Nowadays spring and JPA integration has become a piece of cake thanks to Spring Boot and spring Data.<\/p>\n
I am gonna setup a postgresql server<\/p>\n
docker pull postgres\r\n#run the container\r\ndocker run --name postgreslocal -e POSTGRES_PASSWORD=postgres -d postgres\r\n#get the ip\r\ndocker inspect --format '{{ .NetworkSettings.IPAddress }}' postgreslocal\r\n#get the port\r\ndocker inspect --format '{{ .NetworkSettings.Ports }}' postgreslocal<\/pre>\nCreate the employees Table<\/p>\n
create schema spring_data_jpa_example;\r\n\r\ncreate table spring_data_jpa_example.employee(\r\n\tid SERIAL PRIMARY KEY,\r\n\tfirstname\tTEXT\tNOT NULL,\r\n\tlastname\tTEXT\tNOT NULL,\t\r\n \temail\t\tTEXT \tnot null,\r\n \tage INT NOT NULL,\r\n \tsalary real,\r\n\tunique(email)\r\n);\r\n\r\ninsert into spring_data_jpa_example.employee (firstname,lastname,email,age,salary) \r\nvalues ('Emmanouil','Gkatziouras','gkatzioura@gmail.com',18,3000.23);<\/pre>\nLet\u2019s begin with our gradle file<\/p>\n
group 'com.gkatzioura'\r\nversion '1.0-SNAPSHOT'\r\n\r\napply plugin: 'java'\r\n\r\nsourceCompatibility = 1.8\r\n\r\nbuildscript {\r\n repositories {\r\n mavenCentral()\r\n }\r\n dependencies {\r\n classpath(\"org.springframework.boot:spring-boot-gradle-plugin:1.3.3.RELEASE\")\r\n }\r\n}\r\n\r\napply plugin: 'idea'\r\napply plugin: 'spring-boot'\r\n\r\nrepositories {\r\n mavenCentral()\r\n}\r\n\r\ndependencies {\r\n compile(\"org.springframework.boot:spring-boot-starter-web\") {\r\n exclude module: \"spring-boot-starter-tomcat\"\r\n }\r\n compile(\"org.postgresql:postgresql:9.4-1206-jdbc42\")\r\n compile(\"org.springframework.boot:spring-boot-starter-jetty\")\r\n compile(\"org.springframework.boot:spring-boot-starter-data-jpa:1.3.3.RELEASE\")\r\n compile(\"com.mchange:c3p0:0.9.5.2\")\r\n testCompile(\"junit:junit:4.11\");\r\n}<\/pre>\nAs you see we added the c3p0 connection pool, the spring-boot-starter-data-jpa for hibernate and the postgres driver. That\u2019s all we need.<\/p>\n
The Application class<\/p>\n
package com.gkatzioura.springdata.jpa;\r\n\r\nimport org.springframework.boot.SpringApplication;\r\nimport org.springframework.boot.autoconfigure.SpringBootApplication;\r\nimport org.springframework.context.ApplicationContext;\r\n\r\n\/**\r\n * Created by gkatzioura on 6\/2\/16.\r\n *\/\r\n@SpringBootApplication\r\npublic class Application {\r\n\r\n\r\n public static void main(String[] args) {\r\n\r\n SpringApplication springApplication = new SpringApplication();\r\n ApplicationContext ctx = springApplication.run(Application.class, args);\r\n }\r\n}<\/pre>\nThe DataSource configuration<\/p>\n
package com.gkatzioura.springdata.jpa.config;\r\n\r\nimport com.mchange.v2.c3p0.ComboPooledDataSource;\r\nimport org.springframework.context.annotation.Bean;\r\nimport org.springframework.context.annotation.Configuration;\r\n\r\nimport javax.sql.DataSource;\r\n\r\n\/**\r\n * Created by gkatzioura on 6\/2\/16.\r\n *\/\r\n@Configuration\r\npublic class DataSourceConfig {\r\n\r\n @Bean\r\n public DataSource createDataSource() throws Exception {\r\n\r\n ComboPooledDataSource ds = new ComboPooledDataSource();\r\n ds.setJdbcUrl(\"jdbc:postgresql:\/\/172.17.0.3:5432\/postgres?user=postgres&password=postgres\");\r\n ds.setDriverClass(\"org.postgresql.Driver\");\r\n\r\n return ds;\r\n }\r\n\r\n}<\/pre>\nThe Jpa Configuration
<\/div> <\/div><\/p>\npackage com.gkatzioura.springdata.jpa.config;\r\n\r\nimport org.hibernate.jpa.HibernatePersistenceProvider;\r\nimport org.springframework.beans.factory.annotation.Autowired;\r\nimport org.springframework.context.annotation.Bean;\r\nimport org.springframework.context.annotation.Configuration;\r\nimport org.springframework.data.jpa.repository.config.EnableJpaRepositories;\r\nimport org.springframework.orm.jpa.JpaTransactionManager;\r\nimport org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;\r\nimport org.springframework.transaction.annotation.EnableTransactionManagement;\r\n\r\nimport javax.sql.DataSource;\r\nimport java.util.Properties;\r\n\r\n\/**\r\n * Created by gkatzioura on 6\/2\/16.