在Spring2.0版本中,Spring首次集成了JPA,很多开发人员都推荐在基于Spring的应用程序中使用JPA实现持久化。实际上,有些人还将Spring-JPA合称为POJO开发的梦之队。
在本示例中使用Hibernate作为JPA的实现,也可以选择类似的其他技术如MyBatis也是可以的。
我这边采用的是Hive作为数据源从中读取records表的数据。
@Bean
public BasicDataSource dataSource(){
BasicDataSource ds = new BasicDataSource();
ds.setDriverClassName("org.apache.hive.jdbc.HiveDriver");
ds.setUrl("jdbc:hive2://192.168.225.100:10000/default");
ds.setUsername("hive");
ds.setPassword("123456");
ds.setInitialSize(5);
ds.setMaxActive(10);
return ds;
基于JPA的应用程序需要使用EntityManagerFactory的实现类来获取EntityManager实例。JPA定义了两种类型的实体管理器:
我这里未来需要做个Web项目做大数据平台的展示,所以选择容器管理类型的实体管理器。
@Bean
public LocalContainerEntityManagerFactoryBean entityManageFactory(DataSource dataSource, JpaVendorAdapter jpaVendorAdapter){
LocalContainerEntityManagerFactoryBean emfb = new LocalContainerEntityManagerFactoryBean();
emfb.setDataSource(dataSource);
emfb.setJpaVendorAdapter(jpaVendorAdapter);
emfb.setPackagesToScan("com.css.test.jpa");
return emfb;
}
这里采用Hibernate作为JPA的实现方式。
@Bean
public JpaVendorAdapter jpaVendorAdapter(){
HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
adapter.setDatabase(Database.HSQL);
adapter.setShowSql(true);
adapter.setGenerateDdl(false);
adapter.setDatabasePlatform("org.hibernate.dialect.HSQLDialect");
return adapter;
}
因为纯粹的JPA方式远胜于基于模板的JPA,所以我这里选择构建不依赖与Spring的JPA Repository。
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
@Repository
@Transactional
public class JpaRecordsRepository implements RecordsRepository {
@PersistenceUnit
private EntityManagerFactory emf;
public void addRecords(Records record){
emf.createEntityManager().persist(record);
}
public Records getRecordsByQuality(Integer quality){
return emf.createEntityManager().find(Records.class, quality);
}
public void saveRecords(Records record){
emf.createEntityManager().merge(record);
}
}
代码清单
JpaConfig.java
/**
* 配置类
* @author HP
*
*/
@Configuration
@ComponentScan
public class JpaConfig {
@Bean
public BasicDataSource dataSource(){
BasicDataSource ds = new BasicDataSource();
ds.setDriverClassName("org.apache.hive.jdbc.HiveDriver");
ds.setUrl("jdbc:hive2://192.168.225.100:10000/default");
ds.setUsername("hive");
ds.setPassword("123456");
ds.setInitialSize(5);
ds.setMaxActive(10);
return ds;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManageFactory(DataSource dataSource, JpaVendorAdapter jpaVendorAdapter){
LocalContainerEntityManagerFactoryBean emfb = new LocalContainerEntityManagerFactoryBean();
emfb.setDataSource(dataSource);
emfb.setJpaVendorAdapter(jpaVendorAdapter);
emfb.setPackagesToScan("com.css.test.jpa");
return emfb;
}
@Bean
public JpaVendorAdapter jpaVendorAdapter(){
HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();
adapter.setDatabase(Database.HSQL);
adapter.setShowSql(true);
adapter.setGenerateDdl(false);
adapter.setDatabasePlatform("org.hibernate.dialect.HSQLDialect");
return adapter;
}
}
Records.java
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
/**
* 实体
* @author HP
*
*/
@Entity(name="records")
public class Records {
@Column
private String year;
@Column
private Integer temperature;
@Column
private Integer quality;
public Records() {
super();
}
public Records(String year, Integer temperature, Integer quality) {
super();
this.year = year;
this.temperature = temperature;
this.quality = quality;
}
public String getYear() {
return year;
}
public void setYear(String year) {
this.year = year;
}
public Integer getTemperature() {
return temperature;
}
public void setTemperature(Integer temperature) {
this.temperature = temperature;
}
@Id
public Integer getQuality() {
return quality;
}
public void setQuality(Integer quality) {
this.quality = quality;
}
@Override
public String toString() {
return "Records [year=" + year + ", temperature=" + temperature + ", quality=" + quality + "]";
}
}
RecordsRepository.java
public interface RecordsRepository {
public void addRecords(Records record);
public Records getRecordsByQuality(Integer quality);
public void saveRecords(Records record);
}
JpaRecordsRepository.java
import javax.persistence.EntityManagerFactory;
import javax.persistence.PersistenceUnit;
import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;
@Repository
@Transactional
public class JpaRecordsRepository implements RecordsRepository {
@PersistenceUnit
private EntityManagerFactory emf;
public void addRecords(Records record){
emf.createEntityManager().persist(record);
}
public Records getRecordsByQuality(Integer quality){
return emf.createEntityManager().find(Records.class, quality);
}
public void saveRecords(Records record){
emf.createEntityManager().merge(record);
}
}
springContext.xml
TestJPA.java
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* 程序入口
* @author HP
*
*/
public class TestJPA {
public static void main(String[] args) {
ApplicationContext ac = new AnnotationConfigApplicationContext(JpaConfig.class);
RecordsRepository rr = ac.getBean(RecordsRepository.class);
Records record = rr.getRecordsByQuality(2);
System.out.println(record);
}
}
Hive中的数据是这样的:
运行测试程序(TestJPA.java)
在编写这个程序的时候有可能产生导入jar包出现问题,我把我的pom.xml文件也贴在这里方便大家查找问题。
pom.xml(运用的技术比较综合内容可能有点多……)
4.0.0
com.strategy
second
war
0.0.1-SNAPSHOT
second Maven Webapp
http://maven.apache.org
5.0.0.RELEASE
jdk.tools
jdk.tools
1.8
system
${JAVA_HOME}/lib/tools.jar
org.apache.hadoop
hadoop-common
2.7.3
org.apache.hadoop
hadoop-hdfs
2.7.3
org.apache.hadoop
hadoop-client
2.7.3
org.apache.hadoop
hadoop-minicluster
2.7.3
junit
junit
4.12
org.springframework
spring-core
${spring.version}
org.springframework
spring-web
${spring.version}
org.springframework
spring-webmvc
${spring.version}
org.springframework
spring-aop
${spring.version}
org.springframework
spring-jdbc
${spring.version}
org.springframework
spring-test
${spring.version}
org.aspectj
aspectjweaver
1.8.4
javax.servlet
javax.servlet-api
3.1.0
com.codahale.metrics
metrics-core
3.0.2
org.apache.hbase
hbase
0.98.13-hadoop2
pom
org.apache.hbase
hbase-client
0.98.13-hadoop2
org.apache.hbase
hbase-common
0.98.13-hadoop2
org.apache.hive
hive-jdbc
2.3.4
org.springframework.data
spring-data-jpa
2.1.3.RELEASE
org.hibernate.javax.persistence
hibernate-jpa-2.0-api
1.0.1.Final
org.hibernate
hibernate-core
5.3.7.Final
javax.persistence
persistence-api
1.0.2
second