JAVA数据库操作二（多个数据库操作+Spring data + jpa)

缺的文件请参考上一篇文章http://blog.csdn.net/makefriend7/article/details/53941458

本文我们将主要实现同时操作两个数据库，（oracle 和mysql)

当然为了展示技巧，本文将以java配置为主

首先是daoContext.xml的内容

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans"   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xmlns:jdbc="http://www.springframework.org/schema/jdbc"   xmlns:c="http://www.springframework.org/schema/c"   xmlns:context="http://www.springframework.org/schema/context"   xmlns:p="http://www.springframework.org/schema/p"   xmlns:jpa="http://www.springframework.org/schema/data/jpa"   xsi:schemaLocation="http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc-3.1.xsdhttp://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa-1.0.xsdhttp://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd"><bean class = "db.MyConfig"/><bean class = "mysqldb.MySqlConfig"/></beans>

好吧。其实有用的就两行。

oralce的配置文件就MyConfig 内容如下

package db;import com.mysql.cj.jdbc.MysqlDataSource;import oracle.jdbc.pool.OracleDataSource;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.jpa.repository.config.EnableJpaRepositories;import org.springframework.orm.jpa.JpaTransactionManager;import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;import org.springframework.orm.jpa.vendor.Database;import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;import org.springframework.transaction.annotation.Transactional;import javax.persistence.EntityManager;import javax.sql.DataSource;import java.sql.SQLException;@Configuration@EnableJpaRepositories(basePackages = "db",        entityManagerFactoryRef="entityManagerFactoryOracle",        transactionManagerRef="transactionManagerOracle")public class MyConfig {    @Bean    public DataSource dataSourceOracle()   throws SQLException {        OracleDataSource dataSource = new OracleDataSource();        dataSource.setUser("abc");        dataSource.setPassword("abc");        dataSource.setURL("jdbc:oracle:thin:@192.168.1.2:1521:orcl");        dataSource.setImplicitCachingEnabled(true);        dataSource.setFastConnectionFailoverEnabled(true);        return dataSource;    }    @Bean    public HibernateJpaVendorAdapter jpaVendorAdapterOracle() {        HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();        adapter.setDatabase(Database.ORACLE);        adapter.setShowSql(true);        adapter.setGenerateDdl(false);        return adapter;    }    @Bean(name = "entityManagerFactoryOracle")    public LocalContainerEntityManagerFactoryBean entityManagerFactoryOracle()  throws SQLException{        LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();        emf.setDataSource(dataSourceOracle());        emf.setPersistenceUnitName("myPersistence1");        emf.setJpaVendorAdapter(jpaVendorAdapterOracle());        emf.setPackagesToScan("entity");        return emf;    }    @Bean(name="transactionManagerOracle")    public JpaTransactionManager transactionManagerOracle()  throws SQLException{        JpaTransactionManager txManager = new JpaTransactionManager(entityManagerFactoryOracle().getObject());        return txManager;    }}

mysql的配置文件如下

package mysqldb;import com.mysql.cj.jdbc.MysqlDataSource;import org.hibernate.jpa.boot.spi.EntityManagerFactoryBuilder;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.jpa.repository.config.EnableJpaRepositories;import org.springframework.orm.jpa.JpaTransactionManager;import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;import org.springframework.orm.jpa.vendor.Database;import org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter;import org.springframework.transaction.annotation.Transactional;import javax.sql.DataSource;import java.sql.Connection;import java.sql.SQLException;@Configuration@EnableJpaRepositories(basePackages = "mysqldb",        entityManagerFactoryRef="entityManagerFactoryMySql",        transactionManagerRef="transactionManagerMySql")public class MySqlConfig {    @Bean    public DataSource dataSourceMySql()   throws SQLException {        MysqlDataSource dataSource = new MysqlDataSource();        dataSource.setUser("abc");        dataSource.setPassword("abc");        dataSource.setURL("jdbc:mysql://localhost:3306/test?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC");        return dataSource;    }    @Bean    public HibernateJpaVendorAdapter jpaVendorAdapterMySql() {        HibernateJpaVendorAdapter adapter = new HibernateJpaVendorAdapter();        adapter.setDatabase(Database.MYSQL);        adapter.setShowSql(true);        adapter.setGenerateDdl(true);        return adapter;    }    @Bean(name = "entityManagerFactoryMySql")    public LocalContainerEntityManagerFactoryBean entityManagerFactoryMySql()  throws SQLException{        LocalContainerEntityManagerFactoryBean emf = new LocalContainerEntityManagerFactoryBean();        emf.setDataSource(dataSourceMySql());        emf.setPersistenceUnitName("myPersistence2");        emf.setJpaVendorAdapter(jpaVendorAdapterMySql());        emf.setPackagesToScan("mysqlentity");        return emf;    }    @Bean(name="transactionManagerMySql")    public JpaTransactionManager transactionManagerMySql()  throws SQLException{        return new JpaTransactionManager(entityManagerFactoryMySql().getObject());    }}

