SSM | 整合（基于图书的增删改查操作）（下）

@RestController
@RequestMapping("/books")
public class BookController {
    @Autowired
    private BookService service;
    @PostMapping // @RequestBody注解用于接收JSON格式数据 POST请求的数据用@RequestParam注解接收
    public int addBook(@RequestBody Book book) {
        return service.addBook(book);
    }
    @PutMapping
    public int updateBookById(@RequestBody Book book) {
        return service.updateBookById(book);
    }
    @DeleteMapping("/{id}")
    public int deleteBookById(@PathVariable Integer id) {
        return service.deleteBookById(id);
    }
    @GetMapping("/{id}")
    public Book getBookById(@PathVariable Integer id) {
        return service.getBookById(id);
    }
    @GetMapping
    public List<Book> selectAll() {
        return service.selectAll();
    }
}

/**
 * 表现层数据封装模型-返回给前端的数据都是Result对象类型
 */
public class Result {
    /**
     * 返回的状态-成功与失败，何种操作
     */
    private Integer code;
    /**
     * 返回的数据
     */
    private Object data;
    /**
     * 成功或失败的响应信息
     */
    private String msg;
    public Result() {
    }
    /**
     * 不带消息
     *
     * @param data
     * @param code
     */
    public Result(Integer code, Object data) {
        this.data = data;
        this.code = code;
    }
    /**
     * 带消息
     *
     * @param data
     * @param code
     * @param msg
     */
    public Result(Integer code, Object data, String msg) {
        this.data = data;
        this.code = code;
        this.msg = msg;
    }
    // getter setter 已省略

/**
 * 定义增删改查操作成功或者失败的状态码-8种
 */
public class Code {
    /**
     * 结尾1代表成功，0代表失败
     */
    public static final Integer ADD_OK = 20011;
    public static final Integer ADD_ERR = 20010;
    public static final Integer DELETE_OK = 20021;
    public static final Integer DELETE_ERR = 20020;
    public static final Integer UPDATE_OK = 20031;
    public static final Integer UPDATE_ERR = 20030;
    public static final Integer SELECT_OK = 20041;
    public static final Integer SELECT_ERR = 20040;
}

@RestControllerAdvice // 将这个类作为异常处理器通知类
public class ProjectExceptionAdvice {
    @ExceptionHandler({Exception.class}) // 拦截所有异常
    public Result doException(Exception e) {
        System.out.println("error ...");
        return new Result(500,null,"error");
    }
}

public class SystemException extends RuntimeException {
    /**
     * 加入异常编号帮助识别是哪一种异常
     */
    private Integer code;
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
    public SystemException(Integer code, String message) {
        super(message);
        this.code = code;
    }
    public SystemException(Integer code, String message, Throwable cause) {
        super(message, cause);
        this.code = code;
    }
}

public class BusinessException extends RuntimeException {
    /**
     * 加入异常编号帮助识别是哪一种异常
     */
    private Integer code;
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
    public BusinessException(Integer code, String message) {
        super(message);
        this.code = code;
    }
    public BusinessException(Integer code, String message, Throwable cause) {
        super(message, cause);
        this.code = code;
    }
}

    /**
     * 异常状态码(可以细分)
     */
    public static final Integer SYSTEM_ERR = 50001;
    public static final Integer SYSTEM_TIMEOUT_ERR = 50002;
    public static final Integer BUSINESS_ERR = 60002;
    public static final Integer SYSTEM_UNKNOWN_ERR = 59999;

  @Override
    public Book getBookById(Integer id) {
        // 模拟业务异常
        if (id == 1) {
            throw new BusinessException(Code.BUSINESS_ERR, "ban!");
        }
        // 模拟系统异常
        try {
            int i = 1 / 0;
        } catch (Exception e) {
            throw new SystemException(Code.SYSTEM_TIMEOUT_ERR, "Time out!", e); // 将可能出现的异常进行包装，转换为自定义异常
        }
        Book book = mapper.getBookById(id);
        return book;
    }

@RestControllerAdvice // 将这个类作为异常处理器通知类
public class ProjectExceptionAdvice {
    @ExceptionHandler({SystemException.class}) // 拦截系统异常
    public Result doSystemException(SystemException e) {
        // 1.记录日志
        // 2.发送消息给运维
        // 3.发送邮件给开发人员
        System.out.println("SystemException ...");
        return new Result(e.getCode(), null, e.getMessage());
    }
    @ExceptionHandler({BusinessException.class}) // 拦截业务异常
    public Result doBusinessException(BusinessException e) {
        System.out.println("BusinessException ...");
        return new Result(e.getCode(), null, e.getMessage());
    }
    @ExceptionHandler({Exception.class}) // 拦截未知异常
    public Result doException(Exception e) {
        // 1.记录日志
        // 2.发送消息给运维
        // 3.发送邮件给开发人员
        System.out.println("Exception ...");
        return new Result(Code.SYSTEM_UNKNOWN_ERR, null, "System busy ...");
    }
}