数据处理(传值& 乱码)

处理前端提交的数据

1.提交的域名称和处理方法的参数名一致时    /hello?name=akagi

    @RequestMapping("/hello")
    public String hello666(String name){
        //封装数据
        System.out.println(name);
        return "jojohello";
    }

2.不一样的时候  @RequestParam      /hello?username=akagi

    @RequestMapping("/hello")
    public String hello666(@RequestParam("username") String name){
        //封装数据
        System.out.println(name);
        return "jojohello";
    }

3.是一个对象的时候,  参数使用对象( 属性名必须一致)即可   /hello?name=akagi & id=1 &age=15

    @RequestMapping("/hello")
    public String hello666(User user){
        //封装数据
        System.out.println(user);
        return "jojohello";
    }

提交给前端数据

1.通过 Model

    @RequestMapping("/hello")  //真实访问地址   项目名/*/hello
    public String hello666(Model model){
        //封装数据
        model.addAttribute("msg","hello anno");
        return "jojohello";  //会被视图解析器处理  jsp目录下的jsp文件
    }

2.通过ModelMap   (继承了LinkMap  除了实现自身方法,同样继承了一些方法和特性)

   @RequestMapping("/hello")  //真实访问地址   项目名/*/hello
    public String hello666(ModelMap model){
        model.addAttribute("msg","hello anno");
        return "jojohello";  //会被视图解析器处理  jsp目录下的jsp文件
    }

 处理乱码

form表单

<form action="${pageContext.request.contextPath }/e/t" method="post">
    <input type="text" name="name">
    <input type="submit">
</form>

接收

   @RequestMapping("/e/t")
    public String text(Model model,String name){
        //封装数据
        model.addAttribute("msg",name);
        System.out.println(name);
        return "jojohello";
    }

过滤器处理乱码  (web.xml)

1.自定义过滤器

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

import javax.servlet.*;
import java.io.IOException;

public class EncodingFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
          request.setCharacterEncoding("utf-8");
          response.setCharacterEncoding("utf-8");
          chain.doFilter(request,response);
    }

    @Override
    public void destroy() {

    }
}

2.调用过滤器

    <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>