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Editor to share with you a sample analysis of the output mode of Springboot exception log. I hope you will get something after reading this article. Let's discuss it together.

Lombok plug-in use

Introducing dependencies and using Lombok in a project can reduce a lot of repetitive code writing. For example, writing ↓ for getter/setter/toString and other methods

Org.projectlombok lombok 1.16.20

Install the lombok plug-in ↓ in idea

Create package entity write entity class User.java (Lombok simplified code is used here) ↓ `

@ Datapublic class User {private Long id; private String name; private Integer age; private String email;}

Click to view the annotated compilation result ↓

Unified exception handling

We want the exception result to be displayed as a unified return result object, and to handle the exception information of the system uniformly, so we need unified exception handling.

Create a unified exception handling class GlobalExceptionHandler.java ↓

Package com.ywj.handler;import com.ywj.constants.ResultCodeEnum;import com.ywj.exception.MyException;import com.ywj.util.ExceptionUtil;import com.ywj.vo.R;import lombok.extern.slf4j.Slf4j;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.ResponseBody @ ControllerAdvice@Slf4jpublic class GlobalExceptionHandler {/ / Global exception handling @ ExceptionHandler (Exception.class) @ ResponseBody public R error (Exception e) {/ / e.printStackTrace (); / / output exception stack information log.error (e.getMessage ()); return R.error () } / / specific exception handling @ ExceptionHandler (ArithmeticException.class) @ ResponseBody public R error (ArithmeticException e) {/ / e.printStackTrace (); / / output exception stack information / / log.error (e.getMessage ()) Log.info ("error message -"); log.error (e.getMessage ()); return R.setResult (ResultCodeEnum.MY_ERROR) } / / Custom exception handling @ ExceptionHandler (MyException.class) @ ResponseBody public R error (MyException e) {/ / e.printStackTrace (); / / output exception stack information / / log.error (e.getMessage ()); log.error (ExceptionUtil.getMessage (e)) Return R.error () .message (e.getMessage ()) .code (e.getCode ());}}

Create a MyException.java generic exception class that inherits RuntimeException ↓

Package com.ywj.exception;import com.ywj.constants.ResultCodeEnum;import lombok.Data;@Data//@ApiModel (value = "Custom Global exception Class") public class MyException extends RuntimeException {/ / @ ApiModelProperty (value = "status Code") private Integer code / * * receive status code and error message * @ param code * @ param message * / public MyException (Integer code, String message) {super (message); this.code = code;} public MyException (ResultCodeEnum resultCodeEnum) {super (resultCodeEnum.getMessage ()) This.code = resultCodeEnum.getCode (); @ Override public String toString () {return "MyException {" + "code=" + code + ", message=" + this.getMessage () +'}';}}

The location needed in the business throws a custom exception ↓

Package com.ywj.controller;import com.ywj.exception.MyException;import org.springframework.stereotype.Controller;import org.springframework.ui.Model;import org.springframework.web.bind.annotation.GetMapping;@Controllerpublic class IndexController {@ GetMapping ("/") public String index (Model model) {/ / System.out.println (10max 0); if (true) {throw new MyException (10086, "Custom exception") } System.out.println ("index"); model.addAttribute ("name", "ywj"); return "index";}}

Additional instructions for other dependent classes ↓

Unified result returns class R ↓

Package com.ywj.vo;import com.ywj.constants.ResultCodeEnum;import lombok.Data;import java.util.HashMap;import java.util.Map;@Data//@ApiModel (value= "global unified return result") public class R {/ / @ ApiModelProperty (value= "success") private Boolean success; / / @ ApiModelProperty (value= "error code") private Integer code / / @ ApiModelProperty (value = "return message") private String message; / / @ ApiModelProperty (value = "return data") private Map data = new HashMap (); private R () {} public static R ok () {R r = new R (); r.setSuccess (ResultCodeEnum.SUCCESS.getSuccess ()) R.setCode (ResultCodeEnum.SUCCESS.getCode ()); r.setMessage (ResultCodeEnum.SUCCESS.getMessage ()); return r;} public static R error () {R r = new R (); r.setSuccess (ResultCodeEnum.UNKNOWN_REASON.getSuccess ()); r.setCode (ResultCodeEnum.UNKNOWN_REASON.getCode ()) R.setMessage (ResultCodeEnum.UNKNOWN_REASON.getMessage ()); return r;} public R data (Map map) {this.setData (map); return this;} public R data (String key, Object value) {this.data.put (key, value); return this } public R message (String message) {this.setMessage (message); return this;} public R code (Integer code) {this.setCode (code); return this;} public R success (Boolean success) {this.setSuccess (success); return this } public static R setResult (ResultCodeEnum resultCodeEnum) {R r = new R (); r.setSuccess (resultCodeEnum.getSuccess ()); r.setCode (resultCodeEnum.getCode ()); r.setMessage (resultCodeEnum.getMessage ()); return r;}}

