Hbase(六) hbase Java API
一、
几个主要 Hbase API 类和数据模型之间的对应关系：
1、 HBaseAdmin
关系： org.apache.hadoop.hbase.client.HBaseAdmin
作用：提供了一个接口来管理 HBase 数据库的表信息。它提供的方法包括：创建表，删 除表，列出表项，使表有效或无效，以及添加或删除表列族成员等。
2、 HBaseConfiguration
关系： org.apache.hadoop.hbase.HBaseConfiguration
作用：对 HBase 进行配置
3、 HTableDescriptor
关系： org.apache.hadoop.hbase.HTableDescriptor
作用：包含了表的名字极其对应表的列族
4、 HColumnDescriptor
关系： org.apache.hadoop.hbase.HColumnDescriptor
作用：维护着关于列族的信息，例如版本号，压缩设置等。它通常在创建表或者为表添 加列族的时候使用。列族被创建后不能直接修改，只能通过删除然后重新创建的方式。
列族被删除的时候，列族里面的数据也会同时被删除。
5、 HTable
关系： org.apache.hadoop.hbase.client.HTable
作用：可以用来和 HBase 表直接通信。此方法对于更新操作来说是非线程安全的。
6、 Put
关系： org.apache.hadoop.hbase.client.Put
作用：用来对单个行执行添加操作
7、 Get
关系： org.apache.hadoop.hbase.client.Get
作用：用来获取单个行的相关信息
8、 Result
关系： org.apache.hadoop.hbase.client.Result
作用：存储 Get 或者 Scan 操作后获取表的单行值。使用此类提供的方法可以直接获取值 或者各种 Map 结构（ key-value 对）
二、具体增删改查 代码具体实现：
package HbaseDome;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Delete;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos.Table;
import org.apache.hadoop.hbase.util.Bytes;
public class Hbasedome implements HBaseDemoInterface{
static Configuration conf =null;
private static final String ZKconnect="192.168.123.212:2181,192.168.123.213:2181,192.168.123.214:2181";
static{
conf=HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", ZKconnect);
}
// static String tableName="student";
// static String[] family={"lie01","lie02"};
public static void main(String[] args) {
Hbasedome a =new Hbasedome();
String tableName="student11";
String[] family={"lie01","lie02"};
try {
HTableDescriptor htds =new HTableDescriptor(tableName);
for(int z=0;z<family.length;z++){
HColumnDescriptor h=new HColumnDescriptor(family[z]);
htds.addFamily(h);
}
// a.descTable("table03");
// a.createTable(tableName, htds);
// a.descTable("table03");
// a.getAllTables();
// a.createTable(tableName,family);
// a.getResult("table03", "usr001");
// a.dropTable("user1");
// a.getAllTables();
// a.putData("table03", "usr005", "liezu01", "name", "liu");
// a.getResult("table03", "usr001");
// a.getResultScann("table03");
// a.getResultScann("table03","");
Result result = a.getResult("table03", "usr001");
System.out.println(result.toString());
List<Cell> cells = result.listCells();
for (int i = 0; i < cells.size(); i++) {
Cell cell = cells.get(i);
System.out.println(cell.toString());
// printCell(cell);
}
// List<KeyValue> list = result.list();
// for (int i = 0; i < list.size(); i++) {
// KeyValue kv = list.get(i);
// printKeyValye(kv);
// }
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static void printKeyValye(KeyValue kv) {
System.out.println(Bytes.toString(kv.getRow()) + "\t" + Bytes.toString(kv.getFamily()) + "\t" + Bytes.toString(kv.getQualifier()) + "\t" + Bytes.toString(kv.getValue()) + "\t" + kv.getTimestamp());
}
public static void printCell(Cell cell) {
System.out.println(Bytes.toString(cell.getRow()) + "\t" + Bytes.toString(cell.getFamily()) + "\t" + Bytes.toString(cell.getQualifier()) + "\t" + Bytes.toString(cell.getValue()) + "\t" + cell.getTimestamp());
}
//创建表
@Override
public void createTable(String tableName, String[] family) throws Exception {
HBaseAdmin admin=new HBaseAdmin(conf);
HTableDescriptor desc =new HTableDescriptor(tableName);
for(int i=0;i<family.length;i++){
desc.addFamily(new HColumnDescriptor(family[i]));
