spring boot配合前端实现跨域请求访问

一.方法:

1. 服务端设置Respone Header头中Access-Control-Allow-Origin
2. 配合前台使用jsonp
3. 继承WebMvcConfigurerAdapter 添加配置类

二.实例:

1.前端:因为我们用了前后端分离,前端用node服务器,node服务器再用了ajax反向代理请求到我的spring boot 服务器。其中node服务器也用了ajax发出请求所以也存在跨域的问题。具体代码:

 app.all(apiRoot + '/*', proxy('127.0.0.1:' + proxyPort, {
  forwardPath: function(req, res) {
   console.log('req: ', req, 'res; ', res);
   return require('url').parse(req.url).path;
  }
 }));

后台(用的是spring boot 1.3.7.RELEASE) :用了一个filter进行了身份验证同时进行了跨域处理，具体代码:

public class AuthFilter implements Filter {
  //  @Autowired
  //这个不能自动注入servlet和filter是被tomcat管理的
  private BaseUserService baseUserService;
  private String[] excludePaths;

  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    System.out.println("initFilter");
    //不能在初始化中通过Appliaction Context获取因为这时候还没初始化Application Context
    //baseUserService = SpringUtils.getBean("baseUserService", BaseUserService.class);
    excludePaths = new String[]{"/api/user/noLogin", "/api/user/tokenError", "/api/user/loginForeground",
        "/api/user/loginBackground", "/api/user/inCorrectUserId"};
  }

  @Override
  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
    HttpServletRequest httpServletRequest = (HttpServletRequest) request;
    HttpServletResponse httpServletResponse = (HttpServletResponse) response;
    //这里填写你允许进行跨域的主机ip
    httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
    //允许的访问方法
    httpServletResponse.setHeader("Access-Control-Allow-Methods", "POST, GET, PUT, OPTIONS, DELETE, PATCH");
    //Access-Control-Max-Age 用于 CORS 相关配置的缓存
    httpServletResponse.setHeader("Access-Control-Max-Age", "3600");
    httpServletResponse.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
    String userId = request.getParameter("userId");
    String token = request.getParameter("token");
    //有token的                           `
    if (userId != null && token != null) {
      try {
        Integer id = Integer.parseInt(userId);
        if (baseUserService == null)
          baseUserService = SpringUtils.getBean("baseUserService", BaseUserService.class);
        int status = baseUserService.checkLogin(id, token);
        if (status == 1) {
          chain.doFilter(request, response);
        } else if (status == 0) {
          httpServletResponse.sendRedirect("/api/user/tokenError");
        } else if (status == -2) {
          httpServletResponse.sendRedirect("/api/user/inCorrectUserId");
        } else {
          httpServletResponse.sendRedirect("/api/user/noLogin");
        }
      } catch (NumberFormatException exception) {
        httpServletResponse.sendRedirect("/api/user/inCorrectUserId");
      }
    } else {
      String path = httpServletRequest.getServletPath();
      if (excludePath(path)) {
        chain.doFilter(request, response);
      } else {
        httpServletRequest.getRequestDispatcher("/api/user/noLogin").forward(request, response);
      }
    }
//    ((HttpServletResponse) response).addHeader("Access-Control-Allow-Origin", "*");
//    CorsFilter corsFilter=new CorsFilter();

  }

  private boolean excludePath(String path) {
    for (int i = 0; i < excludePaths.length; i++) {
      if (path.equals(excludePaths[i]))
        return true;
    }
    return false;
  }

  @Override
  public void destroy() {
    System.out.println("destroy method");
  }

}

这种方法还适用于servlet中,特别注意的是一定要在filter动作之前加上这句话,也就是在代码的最前面加上这个话。

跨域资源共享 CORS 详解(相关链接)

2.详细请看(点开)
3.具体代码:

package edu.ecnu.yjsy.conf; 

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter; 

@Configuration
public class CorsConfig extends WebMvcConfigurerAdapter { 

  @Override
  public void addCorsMappings(CorsRegistry registry) {
    registry.addMapping("/**")
        .allowedOrigins("*")
        .allowCredentials(true)
        .allowedMethods("GET", "POST", "DELETE", "PUT")
        .maxAge(3600);
  } 

}

这里有个坑spring boot 以前的版本这样设置可以用但是 我用的1.3.7.RELEASE spring boot 不能用,所以用第二种方式是万能的

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