前后端分离

1、用户认证流程

• 登录成功后调用：AuthenticationSuccessHandler
• 登录失败后调用：AuthenticationFailureHandler

2、引入fastjson

<dependency>
    <groupId>com.alibaba.fastjson2</groupId>
    <artifactId>fastjson2</artifactId>
    <version>2.0.37</version>
</dependency>

3、认证成功的响应

3.1、成功结果处理

package com.neuedu.securitydemo.config;

public class MyAuthenticationSuccessHandler implements AuthenticationSuccessHandler {
    @Override
    public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException {

        //获取用户身份信息
        Object principal = authentication.getPrincipal();

        //创建结果对象
        HashMap result = new HashMap();
        result.put("code", 0);
        result.put("message", "登录成功");
        result.put("data", principal);

        //转换成json字符串
        String json = JSON.toJSONString(result);

        //返回响应
        response.setContentType("application/json;charset=UTF-8");
        response.getWriter().println(json);
    }
}

3.2、SecurityFilterChain配置

form.successHandler(new MyAuthenticationSuccessHandler()) //认证成功时的处理

4、认证失败响应

4.1、失败结果处理

package com.neuedu.securitydemo.config;

public class MyAuthenticationFailureHandler implements AuthenticationFailureHandler {

    @Override
    public void onAuthenticationFailure(HttpServletRequest request, HttpServletResponse response, AuthenticationException exception) throws IOException, ServletException {

        //获取错误信息
        String localizedMessage = exception.getLocalizedMessage();

        //创建结果对象
        HashMap result = new HashMap();
        result.put("code", -1);
        result.put("message", localizedMessage);

        //转换成json字符串
        String json = JSON.toJSONString(result);

        //返回响应
        response.setContentType("application/json;charset=UTF-8");
        response.getWriter().println(json);
    }
}

4.2SecurityFilterChain配置

form.failureHandler(new MyAuthenticationFailureHandler()) //认证失败时的处理

5、注销响应

5.1、注销结果处理

package com.neuedu.securitydemo.config;

public class MyLogoutSuccessHandler implements LogoutSuccessHandler {

    @Override
    public void onLogoutSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException {

        //创建结果对象
        HashMap result = new HashMap();
        result.put("code", 0);
        result.put("message", "注销成功");

        //转换成json字符串
        String json = JSON.toJSONString(result);

        //返回响应
        response.setContentType("application/json;charset=UTF-8");
        response.getWriter().println(json);
    }
}

5.2、SecurityFilterChain配置

http.logout(logout -> {
    logout.logoutSuccessHandler(new MyLogoutSuccessHandler()); //注销成功时的处理
});

6、请求未认证的接口

6.1、实现AuthenticationEntryPoint接口

Servlet Authentication Architecture :: Spring Security

当访问一个需要认证之后才能访问的接口的时候，Spring Security会使用AuthenticationEntryPoint将用户请求跳转到登录页面，要求用户提供登录凭证。

这里我们也希望系统返回json结果，因此我们定义类实现AuthenticationEntryPoint接口

package com.neuedu.securitydemo.config;

public class MyAuthenticationEntryPoint implements AuthenticationEntryPoint {
    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException, ServletException {

        //获取错误信息
        //String localizedMessage = authException.getLocalizedMessage();

        //创建结果对象
        HashMap result = new HashMap();
        result.put("code", -1);
        result.put("message", "需要登录");

        //转换成json字符串
        String json = JSON.toJSONString(result);

        //返回响应
        response.setContentType("application/json;charset=UTF-8");
        response.getWriter().println(json);
    }
}

6.2、SecurityFilterChain配置

//错误处理
http.exceptionHandling(exception  -> {
    exception.authenticationEntryPoint(new MyAuthenticationEntryPoint());//请求未认证的接口
});

7、跨域

跨域全称是跨域资源共享(Cross-Origin Resources Sharing,CORS)，它是浏览器的保护机制，只允许网页请求统一域名下的服务，同一域名指=>协议、域名、端口号都要保持一致，如果有一项不同，那么就是跨域请求。在前后端分离的项目中，需要解决跨域的问题。

在SpringSecurity中解决跨域很简单，在配置文件中添加如下配置即可

//跨域
http.cors(withDefaults());