table>
</form>

MessageServlet:

[code=language-java]
@WebServlet("/MessageServlet")
public class MessageServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**
* @see HttpServlet#HttpServlet()
*/
public MessageServlet() {
super();
// TODO Auto-generated constructor stub
}

/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doPost(request, response);
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String title = request.getParameter("title");
String content =request.getParameter("content");
request.setAttribute("title", title);
request.setAttribute("content", content);
request.getRequestDispatcher("zuoye1.jsp").forward(request, response);
}

}

效果：



结果：