注意：一般一个站点的所有页面的编码，包括数据库编码都要保持一致，下面默认的编码都是UTF-8
----------------------------------例1：直接提交到jsp页面----------------------------------
input_info.html
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <form action="display_info.jsp" method="post"> <!-- 输入中文来测试 --> 请输入要显示的内容：<input type="text" name="info"> <input type="submit" value="显示"> </form> </body> </html>
display_info.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> </head> <body> <!-- 注意这里并没有调用request.setCharacterEncoding()， 你把CharacterEncodingFilter关闭了试试，看看结果有什么 不一样 --> <% String str = (String) request.getParameter("info"); %> <h1><%=str%></h1> </body> </html>
CharacterEncodingFilter.java
charset参数是从web.xml中配置好的，这里读取进来
1 public final class CharacterEncodingFilter implements Filter { 2 private String encoding = null; 3 private boolean enable = false; 4 public void destroy() { 5 this.encoding = null; 6 } 7 /** 8 * 完成request.setCharacterEncoding(encoding); 9 */ 10 public void doFilter(ServletRequest request, ServletResponse response, 11 FilterChain chain) throws IOException, ServletException { 12 if (this.enable) { 13 String encoding = this.selectEncoding(request); 14 if (encoding != null && !encoding.equals("")) { 15 request.setCharacterEncoding(encoding); 16 } 17 } 18 // Pass control on to the next filter 19 chain.doFilter(request, response); 20 // After other filters are done: 21 if (this.enable) { 22 String encoding = this.selectEncoding(request); 23 if (encoding != null && !encoding.equals("")) { 24 // response.setCharacterEncoding(encoding); // 实验证明这货没起什么作用，所以，不要也行 25 } 26 } 27 } 28 /** 29 * 读取encoding参数以及enable参数，enable参数与encoding的功能无关，只是用来启用或者停用这个filter的 30 */ 31 public void init(FilterConfig filterConfig) throws ServletException { 32 this.encoding = filterConfig.getInitParameter("encoding"); 33 if (!Charset.isSupported(encoding)) { 34 encoding = null; // 如果不支持的话，只能选择默认的encoding了，这个filter就不起作用 35 } 36 // 读取enable参数 37 String enableString = filterConfig.getInitParameter("enable"); 38 if (enableString.equalsIgnoreCase("true")) { 39 this.enable = true; 40 } else { 41 this.enable = false; 42 } 43 } 44 }
web.xml
1 <filter> 2 <filter-name>charset-encoding</filter-name> 3 <filter-class>org.foo.filterdemo.CharacterEncodingFilter</filter-class> 4 <init-param> 5 <param-name>encoding</param-name> 6 <param-value>UTF-8</param-value> 7 </init-param> 8 <init-param> 9 <param-name>enable</param-name> 10 <param-value>true</param-value> 11 </init-param> 12 </filter> 13 <filter-mapping> 14 <filter-name>charset-encoding</filter-name> 15 <url-pattern>/*</url-pattern> 16 </filter-mapping>
--------例2：提交到Servlet，Serlvet再设置为request的attribute，再提交到jsp页面--------
AttributeSetterServlet.java
1 public class AttributeSetterServlet extends HttpServlet { 2 /** 3 * Generated serialVersionUID 4 */ 5 private static final long serialVersionUID = 8458482445490259121L; 6 7 @Override 8 public void doGet(HttpServletRequest req, HttpServletResponse resp) 9 throws ServletException, IOException { 10 // 在这里也没有调用request.setCharacterEncoding()， 11 // 你把CharacterEncodingFilter关闭了试试，看看结果有什么 12 // 不一样 13 String attr = req.getParameter("attr"); 14 if (attr != null) { 15 // System.out.println(this + ", " + attr); // @Debug 16 attr += " -- 这是一个小尾巴"; 17 req.setAttribute("attr", attr); 18 req.getRequestDispatcher("display_attribute.jsp").forward(req, resp); 19 } 20 } 21 @Override 22 public void doPost(HttpServletRequest req, HttpServletResponse resp) 23 throws ServletException, IOException { 24 this.doGet(req, resp); 25 } 26 }
input_attribute.html
1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2 <html> 3 <head> 4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5 <title>Insert title here</title> 6 </head> 7 <body> 8 <form action="AttributeSetterServlet" method="post"> 9 <!-- 输入中文来测试 --> 10 请输入要设置的attribute：<input type="text" name="attr"> 11 <input type="submit" value="显示"> 12 </form> 13 </body> 14 </html>
display_attribute.jsp
<%@ page language="java" contentType="text/html" pageEncoding="UTF-8"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <title>Insert title here</title> </head> <body> <h1>设置的attribute是：<%=request.getAttribute("attr")%></h1> </body> </html>
web.xml中添加如下代码：
1 <servlet> 2 <servlet-name>attribute-setter-servlet</servlet-name> 3 <servlet-class> 4 org.foo.servletdemo.AttributeSetterServlet 5 </servlet-class> 6 </servlet> 7 <servlet-mapping> 8 <servlet-name>attribute-setter-servlet</servlet-name> 9 <url-pattern>/AttributeSetterServlet</url-pattern> 10 </servlet-mapping>