Result enumeration constant class ResultCodeEnum ↓

Package com.ywj.constants;import lombok.Getter @ Getterpublic enum ResultCodeEnum {SUCCESS (true, 20000, "success"), UNKNOWN_REASON (false, 20001, "unknown error"), BAD_SQL_GRAMMAR (false, 21001, "sql syntax error"), JSON_PARSE_ERROR (false, 21002, "json parsing exception"), PARAM_ERROR (false, 21003, "incorrect parameters"), FILE_UPLOAD_ERROR (false, 21004) "File upload error"), EXCEL_DATA_IMPORT_ERROR (false, 21005, "Excel data import error"), MY_ERROR (false, 21006, "arithmetic exception error") Whether the private Boolean success;// response is successful or not. Private Integer code;// return code private String message;// return message ResultCodeEnum (Boolean success, Integer code, String message) {this.success = success; this.code = code; this.message = message;}}

Exception stack information output utility class ExceptionUtil ↓

Package com.ywj.util;import java.io.IOException;import java.io.PrintWriter;import java.io.StringWriter;public class ExceptionUtil {public static String getMessage (Exception e) {StringWriter sw = null; PrintWriter pw = null; try {sw = new StringWriter (); pw = new PrintWriter (sw) / / output the stack information of the error to printWriter e.printStackTrace (pw); pw.flush (); sw.flush () } finally {if (sw! = null) {try {sw.close ();} catch (IOException E1) {e1.printStackTrace () } if (pw! = null) {pw.close ();}} return sw.toString ();}}

The above is just an explanation. You can copy the relevant classes of the data folder directly to the company package, for example, under the ywj package. The project structure is as follows: ↓.

Unified Log output configuration Log level ↓

The behavior of the Logger is hierarchical. As shown in the following table:

Divided into: OFF, FATAL, ERROR, WARN, INFO, DEBUG, ALL

By default, the log level printed by spring boot from the console is only INFO and above. You can configure the log level ↓.

# set log level logging.level.root=WARN

The above methods can only print the log on the console, ↑.

Logback log ↓

Spring boot internally uses Logback as the framework for logging implementation.

Logback and log4j are very similar, and if you are familiar with log4j, you will soon be comfortable with logback.

Configure logback Log ↓

Delete the log configuration in application.properties

Install the idea color log plug-in: grep-console

Create logback-spring.xml in resources

Logback INFO ${CONSOLE_LOG_PATTERN} UTF-8 ${log.path} / log_info.log % d {yyyy-MM-dd HH:mm:ss.SSS} [% thread]%-5level% logger {50} -% msg%n UTF-8 ${log.path} / info/log-info-%d {yyyy-MM-dd}.% i.log 100MB 15 INFO ACCEPT DENY ${log.path} / log_warn.log% d {yyyy-MM-dd HH:mm:ss.SSS} [% thread]%-5level% logger {50} -% msg% N UTF-8 ${log.path} / warn/log-warn-%d {yyyy-MM-dd}.% i.log 100MB 15 warn ACCEPT DENY ${log.path} / log_error.log% d {yyyy-MM-dd HH:mm:ss.SSS} [% thread]%-5level% logger {50} -% msg%n UTF-8 ${log.path} / error/log-error-%d {yyyy- MM-dd}.% i.log 100MB 15 ERROR ACCEPT DENY

Finally, don't forget to use profiles in the application.yml configuration file to activate ↓ in the dev development environment or other environments such as the production environment pro

Server: port: 8888spring: mvc: view: prefix: / WEB-INF/jsp/ suffix: .jsp profiles: active: dev#logging:# level:# root: warn copy and paste

In fact, the above is just an explanation, do not want to be too troublesome, directly copy the relevant classes and log configuration files in the data folder to the project can ↑↓

After reading this article, I believe you have some understanding of "sample Analysis of Springboot exception Log output". If you want to know more about it, you are welcome to follow the industry information channel. Thank you for reading!

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