一、数据库搭建
-- 创建Keyspace
CREATE KEYSPACE school WITH replication = {'class':'SimpleStrategy', 'replication_factor' : 1};
-- 创建表
CREATE TABLE student(
id int PRIMARY KEY,
name text,
age int,
genders int,
address text ,
interest set<text>,
phone list<text>,
education map<text, text>
);
二、引入依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-cassandra</artifactId> </dependency> <!-- hutool是下面多线程导入数据引入 --> <dependency> <groupId>cn.hutool</groupId> <artifactId>hutool-all</artifactId> <version>5.8.26</version> </dependency>
三、配置文件
spring:
application:
name: Spring-Cassandra
cassandra:
keyspace-name: school
contact-points:
- 192.168.204.131:9042
port: 9042
username: ***
password: ******
local-datacenter: datacenter1
request:
timeout: 60s
检查Cassandra的local-datacenter，可执行下面命令：
[root@localhost apache-cassandra]# bin/nodetool status
四、创建一个实体类：
import lombok.Data;
import org.springframework.data.cassandra.core.mapping.Column;
import org.springframework.data.cassandra.core.mapping.PrimaryKey;
import org.springframework.data.cassandra.core.mapping.Table;
import java.io.Serializable;
import java.util.List;
import java.util.Map;
import java.util.Set;
@Data
@Table(value="student")
public class Student implements Serializable {
@PrimaryKey
private Integer id;
@Column("name")
private String name;
@Column("age")
private Integer age;
@Column("genders")
private Integer genders;
@Column("address")
private String address;
@Column("interest")
private Set<String> interest;
@Column("phone")
private List<String> phone;
@Column("education")
private Map<String, String> education;
}
五、创建一个Controller
private final StudentService studentService;
@GetMapping("student")
public List<Student> getStudentByName(String name) {
return studentService.getStudentByName(name);
}
@GetMapping("count")
public Long count() {
return studentService.count();
}
@GetMapping("list")
public List<Student> list(String name) {
Student student = new Student();
student.setName(name);
return studentService.list(student);
}
@GetMapping("save")
public String sava() {
for(int i = 0; i<100; i++) {
try {
Thread.sleep(200);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
int finalI = i;
ThreadUtil.execute(() -> {
System.out.println("线程"+ finalI +"运行");
List<Student> list = Lists.newArrayList();
for(int j=0; j<100; j++) {
UUID uuid = UUID.randomUUID();
int hash = uuid.toString().hashCode();
int maxTenDigit = (int) Math.pow(10, 10) - 1; // 10位整数的最大值
int modHash = Math.abs(hash % maxTenDigit);
Student student = new Student();
student.setId(modHash);
int random = (int) (Math.random() * 100);
student.setName("GG"+ random);
student.setAge(random);
student.setGenders(1);
student.setAddress("China");
list.add(student);
// studentService.save(student);
}
System.out.println("线程"+ finalI +"开始批量插入");
studentService.batchSave(list);
System.out.println("线程"+ finalI +"结束批量插入");
});
}
System.out.println("线程结束");
// ThreadUtil.waitForDie();
return "success";
}
注意：Cassandra 本身不适合用来做数据分析统计，比如 count，是需要去遍历数据库的，分布式数据库，那么就要通通遍历一次。小数据还可以，数据量大会报查询超时错误。
六、编写service查询数据
service接口省略
1、JPA方式查询
service实现
private final StudentMapper studentMapper;
@Override
public List<Student> getStudentByName(String name) {
return studentMapper.getStudentByName(name);
}
mapper接口
@Query(value = "select id, address, age, genders, name, interest, phone, education from student where name = ?0 ALLOW filtering") List<Student> getStudentByName(String name);
Allow filtering:
如果你的查询条件里，有一个是根据索引查询，那其它非索引非主键字段，可以通过加一个ALLOW FILTERING来过滤实现；
虽然查询非索引非主键字段，但是只要加了ALLOW FILTERING条件，它会先根据索引查出来的值，再对结果进行过滤；
（如果不加ALLOW FILTERING，而又有非索引列，这样是不允许的； 加上ALLOW FILTERING，相当于在结果后再进行过滤。）
2、CassandraTemplate方式查询
private final CassandraTemplate cassandraTemplate;
@Override
public List<Student> list(Student queryInfo) {
Query query = Query
.query(where("name").is(queryInfo.getName()));
query = query.withAllowFiltering();
query = query.columns(Columns.from("id", "name", "age", "address", "genders", "interest", "phone", "education"));
System.out.println(query);
return this.cassandraTemplate.select(query, Student.class);
}
@Override
public void save(Student student) {
this.cassandraTemplate.insert(student);
}
/**
* 批量插入
*/
@Override
public void batchSave(List<Student> list) {
CassandraBatchOperations batchOps = cassandraTemplate.batchOps();
batchOps.insert(list);
batchOps.execute();
}
@Override
public Long count() {
return cassandraTemplate.count(Student.class);
}
