serverlet_serverlet的原理_jquery serverlet组件(2)

简介过滤器：

A.每个过滤器都会在 web.xml中有单独的配置：

<filter>

<filter-name>过滤器的别名</filtr-name>

<filter-class>过滤器的物理地址，带有完整的包路径的</filter-class>

</filter>

<filter-mapping>

<filter-name>过滤器的别名</filter-name>

<filter-patterm>过滤器访问的路径</filter-patterm>

</filter-mapping>

B.当由于某种原因想要删除servlet类时，删除后在web.xml中还会保留删除的servlet类的记录，

所以必须手动在web.xml中删除一下已删除的servlet类的信息

过滤器的在web.xml中的典型配置和主要代码如下：

web.xml:

<filter>

<filter-name>CharacterEncodingFilter</filter-name>

<filter-class>net.vschool.web.CharacterEncodingFilter</filter-class>

<init-param>

<param-name>encoding</param-name>

<param-value>GBK</param-value>

</init-param>

</filter>

<filter-mapping>

<filter-name>CharacterEncodingFilter</filter-name>

<url-pattern>/*</url-pattern>

</filter-mapping>

CharacterEncodingFilter.java:

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;

public class CharacterEncodingFilter implements Filter

{

protected String encoding = null;

public void init(FilterConfig filterConfig) throws ServletException

{

this.encoding = filterConfig.getInitParameter("encoding");

}

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException

{

request.setCharacterEncoding(encoding);

response.setContentType("text/html;charset="+encoding);

chain.doFilter(request, response);

}

}

7.解决的乱码

在jdbc.url中明确字符集 (不适用于sqlserver)

在连接时：con=DriverManager.getConnection(url,"sa","");

url="jdbc:协议：子协议：//IP：端口; 库 ? useUnicode=true & characterEncoding=gb2312";

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