YDB系统JDBC接口访问工具

YDB：实时在线分析（OLAP）系统

YDB：实时在线分析（OLAP）系统：是我公司自主研发的一个大型分布式索引系统。旨在为数据总量为万亿级别、每天千亿级别数据增量的项目提供近似实时的数据导入，并提供近似实时响应的多维查询与统计服务。

JDBC接口

JDBC (Java Database Connectivity) API，即Java数据库编程接口，是一组标准的Java语言中的接口和类，使用这些接口和类，Java客户端程序可以访问各种不同类型的数据库。比如建立数据库连接、执行SQL语句进行数据的存取操作。

使用方法

$ java -jar ysql.jar -c drop table test; create table test(user string, password string); desc test;$ java -jar ysql.jar -f input$ cat input# 删除测试表格drop table test; # 新建测试表格create table test(user string, password string);# 查询表格结构desc test;

源代码

package cn.net.ycloud.ejdazhi;import java.io.BufferedReader;import java.io.File;import java.io.FileReader;import java.io.IOException;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.ResultSetMetaData;import java.sql.SQLException;import java.sql.Statement;import java.util.ArrayList;import java.util.List;import org.slf4j.Logger;import org.slf4j.LoggerFactory;public class YSql {    public static void main(String[] args) {        YSql ysql = new YSql();        ysql.start(args);    }    public void printUsage() {        System.out.println("usage:");        System.out.println("    java -jar ysql.jar -c <sql command>[;<sql command>]...");        System.out.println("    java -jar ysql.jar -f filename");    }    static Logger logger = LoggerFactory.getLogger(YSql.class);    private List<String> mSqls = new ArrayList<>();    public void setSqls(String[] strings) {        for (String string : strings) {            if (string.trim().length() == 0) continue;            mSqls.add(string);            logger.info(string);        }    }    public void start(String[] args) {        try {            parseParams(args);            executeSql();        } catch (Exception e) {            e.printStackTrace();            logger.info(e.getMessage());        }    }    private void parseParams(String[] args) throws IOException {        String string = null;        if (args.length >= 2) {            if ("-c".equals(args[0])) {                string = combineParams(args);            } else if ("-f".equals(args[0])) {                string = parseFile(args[1]);            }        }         if (null != string) setSqls(string.split(";"));        else  printUsage();    }    private String parseFile(String filename) throws IOException {        File file = new File(filename);        BufferedReader br = new BufferedReader(new FileReader(filename));        StringBuilder sb = new StringBuilder();        String line = null;        while ((line = br.readLine()) != null) {            if (line.indexOf('#') == 0) continue;            sb.append(line).append(" ");        }        br.close();        return sb.toString();    }    // combine from 1 to n and add space    private String combineParams(String[] strings) {        StringBuilder sb = new StringBuilder();        int n = strings.length;        for (int i = 1; i < n; i++) {            sb.append(strings[i]).append(" ");        }        return sb.toString();    }    private void executeSql() throws ClassNotFoundException, SQLException {        if (mSqls.size() == 0) return;        Class.forName("org.apache.hive.jdbc.HiveDriver");        Connection conn = DriverManager.getConnection("jdbc:hive2://192.168.3.54:10000/default", "ycloud", "");        Statement smst = conn.createStatement();        for (String sql : mSqls) {            ResultSet rs = smst.executeQuery(sql);            ResultSetMetaData md = rs.getMetaData();            int columns = md.getColumnCount();            for (int i = 1; i <= columns; i++) {                System.out.print(md.getColumnName(i));                System.out.print("\t\t");            }            System.out.println();            while (rs.next()) {               for (int i = 1; i <= columns; i++) {                    System.out.print(rs.getString(i));                    System.out.print("\t\t");                }                System.out.println();            }            rs.close();        }        conn.close();    }}