一、插件实现功能情况

本工具类已经实现MySQL数据的连接和数据库的关闭，并通过线程池进行数据限制。本文源码在gitee上开源，开源地址为：https://gitee.com/huangmingquan/selfmade_database_conntool，欢迎大家提交代码。

二、文件组织结构

下图为本工具类的文件预览图

三、maven配置文件pom.xml

下面是本工程文件的依赖库文件

  <dependencies>
    <!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>fastjson</artifactId>
      <version>1.2.47</version>
    </dependency>
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.17</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.7.25</version>
    </dependency>
    <dependency>
      <groupId>org.apache.hadoop</groupId>
      <artifactId>hadoop-client</artifactId>
      <version>3.2.1</version>
    </dependency>
    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>1.6.1</version>
    </dependency>
    <dependency>
      <groupId>jaxen</groupId>
      <artifactId>jaxen</artifactId>
      <version>1.1.1</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/jaxen/jaxen -->
    <dependency>
      <groupId>jaxen</groupId>
      <artifactId>jaxen</artifactId>
      <version>1.1.1</version>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.47</version>
    </dependency>
  </dependencies>

四、conn.xml

本文件主要存储连接配置的信息

<connection>
    <database id="mysql">
        <dependencies>
            <name>driver</name>
            <value>com.mysql.jdbc.Driver</value>
        </dependencies>
        <dependencies>
            <name>url</name>
            <value>jdbc:mysql://192.168.130.100:3306/zuoye?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf-8</value>
        </dependencies>
        <dependencies>
            <name>user</name>
            <value>root</value>
        </dependencies>
        <dependencies>
            <name>password</name>
            <value>ok</value>
        </dependencies>
    </database>
</connection>

五、Conn类

本类主要实现单个数据的连接和释放

    Map<String,String>m=null;
    Connection conn = null;//定义连接
    Statement stmt = null;//初始化statement对象
     public Connection con(String database_name) throws DocumentException, ClassNotFoundException, SQLException {
         ConSourse c=new ConSourse();
         Map<String, String> m = c.getConInfo_Xml("mysql");
         Class.forName(m.get("driver"));
         conn = DriverManager.getConnection(m.get("url"),m.get("user"),m.get("password"));//连接数据库
         stmt = conn.createStatement();//创建一个 Statement 对象
         return conn;
     }
    public void close(Connection database_connection) throws SQLException {
        if (database_connection!=null)
            database_connection.close();
    }

六、ConSourse类

本类主要实现数据库的连接数据从conn.xml中读出

 //定义XML的读者
    static SAXReader reader;
    //定义文件路径
    static Document document;
    //XML根
    static Element root;
    //连接XML数据库
    private static void conXml() throws DocumentException {
        //实现读者
        reader = new SAXReader();
        //打开文件路径
        document = reader.read(new File("src/main/java/conf/conn.xml"));
        //获取根
        root = document.getRootElement();
    }
    static Map<String, String> getConInfo_Xml(String dataSourceId) throws DocumentException {
        //实现连接
        conXml();
        //获取配置信息的根
        Element datasource =(Element) root.selectSingleNode("database[@id='" + dataSourceId + "']");
        //用图来存储配置信息
        Map<String, String> map = new HashMap<>();
        //获得配置信息的列表
        List<Element> list = datasource.elements("dependencies");
        //遍历获取配置信息
        for (Element element : list) {
            //获取配置信息名称
            String name = element.elementText("name");
            //获取配置信息的值
            String value = element.elementText("value");
            //将配置信息压入图中
            map.put(name, value);
        }
        //返回配置信息的图
        return map;
    }

七、mysql_conPool

数据库连接池

private static int POOL_SIZE =5;
    Connection con=null;
    public synchronized Connection coonpool(String database_name) throws InterruptedException {
        if(POOL_SIZE<0){
            Thread.sleep(1000);
            coonpool(database_name);
        }
        POOL_SIZE--;
        Conn c=new Conn();

        try {
            con= c.con(database_name);
            System.out.println("连接成功");
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return con;
    }
    public synchronized void closepool(Connection con) throws SQLException {
        POOL_SIZE++;
        Conn c=new Conn();
        c.close(con);
        System.out.println("数据库已关闭");
    }

八、主方法main（）

 public static void main(String[] args) throws InterruptedException, SQLException {
        Connection con=null;
        mysql_conPool p=new mysql_conPool();
        con=p.coonpool("mysql");
        p.closepool(con);
    }