Cassandra window使用
1． 下载：http://cassandra.apache.org/download/。
2． 解压后，bin目录下，cassandra.bat 直接启动。 Cassandra-cli.bat进入cassandra。
3． 安装python2.7.10 版本太高，可能会不兼容，安装python 使用 CQL 操作cassandra数据库。
4． 配置环境变量后，以管理员方式运行 cmd ：
powershell Set-ExecutionPolicy Unrestricted 成功如下：
5. cmd cqlsh.bat进入cql编辑；（没有安装python 无法使用cqlsh.bat）
CREATE KEYSPACE IF NOT EXISTS pimin_net
WITH REPLICATION = {'class': 'SimpleStrategy','replication_factor':1};
USE pimin_net;
CREATE TABLE IF NOT EXISTS users (
id uuid,
first_name varchar,
last_name varchar,
age int,
emails set<text>,
avatar blob,
PRIMARY KEY (id)
);
SELECT * FROM users;
用户表（users）包含了主键、firest_name、last_name、年龄、多个邮箱地址以及头像。关于使用java驱动，建议使用eclipse+maven创建，比如我们创建一个cassandra.test的工程。在pom.xml里面加入
<dependency>
<groupId>com.datastax.cassandra</groupId>
<artifactId>cassandra-driver-core</artifactId>
<version>2.1.0</version>
</dependency>
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1 2 3 4 5 |
<dependency> <groupId>com.datastax.cassandra</groupId> <artifactId>cassandra-driver-core</artifactId> <version>2.1.0</version> </dependency> |
如果环境不允许使用maven，那么就自己找依赖包吧：cassandra-driver-core-2.1.0.jar、netty-3.9.0.Final.jar、guava-16.0.1.jar、metrics-core-3.0.2.jar和slf4j-api-1.7.5.jar。
解压目录 lib和 apache-cassandra-2.1.16\tools\lib 下，有jar包。
下面是所有java测试代码：实现连接Cassandra集群，新增数据，查询数据。其他的情况类似。
如果需要远程连接，那么cassandra.yaml里面的rpc_address就需要改变为您当前环境实际的IP地址，否则会报错！ 本地：client.connect("127.0.0.1");
package cassandra;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.HashSet;
import java.util.Set;
import java.util.UUID;
import com.datastax.driver.core.BoundStatement;
import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Host;
import com.datastax.driver.core.Metadata;
import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.ResultSet;
import com.datastax.driver.core.Row;
import com.datastax.driver.core.Session;
public class TestJava {
private Cluster cluster;
private Session session;
public Cluster getCluster() {
return cluster;
}
public void setCluster(Cluster cluster) {
this.cluster = cluster;
}
public Session getSession() {
return session;
}
public void setSession(Session session) {
this.session = session;
}
/**
* 连接节点
*
* @param node
*/
public void connect(String node) {
cluster = Cluster.builder().addContactPoint(node).build();
Metadata metadata = cluster.getMetadata();
System.out.printf("Connected to cluster: %s\n", metadata.getClusterName());
for (Host host : metadata.getAllHosts()) {
System.out.printf("Datatacenter: %s; Host: %s; Rack: %s\n", host.getDatacenter(), host.getAddress(), host.getRack());
}
this.session = cluster.connect();
}
public void insertData() {
PreparedStatement insertStatement = getSession().prepare(
"INSERT INTO pimin_net.users "
+ "(id, first_name, last_name, age, emails,avatar) "
+ "VALUES (?, ?, ?, ?, ?, ?);");
BoundStatement boundStatement = new BoundStatement(insertStatement);
Set<String> emails = new HashSet<String>();
emails.add("xxx@qq.com");
emails.add("xxx@163.com");
java.nio.ByteBuffer avatar = null;
try {
avatar = toByteBuffer("f:\\user.png");
avatar.flip();
System.out.println("头像大小：" + avatar.capacity());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
getSession().execute(boundStatement.bind(UUID.fromString("756716f7-2e54-4715-9f00-91dcbea6cf50"),
"pi", "min", 10, emails, avatar));
}
public void loadData() {
ResultSet resultSet = getSession().execute(
"SELECT first_name,last_name,age,avatar FROM pimin_net.users;");
System.out
.println(String
.format("%-30s\t%-20s\t%-20s\n%s", "first_name","last_name", "age",
"-------------------------------+-----------------------+--------------------"));
for (Row row : resultSet) {
System.out.println(String.format("%-30s\t%-20s\t%-20s",
row.getString("first_name"), row.getString("last_name"),
row.getInt("age")));
ByteBuffer byteBuffer = row.getBytes("avatar");
System.out.println("头像大小：" + (byteBuffer.limit() - byteBuffer.position()));
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream("f:\\2.png");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fileOutputStream.write(byteBuffer.array(),
byteBuffer.position(),
byteBuffer.limit() - byteBuffer.position());
fileOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
System.out.println();
}
public void close() {
cluster.close();
}
/**
* 读取文件
*
* @param filename
* @return
* @throws IOException
*/
public static ByteBuffer toByteBuffer(String filename) throws IOException {
File f = new File(filename);
if (!f.exists()) {
throw new FileNotFoundException(filename);
}
FileChannel channel = null;
FileInputStream fs = null;
try {
fs = new FileInputStream(f);
channel = fs.getChannel();
ByteBuffer byteBuffer = ByteBuffer.allocate((int) channel.size());
while ((channel.read(byteBuffer)) > 0) {
// do nothing
// System.out.println("reading");
}
return byteBuffer;
} catch (IOException e) {
e.printStackTrace();
throw e;
} finally {
try {
channel.close();
} catch (IOException e) {
e.printStackTrace();
}
try {
fs.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public static void main(String[] args) {
TestJava client = new TestJava();
client.connect("127.0.0.1");
client.insertData();
client.loadData();
client.session.close();
client.close();
}
}