这两个配置文件一出，大部分的工作就完成啦。

作为测试。我们分别定义表MyEntity在 oracle中，表MySqlEntity在mysql中

package entity;import javax.persistence.*;import java.math.BigDecimal;@Entitypublic class MyEntity {    @Id    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "prooduct_id_seq")    @SequenceGenerator(name="prooduct_id_seq", sequenceName = "PRODUCT_ID_SEQ", allocationSize = 100)    private Integer id;    @Version    private Integer version;    private String testString;    private BigDecimal testNumber;    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public Integer getVersion() {        return version;    }    public void setVersion(Integer version) {        this.version = version;    }    public String getTestString() {        return testString;    }    public void setTestString(String testString) {        this.testString = testString;    }    public BigDecimal getTestNumber() {        return testNumber;    }    public void setTestNumber(BigDecimal testNumber) {        this.testNumber = testNumber;    }}

MySqlEntity的内容如下

package mysqlentity;import javax.persistence.*;import java.math.BigDecimal;@Entitypublic class MySqlEntity {    @Id    @Column(name = "id", nullable = false, length = 64)    private Integer id;    @Version    private Integer version;    private String testString;    private BigDecimal testNumber;    public Integer getId() {        return id;    }    public void setId(Integer id) {        this.id = id;    }    public Integer getVersion() {        return version;    }    public void setVersion(Integer version) {        this.version = version;    }    public String getTestString() {        return testString;    }    public void setTestString(String testString) {        this.testString = testString;    }    public BigDecimal getTestNumber() {        return testNumber;    }    public void setTestNumber(BigDecimal testNumber) {        this.testNumber = testNumber;    }}

测试嘛。就随便弄俩个数据库操作

oracle 的

package db;import entity.MyEntity;import org.springframework.data.jpa.repository.JpaRepository;import java.math.BigDecimal;import java.util.List;public interface MyEntityRepository extends JpaRepository<MyEntity, Long> {    List<MyEntity> findByVersion(Integer version);}

mysql的

package mysqldb;import entity.MyEntity;import mysqlentity.MySqlEntity;import org.springframework.data.jpa.repository.JpaRepository;import java.util.List;public interface MySqlEntityRepository extends JpaRepository<MySqlEntity, Long> {    List<MySqlEntity> findByVersion(Integer version);}

最后就是测试用的MyService

package service;import db.MyEntityRepository;import entity.MyEntity;import mysqldb.MySqlEntityRepository;import mysqlentity.MySqlEntity;import org.springframework.beans.factory.annotation.Autowired;import java.util.List;public class MyService {    @Autowired    public MyEntityRepository myEntityRepository;    @Autowired    public MySqlEntityRepository mySqlEntityRepository;    public String processCommand(String anything)    {        String str = "hello";        List<MyEntity> myEntityList = myEntityRepository.findAll();        List<MyEntity> myEntityList2 = myEntityRepository.findByVersion(3);        List<MySqlEntity> myEntityList3 =  mySqlEntityRepository.findAll();        return str;    }}

怎么样？代码都跑起来了吧。。很容易就实现了JAVA同时操作两个数据库，下一篇将介绍如何操作ES