简单的实现登录拦截及统一异常处理（自定义异常）

webmvc配置类：

@configuration
public class webmvcconfig extends webmvcconfigurationsupport{

    @override
    protected void addinterceptors(interceptorregistry registry) {
        registry.addinterceptor(new logininterceptor())
        .addpathpatterns("/**")
        .excludepathpatterns("/user/login")；
    }
}

注：registry.addinterceptor(拦截器类对象).addpathpatterns("需要拦截的请求路径").excludepathpatterns("可以放行的请求路径");

 

拦截器类，这里为登录拦截

public class logininterceptor implements handlerinterceptor{

    @override
    public void aftercompletion(httpservletrequest arg0, httpservletresponse arg1, object arg2, exception arg3)
            throws exception {
        // todo auto-generated method stub
        
    }

    @override
    public void posthandle(httpservletrequest arg0, httpservletresponse arg1, object arg2, modelandview arg3)
            throws exception {
        // todo auto-generated method stub
        
    }

    @override
    public boolean prehandle(httpservletrequest hservletrequest, httpservletresponse hservletresponse, object object) throws exception {
        // 案例采用session存储登录用户，所以从session获取登录用户
　　　　 httpsession session = hservletrequest.getsession();
        tuser tuser=(tuser)session.getattribute("user");
        // 判断session里是否能取出用户
        if(tuser==null) {
            returnerrormessage(hservletresponse, "当前操作需要先进行用户登录");
            return false;
        }
        return true;
    }

    private void returnerrormessage(httpservletresponse response, string errormessage) throws ioexception {
        response.setcharacterencoding("utf-8");
        map<string, object> var=new hashmap<>();
        var.put("success", false);
        var.put("errormessage", errormessage);
        response.setcontenttype("application/json");
        printwriter out = response.getwriter();
        objectmapper mapper = new objectmapper();
        string jsonofrst =mapper.writevalueasstring(var);
        out.print(jsonofrst);
        out.flush();
    }
}

到这里实现了简单的登录拦截，但是上面通过response对象获取的输出流来写入错误信息，下面采用自定义异常来处理

 

异常类

public class unloggedexception extends runtimeexception{
    private static final long serialversionuid = 181074719716690931l;
    
    public unloggedexception() {
        super("当前操作需要先进行登录");
    }
}

修改拦截器类的prehandle方法，于是returnerrormessage方法可以去掉了

@override
    public boolean prehandle(httpservletrequest hservletrequest, httpservletresponse hservletresponse, object object) throws exception {
        httpsession session = hservletrequest.getsession();
        tuser tuser=(tuser)session.getattribute("user");
        if(tuser==null) {
            throw new unloggedexception();
        }
        return true;
    }

最后配置异常处理类

@controlleradvice
@responsebody
public class globalexceptionhandler {
    @exceptionhandler
    public jsonobject handleexception(exception e) {
        return actionhelper.responsefailed(e.getmessage());
    }
}

上面的返回值及actionhelper为我使用的返回工具类，依赖为com.alibaba的fastjson，版本参考1.2.49。

可以根据实际情况修改返回方式及返回值。

此后所有的异常，都可以通过自定义异常的方式，交由异常处理类来进行处理，返回结果。