springboot使用过滤器-摩杜云开发者社区

FilterRegistrationBean 用来注册 Filter 对象

Filter是Servlet规范中的过滤器，可以处理请求，对请求的参数，属性进行调整。常常在过滤器中处理字符编码

1.1 在框架中使用过滤器：34

1. 创建自定义过滤器类

2. 注册Filter过滤器对象

自定义过滤器MyFilter

package com.bjpowernode.web;

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

//自定义过滤器  34
public class MyFilter implements Filter {
    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("执行了MyFilter，doFilter");
        filterChain.doFilter(servletRequest,servletResponse);
    }
}

注册过滤器WebApplicationConfig

package com.bjpowernode.config;

import com.bjpowernode.web.MyFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

//注册过滤器  34
@Configuration
public class WebApplicationConfig {

    @Bean
    public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean bean  = new FilterRegistrationBean();
        bean.setFilter( new MyFilter());
        bean.addUrlPatterns("/user/*");
        return bean;
    }
}

控制器CustomFilterController

package com.bjpowernode.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

//springboot中使用过滤器  34
@Controller
public class CustomFilterController {

    @RequestMapping("/user/account")
    @ResponseBody
    public String userAccount(){
        return "user/account";
    }


    @RequestMapping("/query")
    @ResponseBody
    public String queryAccount(){
        return "/query";
    }


}

测试

浏览器访问http://localhost:8080/user/account会执行过滤器

springboot使用过滤器

浏览器访问http://localhost:8080/query不会执行过滤器

2. 字符集过滤器的应用 35

CharacterEncodingFilter : 解决post请求中乱码的问题

在SpringMVC框架，在web.xml 注册过滤器。配置他的属性。

2.1 第一种方式： 35-37

代码在course7_1中

使用步骤：

2.1.1 配置字符集过滤器

MyServlet

package com.powernode.web;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

//定义一个servlet
//字符集过滤器的应用  36
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html");//这里我们不指定编码方式，用过滤器指定
        PrintWriter out = resp.getWriter();
        out.println("===在Servlet输出中文,默认编码ISO-8859-1===");
        out.flush();
        out.close();
    }
}

WebSystemConfig

package com.powernode.config;

import com.powernode.web.MyServlet;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.filter.CharacterEncodingFilter;
import sun.misc.CharacterEncoder;

//注册servlet  35-36
@Configuration
public class WebSystemConfig {

    //注册Servlet
    @Bean
    public ServletRegistrationBean servletRegistrationBean(){
        MyServlet myServlet = new MyServlet();
        ServletRegistrationBean reg = new ServletRegistrationBean(myServlet,"/myservlet");
        return reg;
    }


    //注册Filter设置字符编码方式  37
    @Bean
    public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean reg = new FilterRegistrationBean();

        //使用框架中的过滤器类
        CharacterEncodingFilter filter  = new CharacterEncodingFilter();
        //指定使用的编码方式
        filter.setEncoding("utf-8");
        //指定请求request ，应答 response都使用encoding的值
        filter.setForceEncoding(true);

        reg.setFilter(filter);
        //指定 过滤的url地址
        reg.addUrlPatterns("/*");


        return reg;
    }
}

重点

在 application.properties , 禁用 Spring Boot 中默认启用的过滤器

修改application.properties文件，让自定义的过滤器起作用

application.properties

#springboot中默认已经设置了CharacterEncodingFilter这个过滤器，他的编码方式为  37
# ISO-8859-1，我们设置为false就是代表关闭了这个，使用我们配置的编码方式
server.servlet.encoding.enabled=false

springboot使用过滤器

2.2 第二种方式 39

代码在course7_2中

修改application.properties文件

Spring Boot 项目默认启用了 CharacterEncodingFilter, 设置他的属性就可以

server.port=9001
server.servlet.context-path=/myboot

#让系统的CharacterEncodingFilter生效   39
server.servlet.encoding.enabled=true
#指定编码方式
server.servlet.encoding.charset=UTF-8
#强制request,response都使用charset的属性值
server.servlet.encoding.force=true

MyServlet

package com.bjpowernode.web;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;

//定义一个servlet
//字符集过滤器的应用  39
public class MyServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html");//这里我们不指定编码方式，用过滤器指定
        PrintWriter out = resp.getWriter();
        out.println("****在Servlet输出中文,默认编码ISO-8859-1*****");
        out.flush();
        out.close();
    }
}

WebSystemConfig

package com.bjpowernode.config;

import com.bjpowernode.web.MyServlet;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.filter.CharacterEncodingFilter;

//注册servlet  39
@Configuration
public class WebSystemConfig {

    //注册Servlet
    @Bean
    public ServletRegistrationBean servletRegistrationBean(){
        MyServlet myServlet = new MyServlet();
        ServletRegistrationBean reg =
                new ServletRegistrationBean(myServlet,"/myservlet");
        return reg;
    }

}

springboot使用过滤器