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：

<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;



/**
 * 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));
		}
	}
}

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/

cassandra 学习之旅<一> 初体验

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