Java 数据库连接 - Sqlite

Java 数据库连接 - Sqlite

PS:
1. 连接依赖库：[sqlite-jdbc-xxx.jar](https://mvnrepository.com/artifact/org.xerial/sqlite-jdbc)(根据连接的数据库版本选择)
2. 支持一次连接执行多次sql语句；
3. 仅本地连接；

使用说明：

public static void main(String[] args) {SqliteManager dbManager = SqliteManager.getInstance();dbManager.connectDB();//执行的sql语句：数据表得存在String sql = "select * from M3u8Task";test(dbManager.exeQuery(sql));//...可执行多条 sql 语句//执行完后记得关闭连接dbManager.closeDB();
}//遍历打印返回数据表属性及数值
private static void test(ResultSet rs) {ResultSetMetaData rsmd;try {rsmd = rs.getMetaData();//获取属性名String[] arr = new String[0];if (rsmd != null) {int count = rsmd.getColumnCount();//统计属性个数arr = new String[count];for (int i = 1; i <= count; i++) {arr[i - 1] = rsmd.getColumnName(i);//把属性名输入arrSystem.out.print(rsmd.getColumnName(i) + "  ");//输出属性名}}System.out.println();while (rs.next()) {for (String s : arr) {System.out.print(rs.getString(s) + "  ");}System.out.println();//控制格式}} catch (SQLException e) {e.printStackTrace();}
}

SqliteManager.java

package util;import java.sql.*;/*** sqlite 数据库连接控制器* sqlite-jdbc-3.32.0.1.jar*/
public class SqliteManager {// 静态成员 支持单例模式private static SqliteManager instance = null;private Connection connection = null;//连接数据库private Statement statement = null;//用于执行sql命令private String path;//数据库文件路径private boolean isConnected;//连接状态// 单例模式public static SqliteManager getInstance() {if (instance == null) {synchronized (SqliteManager.class) {if (instance == null) {instance = new SqliteManager();}}}return instance;}public SqliteManager() {isConnected = false;try {Class.forName("org.sqlite.JDBC");//加载数据库驱动} catch (Exception e) {e.printStackTrace();}//默认地址：程序打包后访问路径有变化this.path = Constants.BOOL.IS_RELEASE ? "db/M3u8.sqlite" : "./MFrame/res/db/M3u8.sqlite";}//1. 连接数据库public boolean connectDB() {if (CommonUtil.isEmpty(path)) {return false;}if (isConnected) {return true;}try {String url = "jdbc:sqlite:" + path;   //定义连接数据库的url(url:访问数据库的URL路径)connection = DriverManager.getConnection(url);    //获取数据库连接statement = connection.createStatement();//得到Statement实例CommonUtil.printLog("数据库连接成功...");}//捕获异常信息catch (SQLException e) {e.printStackTrace();statement = null;isConnected = false;}return isConnected;}//2. 关闭连接public void closeDB() {try {if (statement != null) {statement.close();statement = null;}if (connection != null) {connection.close();}} catch (SQLException e) {e.printStackTrace();}isConnected = false;CommonUtil.printLog("关闭数据库连接！");}//3. 查询操作 -> 返回查询结果public ResultSet exeQuery(String sql) {ResultSet rs = null;try {if (statement != null) {rs = statement.executeQuery(sql);}} catch (SQLException e) {e.printStackTrace();}return rs;}//4. 更新操作 -> 返回查询结果//return: (1) the row count for SQL Data Manipulation Language (DML) statements//		  (2) 0 for SQL statements that return nothingpublic int exeUpdate(String sql) {int result = 0;try {if (statement != null) {result = statement.executeUpdate(sql);}} catch (SQLException e) {e.printStackTrace();}return result;}
}