shiro 返回json字符串 + 自定义filter

前言:

　　在前后端分离的项目中, 在使用shiro的时候, 我们绝大部分时候, 并不想让浏览器跳转到那个页面去, 而是告诉前端, 你没有登录, 或者没有访问权限. 那这时候, 我们就需要返回json字符串给前端, 让前端解析后, 根据状态执行相应的操作.

实现:

由于我现在的系统, 权限并不复杂, 所以在这里, 我自定义了一个过滤器. 

当然, 如果想要更加省事, 可以继承user(org.apache.shiro.web.filter.authc.UserFilter) 或者 authc(org.apache.shiro.web.filter.authc.FormAuthenticationFilter) 过滤器, 当然, 也可以是别的过滤器.

1. 自定义过滤器

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.subject.Subject;
import org.apache.shiro.web.filter.AccessControlFilter;

import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletResponse;

public class JsonAuthLoginFilter extends AccessControlFilter {

    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue)
            throws Exception {
        Subject subject = SecurityUtils.getSubject();

        if(null != subject){
            if(subject.isRemembered()){
                return Boolean.TRUE;
            }
            if(subject.isAuthenticated()){
                return Boolean.TRUE;
            }
        }

        return Boolean.FALSE ;
    }

    @Override
    protected boolean onAccessDenied(ServletRequest request, ServletResponse response) throws Exception {
        JsonResponse<Void> res = JsonResponse.noLogin("请先登录");
        WebUtils.out((HttpServletResponse) response, res);
        return Boolean.FALSE ;
    }
}

这里的JsonResponse是返回实体.

import com.alibaba.fastjson.annotation.JSONField;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;

import java.io.Serializable;

@ApiModel
public class JsonResponse<T> implements Serializable {

    private static final long serialVersionUID = -7817536542662556767L;

    @ApiModelProperty("请求成功/失败标志")
    private boolean success;

    @ApiModelProperty("状态码, -1:没有登录, -2:没有权限, -3:系统报错, 0: 后台返回错误信息, 1: 成功访问")
    private int code;

    @ApiModelProperty("访问提示信息")
    private String msg;

    @ApiModelProperty("后台返回数据")
    private T data;

    public JsonResponse() {
    }

    public JsonResponse(boolean success) {
        this();
        this.success = success;
    }

    public JsonResponse(boolean success, String msg) {
        this(success);
        this.msg = msg;
    }

    public JsonResponse(boolean success, String msg, int code) {
        this(success, msg);
        this.code = code;
    }

    public JsonResponse(boolean success, String msg, int code, T data) {
        this(success, msg, code);
        this.data = data;
    }

    public boolean isSuccess() {
        return success;
    }

    public void setSuccess(boolean success) {
        this.success = success;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public T getData() {
        return data;
    }

    public void setData(T data) {
        this.data = data;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public static JsonResponse<Void> SUCCESS = new JsonResponse<>(true);

    public static <T> JsonResponse<T> success(T data) {
        return new JsonResponse<>(true, null, JsonResStateEnum.SUCCESS, data);
    }

    public static <T> JsonResponse<T> success(T data, String msg) {
        return new JsonResponse<>(true, msg, JsonResStateEnum.SUCCESS, data);
    }

    public static <T> JsonResponse<T> error(String msg) {
        return new JsonResponse<>(false, msg, JsonResStateEnum.USER_ERROR);
    }

    public static <T> JsonResponse<T> error(String msg,  T data) {
        return new JsonResponse<>(false, msg, JsonResStateEnum.USER_ERROR, data);
    }

    public static <T> JsonResponse<T> error(String msg, int code) {
        return new JsonResponse<>(false, msg, code);
    }

    public static <T> JsonResponse<T> noLogin(String msg) {
        return new JsonResponse<>(false, msg, JsonResStateEnum.NO_LOGIN);
    }

    public static <T> JsonResponse<T> noPermission(String msg) {
        return new JsonResponse<>(false, msg, JsonResStateEnum.NO_PERMISSION);
    }
}