System.out.println("11111111111"+family[i]);
}
if(admin.tableExists(tableName)){
System.out.println("表已经存在，别瞎输行吗");
// System.exit(0);
}else{
admin.createTable(desc);
System.out.println("表创建成功");
}
}
//创建表
@Override
public void createTable(String tableName, HTableDescriptor htds) throws Exception {
HBaseAdmin admin=new HBaseAdmin(conf);
boolean tableExists1 = admin.tableExists(Bytes.toBytes(tableName));
System.out.println(tableExists1 ? "表已存在" : "表不存在");
admin.createTable(htds);
boolean tableExists = admin.tableExists(Bytes.toBytes(tableName));
System.out.println(tableExists ? "创建表成功" : "创建失败");
}
@Override
public void descTable(String tableName) throws Exception {
HBaseAdmin admin=new HBaseAdmin(conf);
HTable table=new HTable(conf, tableName);
HTableDescriptor desc =table.getTableDescriptor();
HColumnDescriptor[] columnFamilies = desc.getColumnFamilies();
for(HColumnDescriptor t:columnFamilies){
System.out.println(Bytes.toString(t.getName()));
}
}
//// 这种方式是替换该表tableName的所有列簇
@Override
public void modifyTable(String tableName) throws Exception {
HBaseAdmin admin=new HBaseAdmin(conf);
HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(tableName));
htd.addFamily(new HColumnDescriptor(Bytes.toBytes("cf3")));
htd.addFamily(new HColumnDescriptor(Bytes.toBytes("cf2")));
admin.modifyTable(tableName, htd);
// 删除该表tableName当中的特定的列簇
// admin.deleteColumn(tableName, "cf3");
System.out.println("修改成功");
}
@Override
public void getAllTables() throws Exception {
HBaseAdmin admin =new HBaseAdmin(conf);
String[] tableNames = admin.getTableNames();
for(int i=0;i<tableNames.length;i++){
System.out.println(tableNames[i]);
}
}
//更新数据 插入数据
@Override
public void putData(String tableName, String rowKey, String familyName, String columnName, String value)
throws Exception {
HTable htable=new HTable(conf, Bytes.toBytes(tableName));
Put put=new Put(Bytes.toBytes(rowKey));
put.add(Bytes.toBytes(familyName), Bytes.toBytes(columnName), Bytes.toBytes(value));
htable.put(put);
}
//为表添加数据
@Override
public void addData(String tableName, String rowKey, String[] column1, String[] value1, String[] column2,
String[] value2) throws Exception {
Put put=new Put(Bytes.toBytes(rowKey));
HTable htable=new HTable(conf, Bytes.toBytes(tableName));
HColumnDescriptor[] columnFamilies = htable.getTableDescriptor().getColumnFamilies();
for(int i=0;i<=columnFamilies.length;i++){
String nameAsString = columnFamilies[i].getNameAsString();
if(nameAsString.equals("lie01")){
for(int j=0;j<column1.length;j++){
put.add(Bytes.toBytes(nameAsString), Bytes.toBytes(column1[j]),Bytes.toBytes(value1[j]));
}
}
if(nameAsString.equals("lie02")){
for(int j=0;j<column2.length;j++){
put.add(Bytes.toBytes(nameAsString), Bytes.toBytes(column2[j]),Bytes.toBytes(value2[j]));
}
}
}
htable.put(put);
System.out.println("addData ok!");
}
//根据rowkey 查询
@Override
public Result getResult(String tableName, String rowKey) throws Exception {
Get get=new Get(Bytes.toBytes(rowKey));
HTable htable=new HTable(conf, Bytes.toBytes(tableName));
Result result=htable.get(get);
// for(KeyValue k:result.list()){
// System.out.println(Bytes.toString(k.getFamily()));
// System.out.println(Bytes.toString(k.getQualifier()));
// System.out.println(Bytes.toString(k.getValue()));
// System.out.println(k.getTimestamp());
// }
return result;
}
//查询指定的某列
@Override
