[JAVA] Cassandra x Spring Boot struggle record

Summary of this article

--Since I have never touched Cassandra, it is a record when I tried to build ~ Spring Boot application to reference / update --The environment is a local PC (Mac)

reference

Cassandra: http://cassandra.apache.org/doc/latest/ SpringDataCassandra: https://spring.io/projects/spring-data-cassandra property Setting item: https://docs.spring.io/spring-boot/docs/current/reference/html/appendix-application-properties.html#data-properties

Building Cassandra

Installation

#Cassandra body
brew install cassandra
# CQL(Cassandra Query Language)
brew install cql

Start-up

cassandra -f

Connection error: ('Unable to connect to any servers', {'127.0.0.1': error(61, "Tried connecting to [('127.0.0.1', 9042)]. Last error: Connection refused")})

It doesn't move. .. .. In my case, it seems that JAVA_HOME shouldn't point to the Java 11 directory. .. .. After redefining it, it will start up safely!

export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_211.jdk/Contents/Home/
cassandra -f

Start with Homebrew anyway!

vi /usr/local/etc/cassandra/cassandra-env.sh
#"Export JAVA" at the end_HOME=/Library/Java/JavaVirtualMachines/jdk1.8.0_211.jdk/Contents/Home/Added

brew services start cassandra

Connect!

cqlsh

cqlsh localhost 9042 With this

Let's play Cassandra alone for a moment

cqlsh

Resume from here The explanation of detailed options is omitted here. .. ..

Add KeySpace

Concept corresponding to Database in MySQL and Oracle

-- #Before adding keyspace
DESCRIBE keyspaces
-- system_traces  system_schema  system_auth  system  system_distributed

-- #Added "sample" keyspace
CREATE KEYSPACE sample WITH REPLICATION = {'class':'SimpleStrategy','replication_factor':1};

-- #Before adding keyspace
DESCRIBE keyspaces
-- system_schema  system_auth  system  sample  system_distributed  system_traces

By the way, the deletion is

DROP KEYSPACE sample;

Move Database

USE sample

Creating a table

Here, we simply assume data with Key and Value.

--Create
CREATE TABLE t_sample (key text PRIMARY KEY, value text);

--Check the list
DESCRIBE tables;

--Check table definition
DESCRIBE table t_sample;

By the way, the deletion is

DROP TABLE t_sample;

Data manipulation

Using the t_sample table created earlier

--Reference (empty)
select * from t_sample;

--Reference (equivalent to above)
select key, value from t_sample;

--Registration
INSERT INTO t_sample (key, value) VALUES ('key1', 'value1');

--Registration (duplicate)
--The query is successful and behaves like an update
INSERT INTO t_sample (key, value) VALUES ('key1', 'value2');

--update
UPDATE t_sample SET value = 'value3' WHERE key = 'key1';

--Delete
DELETE FROM t_sample WHERE key = 'key1';

It's my first experience to be updated instead of being played if I violate the primary

Build Spring application

project creation

build.gradle

plugins {
    id 'org.springframework.boot' version '2.2.4.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '11'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-cassandra'
    //webflux is for operation check
    implementation 'org.springframework.boot:spring-boot-starter-webflux'
    compileOnly('org.projectlombok:lombok')
    annotationProcessor('org.projectlombok:lombok')
}

application.yml

spring:
  data:
    cassandra:
      keyspace-name: sample

Create model class for table

Sample.java

import lombok.Value;
import org.springframework.data.cassandra.core.mapping.PrimaryKey;
import org.springframework.data.cassandra.core.mapping.Table;

@Data
@Table("t_sample")
public class Sample {
    @PrimaryKey
    private String key;
    private String value;
}

Try to register / reference / delete

Application.java

@Slf4j
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        //SpringApplication.run(Application.class);

        Cluster cluster = Cluster.builder()
                .addContactPoints("localhost")
                .withoutJMXReporting()  //Error if not attached
                .build();
        Session session = cluster.connect("sample");

        var template = new CassandraTemplate(session);
        var data = new Sample("key1", "value1");

        template.insert(data);
        //Search all
        var selected = template.select("SELECT * from t_sample", Sample.class);
        log.info("selected: {}", selected);
        //update
        data = new Sample("key1", "value2");
        template.update(data);
        //Conditional search
        selected = template.select(Query.query(Criteria.where("key").is("key1")), Sample.class);
        log.info("selected: {}", selected);
        //Delete (PK specified)
        template.deleteById("key1", Sample.class);
        //Get the number
        var count = template.count(Sample.class);
        log.info("count: {}", count);

        //Connection closed
        session.close();
        cluster.close();
    }
}

The following error occurred unless .withoutJMXReporting () was described.

Exception in thread "main" java.lang.NoClassDefFoundError: com/codahale/metrics/JmxReporter

Try to make it look like a web application

First of all, investigate how much "spring-boot-starter-data-cassandra" will register beans

Cluster

--ʻOrg.springframework.boot.autoconfigure.cassandra.CassandraAutoConfigurationis registered as a bean --It seems good to set properties underspring.data.cassandra --spring.data.cassandra.keyspace-name = sample`

Session

――Is it Session or Session Factory? --ʻOrg.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfigurationis registered as a bean --This also seems to reflect the settings underspring.data.cassandra`

CassandraTemplate

--Similar to Session, ʻorg.springframework.boot.autoconfigure.data.cassandra.CassandraDataAutoConfiguration` is registered as a bean.

Conclusion ... Suddenly use Cassandra Template and it's OK!

CassandraController.java

@RequiredArgsConstructor
@RestController
public class CassandraController {
    private final CassandraTemplate template;

    // curl localhost:8080
    @GetMapping("")
    public List<Sample> all() {
        return template.select("SELECT * FROM t_sample", Sample.class);
    }

    // curl localhost:8080/key1
    @GetMapping("/{key}")
    public Sample getByKey(@PathVariable String key) {
        return template.selectOneById(key, Sample.class);
    }

    // curl localhost:8080/insert -d '{"key":"key1","value":"value1"}' -X PATCH -H 'Content-Type: application/json'
    @PatchMapping("/**")
    public Sample patch(@RequestBody Sample sample) {
        return template.insert(sample);
    }

    // curl localhost:8080/key1 -X DELETE
    @DeleteMapping("/{key}")
    public Boolean delete(@PathVariable String key) {
        return template.deleteById(key, Sample.class);
    }
}

Reactive support

Just use ReactiveCassandraTemplate! Don't forget to change the return type to Flux or Mono! (It is also OK as a publisher at once)

ReactiveCassandraController.java

@RequiredArgsConstructor
@RestController
@RequestMapping("/reactive")
public class ReactiveCassandraController {
    private final ReactiveCassandraTemplate template;

    // curl localhost:8080/reactive
    @GetMapping("")
    public Flux<Sample> all() {
        return template.select("SELECT * FROM t_sample", Sample.class);
    }

    // curl localhost:8080/reactive/key1
    @GetMapping("/{key}")
    public Mono<Sample> getByKey(@PathVariable String key) {
        return template.selectOneById(key, Sample.class);
    }

    // curl localhost:8080/reactive/insert -d '{"key":"key1","value":"value1"}' -X PATCH -H 'Content-Type: application/json'
    @PatchMapping("/**")
    public Mono<Sample> patch(@RequestBody Sample sample) {
        return template.insert(sample);
    }

    // curl localhost:8080/reactive/key1 -X DELETE
    @DeleteMapping("/{key}")
    public Mono<Boolean> delete(@PathVariable String key) {
        return template.deleteById(key, Sample.class);
    }

}