OSGi 系列（十六）之 JDBC Service

OSGi 系列（十六）之 JDBC Service

compendium 规范提供了 org.osgi.service.jdbc.DataSourceFactory 服务

1. 快速入门

1.1 环境准备

<dependency>
    <groupId>org.osgi</groupId>
    <artifactId>org.osgi.core</artifactId>
    <version>5.0.0</version>
</dependency>
<dependency>
    <groupId>org.osgi</groupId>
    <artifactId>org.osgi.compendium</artifactId>
    <version>5.0.0</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.38</version>
</dependency>
<dependency>
    <groupId>org.ops4j.pax.jdbc</groupId>
    <artifactId>pax-jdbc</artifactId>
    <version>0.8.0</version>
</dependency>

1.2 获取连接

import java.sql.*;
import java.util.Properties;

import javax.sql.DataSource;
import org.osgi.service.jdbc.DataSourceFactory;

public class JDBCServiceDemo {
    private DataSourceFactory dataSourceFactory;

    public void setDataSourceFactory(DataSourceFactory dataSourceFactory) {
        this.dataSourceFactory = dataSourceFactory;
    }
    
    public void jdbc()throws Exception {

        System.out.println(dataSourceFactory);

        Properties props = new Properties();
        props.put(DataSourceFactory.JDBC_URL, "jdbc:mysql://localhost:3306/test?characterEncoding=utf-8");
        props.put(DataSourceFactory.JDBC_USER, "root");
        props.put(DataSourceFactory.JDBC_PASSWORD, "root");
        DataSource ds = dataSourceFactory.createDataSource(props);
        Connection conn = ds.getConnection();

        //3、编写sql
        String  sql="select * from sys_user where id=?";
        //4、创建语句执行者
        PreparedStatement st = conn.prepareStatement(sql);
        //5、设置参数
        st.setString(1, "1");
        //6、执行sql
        ResultSet rs = st.executeQuery();
        //7、处理结果
        while(rs.next()){
            System.out.println(rs.getString("id") + "=>" + rs.getString("username"));
        }
        //8、释放资源.
        rs.close();
        st.close();

        System.out.println(conn);
        System.out.println(conn.getCatalog());
        conn.close();
    }
}

1.3 OSGI-INF/blueprint 下配制 blueprint.xml

<?xml version="1.0" encoding="UTF-8"?>
<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xsi:schemaLocation="http://www.osgi.org/xmlns/blueprint/v1.0.0 http://www.osgi.org/xmlns/blueprint/v1.0.0/blueprint.xsd">

    <reference id="dataSourceFactory" interface="org.osgi.service.jdbc.DataSourceFactory" filter="(osgi.jdbc.driver.class=com.mysql.jdbc.Driver)"/>
    
    <bean class="com.edu.osgi.jdbc.JDBCServiceDemo" init-method="jdbc">
        <property name="dataSourceFactory" ref="dataSourceFactory" />
    </bean>
</blueprint>

1.4 karaf 测试

(1) 安装依赖

# 安装 mysql驱动
install -s mvn:mysql/mysql-connector-java/5.1.38
# 安装 osgi jdbc
install -s mvn:org.osgi/org.osgi.service.jdbc/1.0.0
# pax-jdbc 实现了 DataSourceFactory 服务
install -s mvn:org.ops4j.base/ops4j-base-spi/1.5.0
install -s mvn:org.ops4j.pax.jdbc/pax-jdbc/0.8.0

(2) 测试结果

安装 pax-jdbc 开启了 DataSourceFactory 服务

2. 补充说明

很多数据驱动已经实现了 DataSourceFactory 服务，如 postgresql

karaf 中安装 postgresql 的 DataSourceFactory 服务：

# osgi 规范
install -s mvn:org.osgi/org.osgi.service.jdbc/1.0.0
# 安装事务
feature:list | grep transaction
feature:install transaction

install -s mvn:org.postgresql/postgresql/9.4-1201-jdbc4
ls DataSourceFactory

可以看到 DataSourceFactory 服务已经开启。