知识大全 JSP中使用request乱码问题的解决

Posted 2022-07-20 知

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　　 JSP显示中文有乱码怎么办用request得到的用户输入的中文怎么是乱码把汉字写到数据库怎么是乱码等等一些关于汉字乱码的问题其实这个问题很简单管它汉字不汉字还是日文还是其他的什么双字节的语言我们一律把它当作UTF 看待 （一）request中的双字节文字 我们来实现在整个应用程序中使用UTF 编码工作之所以选择UTF 不仅仅之于上述原因我们知道java的就是基于在UTF 之上的所以我们选择UTF 应该没错首先把我们的 java jsp文件都用UTF 编码来保存如果以前的没有用UTF 保存也无所谓但是建议以后写的都用UTF 来保存并在 jsp里面写:

以下是引用片段 <%@page contentType= text/; charset=UTF %>而不是 %@page contentType= text/; charset=UTF % 然后在web xml添加下面一段以下是引用片段 <web app> <filter> <filter name>Set Character Encoding</filter name> <filter class> redv projects eduadmin util filters SetCharacterEncodingFilter</filter class> <init param> <param name>encoding</param name> <param value>UTF </param value> </init param> </filter> <filter mapping> <filter name>Set Character Encoding</filter name> <url pattern>/*</url pattern> </filter mapping> </web app> 其中 redv projects eduadmin util filters SetCharacterEncodingFilter的代码如下 package redv projects eduadmin util filters; import java io IOException; import javax servlet Filter; import javax servlet FilterChain; import javax servlet FilterConfig; import javax servlet ServletException; import javax servlet ServletRequest; import javax servlet ServletResponse; import javax servlet UnavailableException; import javax servlet import javax servlet public class SetCharacterEncodingFilter implements Filter protected String encoding = null; protected FilterConfig filterConfig = null; protected boolean ignore = true; public void destroy() this encoding = null; this filterConfig = null; public void doFilter(ServletRequest request ServletResponse response FilterChain chain) throws IOException ServletException // Conditionally select and set the character encoding to be used if (ignore || (request getCharacterEncoding() == null)) String encoding = selectEncoding(request); if (encoding != null) request setCharacterEncoding(encoding); //Overrides the name of the character encoding used in the body of this request This method must be called prior to reading request parameters or reading input using getReader() // Pass control on to the next filter chain doFilter(request response); public void init(FilterConfig filterConfig) throws ServletException this filterConfig = filterConfig; this encoding = filterConfig getInitParameter( encoding ); String value = filterConfig getInitParameter( ignore ); if (value == null) this ignore = true; else if (value equalsIgnoreCase( true )) this ignore = true; else if (value equalsIgnoreCase( yes )) this ignore = true; else this ignore = false; protected String selectEncoding(ServletRequest request) return (this encoding);

　　这样我们的request请求就是以UTT 编码的在JSP程序中就可以使用 request getParameter( myKey )来直接得到UTF 编码的字符串了而不需要像这样 new String(request getParameter( myKey ) getBytes( ISO ) GBK )来解决那些乱码了

　　 （二）数据库处理的双字节文字 另外一个就是写入数据库的问题我们知道我们在使用mysql的时候可以改用这样的url来处理汉字编码问题 jdbc:mysql://localhost: /upas?useUnicode=true& characterEncoding=gb 那么对于那些我们无法像mysql这样解决的怎么办呢？难道我们每次都这样写吗 ( lian )

import java sql *; Class forName( gjt mm mysql Driver ); Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; try con = DriverManager getConnection( jdbc:mysql://localhost: /test root ); pstmt = con prepareStatement( SELECT f f FROM tbl WHERE f = ? AND f = ? ); pstmt setString( new String(f getBytes( GBK ) ISO ); pstmt setString( new String(f getBytes( GBK ) ISO ); rs = pstmt executeQuery(); String f f ; while(rs next()) f = new String(rs getString( ) getBytes( ISO ) GBK ); f = new String(rs getString( ) getBytes( ISO ) GBK ); finally //close resouces

　　其实我们完全可以这样写

import java sql *; import redv sql encoding *; Class forName( gjt mm mysql Driver ); Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; try con = DriverManager getConnection( jdbc:mysql://localhost: /test root ); //接管数据库连接实例 boolean coding = true; EncodingConnection codingConnection = new EncodingConnection(con coding ISO GBK ); //获得接管后的数据库连接实例以后直接使用con已经是经过EncodingConnection重新包装过的实例 con = codingConnection getConnection(); pstmt = con prepareStatement( SELECT f f FROM tbl WHERE f = ? AND f = ? ); pstmt setString( f ); pstmt setString( f ); rs = pstmt executeQuery(); String f f ; while(rs next()) f = rs getString( ); f = rs getString( ); finally //close resouces cha138/Article/program/Java/JSP/201311/19877