Written in the front: The Java back-end advanced interview questions necessary for the interview in 2020. A review guide is summarized on Github. The content is detailed, with pictures and texts. Friends who need to learn can star!
GitHub address: https://github.com/abel-max/Java-Study-Note/tree/master
A log record table
The log record table mainly contains several fields, business module, operation type, interface address, processing status, error information and operation time. The database design is as follows:
CREATE TABLE `sys_oper_log` (
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '日志主键',
`title` varchar(50) CHARACTER SET utf8 DEFAULT '' COMMENT '模块标题',
`business_type` int(2) DEFAULT '0' COMMENT '业务类型（0其它 1新增 2修改 3删除）',
`method` varchar(255) CHARACTER SET utf8 DEFAULT '' COMMENT '方法名称',
`status` int(1) DEFAULT '0' COMMENT '操作状态（0正常 1异常）',
`error_msg` varchar(2000) CHARACTER SET utf8 DEFAULT '' COMMENT '错误消息',
`oper_time` datetime DEFAULT NULL COMMENT '操作时间',
PRIMARY KEY (`id`)
) ENGINE=InnoDB CHARSET=utf8mb4 CHECKSUM=1 COMMENT='操作日志记录'
The corresponding entity classes are as follows:
@Data
@NoArgsConstructor
@AllArgsConstructor
public class SysOperLog implements Serializable {
private static final long serialVersionUID = 1L;
/** 日志主键 */
private Long id;
/** 操作模块 */
private String title;
/** 业务类型（0其它 1新增 2修改 3删除） */
private Integer businessType;
/** 请求方法 */
private String method;
/** 错误消息 */
private String errorMsg;
private Integer status;
/** 操作时间 */
private Date operTime;
}
Two custom annotations and processing
The custom annotation contains two attributes, one is the business module title and the other is the operation type businessType.
@Target({ ElementType.PARAMETER, ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Log {
/**
* 模块
*/
String title() default "";
/**
* 功能
*/
BusinessType businessType() default BusinessType.OTHER;
}
Use aop to process custom annotations
@Aspect
@Component
@Slf4j
public class LogAspect {
@Autowired
private AsyncLogService asyncLogService;
// 配置织入点
@Pointcut("@annotation(com.javatrip.aop.annotation.Log)")
public void logPointCut() {}
/**
* 处理完请求后执行
*
* @param joinPoint 切点
*/
@AfterReturning(pointcut = "logPointCut()", returning = "jsonResult")
public void doAfterReturning(JoinPoint joinPoint, Object jsonResult) {
handleLog(joinPoint, null, jsonResult);
}
/**
* 拦截异常操作
*
* @param joinPoint 切点
* @param e 异常
*/
@AfterThrowing(value = "logPointCut()", throwing = "e")
public void doAfterThrowing(JoinPoint joinPoint, Exception e) {
handleLog(joinPoint, e, null);
}
protected void handleLog(final JoinPoint joinPoint, final Exception e, Object jsonResult) {
try {
// 获得注解
Log controllerLog = getAnnotationLog(joinPoint);
if (controllerLog == null) {
return;
}
SysOperLog operLog = new SysOperLog();
operLog.setStatus(0);
if (e != null) {
operLog.setStatus(1);
operLog.setErrorMsg(StringUtils.substring(e.getMessage(), 0, 2000));
}
// 设置方法名称
String className = joinPoint.getTarget().getClass().getName();
String methodName = joinPoint.getSignature().getName();
operLog.setMethod(className + "." + methodName + "()");
// 处理设置注解上的参数
getControllerMethodDescription(joinPoint, controllerLog, operLog);
// 保存数据库
asyncLogService.saveSysLog(operLog);
} catch (Exception exp) {
log.error("==前置通知异常==");
log.error("日志异常信息 {}", exp);
}
}
/**
* 获取注解中对方法的描述信息 用于Controller层注解
*
* @param log 日志
* @param operLog 操作日志
* @throws Exception
*/
public void getControllerMethodDescription(JoinPoint joinPoint, Log log, SysOperLog operLog) {
// 设置action动作
operLog.setBusinessType(log.businessType().ordinal());
// 设置标题
operLog.setTitle(log.title());
}
/**
* 是否存在注解，如果存在就获取
*/
private Log getAnnotationLog(JoinPoint joinPoint) {
Signature signature = joinPoint.getSignature();
MethodSignature methodSignature = (MethodSignature) signature;
Method method = methodSignature.getMethod();
if (method != null) {
return method.getAnnotation(Log.class);
}
return null;
}
}
Enumeration class of operation type:
public enum BusinessType {
/**
* 其它
*/
OTHER,
/**
* 新增
*/
INSERT,
/**
* 修改
*/
UPDATE,
/**
* 删除
*/
DELETE,
}
Using the asynchronous method will save the operation log database, in order to facilitate the direct use jdbcTemplate I be in service in warehousing operations.
@Service
public class AsyncLogService {
@Autowired
private JdbcTemplate jdbcTemplate;
/**
* 保存系统日志记录
*/
@Async
public void saveSysLog(SysOperLog log) {
String sql = "INSERT INTO sys_oper_log(title,business_type,method,STATUS,error_msg,oper_time) VALUES(?,?,?,?,?,?)";
jdbcTemplate.update(sql,new Object[]{log.getTitle(),log.getBusinessType(),log.getMethod(),log.getStatus(),log.getErrorMsg(),new Date()});
}
}
Three write interface test
Write custom annotations on business methods to test the effect
@RestController
@RequestMapping("person")
public class PersonController {
@GetMapping("/{name}")
@Log(title = "system",businessType = BusinessType.OTHER)
public Person getPerson(@PathVariable("name") String name, @RequestParam int age){
return new Person(name,age);
}
@PostMapping("add")
@Log(title = "system",businessType = BusinessType.INSERT)
public int addPerson(@RequestBody Person person){
if(StringUtils.isEmpty(person)){
return -1;
}
return 1;
}
@PutMapping("update")
@Log(title = "system",businessType = BusinessType.UPDATE)
public int updatePerson(@RequestBody Person person){
if(StringUtils.isEmpty(person)){
return -1;
}
return 1;
}
@DeleteMapping("/{name}")
@Log(title = "system",businessType = BusinessType.DELETE)
public int deletePerson(@PathVariable(name = "name") String name){
if(StringUtils.isEmpty(name)){
return -1;
}
return 1;
}
}
Of course, you can also store the request parameters and response results in the database, so that you can see the operation records of the specific interface.