cassandra 學習之旅 初體驗

1、安裝

1.1、下載地址

1.2、Linux下安裝

以下命令使用root用戶執行，以下爲單機版

新建cassandra用戶

groupadd cassandra

useradd -s /bin/bash -g cassandra -d /opt/cassandra cassandra

解壓並賦給cassandra權限

tar -zxvf apache-cassandra-2.2.0-bin.tar.gz  -C /opt/cassandra

chown -R cassandra:cassandra /opt/cassandra

啓動

cd /opt/cassandra/apache-cassandra-2.2.0/bin

su cassandra ./cassandra

如果沒有報錯， 出現如下信息表示啓動成功

INFO  02:45:30 No gossip backlog; proceeding

關閉

ps -aux |grep cassandra

kill pid#pid爲cassandra的pid

2、cassandra之旅

以下命令使用cassandra用戶執行

安裝好之後，那麼如何使用呢？

先修改配置文件，使遠程客戶端能連上，

vim cassandra.yaml

將下面兩個配置項的值由localhost改爲IP地址,示例如下

listen_address: 192.168.0.101

rpc_address: 192.168.0.101

2.1、使用cassandra自帶的命令行

cd /opt/cassandra/apache-cassandra-2.2.0/bin

./cqlsh 192.168.0.101

出現如下命令行, 則表示連接成功

cqlsh> 

下面輸入簡單的幾個cql命令, 詳細的cql使用,請參見CQL for Cassandra 2.0 & 2.1

--創建keyspace, 類似SQL Database

create keyspace if not exists test_1 with replication = {'class': 'SimpleStrategy', 'replication_factor': 1};

--創建cf, 類似SQL Table

create table users (id int, user_name varchar, primary key(id));

--修改表

alter table users add age int;

--插入數據

insert into users (id, user_name) values (1, 'zhangsan');

--修改數據

update users set user_name = 'zhangsan111' where id = 1;

update users set age = 5 where id = 1;

--查詢

select * from users;

select count(*) from users;

 

cassandra的查詢具有以下約束：

第一主鍵 只能用=或IN查詢

第二主鍵 支持= ,> ,<, >= ,<= 但是必須後面加 ALLOW FILTERING

索引列 只能用=查詢

 

--刪除數據

delete from users where id =1;

2.2、代碼實現表的CRUD操作

我這裏以JAVA舉例

MAVEN依賴如下：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.league</groupId>
    <artifactId>cassandra</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <spring.framework.version>3.2.8.RELEASE</spring.framework.version>
    <repositories>
        <repository>
            <id>spring-milestone</id>
            <name>Spring Maven MILESTONE Repository</name>
            <url>http://repo.spring.io/libs-milestone</url>
        </repository>
        <repository>
            <id>com.springsource.repository.maven.release</id>
            <url>http://maven.springframework.org/release/</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>oracleReleases</id>
            <name>Oracle Released Java Packages</name>
            <url>http://download.oracle.com/maven</url>
        </repository>
        <repository>
            <id>JBossRepo1</id>
            <name>Jboss1</name>
            <url>https://repository.jboss.org/nexus/content/groups/public-jboss/</url>
        </repository>
        <repository>
            <id>JBossRepo</id>
            <name>Jboss</name>
            <url>https://repository.jboss.org/nexus/content/repositories/releases/</url>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-cassandra</artifactId>
            <version>1.0.0.RELEASE</version>
        </dependency>
    </dependencies>

</project>

 

import java.util.List;
import java.util.UUID;

import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.data.cassandra.core.CassandraOperations;

import com.datastax.driver.core.querybuilder.QueryBuilder;
import com.datastax.driver.core.querybuilder.Select;
import com.league.cassandra.pojo.Person;



/**
 * 創建表:  create table person (id varchar, name varchar, age int, primary key(id));
 *
 */
public class App {


    public static void main(String[] args) {
        ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("demo1.xml");
        CassandraOperations cassandraTemplate = context.getBean("cassandraTemplate", CassandraOperations.class);

        long t1 = System.currentTimeMillis();

        //insert
        Person person = null;
        for (int i=0; i<100; i++){
            person = new Person(UUID.randomUUID().toString(), "NAME," + (i+1), i);
            cassandraTemplate.insert(person);
        }
        System.out.println("insert cost " + (System.currentTimeMillis() - t1));

        //query cql
        List<Person> persons = cassandraTemplate.select("select * from person", Person.class);
        print(persons);
        System.out.println("Count: " + persons.size());
        System.out.println("query cost " + (System.currentTimeMillis() - t1));

