spring data jpa .基本使用,多条件复合查询，报表查询。
本文较为简单的介绍在实际代码中如何编码。点击进入官网
第一次接触 spring data jpa 就被它吸引。非常强大的数据库操作包。
使用起来也十分简单。
第一步，实体类与表结构的对应。
实体类与数据库的关系。
有两种方法，
1，配置数据库地址，自动通过配置的实体包下的类创建对应的数据库表结构和表关系。
2，在数据库中创建表结构，表关系。通过数据库生成对应的实体类。
#mssql db.driver=net.sourceforge.jtds.jdbc.Driver db.url=jdbc:jtds:sqlserver://localhost:1433/dbName db.username= db.password= #mysql #db.driver=com.mysql.jdbc.Driver #hibernate.dialect=org.hibernate.dialect.MySQLDialect #db.url=jdbc\:mysql\://locahost\:3306/dbName?useUnicode\=true&characterEncoding\=utf-8 db.username= db.password= #sybase db.driver=com.sybase.jdbc3.jdbc.SybDriver hibernate.dialect=org.hibernate.dialect.SybaseASE15Dialect db.url=jdbc:sybase:Tds:localhost:5000/dbName?language=us_english&charset=cp936 db.username= db.password= #######其他配置 spring.jpa.generate-ddl=true spring.jpa.hibernate.ddl-auto=create-drop #Hibernate Configuration # dialect for sybase ase hibernate.hbm2ddl.auto=update #hibernate.hbm2ddl.auto=create-drop #hibernate.ejb.naming_strategy=org.hibernate.cfg.ImprovedNamingStrategy hibernate.show_sql=true hibernate.format_sql=true current_session_context_class=thread entitymanager.packages.to.scan=pack.entity
读取配置文件
@Configuration
@EnableWebMvc
@EnableTransactionManagement
//@ComponentScan("com.spr")
@PropertySource("classpath:db.properties")
@EnableJpaRepositories("pack.repository")
public class JpaConfig {
private static final String PROPERTY_NAME_DATABASE_DRIVER = "db.driver";
private static final String PROPERTY_NAME_DATABASE_PASSWORD = "db.password";
private static final String PROPERTY_NAME_DATABASE_URL = "db.url";
private static final String PROPERTY_NAME_DATABASE_USERNAME = "db.username";
private static final String PROPERTY_NAME_HIBERNATE_DIALECT = "hibernate.dialect";
private static final String PROPERTY_NAME_HIBERNATE_SHOW_SQL = "hibernate.show_sql";
private static final String PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN = "entitymanager.packages.to.scan";
private static final String PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO = "hibernate.hbm2ddl.auto";
@Resource
private Environment env;
@Bean
public DataSource dataSource() {
DriverManagerDataSource dataSource = new DriverManagerDataSource();
dataSource.setDriverClassName(env.getRequiredProperty(PROPERTY_NAME_DATABASE_DRIVER));
dataSource.setUrl(env.getRequiredProperty(PROPERTY_NAME_DATABASE_URL));
dataSource.setUsername(env.getRequiredProperty(PROPERTY_NAME_DATABASE_USERNAME));
dataSource.setPassword(env.getRequiredProperty(PROPERTY_NAME_DATABASE_PASSWORD));
return dataSource;
}
@Bean
public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
entityManagerFactoryBean.setDataSource(dataSource());
entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistence.class);
entityManagerFactoryBean.setPackagesToScan(
env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
entityManagerFactoryBean.setJpaProperties(hibProperties());
return entityManagerFactoryBean;
}
// private Properties hibProperties() {
// Properties properties = new Properties();
// properties.put(PROPERTY_NAME_HIBERNATE_DIALECT, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
// properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL, env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));
// return properties;
// }
private Properties hibProperties() {
Properties properties = new Properties();
properties.put(PROPERTY_NAME_HIBERNATE_DIALECT,
env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_DIALECT));
properties.put(PROPERTY_NAME_HIBERNATE_SHOW_SQL,
env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_SHOW_SQL));
properties.put("hibernate.temp.use_jdbc_metadata_defaults", "false");
properties.put(PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO,
env.getRequiredProperty(PROPERTY_NAME_HIBERNATE_HBM2DDL_AUTO));
return properties;
}
@Bean
public JpaTransactionManager transactionManager() {
JpaTransactionManager transactionManager = new JpaTransactionManager();
transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
return transactionManager;
}
// @Bean
// public PlatformTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) throws SQLException {
//
// JpaTransactionManager txManager = new JpaTransactionManager();
// txManager.setEntityManagerFactory(entityManagerFactory);
// return txManager;
// }
}public interface CreditApplyRecordRepository extends PagingAndSortingRepository, JpaSpecificationExecutor {
Set findByIdIn(Set ids);
}
关于 Repository 在官网查看相关说明，在Repository中定义方法命名规则
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完成以上步骤就可以在业务中使用 数据库的增删改查。
下面来说如果完成 不定条件符合查询。
上面示例中 CreditApplyRecordRepository 继承 JpaSpecificationExecutor。改接口
JpaSpecificationExecutor介绍
关于 JpaSpecificationExecutor 的使用
想初始化一个 predicate 。类似1==1的。没有找到就在下面
Page creditCard = creditCardRepo.findAll(new Specification() {
@Override
public Predicate toPredicate(Root root, CriteriaQuery cq, CriteriaBuilder cb) {
Predicate predicate = null;
// if (null != appDateStart && null != appDateEnd) {
// predicate = cb.between(root.get("appdate"), appDateStart, appDateEnd);
// }
Set orgNums = new HashSet();
orgNums.add(orgNum);
if (null != orgNum) {
if (null != predicate) {
Expression exOrgNum = root.get("organNum");
predicate = cb.and(predicate, exOrgNum.in(orgNums));
} else {
Path exOrgNum = root.get("organNum");
predicate = exOrgNum.in(orgNums);
}
}
if (null != brand&&!("".equals(brand))) {
if (null != predicate) {
predicate = cb.and(predicate, cb.equal(root.get("brand"), brand));
} else {
predicate = cb.equal(root.get("brand"), brand);
}
}
if (null != currency&&!("".equals(currency))) {
if (null != predicate) {
predicate = cb.and(predicate, cb.equal(root.get("currency"), currency));
} else {
predicate = cb.equal(root.get("currency"), currency);
}
}
if (null != grade&&!("".equals(grade))) {
if (null != predicate) {
predicate = cb.and(predicate, cb.equal(root.get("grade"), grade));
} else {
predicate = cb.equal(root.get("grade"), grade);
}
}
if (null != media&&!("".equals(media))) {
if (null != predicate) {
predicate = cb.and(predicate, cb.equal(root.get("media"), media));
} else {
predicate = cb.equal(root.get("media"), media);
}
}
if (null != cardType&&!("".equals(cardType))) {
if (null != predicate) {
predicate = cb.and(predicate, cb.equal(root.get("cardType"), cardType));
} else {
predicate = cb.equal(root.get("cardType"), cardType);
}
}
if (null != predicate) {
cq.where(predicate);
}
return null;
}
},
new PageRequest(pageIndex, pageSize)
); 关于统计报表类的
@PersistenceContext
EntityManager entityManager;
String sql = String.format("sql_");
Query query = entityManager.createNativeQuery(sql);
List objecArraytList = query.getResultList();