public Result getResult(String tableName, String rowKey, String familyName, String columnName) throws Exception {
Get get=new Get(Bytes.toBytes(rowKey));
HTable htable=new HTable(conf, Bytes.toBytes(tableName));
get.addColumn(Bytes.toBytes(familyName),Bytes.toBytes(columnName));
Result result=htable.get(get);
for(KeyValue k:result.list()){
System.out.println(Bytes.toString(k.getFamily()));
System.out.println(Bytes.toString(k.getQualifier()));
System.out.println(Bytes.toString(k.getValue()));
System.out.println(k.getTimestamp());
}
return result;
}
//遍历查询表
@Override
public ResultScanner getResultScann(String tableName) throws Exception {
Scan scan=new Scan();
ResultScanner rs =null;
HTable htable=new HTable(conf, tableName);
try{
rs=htable.getScanner(scan);
for(Result r: rs){
for(KeyValue kv:r.list()){
System.out.println(Bytes.toString(kv.getRow()));
System.out.println(Bytes.toString(kv.getFamily()));
System.out.println(Bytes.toString(kv.getQualifier()));
System.out.println(Bytes.toString(kv.getValue()));
System.out.println(kv.getTimestamp());
}
}
}finally{
rs.close();
}
return rs;
}
@Override
public ResultScanner getResultScann(String tableName, Scan scan) throws Exception {
ResultScanner rs =null;
HTable htable=new HTable(conf, tableName);
try{
rs=htable.getScanner(scan);
for(Result r: rs){
for(KeyValue kv:r.list()){
System.out.println(Bytes.toString(kv.getRow()));
System.out.println(Bytes.toString(kv.getFamily()));
System.out.println(Bytes.toString(kv.getQualifier()));
System.out.println(Bytes.toString(kv.getValue()));
System.out.println(kv.getTimestamp());
}
}
}finally{
rs.close();
}
return rs;
}
//查询表中的某一列
@Override
public Result getResultByColumn(String tableName, String rowKey, String familyName, String columnName)
throws Exception {
HTable htable=new HTable(conf, tableName);
Get get=new Get(Bytes.toBytes(rowKey));
get.addColumn(Bytes.toBytes(familyName),Bytes.toBytes(columnName));
Result result=htable.get(get);
for(KeyValue kv: result.list()){
System.out.println(Bytes.toString(kv.getFamily()));
System.out.println(Bytes.toString(kv.getQualifier()));
System.out.println(Bytes.toString(kv.getValue()));
System.out.println(kv.getTimestamp());
}
return result;
}
//查询某列数据的某个版本
@Override
public Result getResultByVersion(String tableName, String rowKey, String familyName, String columnName,
int versions) throws Exception {
HTable htable=new HTable(conf, tableName);
Get get =new Get(Bytes.toBytes(rowKey));
get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName));
get.setMaxVersions(versions);
Result result=htable.get(get);
for(KeyValue kv: result.list()){
System.out.println(Bytes.toString(kv.getFamily()));
System.out.println(Bytes.toString(kv.getQualifier()));
System.out.println(Bytes.toString(kv.getValue()));
System.out.println(kv.getTimestamp());
}
return result;
}
//删除指定某列
@Override
public void deleteColumn(String tableName, String rowKey, String falilyName, String columnName) throws Exception {
HTable htable=new HTable(conf, tableName);
// Delete delete1=new Delete(Bytes.toBytes(rowKey));
Delete de =new Delete(Bytes.toBytes(rowKey));
de.deleteColumn(Bytes.toBytes(falilyName), Bytes.toBytes(columnName));
htable.delete(de);
}
//删除指定的某个rowkey
@Override
public void deleteColumn(String tableName, String rowKey) throws Exception {
HTable htable=new HTable(conf, tableName);
Delete de =new Delete(Bytes.toBytes(rowKey));
