java

2016-02-17 09:53:55 130 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

【Java】JAVA知识总结浅析 Java是一门功能强大的编程语言，广泛应用于多个领域。Java的编程思想，包括面向过程和面向对象编程，Java的发展历史，各版本的特点，JVM原理，数据类型，Java SE与Java EE的区别，应用场景，JDK与JDBC，Java Web技术，Spring Boot系列，以及MyBatis框架的基本实现，最后还将讨论Java在大数据、人工智能、嵌入式和Android等领域的应用。阅读详情

import java.io.File;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import jxl.Workbook;
import jxl.format.Colour;
import jxl.write.Label;
import jxl.write.WritableCellFormat;
import jxl.write.WritableFont;
import jxl.write.WritableSheet;
import jxl.write.WritableWorkbook;

public class Java_oracle {

public static void main(String[] args) {
try{
Class.forName("oracle.jdbc.driver.OracleDriver");
Connection ct=DriverManager.getConnection("jdbc:oracle:thin:@172.28.1.20:1521:uniondb","unionuser","unionoptr");
Statement sm=ct.createStatement();
ResultSet rs=sm.executeQuery("select * from nodeb");
WritableFont font1 = new WritableFont(
WritableFont.createFont("宋体"), 10, WritableFont.BOLD);
font1.setColour(Colour.BLACK);
WritableCellFormat format1 = new WritableCellFormat(font1);
format1.setAlignment(jxl.format.Alignment.CENTRE);
format1.setVerticalAlignment(jxl.format.VerticalAlignment.CENTRE);

WritableWorkbook book = Workbook.createWorkbook(new File("01"+".xls"));
WritableSheet sheet =book.createSheet("第一页",0);
Label labelA = new Label(0,0,"name",format1 );
Label labelB = new Label(1,0,"add", format1);
Label labelC = new Label(2,0,"sex", format1);
sheet.addCell(labelA);
sheet.addCell(labelB);
sheet.addCell(labelC);
List list = new ArrayList();
while(rs.next())
{
String INT_ID = rs.getString("INT_ID");
String OBJECT_RDN = rs.getString("OBJECT_RDN");
String OMC_ID = rs.getString("OMC_ID");
String NODEBID = rs.getString("NODEBID");
String NAME = rs.getString("NAME");
String RELATED_MGW = rs.getString("RELATED_MGW");
String MGW_NAME = rs.getString("MGW_NAME");
String RNCID = rs.getString("RNCID");
String RELATED_RNC = rs.getString("RELATED_RNC");
String RNC_NAME = rs.getString("RNC_NAME");
String VENDOR_ID = rs.getString("VENDOR_ID");
String TIME_STAMP = rs.getString("TIME_STAMP");
String UPDATE_STAMP = rs.getString("UPDATE_STAMP");
String CITY_ID = rs.getString("CITY_ID");
String CONFIRMED = rs.getString("CONFIRMED");
String NODEB_IUB = rs.getString("NODEB_IUB");
String LATITUDE = rs.getString("LATITUDE");
String LONGITUDE = rs.getString("LONGITUDE");
String DLCE = rs.getString("DLCE");
String ULCE = rs.getString("ULCE");
String PROVINCE_NAME = rs.getString("PROVINCE_NAME");
String REGION_NAME = rs.getString("REGION_NAME");
String VENDOR_NAME = rs.getString("VENDOR_NAME");
String NUMFA = rs.getString("NUMFA");
String DEVICE_TYPE = rs.getString("DEVICE_TYPE");
String VERSION = rs.getString("VERSION");
String SECTOR_TYPE = rs.getString("SECTOR_TYPE");
String FREQ = rs.getString("FREQ");
String NUM_OF_E1 = rs.getString("NUM_OF_E1");
String NUM_OF_FE = rs.getString("NUM_OF_FE");
String IUB_ATMCONFBANDWIDTH = rs.getString("IUB_ATMCONFBANDWIDTH");
String IUB_IPCONFBANDWIDTH = rs.getString("IUB_IPCONFBANDWIDTH");
String PRODUCTNAME = rs.getString("PRODUCTNAME");
String DN = rs.getString("DN");
String RUN_STATE = rs.getString("RUN_STATE");
String CO_SC_NAME = rs.getString("CO_SC_NAME");
String CO_OCV_SYS_VERSION = rs.getString("CO_OCV_SYS_VERSION");
String AVG_AVAIL_CE = rs.getString("AVG_AVAIL_CE");
String RELATED_SGSN = rs.getString("RELATED_SGSN");
String BBU_NUM = rs.getString("BBU_NUM");
String RRU_NUM = rs.getString("RRU_NUM");
String VENDOR_NODEB_ID = rs.getString("VENDOR_NODEB_ID");
list.add(INT_ID);
list.add(OBJECT_RDN);
list.add(OMC_ID);
list.add(NODEBID);
list.add(NAME);
list.add(RELATED_MGW);
list.add(MGW_NAME);
list.add(RNCID);
list.add(RELATED_RNC);
list.add(RNC_NAME);
list.add(VENDOR_ID);
list.add(TIME_STAMP);
list.add(UPDATE_STAMP);
list.add(CITY_ID);
list.add(CONFIRMED);
list.add(NODEB_IUB);
list.add(LATITUDE);
list.add(LONGITUDE);
list.add(DLCE);
list.add(ULCE);
list.add(PROVINCE_NAME);
list.add(REGION_NAME);
list.add(VENDOR_NAME);
list.add(NUMFA);
list.add(DEVICE_TYPE);
list.add(VERSION);
list.add(SECTOR_TYPE);
list.add(FREQ);
list.add(NUM_OF_E1);
list.add(NUM_OF_FE);
list.add(IUB_ATMCONFBANDWIDTH);
list.add(IUB_IPCONFBANDWIDTH);
list.add(PRODUCTNAME);
list.add(DN);
list.add(RUN_STATE);
list.add(CO_SC_NAME);
list.add(CO_OCV_SYS_VERSION);
list.add(AVG_AVAIL_CE);
list.add(RELATED_SGSN);
list.add(BBU_NUM);
list.add(RRU_NUM);
list.add(VENDOR_NODEB_ID);
//System.out.println(list.size());
}
for(int i =0 ;i<list.size();i++){
//System.out.print(list.get(i))
Label labelAi = new Label(0, i +1 , list.get(i).toString());
sheet.addCell(labelAi);
}
book.write();
book.close();
System.out.println("创建文件成功!");
rs.close();
sm.close();
ct.close();
}

catch (Exception e)
{
e.printStackTrace();
}

}

}

我在运行的时候报出
java.lang.NullPointerException
at Java_oracle.main(Java_oracle.java:134)
这个错误，求大神解决一下

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