JavaWeb设置字符编码过滤器

一、不用框架时设置字符编码过滤器

代码如下（示例）：

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.annotation.WebInitParam;
import java.io.IOException;

@WebFilter("*")
public class CharacterEncodingFilter implements Filter {
          
   

    private String encoding = "utf-8";

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
          
   
	  String encodingStr = filterConfig.getInitParameter("encoding");
	  if (!encodingStr.isEmpty()) {
          
   
		encoding = encodingStr;
	  }
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
          
   
	  servletRequest.setCharacterEncoding(encoding);
	  filterChain.doFilter(servletRequest, servletResponse);
    }

    @Override
    public void destroy() {
          
   

    }

}

在初始化时先获取字符编码，然后在doFilter()方法里设置字符编码。 filterChain.doFilter(servletRequest, servletResponse); 这一行是在设置完编码后放行的语句。

二、使用SpringMVC框架设置字符编码过滤器

1. 使用xml配置文件

代码如下（示例）：

<filter>
        <filter-name>CharacterEncodingFilter</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param>
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param>
            <param-name>forceResponseEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>

在web.xml中加入这段代码就可以了，在param-value这个标签中可以设计具体的字符编码。

2. 使用配置类

public class WebInit extends AbstractAnnotationConfigDispatcherServletInitializer {
          
   
    @Override
    protected Filter[] getServletFilters() {
          
   
	  CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
	  characterEncodingFilter.setEncoding("UTF-8");
	  characterEncodingFilter.setForceResponseEncoding(true);
	  HiddenHttpMethodFilter hiddenHttpMethodFilter = new HiddenHttpMethodFilter();
	  return new Filter[]{
          
   characterEncodingFilter, hiddenHttpMethodFilter};
    }
}

创建一个继承AbstractAnnotationConfigDispatcherServletInitializer 的类，然后加入这段代码就可以了。