README.md

Project Specific Documentation

This is a reference spring project showing different functionalities. The idea is to use this as a reference for copying out snippets and functionalities.

Imp VM Parameters:

• -Dfile.encoding=UTF-8 ( to read sql initialization script properly )
• -Dsecret.api.value=secretValue
• -Dspring.profiles.active=local ( windows dev )
• -Dspring.profiles.active=dev ( from unix/deployed instance )

-Xmx512m -Xms512m -Xlog:class+load=info:file=classload.log -Xlog:gc*:file=C:\_TEMP\Logs\GCLogs\gc.log -Xmx512m -Dfile.encoding=UTF-8 -Dsecret.api.value=secretValue -Dspring.profiles.active=local

Local endpoints active are below - all end points are not mapped here. This is to give the user starting point. Please use the swagger for comprehensive list of endpoints.

• http://localhost:60501/swagger-ui/index.html
• http://localhost:60501/v3/api-docs
• http://localhost:60501/status
• http://localhost:60501/h2-console

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Logging

The following can be used to set application/package/class level logging

logging.level.root=INFO
logging.level.com.java.springboot.controllers.StatusController=TRACE

Spring Logging Documentation :

• Standard Spring Logging Doc https://docs.spring.io/spring-boot/how-to/logging.html
• https://docs.spring.io/spring-boot/reference/features/logging.html#features.logging.custom-log-configuration
• https://logback.qos.ch/manual/appenders.html

Logback

• by default spring uses logback, which can be configured by logback.xml
• use logback-spring.xml instead of logback.xml as it allows spring to load custom configs
• profile specific config can be loaded with <springProfile name="dev">
• understanding how maxHistory works - https://pauldally.medium.com/why-is-my-logback-rolling-policy-keeping-more-than-maxhistory-files-66fbc865f38
• maxHistory changes behaviour based on policyType
• use if you want to use the default spring config in your logback along with your own config
  • <include resource="org/springframework/boot/logging/logback/base.xml" />
• Spring Boot Logging Documentation
  • https://docs.spring.io/spring-boot/docs/2.0.x/reference/html/boot-features-logging.html#:~:text=By%20default%2C%20Spring%20Boot%20logs,for%20example%2C%20in%20your%20application.
  • profile specific logging in logback - https://howtodoinjava.com/spring-boot/profile-specific-logging

Understanding the current logback config

• for logback it will create log files in C:\_TEMP\Logs\SpringBootLogs\CustomFileAppender\customLog.log
• Functionalities ( Console logging, Rolling file logging, Specific java package based logging )
• Console logging is inherited from <include resource="org/springframework/boot/logging/logback/base.xml" />
• Additional file logging is done using myRollingFileAppender
• Specific package based file logging is done with myCustomFileAppender using <logger>
• LogBook library can be used to log HTTP request/responses
  • enabled by logging.level.org.zalando.logbook.Logbook=TRACE
  • https://www.baeldung.com/spring-logbook-http-logging
• Structured logging added with logstash encoder and jsonConsoleAppender appender
  • https://www.baeldung.com/java-structured-logging

Using Log4J

• add log4j2 dependency and exclude default logging dependency
• implementation 'org.springframework.boot:spring-boot-starter-log4j2:3.3.4
• exclude group: "org.springframework.boot", module:"spring-boot-starter-logging"

Using LogBack

• comment log4j2 dependency and remove spring logging exclude
• comment implementation 'org.springframework.boot:spring-boot-starter-log4j2:3.3.4
• commentexclude group: "org.springframework.boot", module:"spring-boot-starter-logging"

Log4j2

• monitorInterval="10" works, but you must update the log4j2.xml in build\resources
• console, file-based and rolling file based implementation added for log4j2
• for envt specific log4j2 files refer - https://www.baeldung.com/spring-log4j2-config-per-profile

References :

• [logback] Understanding duplicate commons-logging issue in spring-boot - spring-projects/spring-framework#20611
  • the same class in commons-logging is implemented by spring-jcl as a fallback in case both are present in classpath
  • org.apache.commons.logging.LogFactory included in commons-logging is given a dummy child LogFactoryService.java
  • this causes the message to show when it gets initialized Standard Commons Logging discovery in action with spring-jcl
    • org.apache.commons.logging.LogFactory
      • https://commons.apache.org/proper/commons-logging/apidocs/org/apache/commons/logging/LogFactory.html
      • https://github.com/spring-projects/spring-framework/blob/6.0.x/spring-jcl/src/main/java/org/apache/commons/logging/LogFactory.java
    • spring-jcl sub-class
      • https://github.com/spring-projects/spring-framework/blob/6.0.x/spring-jcl/src/main/java/org/apache/commons/logging/LogFactoryService.java
    • Problems with Apache Commons Logging ( JCL ) - https://stackoverflow.com/questions/3222895/what-is-the-issue-with-the-runtime-discovery-algorithm-of-apache-commons-logging/
    • Commons logging was my fault blog - https://radio-weblogs.com/0122027/2003/08/15.html
• [log4j2] Disadvantages of MemoryMappedAppender - https://stackoverflow.com/questions/22630547/disadvantages-of-using-memory-mapped-files
• [logback] logback conversion words - https://logback.qos.ch/manual/layouts.html#conversionWord
• [logback] baeldung logback articles - https://www.baeldung.com/tag/logback
• Mapped Dynamic Contexts (MDCs) are used for thread-specific logging - https://www.baeldung.com/mdc-in-log4j-2-logback
• Nested Dignostic Context ( NDC - not supported in SLF4J ) - https://www.baeldung.com/java-logging-ndc-log4j
• [log4j2] How to send logging into to Syslog Server - https://www.baeldung.com/log4j-to-syslog

