springboot 实战:异常与重定向问题

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@RequestMapping("/redirect/[code]")
    public RedirectView redirectView(@PathVariable("code") int code,
                               HttpSession session){
 
        RedirectView red = new RedirectView("/",true);
            //判断是不是301异常
            if (code == 301){
                //默认为302转移，此处设置为永久性转移
                red.setStatusCode(HttpStatus.MOVED_PERMANENTLY);
            }
            return red;
    }

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@RequestMapping("/redirect/[code]")
    public RedirectView redirectView(@PathVariable("code") int code,
                               HttpSession session){
 
        //这种跳转都是302跳转，通过一个redirect前缀告诉请求，要跳转到首页
        //所有的redirect请求都会跳转到首页
        return "redirect:/";
    }

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1.重定向页面
    @RequestMapping("/redirect/[code]")
    public String redirectView(@PathVariable("code") int code,
                               HttpSession session){
 
        //这种跳转都是302跳转，通过一个redirect前缀告诉请求，要跳转到首页
        //所有的redirect请求都会跳转到首页
        //通过session来传递信息
        session.setAttribute("msg","Jump from redirect");
        return "redirect:/";
    }
2.首页
    @RequestMapping("/")
    @ResponseBody
    public String index(HttpSession session){
        //在首页中显示重定向中的session
        return "Hello World!" + session.getAttribute("msg");
    }

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@RequestMapping("/admin")
    @ResponseBody
    public String admin(@RequestParam("key") String key){
    //如果key=“admin”
        if ("admin".equals(key)){
            return "hello admin";
        }
    //否则抛出异常
        throw new IllegalArgumentException("Key Wrong!");
    }

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@ExceptionHandler()
    @ResponseBody
    public String error(Exception e){
        return "error:" + e.getMessage();
    }

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@RestController
@RequestMapping("user")
public class UserController {
    @ExceptionHandler(value = Exception.class)
    public void solveException(){
        //异常处理逻辑
    }
    
}

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@Data
@AllArgsConstructor
public class MyException extends RuntimeException{
    private Integer code;
    private String msg;
    public MyException(ResultEnum resultEnum){
        this.msg = resultEnum.getMsg();
        this.code = resultEnum.getCode();
    }
}

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@Data
@AllArgsConstructor
@NoArgsConstructor
public class Result {
    private int code;
    private String msg;
}

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public enum  ResultEnum {
    UNKNOW_ERROR(-1,"未知错误"),
    USER_ERROR(-2,"用户信息错误"),
    SUCCESS(0,"成功");
    private  Integer code;
    private  String msg;
    ResultEnum(Integer code, String msg) {
        this.code = code;
        this.msg = msg;
    }
    //省略getter和setter
}

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public class ResultUtil {
    public static Result error(Integer code, String msg) {
        Result result = new Result();
        result.setCode(code);
        result.setMsg(msg);
        return result;
    }
}

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@ControllerAdvice
@Slf4j
public class MyExceptionHandler {
 //接收的是Exception，也就是只要是异常都会执行这方法
    @ExceptionHandler(value=Exception.class)
    @ResponseBody
    public Result handle(Exception e){
        if(e instanceof MyException){
            MyException myException = (MyException) e;
            return ResultUtil.error(myException.getCode(),myException.getMsg());
        }else{
            return ResultUtil.error(-1,"未知错误");
        }
    }
}

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@RestController
@RequestMapping("user")
public class UserController {
    @GetMapping("exception")
    public void catchException() throws Exception{
        throw new MyException(ResultEnum.USER_ERROR);
    }
 }