        //query select
        Select s = QueryBuilder.select().from("Person");
        //s.limit(50);//用於返回多少條數
        //s.where(QueryBuilder.eq("id", "ab081ad1-9b1c-43de-a605-1c36113a3d53"));
        List<Person> personsResults = cassandraTemplate.select(s, Person.class);
        print(personsResults);
        System.out.println("Count: " + personsResults.size());
        System.out.println("query cost " + (System.currentTimeMillis() - t1));

        cassandraTemplate.getSession().close();
        context.close();
    }

    public static void print(Person person){
        System.out.println(person);
    }

    public static void print(List<Person> persons){
        for (int i=0; i<persons.size(); i++){
            System.out.print(i + "\t");
            print(persons.get(i));
        }
    }
}

 

 

package com.league.cassandra.pojo;

import org.springframework.data.cassandra.mapping.PrimaryKey;
import org.springframework.data.cassandra.mapping.Table;

@Table
public class Person {

 @PrimaryKey
 private String id;

 private String name;

 private int age;

 public Person(String id, String name, int age) {
  this.id = id;
  this.name = name;
  this.age = age;
 }

 public String getId() {
  return id;
 }

 public String getName() {
  return name;
 }

 public int getAge() {
  return age;
 }

 @Override
 public String toString() {
  return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
 }

}

 

 cassandra.properties

cassandra.contactpoints=192.168.0.101
cassandra.port=9042
cassandra.keyspace=test_1

 

demo1.xml

<?xml version='1.0'?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:cassandra="http://www.springframework.org/schema/data/cassandra"
  xmlns:context="http://www.springframework.org/schema/context"
  xsi:schemaLocation="http://www.springframework.org/schema/cql http://www.springframework.org/schema/cql/spring-cql-1.0.xsd
    http://www.springframework.org/schema/data/cassandra http://www.springframework.org/schema/data/cassandra/spring-cassandra-1.0.xsd
    http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">

  <!-- Loads the properties into the Spring Context and uses them to fill
    in placeholders in the bean definitions -->
  <context:property-placeholder location="classpath:cassandra.properties" />

  <!-- REQUIRED: The Cassandra Cluster -->
  <cassandra:cluster contact-points="${cassandra.contactpoints}"
    port="${cassandra.port}" />

  <!-- REQUIRED: The Cassandra Session, built from the Cluster, and attaching
    to a keyspace -->
  <cassandra:session keyspace-name="${cassandra.keyspace}" />

  <!-- REQUIRED: The Default Cassandra Mapping Context used by CassandraConverter -->
  <cassandra:mapping />

  <!-- REQUIRED: The Default Cassandra Converter used by CassandraTemplate -->
  <cassandra:converter />

  <!-- REQUIRED: The Cassandra Template is the building block of all Spring
    Data Cassandra -->
  <cassandra:template id="cassandraTemplate" />

  <!-- OPTIONAL: If you are using Spring Data Cassandra Repositories, add
    your base packages to scan here
  <cassandra:repositories base-package="org.spring.cassandra.example.repo" />
   -->

</beans>

spring整合cassandra，更多請參見 官方文檔

 

關於cassandra學習過程中, 更多的參考文檔如下:

NoSQL誕生的原因和優缺點 http://blog.csdn.net/chenhuajie123/article/details/9374969 

Cassandra中實現SQL操作  http://dongxicheng.org/nosql/cassandra-sql/

Cassandra 2.1 數據查詢語法   http://www.tuicool.com/articles/qAVBna7

CQL for Cassandra 2.0 & 2.1 http://docs.datastax.com/en/cql/3.1/cql/cql_reference/update_r.html

http://cassandra.apache.org/doc/cql3/CQL.html

datastax指南:  https://academy.datastax.com/demos/brief-introduction-apache-cassandra

spring整合cassandra http://docs.spring.io/spring-data/cassandra/docs/1.0.2.RELEASE/reference/htmlsingle/#cassandra-getting-started

配置項設置:  http://pimin.net/archives/297

文章參考:  http://tech.chinaunix.net/a2010/1225/1142/000001142663.shtml

一網打盡當下NoSQL類型、適用場景及使用公司  http://www.csdn.net/article/2013-07-24/2816330-how-to-choose-nosql-db

cassandra實戰書: http://book.51cto.com/art/201105/264261.htm

cassandra最佳實踐:  http://www.infoq.com/cn/articles/best-practices-cassandra-data-model-design-part2/

Cassandra – 數據結構設計概念和原則  http://my.oschina.net/silentriver/blog/182814

Cassandra研究報告    http://blog.csdn.net/zyz511919766/article/details/38683219/