htable.delete(de);
}
//让该表失效
@Override
public void disableTable(String tableName) throws Exception {
HBaseAdmin admin=new HBaseAdmin(conf);
admin.disableTable(tableName);
}
//删除表
@Override
public void dropTable(String tableName) throws Exception {
HBaseAdmin admin=new HBaseAdmin(conf);
admin.disableTable(tableName);
admin.deleteTable(tableName);
}
}
package com.ghgj.hbase.test1610;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.HColumnDescriptor;
import org.apache.hadoop.hbase.HTableDescriptor;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HBaseAdmin;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.client.ResultScanner;
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.util.Bytes;
public class HBaseAPIDemo1610 implements HBaseDemoInterface {
private static final String ROWKEY = "p001";
private static final String ROWKEY2 = "p002";
private static final String FAMILY1 = "cf1";
private static final String FAMILY2 = "cf2";
private static final String KEY = "name";
private static final String VALUE = "huangbo";
private static final String TABLE_NAME = "person";
private static final String[] COLUMN_FAMILY = new String[] { FAMILY1, FAMILY2 };
static Configuration conf = null;
static HBaseAdmin admin = null;
static HTable table = null;
static {
try {
conf = HBaseConfiguration.create();
conf.set("hbase.zookeeper.quorum", "hadoop03:2181,hadoop04:2181,hadoop05:2181");
admin = new HBaseAdmin(conf);
table = new HTable(conf, TABLE_NAME);
} catch (IOException e) {
// e.printStackTrace();
System.out.println("报错");
}
}
public static void main(String[] args) throws Exception {
HBaseAPIDemo1610 hbase = new HBaseAPIDemo1610();
// 测试创建表
hbase.createTable(TABLE_NAME, COLUMN_FAMILY);
// 测试创建表
HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(TABLE_NAME));
for (int i = 0; i < COLUMN_FAMILY.length; i++) {
HColumnDescriptor cf1 = new HColumnDescriptor(COLUMN_FAMILY[i]);
htd.addFamily(cf1);
}
hbase.createTable(TABLE_NAME, htd);
// 查看表属性
hbase.descTable(TABLE_NAME);
// 查询所有的表
hbase.getAllTables();
// 测试修改表
hbase.modifyTable(TABLE_NAME);
// 插入数据
hbase.putData(TABLE_NAME, ROWKEY, FAMILY1, KEY, VALUE);
// 测试插入一堆数据
String[] column1 = new String[] { "name1", "age", "province" };
String[] value1 = new String[] { "huangbo", "33", "xinjiang" };
String[] column2 = new String[] { "gender" };
String[] value2 = new String[] { "male" };
hbase.addData(TABLE_NAME, ROWKEY2, column1, value1, column2, value2);
// 通过rowkey查询数据
Result result = hbase.getResult(TABLE_NAME, ROWKEY2);
System.out.println(result.toString());
List<KeyValue> list = result.list();
for (int i = 0; i < list.size(); i++) {
KeyValue kv = list.get(i);
printKeyValye(kv);
}
// 通过rowkey, family, province查询数据
Result result1 = hbase.getResult(TABLE_NAME, ROWKEY2, FAMILY1, "province");
List<Cell> cells = result1.listCells();
for (int i = 0; i < cells.size(); i++) {
Cell cell = cells.get(i);
printCell(cell);
}
// 扫描全表数据
ResultScanner resultScann = hbase.getResultScann(TABLE_NAME);
printResultScanner(resultScann);
/*Iterator<Result> iterator = resultScann.iterator();
while(iterator.hasNext()){
Result next = iterator.next();
}*/
// 通过scan扫描全表数据，scan中可以加入一些过滤条件
Scan scan = new Scan();
scan.setStartRow(Bytes.toBytes("user"));
scan.setStopRow(Bytes.toBytes("zk002"));
scan.setTimeRange(1488252774189l, 1488252774191l);
ResultScanner resultScann1 = hbase.getResultScann(TABLE_NAME, scan);
printResultScanner(resultScann1);
// 两种方式查询最大版本数的hbase数据
Result resultByVersion = hbase.getResultByVersion(TABLE_NAME, ROWKEY, FAMILY1, "name", 3);
printResult(resultByVersion);
System.out.println("-------------------");
ResultScanner rs = hbase.getResultByVersion(ROWKEY, FAMILY1, "name", 3);
printResultScanner(rs);
// 删除表
hbase.dropTable(TABLE_NAME);
}
public static void printResultScanner(ResultScanner resultScann) {
for (Result result : resultScann) {
printResult(result);
}
}
public static void printResult(Result result) {
List<Cell> cells = result.listCells();
for (int i = 0; i < cells.size(); i++) {
Cell cell = cells.get(i);
printCell(cell);
}
}
public static void printCell(Cell cell) {
System.out.println(Bytes.toString(cell.getRow()) + "\t" + Bytes.toString(cell.getFamily()) + "\t" + Bytes.toString(cell.getQualifier()) + "\t" + Bytes.toString(cell.getValue()) + "\t" + cell.getTimestamp());
}
public static void printKeyValye(KeyValue kv) {
System.out.println(Bytes.toString(kv.getRow()) + "\t" + Bytes.toString(kv.getFamily()) + "\t" + Bytes.toString(kv.getQualifier()) + "\t" + Bytes.toString(kv.getValue()) + "\t" + kv.getTimestamp());
}
// create 'tablename','cf1','cf2'
@Override
public void createTable(String tableName, String[] family) throws Exception {
HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(tableName));
for (int i = 0; i < family.length; i++) {
HColumnDescriptor cf1 = new HColumnDescriptor(family[i]);
htd.addFamily(cf1);
}
admin.createTable(htd);
boolean tableExists = admin.tableExists(Bytes.toBytes(tableName));
System.out.println(tableExists ? "创建表成功" : "创建失败");
}
@Override
public void createTable(String tableName, HTableDescriptor htd) throws Exception {
admin.createTable(htd);
boolean tableExists = admin.tableExists(Bytes.toBytes(tableName));
System.out.println(tableExists ? "创建表成功" : "创建失败");
}
// desc 'person'
@Override
public void descTable(String tableName) throws Exception {
HTableDescriptor tableDescriptor = table.getTableDescriptor();
HColumnDescriptor[] columnFamilies = tableDescriptor.getColumnFamilies();
for (HColumnDescriptor hcd : columnFamilies) {
// System.out.println(hcd.toString()+"\t");
System.out.println(Bytes.toString(hcd.getName()));
}
}
@Override
public void modifyTable(String tableName) throws Exception {
// 这种方式是替换该表tableName的所有列簇
HTableDescriptor htd = new HTableDescriptor(TableName.valueOf(tableName));
htd.addFamily(new HColumnDescriptor(Bytes.toBytes("cf3")));
htd.addFamily(new HColumnDescriptor(Bytes.toBytes("cf2")));
admin.modifyTable(tableName, htd);
// 删除该表tableName当中的特定的列簇
// admin.deleteColumn(tableName, "cf3");
System.out.println("修改成功");
}
// list
@Override
public void getAllTables() throws Exception {
TableName[] listTableNames = admin.listTableNames();
for (TableName tn : listTableNames) {
System.out.println(tn.toString());
}
}
// put 'tablename','rowkey','familyname:key','value'
@Override
public void putData(String tableName, String rowKey, String familyName, String columnName, String value) throws Exception {
// HTable table = new HTable(conf, tableName);
Put put = new Put(Bytes.toBytes(rowKey));
put.add(Bytes.toBytes(familyName), Bytes.toBytes(columnName), Bytes.toBytes(value));
table.put(put);
System.out.println("插入成功");
}
/**
* @param tableName
* 表名
* @param rowKey
* rowkey
