springmvc全局异常处理

idea使用springmvc的全局异常处理

1. 首先需要在pom添加依赖

<dependency>
  <groupId>org.apache.tomcat</groupId>
  <artifactId>jsp-api</artifactId>
  <version>6.0.36</version>
</dependency>

     2、新建一个异常处理类，实现HandlerExceptionResolver接口并重写resolveException方法。代码如下

import com.mmall.exception.PermissionException;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Slf4j
@Component
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 ) {
                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());
            }
        } 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());
        } else {
            log.error("unknow exception, url:" + url, ex);
            JsonData result = JsonData.fail(defaultMsg);
            mv = new ModelAndView("jsonView", result.toMap());
        }

        return mv;
    }
}

  3、其中PermissionException是自己定义的异常

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);
    }
}

4、JsonData是返回给前端的Bean

import lombok.Data;

import java.util.HashMap;
import java.util.Map;

@Data
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(){
        JsonData jsonData =new JsonData(true);
        return jsonData;
    }

    public static JsonData fail(String msg){
        JsonData jsonData =new JsonData(false);
        jsonData.msg=msg;
        return  jsonData;
    }
    public Map<String, Object> toMap() {
        HashMap<String, Object> result = new HashMap<String, Object>();
        result.put("ret", ret);
        result.put("msg", msg);
        result.put("data", data);
        return result;
    }
}

5、其中jsonview是spring配置文件定义的一个bean

<bean id="jsonView" class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"/>