cassandra 学习之旅<一> 初体验

1、安装

1.1、下载地址

1.2、Linux下安装

以下命令使用root用户执行，以下为单机版

新建cassandra用户

groupadd cassandra

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

解压并赋给cassandra权限

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

chown -R cassandra:cassandra /opt/cassandra

启动

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

su cassandra ./cassandra

如果没有报错， 出现如下信息表示启动成功

INFO 02:45:30 No gossip backlog; proceeding

关闭

ps -aux |grep cassandra

kill pid#pid为cassandra的pid

2、cassandra之旅

以下命令使用cassandra用户执行

安装好之后，那么如何使用呢？

先修改配置文件，使远程客户端能连上，

vim cassandra.yaml

将下面两个配置项的值由localhost改为IP地址,示例如下

listen_address: 192.168.0.101

rpc_address: 192.168.0.101

2.1、使用cassandra自带的命令行

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

./cqlsh 192.168.0.101

出现如下命令行, 则表示连接成功

cqlsh>

下面输入简单的几个cql命令, 详细的cql使用,请参见CQL for Cassandra 2.0 & 2.1

--创建keyspace, 类似SQL Database

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

--创建cf, 类似SQL Table

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

--修改表

alter table users add age int;

--插入数据

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

--修改数据

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

update users set age = 5 where id = 1;

--查询

select * from users;

select count(*) from users;

cassandra的查询具有以下约束：

第一主键 只能用=或IN查询

第二主键 支持= ,> ,<, >= ,<= 但是必须后面加 ALLOW FILTERING

索引列 只能用=查询

--删除数据

delete from users where id =1;

2.2、代码实现表的CRUD操作

我这里以JAVA举例

MAVEN依赖如下：

Xml代码


<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>

Java代码


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;

/**

* 创建表: 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);//用于返回多少条数

//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));

}

}

}

Java代码


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

Properties代码


cassandra.contactpoints=192.168.0.101

cassandra.port=9042

cassandra.keyspace=test_1

demo1.xml

Xml代码


<?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，更多请参见 官方文档

关于cassandra学习过程中, 更多的参考文档如下:

NoSQL诞生的原因和优缺点 http://blog.csdn.net/chenhuajie123/article/details/9374969
Cassandra中实现SQL操作 http://dongxicheng.org/nosql/cassandra-sql/
Cassandra 2.1 数据查询语法 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
配置项设置: http://pimin.net/archives/297
文章参考: http://tech.chinaunix.net/a2010/1225/1142/000001142663.shtml
一网打尽当下NoSQL类型、适用场景及使用公司 http://www.csdn.net/article/2013-07-24/2816330-how-to-choose-nosql-db
cassandra实战书: http://book.51cto.com/art/201105/264261.htm
cassandra最佳实践: http://www.infoq.com/cn/articles/best-practices-cassandra-data-model-design-part2/
Cassandra – 数据结构设计概念和原则 http://my.oschina.net/silentriver/blog/182814
Cassandra研究报告 http://blog.csdn.net/zyz511919766/article/details/38683219/