Java SpringBoot全局异常处理注解 @ControllerAdvice + @ExceptionHandler

1、统一返回结构体：

import lombok.Data;

@Data
public class Result<T> {
    private Integer code;   // 状态码 200成功 500异常
    private String msg;
    private T data;

    public static <T> Result<T> success(T data) {
        Result<T> res = new Result<>();
        res.setCode(200);
        res.setMsg("操作成功");
        res.setData(data);
        return res;
    }

    public static <T> Result<T> fail(Integer code, String msg) {
        Result<T> res = new Result<>();
        res.setCode(code);
        res.setMsg(msg);
        res.setData(null);
        return res;
    }
}

2、自定义业务异常

public class BusinessException extends RuntimeException {
    private Integer code;

    public BusinessException(Integer code, String message) {
        super(message);
        this.code = code;
    }

    public Integer getCode() {
        return code;
    }
}

3、全局异常处理核心类

import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
import org.springframework.validation.BindException;
import javax.servlet.http.HttpServletRequest;

@RestControllerAdvice // 拦截所有@RestController控制器异常
public class GlobalExceptionHandler {

    // 1. 自定义业务异常
    @ExceptionHandler(BusinessException.class)
    public Result<?> businessExceptionHandler(BusinessException e, HttpServletRequest request) {
        return Result.fail(e.getCode(), e.getMessage());
    }

    // 2. 参数校验异常（@Valid / @NotBlank 等校验抛出）
    @ExceptionHandler(BindException.class)
    public Result<?> bindExceptionHandler(BindException e) {
        String msg = e.getBindingResult().getFieldError().getDefaultMessage();
        return Result.fail(400, "参数错误：" + msg);
    }

    // 3. 空指针异常
    @ExceptionHandler(NullPointerException.class)
    public Result<?> nullPointExceptionHandler(NullPointerException e) {
        e.printStackTrace();
        return Result.fail(500, "系统空指针异常");
    }

    // 4. 算术异常、数组越界等通用运行时异常
    @ExceptionHandler(RuntimeException.class)
    public Result<?> runtimeExceptionHandler(RuntimeException e) {
        e.printStackTrace();
        return Result.fail(500, "运行异常：" + e.getMessage());
    }

    // 5. 兜底：所有Exception最大捕获
    @ExceptionHandler(Exception.class)
    public Result<?> exceptionHandler(Exception e) {
        e.printStackTrace();
        return Result.fail(500, "服务器内部异常");
    }
}

4、测试类

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {

    @GetMapping("/test1")
    public Result<?> test1() {
        // 主动抛业务异常
        throw new BusinessException(4001, "用户名不存在");
    }

    @GetMapping("/test2")
    public Result<?> test2() {
        String s = null;
        s.length(); // 空指针
        return Result.success("ok");
    }
}