SpringMVC学习 && 乱码问题解决

测试代码：hello页面只负责取msg数据

<form action="/e1" method="post">
    <input type="text" name="name">
    <input type="submit">
</form>

@Controller
public class EncodingController {
    @RequestMapping("/e1")
    public String test(String name, Model model){
        model.addAttribute("msg",name);
        return "hello";
    }
}

测试数据：

测试结果：
 
解决方式一：自己写编码过滤器

public class EncodingFilter implements Filter {
    public void init(FilterConfig filterConfig) throws ServletException { }
    
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        servletRequest.setCharacterEncoding("utf-8");
        servletResponse.setCharacterEncoding("utf-8");
        filterChain.doFilter(servletRequest,servletResponse);
    }
    
    public void destroy() { }
}

<filter>
    <filter-name>encoding</filter-name>
    <filter-class>com.Nana.filter.EncodingFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

缺点：不够强大
 

解决方式二：使用SpringMVC编码过滤器

<filter>
    <filter-name>encoding</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>
</filter>
<filter-mapping>
    <filter-name>encoding</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

缺点：某些极端情况下，这个过滤器对get支持不好
 

解决方式三：使用别人写好的过滤器

1. 修改tomcat配置文件，设置编码

   <Connector URIEncoding="utf-8" port="8080" protocol="HTTP/1.1"
             connectionTimeout="20000"
             redirectPort="8443" />
   

2. 自定义过滤器

   package com.Nana.filter;
   
   import javax.servlet.*;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletRequestWrapper;
   import javax.servlet.http.HttpServletResponse;
   import java.io.IOException;
   import java.io.UnsupportedEncodingException;
   import java.util.Map;
   
   /**
   * 解决get和post请求 全部乱码的过滤器
   */
   public class GenericEncodingFilter implements Filter {
   
      @Override
      public void destroy() {
     }
   
      @Override
      public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
          //处理response的字符编码
          HttpServletResponse myResponse=(HttpServletResponse) response;
          myResponse.setContentType("text/html;charset=UTF-8");
   
          // 转型为与协议相关对象
          HttpServletRequest httpServletRequest = (HttpServletRequest) request;
          // 对request包装增强
          HttpServletRequest myrequest = new MyRequest(httpServletRequest);
          chain.doFilter(myrequest, response);
     }
   
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
     }
   
   }
   
   //自定义request对象，HttpServletRequest的包装类
   class MyRequest extends HttpServletRequestWrapper {
   
      private HttpServletRequest request;
      //是否编码的标记
      private boolean hasEncode;
      //定义一个可以传入HttpServletRequest对象的构造函数，以便对其进行装饰
      public MyRequest(HttpServletRequest request) {
          super(request);// super必须写
          this.request = request;
     }
   
      // 对需要增强方法 进行覆盖
      @Override
      public Map getParameterMap() {
          // 先获得请求方式
          String method = request.getMethod();
          if (method.equalsIgnoreCase("post")) {
              // post请求
              try {
                  // 处理post乱码
                  request.setCharacterEncoding("utf-8");
                  return request.getParameterMap();
             } catch (UnsupportedEncodingException e) {
                  e.printStackTrace();
             }
         } else if (method.equalsIgnoreCase("get")) {
              // get请求
              Map<String, String[]> parameterMap = request.getParameterMap();
              if (!hasEncode) { // 确保get手动编码逻辑只运行一次
                  for (String parameterName : parameterMap.keySet()) {
                      String[] values = parameterMap.get(parameterName);
                      if (values != null) {
                          for (int i = 0; i < values.length; i++) {
                              try {
                                  // 处理get乱码
                                  values[i] = new String(values[i]
                                         .getBytes("ISO-8859-1"), "utf-8");
                             } catch (UnsupportedEncodingException e) {
                                  e.printStackTrace();
                             }
                         }
                     }
                 }
                  hasEncode = true;
             }
              return parameterMap;
         }
          return super.getParameterMap();
     }
   
      //取一个值
      @Override
      public String getParameter(String name) {
          Map<String, String[]> parameterMap = getParameterMap();
          String[] values = parameterMap.get(name);
          if (values == null) {
              return null;
         }
          return values[0]; // 取回参数的第一个值
     }
   
      //取所有值
      @Override
      public String[] getParameterValues(String name) {
          Map<String, String[]> parameterMap = getParameterMap();
          String[] values = parameterMap.get(name);
          return values;
     }
   }
   

3. 在web.xml中配置这个过滤器
    

/和/*区别：

• /会匹配到/springmvc这样的路径型url，不会匹配到模式为*.jsp这样的后缀型url

• 会匹配所有的url：路径型的和后缀型的url(包括/springmvc，.jsp，.js和*.html等)

• 两个符号要慎重选用