增加内容后发现数据库里面的文字乱码，解决方案

1、首先检查数据库的编码格式，注意，数据库的编码格式和jsp页面的编码格式需要一致！

jsp页面字符编码（默认是utf-8）：
request.setCharacterEncoding(“utf-8”)

数据库url连接后面需要有：
?useSSL=true&useUnicode=true&characterEncoding=UTF-8

如果上面都检查好了，问题还没有解决，可以设置一个字符编码过滤器：
package filter;

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.annotation.WebFilter;

public class CharacterEncodingFilter implements Filter {
protected String encoding=null;

public CharacterEncodingFilter() {
    
}

public void destroy() {
    
}

public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    request.setCharacterEncoding(encoding);
    response.setCharacterEncoding(encoding);
    response.setContentType("text/html;charset="+encoding);
    chain.doFilter(request, response);
}

public void init(FilterConfig fConfig) throws ServletException {
    encoding=fConfig.getInitParameter("encoding");
}

}

web.xml配置：

<filter>
     <filter-name>CharacterEncodingFilter</filter-name>
     <filter-class>filter.CharacterEncodingFilter</filter-class>
     <init-param>
         <param-name>encoding</param-name>
         <param-value>UTF-8</param-value>
     </init-param>
</filter>
<filter-mapping>
     <filter-name>CharacterEncodingFilter</filter-name>
     <url-pattern>/*</url-pattern>
</filter-mapping>