JsonResStateEnum是自定义状态枚举

public interface JsonResStateEnum  {

    /**
     * 没有登录时的状态
     */
    public static final  Integer NO_LOGIN = -1;

    /**
     * 没有访问权限时的状态
     */
    public static final  Integer NO_PERMISSION = -2;

    /**
     * 系统错误时的错误, 不可掌控错误
     */
    public static final  Integer SYSTEM_ERROR = -3;

    /**
     * token验证错误
     */
    public static final Integer TOKEN_ERROR = -4;

    /**
     * 由用户自定义返回的错误, 受用户掌控
     */
    public static final  Integer USER_ERROR = 0;

    /**
     * 正常状态
     */
    public static final  Integer SUCCESS = 1;

}

WebUtils.out是自定义的方法, 意在返回json字符串

public static  void out(HttpServletResponse response, JsonResponse jsonObj){
        PrintWriter out = null;
        try {
            response.setCharacterEncoding("UTF-8");
            response.setContentType("application/json; charset=utf-8");
            out = response.getWriter();
            out.write(JSON.toJSONString(jsonObj));
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (out != null) {
                out.close();
            }
        }
}

通过这个过滤器, 可以过滤没有登录的用户, 并将json字符串返回给前端.

但是, 如果我登录之后, 去访问没有权限的资源, 这样子就不能解决了. 需要一个全局错误处理.

2. 全局错误处理

import com.alibaba.fastjson.JSON;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authz.AuthorizationException;
import org.apache.shiro.authz.UnauthenticatedException;
import org.apache.shiro.authz.UnauthorizedException;
import org.apache.shiro.session.UnknownSessionException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class MyMvcExceptionHandler implements HandlerExceptionResolver {

    protected final Logger logger = LoggerFactory.getLogger(getClass());

    @Override
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {

        logger.error(ex.getMessage(), ex);

        if (ex instanceof UnauthenticatedException || ex instanceof AuthenticationException || ex instanceof UnknownSessionException) {
            return outJson(request, response, JsonResponse.noLogin("请先登录"));
        }
        if (ex instanceof UnauthorizedException || ex instanceof AuthorizationException) {
            return outJson(request, response, JsonResponse.noPermission("没有访问权限"));
        }
        return outJson(request, response, JsonResponse.error(ex.getMessage(), JsonResStateEnum.SYSTEM_ERROR));
    }

    private ModelAndView outJson(HttpServletRequest request, HttpServletResponse response, JsonResponse res) {
        ModelAndView mv = new ModelAndView();
        /*  使用response返回    */
        response.setStatus(HttpStatus.OK.value()); //设置状态码
        response.setContentType(MediaType.APPLICATION_JSON_VALUE); //设置ContentType
        response.setCharacterEncoding("UTF-8"); //避免乱码
        response.setHeader("Cache-Control", "no-cache, must-revalidate");
        try {
            String json = JSON.toJSONString(res);
            response.getWriter().write(json);
        } catch (IOException e) {
            logger.error("与客户端通讯异常:" + e.getMessage(), e);
        }

        return mv;
    }
}

3. 配置

在application.xml配置文件中

<bean id="exceptionHandler" class="common.myexception.MyMvcExceptionHandler"/>

<bean name="loginFilter" class="shiro.filter.JsonAuthLoginFilter" />

<bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean">
    <property name="securityManager" ref="securityManager"/>
    <property name="loginUrl" value="${shiro.loginUrl}"/>
    <property name="filters">
        <map>
            <entry key="login" value-ref="loginFilter" />
        </map>
    </property>
    <property name="filterChainDefinitions">
        <value>
            /logout=logout
            /user/retrievePwd = anon
            /user/signOut = anon
            /user/loginGet = anon
            /swagger-ui.html = anon
            /swagger-resources = anon
            /swagger-resources/** = anon
            /v2/api-docs = anon
            /webjars/** = anon
            /webjars/springfox-swagger-ui/** = anon
            /user/login = anon
            /user/register = anon
            /** = login
        </value>
    </property>
</bean>

4. 结果: