YDB系统JDBC接口访问工具

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();
}
}