Microservice Design Pattern

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Microservice design principles –

1.       Domain driven design

2.       Single responsibility principle

3.       High cohesion & low coupling

4.       Decentralized data

5.       Failure isolation

6.       Fault tolerance

7.       Hexagonal architecture

8.       Continuous delivery with DevOps

9.       Continuous monitoring & distributed tracing

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Microservice design pattern –

1.       Decomposition pattern

2.       Integration patter

3.       Database pattern

4.       Observability pattern

5.       Cross cutting concern pattern

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Decomposition pattern: -

1.       Decomposed by business capability

2.       Decomposed by subdomain

3.       Strangler pattern

4.       Bulkhead pattern

5.       Sidecar patter

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Integration patter

1.       API gateway pattern

2.       Aggregators pattern

3.       Proxy pattern

4.       Gateway routing pattern

5.       Chained routing pattern

6.       Chained microservices pattern

7.       Branch pattern

8.       Client-side UI composition pattern

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Database pattern

1.       Database per service

2.       Shared database per service

3.       CQRS pattern

4.       Event sourcing pattern

5.       SAGA Pattern

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Observability pattern

1.       Log aggregation pattern

2.       Performance metrics pattern

3.       Distributed tracing pattern

4.       Health check pattern

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Cross cutting concern pattern

1.       External configuration pattern

2.       Service discovery pattern

3.       Circuit breaker pattern

4.       Blue green deployment pattern

5.       Canary deployment pattern

Date Format conversion

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Important code snippet for Date conversions and methods-

Here we are covering different conversion of date more frequently used-

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Covert Date String to Date object

package com.featuretest.basics;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.util.Date;

class TestMain {

public static void main(String[] args) throws ParseException {

      String dateString = "31/05/1988";

      Date dateObj = new SimpleDateFormat("dd/MM/yyyy").parse(dateString);

      System.out.println(dateString + "\t" + dateObj);

}

}

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Covert Date object to localDateTime

package com.featuretest.basics;

import java.text.ParseException;

import java.time.LocalDateTime;

import java.time.ZoneId;

import java.util.Date;

class TestMain {

public static void main(String[] args) throws ParseException {

      Date date = new Date();

      LocalDateTime localDateTime = date.toInstant().atZone(ZoneId.systemDefault()).toLocalDateTime();

      System.out.println(localDateTime);

}

}

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Date conversion from one format to another

package com.featuretest.basics;

import java.text.ParseException;

import java.text.SimpleDateFormat;

import java.time.LocalDate;

import java.time.LocalDateTime;

import java.time.format.DateTimeFormatter;

import java.util.Date;

class TestMain {

public static void main(String[] args) {

String dateString = "2019-12-19 04:10:00";

String convertedDate = dateFormatConversion(dateString, "yyyy-MM-dd hh:mm:ss", "yyyy-MM-dd");

System.out.println(convertedDate);

           

// Using Java 8 DateTime API

String convertedDateJava8 = dateFormatConversionJava8(dateString, "yyyy-MM-dd hh:mm:ss", "yyyy-MM-dd");

System.out.println(convertedDateJava8);

}

     

private static String dateFormatConversion(String dateString, String inputDF, String outputDF) {

SimpleDateFormat sdf = new SimpleDateFormat(inputDF);

Date date = null;

try {

      date = sdf.parse(dateString);

} catch (ParseException e) {

      e.printStackTrace();

}

SimpleDateFormat newFormat = new SimpleDateFormat(outputDF);

String output = newFormat.format(date);

return output;

}

     

private static String dateFormatConversionJava8(String dateString, String inputDF, String outputDF) {

DateTimeFormatter oldDTF = DateTimeFormatter.ofPattern(inputDF);

DateTimeFormatter newDTF = DateTimeFormatter.ofPattern(outputDF);

LocalDateTime datetime = LocalDateTime.from(LocalDate.parse(dateString, oldDTF).atStartOfDay());

return datetime.format(newDTF);

}

}

Enable HTTPS URL for Spring Boot wep application

Enable SSL certificate in spring boot application.

To enable https URL first we need to create an SSL certificate and configure the SSL certificate with spring boot application.

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Create SSL certificate –

Navigate to the java installation directory, inside bin folder there is keytool executable file.

Run below command to generate jks file.

keytool -genkeypair -alias cert -keyalg RSA -keysize 2048 -keystore cert.jks -validity 3650

Run below command to get the content of keystore-

keytool -list -v -keystore cert.jks

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Create a spring boot application–

Copy the certificate jks file in src/main/resources folder

Add below property in you application.yml file

server.port: 8443

server.ssl.key-alias: cert

server.ssl.key-store-password: ********

server.ssl.key-store: classpath:cert.jks

server.ssl.key-store-provider: SUN

server.ssl.key-store-type: JKS

Now you can access the url with https 
Refer below repository for project-
Enable SSL URL for web application