\r\n *\/\r\n@Configuration\r\n@EnableJpaRepositories(entityManagerFactoryRef = \"entityManagerFactory\",\r\n transactionManagerRef = \"transactionManager\",\r\n basePackages = {\"com.gkatzioura.springdata.jpa.persistence\"})\r\n@EnableTransactionManagement\r\npublic class JPAConfig {\r\n\r\n @Autowired\r\n private DataSource dataSource;\r\n\r\n @Bean\r\n public LocalContainerEntityManagerFactoryBean entityManagerFactory() {\r\n\r\n LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();\r\n entityManagerFactoryBean.setDataSource(dataSource);\r\n entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);\r\n entityManagerFactoryBean.setJpaProperties(hibernateProperties());\r\n entityManagerFactoryBean.setPackagesToScan(new String[] {\"com.gkatzioura.springdata.jpa.persistence\"});\r\n return entityManagerFactoryBean;\r\n }\r\n\r\n @Bean\r\n public JpaTransactionManager transactionManager() {\r\n\r\n JpaTransactionManager transactionManager = new JpaTransactionManager();\r\n transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());\r\n return transactionManager;\r\n }\r\n\r\n\r\n private Properties hibernateProperties() {\r\n\r\n Properties properties = new Properties();\r\n properties.put(\"hibernate.dialect\",\"org.hibernate.dialect.PostgreSQL9Dialect\");\r\n properties.put(\"hibernate.globally_quoted_identifiers\",\"true\");\r\n\r\n return properties;\r\n }\r\n\r\n}<\/pre>\nOur entity for the table employee<\/p>\n
package com.gkatzioura.springdata.jpa.persistence.entity;\r\n\r\nimport javax.persistence.*;\r\n\r\n\/**\r\n * Created by gkatzioura on 6\/2\/16.\r\n *\/\r\n@Entity\r\n@Table(name = \"employee\", schema=\"spring_data_jpa_example\")\r\npublic class Employee {\r\n\r\n @Id\r\n @Column(name = \"id\")\r\n @GeneratedValue(strategy = GenerationType.SEQUENCE)\r\n private Long id;\r\n\r\n @Column(name = \"firstname\")\r\n private String firstName;\r\n\r\n @Column(name = \"lastname\")\r\n private String lastname;\r\n\r\n @Column(name = \"email\")\r\n private String email;\r\n\r\n @Column(name = \"age\")\r\n private Integer age;\r\n\r\n @Column(name = \"salary\")\r\n private Integer salary;\r\n\r\n public Long getId() {\r\n return id;\r\n }\r\n\r\n public void setId(Long id) {\r\n this.id = id;\r\n }\r\n\r\n public String getFirstName() {\r\n return firstName;\r\n }\r\n\r\n public void setFirstName(String firstName) {\r\n this.firstName = firstName;\r\n }\r\n\r\n public String getLastname() {\r\n return lastname;\r\n }\r\n\r\n public void setLastname(String lastname) {\r\n this.lastname = lastname;\r\n }\r\n\r\n public String getEmail() {\r\n return email;\r\n }\r\n\r\n public void setEmail(String email) {\r\n this.email = email;\r\n }\r\n\r\n public Integer getAge() {\r\n return age;\r\n }\r\n\r\n public void setAge(Integer age) {\r\n this.age = age;\r\n }\r\n\r\n public Integer getSalary() {\r\n return salary;\r\n }\r\n\r\n public void setSalary(Integer salary) {\r\n this.salary = salary;\r\n }\r\n}<\/pre>\nThe repository that will help us access all users<\/p>\n
package com.gkatzioura.springdata.jpa.persistence.repository;\r\n\r\nimport com.gkatzioura.springdata.jpa.persistence.entity.Employee;\r\nimport org.springframework.data.jpa.repository.JpaRepository;\r\nimport org.springframework.stereotype.Repository;\r\n\r\n\/**\r\n * Created by gkatzioura on 6\/2\/16.\r\n *\/\r\n@Repository\r\npublic interface EmployeeRepository extends JpaRepository<Employee,Long>{\r\n}<\/pre>\nAnd a controller that will fetch all the data<\/p>\n
package com.gkatzioura.springdata.jpa.controller;\r\n\r\nimport com.gkatzioura.springdata.jpa.persistence.entity.Employee;\r\nimport com.gkatzioura.springdata.jpa.persistence.repository.EmployeeRepository;\r\nimport org.springframework.beans.factory.annotation.Autowired;\r\nimport org.springframework.web.bind.annotation.RequestMapping;\r\nimport org.springframework.web.bind.annotation.RestController;\r\n\r\nimport java.util.List;\r\n\r\n\/**\r\n * Created by gkatzioura on 6\/2\/16.\r\n *\/\r\n@RestController\r\npublic class TestController {\r\n\r\n @Autowired\r\n private EmployeeRepository employeeRepository;\r\n\r\n @RequestMapping(\"\/employee\")\r\n public List<Employee> getTest() {\r\n\r\n return employeeRepository.findAll();\r\n }\r\n}<\/pre>\nPretty convenient considering the dependencies and the xml configuration overhead of the past.<\/p>\n
You can find the source code on github<\/a> .<\/p>\n\n