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Env Controller

• http://localhost:60501/api/v1/envinfo
• http://localhost:60501/api/v1/envinfo/rmxbean

View endpoints are as follows

• http://localhost:60501/
• http://localhost:60501/home
• http://localhost:60501/countries
• http://localhost:60501/starter
• http://localhost:60501/starter-blank

Csv endpoints as follows ( i18n handled by jvm param )

• http://localhost:60501/api/v1/csv/file/users
• http://localhost:60501/api/v1/csv/download/users
• http://localhost:60501/api/v1/csv/read/users ( read csv file )

Upload (Multipart) and Download File

• http://localhost:60501/api/v1/csv/upload/labels?overWrite=true
• http://localhost:60501/api/v1/csv/download/labels

Json endpoints as follows :

• http://localhost:60501/api/v1/json/file/users
• http://localhost:60501/api/v1/json/read/users

PDF Controller Using PDF Box : ( i18n achieved with dynamic font loading )

• http://localhost:60501/api/v1/pdf/file/users
• http://localhost:60501/api/v1/pdf/download/users
• http://localhost:60501/api/v1/pdf/download/password/users

Excel Controller using apache poi :

• http://localhost:60501/api/v1/excel/read/users
• http://localhost:60501/api/v1/excel/download/users
• http://localhost:60501/api/v1/excel/download/sample

XML Controller using JAXB :

• http://localhost:60501/api/v1/xml/read/users
• http://localhost:60501/api/v1/xml/file/users
• http://localhost:60501/api/v1/xml/download/users

Xpath Controller :

• http://localhost:60501/api/v1/xpath/transform/tutorials

XSLT Controller :

• http://localhost:60501/api/v1/xslt/transform/users
• http://localhost:60501/api/v1/xslt/transform/download/users

Protocol Buffer Controller ( save/read from disk ) :

• http://localhost:60501/api/v1/protobuf/read/users
• http://localhost:60501/api/v1/protobuf/file/users

Global Custom Error Handling Page :

• http://localhost:60501/api/v1/countries/err

Caching and Scheduling, Conditional On Property ( LabelController ) :

TODO

• @Cacheable
• @Mockito
• Java File IO

h2 database configuration

password is 'password'

JVM Params :

• -Duser.timezone=UTC -Dfile.encoding=utf-8

Intellij Configuration :

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###Features

• Internationalization added for file encodings
• save to csv locally & download

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###References

• String Functions in Free Marker :
  • https://freemarker.apache.org/docs/ref_builtins_string.html
• Data Types in H2 Database :
  • https://www.h2database.com/html/datatypes.html
• Free Unicode Font
  • https://djmilch.wordpress.com/2016/01/19/free-font-noto-sans-cjk-in-ttf/
• Json Parsing Tutorials
  • https://devqa.io/how-to-parse-json-in-java/
  • https://www.baeldung.com/guide-to-jayway-jsonpath
  • JSON Path Cheat Sheet -https://support.smartbear.com/alertsite/docs/monitors/api/endpoint/jsonpath.html
  • https://lzone.de/cheat-sheet/JSONPath
• Base64 Tutorial
  • https://www.baeldung.com/java-base64-encode-and-decode
  • URL and Filename safe Alphabet - https://www.ietf.org/rfc/rfc4648.txt
• XSLT Cheat Sheet
  • https://www.technical-recipes.com/2022/xslt-example-cheat-sheet/
  • https://www.baeldung.com/java-extensible-stylesheet-language-transformations
  • https://www.w3schools.com/xml/xsl_choose.asp
  • https://www.ibm.com/support/pages/creating-utf-8-documents-xslt
• Protocol Buffer :
  • https://www.baeldung.com/google-protocol-buffer
  • https://www.baeldung.com/spring-rest-api-with-protocol-buffers#overview
  • https://github.com/protocolbuffers/protobuf/releases
  • $ protoc --java_out=${OUTPUT_DIR} path/to/your/proto/file
    • ..\src\main>protoc --java_out=java resources\protobuf\baeldung.proto
• Global Error Handler :
  • https://stackoverflow.com/questions/63022189/get-stack-trace-from-httpservletrequest-in-spring-boot
  • https://www.baeldung.com/exception-handling-for-rest-with-spring
• Country language Codes ( en, ja, zh ) : ISO 639-1 Code
  • https://www.loc.gov/standards/iso639-2/php/code_list.php
• General Spring Related Info
  • https://stackoverflow.com/questions/21218868/explain-why-constructor-inject-is-better-than-other-options
• Cron Expressions
  • https://www.baeldung.com/cron-expressions
• SPEL Support in JPA
  • https://spring.io/blog/2014/07/15/spel-support-in-spring-data-jpa-query-definitions/
• Hibernate Logging Properties
  • https://thorben-janssen.com/hibernate-logging-guide/
• Using Environment Variables
  • https://www.baeldung.com/spring-boot-properties-env-variables

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Spring Boot Reference Documentation

For further reference, please consider the following sections:

• Official Gradle documentation
• Spring Boot Gradle Plugin Reference Guide
• Create an OCI image
• Spring Boot DevTools
• Spring Web
• Apache Freemarker

Guides

The following guides illustrate how to use some features concretely:

• Building a RESTful Web Service
• Serving Web Content with Spring MVC
• Building REST services with Spring

Additional Links

These additional references should also help you:

• Gradle Build Scans – insights for your project's build