1.数据库建立为UTF-8格式
2.项目右键属性为UTF-8格式
3.所有页面申明为UTF-8
4.JDBC URL设为：UTF-8
jdbc:mysql://localhost:3306/company?useUnicode=true&characterEncoding=utf-8
5.数据库Driver选择UTF-8格式
6.Tomcat编码改成UTF-8
在server.xml里面增加URIEncoding="UTF-8"

<Connector port="8080" maxHttpHeaderSize="8192" maxThreads="150" minSpareThreads="25" maxSpareThreads="75" enableLookups="false" redirectPort="8443" acceptCount="100" connectionTimeout="20000" disableUploadTimeout="true" URIEncoding="UTF-8" />

7.加编码过滤器SetCharacterEncodingFilter.java 
注意：根据所在包名确定具体使用哪个包

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 SetCharacterEncodingFilter implements Filter {
protected String encoding = null;
protected FilterConfig filterConfig = null;
protected boolean ignore = true;
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;
}
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
// TODO 自动生成方法存根
if (ignore || (request.getCharacterEncoding() == null)) {
String encoding = selectEncoding(request);
if (encoding != null)
request.setCharacterEncoding(encoding);
}
chain.doFilter(request, response);
}
public void destroy() {
// TODO 自动生成方法存根
this.encoding = null;
this.filterConfig = null;
}
protected String selectEncoding(ServletRequest request) {
return (this.encoding);
}
}

在web.xml里面映射配置