* @param column1
* 第一个列簇的key数组
* @param value1
* 第一个列簇的value数组，key数组和value数组长度必须一样
* @param column2
* 第二列簇的key数组
* @param value2
* 第二个列簇的values数组， 同上同理
* @throws Exception
*/
@Override
public void addData(String tableName, String rowKey, String[] column1, String[] value1, String[] column2, String[] value2) throws Exception {
List<Put> puts = new ArrayList<Put>();
for (int i = 0; i < column1.length; i++) {
Put put = new Put(Bytes.toBytes(rowKey));
put.add(Bytes.toBytes(FAMILY1), Bytes.toBytes(column1[i]), Bytes.toBytes(value1[i]));
puts.add(put);
}
for (int i = 0; i < column2.length; i++) {
Put put = new Put(Bytes.toBytes(rowKey));
put.add(Bytes.toBytes(FAMILY2), Bytes.toBytes(column2[i]), Bytes.toBytes(value2[i]));
puts.add(put);
}
table.put(puts);
System.out.println("插入一堆数据成功");
}
// get 'tablename','rowkey'
@Override
public Result getResult(String tableName, String rowKey) throws Exception {
Get get = new Get(Bytes.toBytes(rowKey));
Result result = table.get(get);
return result;
}
@Override
public Result getResult(String tableName, String rowKey, String familyName, String columnName) throws Exception {
Get get = new Get(Bytes.toBytes(rowKey));
get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName));
Result result = table.get(get);
return result;
}
@Override
public ResultScanner getResultScann(String tableName) throws Exception {
Scan scan = new Scan();
ResultScanner scanner = table.getScanner(scan);
// ResultScanner scanner = table.getScanner(Bytes.toBytes(FAMILY2));
// ResultScanner scanner = table.getScanner(Bytes.toBytes(FAMILY1),
// Bytes.toBytes("name1"));
return scanner;
}
@Override
public ResultScanner getResultScann(String tableName, Scan scan) throws Exception {
return table.getScanner(scan);
}
@Override
public Result getResultByColumn(String tableName, String rowKey, String familyName, String columnName) throws Exception {
return null;
}
// get 'person','p001',{COLUMNS => 'cf1:name', VERSIONS => 3}
@Override
public Result getResultByVersion(String tableName, String rowKey, String familyName, String columnName, int versions) throws Exception {
Get get = new Get(Bytes.toBytes(rowKey));
get.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName));
get.setMaxVersions(versions);
Result result = table.get(get);
return result;
}
public ResultScanner getResultByVersion(String rowKey, String familyName, String columnName, int versions) throws Exception {
Scan scan = new Scan(Bytes.toBytes(rowKey), Bytes.toBytes(rowKey));
scan.addColumn(Bytes.toBytes(familyName), Bytes.toBytes(columnName));
scan.setMaxVersions(versions);
ResultScanner scanner = table.getScanner(scan);
return scanner;
}
@Override
public void deleteColumn(String tableName, String rowKey, String falilyName, String columnName) throws Exception {
}
@Override
public void deleteColumn(String tableName, String rowKey) throws Exception {
}
@Override
public void disableTable(String tableName) throws Exception {
admin.disableTable(tableName);
}
@Override
public void dropTable(String tableName) throws Exception {
try {
admin.deleteTable(tableName);
} catch (Exception e) {
// e.printStackTrace();
disableTable(tableName);
admin.deleteTable(tableName);
System.out.println("ssssssss");
} finally {
boolean tableExists = admin.tableExists(Bytes.toBytes(tableName));
System.out.println(tableExists ? "删除失败" : "删除成功");
}
}
}
