common包下，json，异常处理

JsonData

@Getter
@Setter
public class JsonData {

    private boolean ret;

    private String msg;

    private Object data;

    public JsonData(boolean ret) {
        this.ret = ret;
    }

    public static JsonData success(Object object, String msg) {
        JsonData jsonData = new JsonData(true);
        jsonData.data = object;
        jsonData.msg = msg;
        return jsonData;
    }

    public static JsonData success(Object object) {
        JsonData jsonData = new JsonData(true);
        jsonData.data = object;
        return jsonData;
    }

    public static JsonData success() {
        return new JsonData(true);
    }

    public static JsonData fail(String msg) {
        JsonData jsonData = new JsonData(false);
        jsonData.msg = msg;
        return jsonData;
    }

    public Map toMap() {
        HashMap result = new HashMap();
        result.put("ret", ret);
        result.put("msg", msg);
        result.put("data", data);
        return result;
    }
}

全局异常处理 SpringExceptionResolver

引入包：
    
    
      org.apache.tomcat
      jsp-api
      6.0.36
    

@Slf4j
public class SpringExceptionResolver implements HandlerExceptionResolver {

    @Override
    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        String url = request.getRequestURL().toString();
        ModelAndView mv;
        String defaultMsg = "System error";

        // 这里我们要求项目中所有请求json数据，都使用.json结尾
        if (url.endsWith(".json")) {
            if (ex instanceof PermissionException || ex instanceof ParamException) {
                JsonData result = JsonData.fail(ex.getMessage());
                mv = new ModelAndView("jsonView", result.toMap());
            } else {
                log.error("unknown json exception, url:" + url, ex);
                JsonData result = JsonData.fail(defaultMsg);
                mv = new ModelAndView("jsonView", result.toMap());
                //对应spring-servlet.xml 
            }
        } else if (url.endsWith(".page")){ // 这里我们要求项目中所有请求page页面，都使用.page结尾
            log.error("unknown page exception, url:" + url, ex);
            JsonData result = JsonData.fail(defaultMsg);
            mv = new ModelAndView("exception", result.toMap());
            //返回到 exception.jsp 页面
        } else {
            log.error("unknow exception, url:" + url, ex);
            JsonData result = JsonData.fail(defaultMsg);
            mv = new ModelAndView("jsonView", result.toMap());
        }
        return mv;
    }
}

spring-servlet.xml配置，才能使用
    

自定义异常

public class PermissionException extends RuntimeException {
    public PermissionException() {
        super();
    }
    public PermissionException(String message) {
        super(message);
    }
    public PermissionException(String message, Throwable cause) {
        super(message, cause);
    }
    public PermissionException(Throwable cause) {
        super(cause);
    }
    protected PermissionException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
        super(message, cause, enableSuppression, writableStackTrace);
    }
}

测试：
@Controller
@RequestMapping("/test")
@Slf4j
public class TestController {

    @RequestMapping("/hello.json")
    @ResponseBody
    public JsonData hello() {
        log.info("hello");
        throw new PermissionException("test exception");
        {
        ret:false,
        msg:"test exception",
        data:null
        }
        // return JsonData.success("hello, permission");
        {
        ret:true,
        msg:null,
        data:"hello,permission"
        }
    }
}