一、在web.xml中的配置
<!-- characterEncodingFilter字符编码过滤器 -->
<filter>
<filter-name>characterEncodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<!--要使用的字符集，一般我们使用UTF-8(保险起见UTF-8最好)-->
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<!--是否强制设置request的编码为encoding，默认false，不建议更改-->
<param-name>forceRequestEncoding</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<!--是否强制设置response的编码为encoding，建议设置为true，下面有关于这个参数的解释-->
<param-name>forceResponseEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>characterEncodingFilter</filter-name>
<!--这里不能留空或者直接写 ' / ' ，否者不起作用-->
<url-pattern>/*</url-pattern>
</filter-mapping>
二、CharacterEncodingFilter过滤器类浅析
打开该类源码，可以看到该类有三个类属性
private String encoding; //要使用的字符集，一般我们使用UTF-8(保险起见UTF-8最好)
private boolean forceRequestEncoding = false; //是否强制设置request的编码为encoding
private boolean forceResponseEncoding = false; //是否强制设置response的编码为encoding
主要方法只有一个，也就是下面这个，代码逻辑很简单，入注释所解释
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException { String encoding = getEncoding();
if (encoding != null) { //如果设置了encoding的值，则根据情况设置request和response的编码
//若设置request强制编码或request本身就没有设置编码
//则设置编码为encoding表示的值
if (isForceRequestEncoding() || request.getCharacterEncoding() == null) {
request.setCharacterEncoding(encoding);
}
//若设置response强制编码，则设置编码为encoding表示的值
if (isForceResponseEncoding()) { //请注意这行代码，下面有额外提醒
response.setCharacterEncoding(encoding);
}
}
filterChain.doFilter(request, response);
}
# 额外提醒
if (isForceResponseEncoding()) {
response.setCharacterEncoding(encoding);
}是在
filterChain.doFilter(request, response);
之前执行的，这也就是说这段代码的作用是设置response的默认编码方式，在之后的代码里是可以根据需求设置为其他编码的，即这里设置的编码可能不是最终的编码
对于get请求中文参数出现乱码解决方法有两个：
修改tomcat配置文件添加编码与工程编码一致，如下：
<Connector URIEncoding="utf-8" connectionTimeout="20000" port="8080" protocol="HTTP/1.1" redirectPort="8443"/>
另外一种方法对参数进行重新编码：
String userName = new String(request.getParamter("userName").getBytes("ISO8859-1"),"utf-8")
ISO8859-1是tomcat默认编码，需要将tomcat编码后的内容按utf-8编码
三、可以自定义拦截器（在web.xml中配置)
<filter>
<filter-name>SetCharacterEncodingFilter</filter-name>
<filter-class>com.itwang.filter.SetCharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>SetCharacterEncodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
public class SetCharacterEncodingFilter implements Filter {
private FilterConfig filterConfig;
public void init(FilterConfig filterConfig) throws ServletException {
this.filterConfig = filterConfig;
}
public void doFilter(ServletRequest req, ServletResponse res,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest request;
HttpServletResponse response;
try {
request = (HttpServletRequest) req;
response = (HttpServletResponse) res;
} catch (ClassCastException e) {
throw new ServletException("non-HTTP request or response");
}
String encoding = filterConfig.getInitParameter("encoding");
if(encoding==null){
encoding = "UTF-8";
}
//POST:
request.setCharacterEncoding(encoding);
response.setCharacterEncoding(encoding);
response.setContentType("text/html;charset="+encoding);
chain.doFilter(request, response);
}
public void destroy() {
}
}
参考：https://blog.csdn.net/lianjunzongsiling/article/details/77926370