关于Java 项目封装sqlite连接池操作持久化数据的方法

Sqlite

sqlite是C实现的一个开源SQL引擎，其api提供sql语法支持，通过sql解析后对存储层的磁盘文件进行操作，完整配置的sqlite库小于400kb，多用于移动端应用，小型项目中。

对Sqlite有兴趣的可以了解下其体系结构

之前自研SQL解析器的时候便是借鉴了SQLcompiler的源码，这里不展开介绍

封装Java的Sqlite连接池

首先maven项目引入依赖sqlite-jdbc，其主要是java版的sqliteapi，关于Sqlite api的操作，大家可以看菜鸟教程

<dependency>
        <groupId>org.xerial</groupId>
        <artifactId>sqlite-jdbc</artifactId>
        <version>3.30.1</version>
    </dependency>

同时引入spring jdbc方便解析数据

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.3.12</version>
        </dependency>

先编写测试用例

import org.junit.Test;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.LinkedList;
import java.util.List;

public class TestSqliteHelper {

    @Test
    public void test() throws SQLException, ClassNotFoundException {
        SqliteHelper sqliteHelper = SqliteHelper.GetSqliteHelper("test.db");

        String sql = "CREATE TABLE COMPANY " +
                "(ID INT PRIMARY KEY     NOT NULL," +
                " NAME           TEXT    NOT NULL, " +
                " AGE            INT     NOT NULL, " +
                " ADDRESS        CHAR(50), " +
                " SALARY         REAL)";

        sqliteHelper.ExecuteUpdate(sql);

        sql = "INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY) " +
                "VALUES (1, 'Paul', 32, 'California', 20000.00 );";

        sqliteHelper.ExecuteUpdate(sql);

        sql = "SELECT * FROM COMPANY;";

        List<String> datas = new LinkedList<>();
        datas = sqliteHelper.ExecuteQuery(sql, new RowMapper<String>() {
                    @Override
                    public String mapRow(ResultSet rs, int index)
                            throws SQLException {
                        return rs.getString("NAME");

                    }
                }
        );

        sqliteHelper.PutSqliteHelper();
    }
}

再根据TDD实现ExecuteUpdate\GetSqliteHelper、ExecuteQuery、PutSqliteHelper等方法

import org.springframework.jdbc.core.RowMapper;

import java.sql.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.locks.ReentrantLock;

public class SqliteHelper {

    /**
     * 磁盘文件名 即db
     */
    private String path = null;

    /**
     * 操作链接
     */
    private Connection connection = null;

    /**
     * 语法执行层
     */
    private Statement statement = null;

    /**
     * 构建一次链接
     *
     * @param path
     * @throws SQLException
     * @throws ClassNotFoundException
     */
    SqliteHelper(String path) throws SQLException, ClassNotFoundException {
        this.path = path;
        this.connection = this.getConnect(path);
    }

    /**
     * 读写锁，也可以使用ConcurrentHashMap
     */
    static ReentrantLock hashMapLock = new ReentrantLock();

    /**
     * Sqlite的连接池
     */
    static HashMap<String, List<SqliteHelper>> sqlitePool = new HashMap<>();

    /**
     * sqlite对磁盘文件的操作是在一次连接上执行
     *
     * @param path sqlite数据存储的磁盘文件
     * @return
     */
    public static SqliteHelper GetSqliteHelper(String path) throws SQLException, ClassNotFoundException {
        hashMapLock.lock();
        List<SqliteHelper> sqliteHelpers = sqlitePool.get(path);
        if (sqliteHelpers == null) {
            sqliteHelpers = new LinkedList<>();
            sqlitePool.put(path, sqliteHelpers);
        }
        SqliteHelper sqliteHelper = new SqliteHelper(path);
        sqliteHelpers.add(sqliteHelper);
        return sqliteHelper;
    }

    public void PutSqliteHelper() throws SQLException {
        hashMapLock.lock();
        List<SqliteHelper> sqliteHelpers = sqlitePool.get(this.path);
        if (sqliteHelpers == null) {
            sqliteHelpers = new LinkedList<>();
            sqlitePool.put(path, sqliteHelpers);
        }
        if(sqliteHelpers.size() > 2){
            releaseConn();
        }else{
            sqliteHelpers.add(this);
        }
    }
    /**
     * 获取Sqlite操作链接
     *
     * @param path sqlite数据表，为磁盘文件名
     * @return
     */
    private Connection getConnect(String path) throws ClassNotFoundException, SQLException {
        Connection c = null;
        Class.forName("org.sqlite.JDBC");
        c = DriverManager.getConnection("jdbc:sqlite:" + path);
        return c;
    }

    /**
     * @param sql 执行的sqlite 语句
     * @param row
     * @param <T> 映射的模板
     * @return
     */
    public <T> List<T> ExecuteQuery(String sql, RowMapper<T> row) throws SQLException {
        try {
            List<T> datas = new ArrayList<>();
            ResultSet resultSet = getStmt().executeQuery(sql);
            while (resultSet.next()) {
                datas.add(row.mapRow(resultSet, resultSet.getRow()));
            }
            resultSet.close();
            return datas;
        } finally {
            releaseConn();
        }
    }

    public void ExecuteUpdate(String sql) throws SQLException {
        getStmt().executeUpdate(sql);
    }

    private Statement getStmt() throws SQLException {
        if (this.statement == null) {
            this.statement = this.connection.createStatement();
        }
        return this.statement;
    }

    private void releaseConn() throws SQLException {
        if (this.connection != null) {
            this.connection.close();
            this.connection = null;
        }

        if (this.statement != null) {
            this.statement.close();
            this.statement = null;
        }
    }

}

到此这篇关于Java 项目封装sqlite连接池操作持久化数据的文章就介绍到这了,更多相关java sqlite连接池操作内容请搜索我们以前的文章或继续浏览下面的相关文章希望大家以后多多支持我们！