学成在线项目学习之自定义异常

package com.xuecheng.framework.domain.cms.response;

import com.xuecheng.framework.model.response.ResultCode;
import lombok.ToString;

/**
 * Created by mrt on 2018/3/5.
 */
@ToString
public enum CmsCode implements ResultCode {
    CMS_ADDPAGE_EXISTSNAME(false,24001,"页面名称已存在！"),
    CMS_GENERATEHTML_DATAURLISNULL(false,24002,"从页面信息中找不到获取数据的url！"),
    CMS_GENERATEHTML_DATAISNULL(false,24003,"根据页面的数据url获取不到数据！"),
    CMS_GENERATEHTML_TEMPLATEISNULL(false,24004,"页面模板为空！"),
    CMS_GENERATEHTML_HTMLISNULL(false,24005,"生成的静态html为空！"),
    CMS_GENERATEHTML_SAVEHTMLERROR(false,24005,"保存静态html出错！"),
    CMS_COURSE_PERVIEWISNULL(false,24007,"预览页面为空！");
    //操作代码
    boolean success;
    //操作代码
    int code;
    //提示信息
    String message;
    private CmsCode(boolean success, int code, String message){
        this.success = success;
        this.code = code;
        this.message = message;
    }

    @Override
    public boolean success() {
        return success;
    }

    @Override
    public int code() {
        return code;
    }

    @Override
    public String message() {
        return message;
    }
}

package com.xuecheng.framework.exception;

import com.xuecheng.framework.model.response.ResultCode;

/**我们自定义异常类,我们所能预见到的异常 都被封装在resultCode中
 * 该类实现两个功能,定义我们自定义异常的异常信息,而是必须包含resultCode属性
 * 我们返给前端 ResponseResult该类的对象,该类的属性来自于resultCode.
 */
public class CustomException extends RuntimeException {
    public ResultCode getResultCode() {
        return resultCode;
    }
    private ResultCode resultCode;

    public CustomException(ResultCode resultCode) {
        //异常信息为错误代码+异常信息(自定义我们的异常信息格式)
        super("错误代码:" + resultCode.code() + "错误信息:" + resultCode.message());
        this.resultCode = resultCode;
    }
}

package com.xuecheng.framework.exception;

import com.xuecheng.framework.model.response.ResultCode;

public class ExceptionCast {
    //使用此静态方法抛出自定义异常
    public static void cast(ResultCode resultCode){
        throw new CustomException(resultCode);
    }
}

@Service

public class PageService {

    @Autowired
    CmsPageRepository cmsPageRepository;

    //添加页面
    public CmsPageResult add(CmsPage cmsPage) {
        //校验页面是否存在,根据页面名称,站点Id,页面webPath查询(是否需要判断cmsPage是否为null呢)
        if (cmsPage == null) {
            ExceptionCast.cast(CmsCode.CMS_GENERATEHTML_DATAISNULL);
            cmsPage = new CmsPage();//对象的成员属性都有初始化值
        }
        CmsPage cmsPage1 = cmsPageRepository.findByPageNameAndSiteIdAndPageWebPath(
                cmsPage.getPageName(),
                cmsPage.getSiteId(),
                cmsPage.getPageWebPath());

        if (cmsPage1 != null) {
            ExceptionCast.cast(CmsCode.CMS_ADDPAGE_EXISTSNAME);
        }

        cmsPage.setPageId(null);//添加页面主键id为null,让主键由spring data mongodb自动为我们生成
        // CmsPage cmspage = cmsPageRepository.save(cmsPage);//返回插入数据库后的对象
        cmsPageRepository.save(cmsPage);
        //返回结果
        CmsPageResult cmsPageResult = new CmsPageResult(CommonCode.SUCCESS, cmsPage);
        return cmsPageResult;
    }
 
}

package com.xuecheng.framework.exception;

import com.xuecheng.framework.model.response.ResponseResult;
import com.xuecheng.framework.model.response.ResultCode;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;


@ControllerAdvice
public class ExceptionCatch {
    private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionCatch.class);
    //捕获 CustomException异常
    @ExceptionHandler(CustomException.class)
    @ResponseBody
    public ResponseResult customException(CustomException e) {
        LOGGER.error("catch exception : {}\r\nexception: ",e.getMessage(), e);//打印被抓取到的自定义的异常类信息到控制台
        ResultCode resultCode = e.getResultCode();
        ResponseResult responseResult = new ResponseResult(resultCode);
        return responseResult;
    }
}