读取数据库写入数组

Question

package list;import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.sql.*;import java.util.ArrayList;
import java.util.List;
public class ConnOracle {

               private static Statement connc;
   private  static Connection connOrac;       //就差把它搞到数组里了
        
  public static void main(String args[]) throws IOException{
    
         try {
            Class.forName("com.mysql.jdbc.Driver").newInstance(); 
            connOrac = DriverManager.getConnection("jdbc:mysql://localhost/ip?user=root&password=1314521&useUnicode=true&characterEncoding=gb2312");
            connc=connOrac.createStatement();
            System.out.println("ok1");
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
           
           
        } catch (Exception e) {
            e.printStackTrace();
        }
   
       
    List<String> userName = new ArrayList<String>();
    String sql="SELECT SUBSTRING(startip,1,9),startip,endip FROM ip WHERE country LIKE '广东%' GROUP BY SUBSTRING(startip,1,9)    HAVING COUNT(*)>3  "  ;
        try {
        ResultSet rs = connc.executeQuery(sql);
  //  int i = 0;
      //  int rowCount = rs.getRow();//首先将指针移动到最后一条记录，获得总记录数
        String[] tastr = new String[rs.getRow()];
        int i=0;     for (rs.next() ){
         tastr[i] = rs.getString(1);
           tastr[i+1] = rs.getString(2);
           tastr[i+2] = rs.getString(3);
           tastr[i+3] = rs.getString(4);
           i++;        
              File f = new File("D:"+File.separator+"testfile.txt");
               //用FileOutputSteam包装文件，并设置文件可追加
              OutputStream out;
try {
out = new FileOutputStream(f,true);

               out.write(tastr[i+2].getBytes()); //向文件中写入数据
              out.write('\r'); // \r\n表示换行
              out.write('\n'); 
               
     out.close(); //关闭输出流
     System.out.println("写入成功！");



} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}                
                   
      } 
       
       
           
      
             
            
  
          
      
         
       
        
     } catch (SQLException ex) {
         System.out.println(ex);
     } 
  // TODO Auto-generated catch block
 
 
  }
                 
}
    
    
    
       

Answer 1

个人觉得应该这样吧： OutputStream out = null; try {
ResultSet rs = connc.executeQuery(sql);
String[][] datas = new String[rs.getRow()][4];

int i = 0;
while (rs.next()) {
datas[i][0] = rs.getString(1);
datas[i][1] = rs.getString(1);
datas[i][2] = rs.getString(1);
datas[i][3] = rs.getString(1);
i++; }
for(String[] data : datas){
for(String d : data){
File f = new File("D:" + File.separator + "testfile.txt");
// 用FileOutputSteam包装文件，并设置文件可追加
out = new FileOutputStream(f, true);
out.write(d.getBytes()); // 向文件中写入数据
}
out.write('\r'); // \r\n表示换行
out.write('\n');
System.out.println("写入成功！");
}
} catch (SQLException ex) {
System.out.println(ex);
} finally{
if(out != null) out.close();
}

Answer 2

代码没错，但是没有成功啊，怎么用usebean写这个啊。。

Answer 3

在Jsp也面里无法定义out啊。。

Answer 4

<%@ page language="java" contentType="text/html; charset=utf-8"
    pageEncoding="utf-8" import="java.sql.*" import=" java.io.*" import ="java.util.*;"%>
     
 <% 
     //  String  uname = request.getParameter("cardno");
       Statement stmtOR;
       Connection connOrac;
      
     try {
            Class.forName("com.mysql.jdbc.Driver").newInstance(); 
            connOrac = DriverManager.getConnection("jdbc:mysql://localhost/ip?user=root&password=1314521&useUnicode=true&characterEncoding=utf8");
            stmtOR=connOrac.createStatement();
            System.out.println("ok1");
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
           
           request.setCharacterEncoding("utf-8");
           
   String cardno = request.getParameter("cardno");
 //  String name = request.getParameter("name");
cardno=new String(cardno.getBytes("ISO-8859-1"),"utf8");
           
           
        // String    cardno=new String(request.getParameter("cardno").getBytes("utf-8"));    
           
   System.out.println(cardno);
             
           
           String type = request.getParameter("type");         if(cardno == null){
     cardno = "";
     }
     if(type == null ){
     type = "";
     }
    
          
    
    
     String sql = "select SUBSTRING(startip,1,9),startip,endip from ip  ";
     if(!"".equals(cardno)){
     sql += " where country like '"+cardno+"%' GROUP BY SUBSTRING(startip,1,9)    HAVING COUNT(*)>3";
     }
     if(!"".equals(type)){
     sql += " and type = '"+type+"';";
        }
        System.out.println(sql);
        ResultSet rs = stmtOR.executeQuery(sql);
       // int i = 0;
       String[] arr=new String[10000];
int i=0;   
        while (rs.next()) {
 
    
     if(i <arr.length) 
              { 
              arr[i]   =   rs.getString("startip"); 
              } 
            //  i++; 
                 
           //   System.out.println(arr[0]);//这条语句可以正常显示出startip字段中数据。 
              File   directory =   new   File(".");   
              directory.getCanonicalPath();//取得当前路径
                    String no1 =System.getProperty("user.dir");
              
              File f = new File("D:"+directory.separator+"ip.txt");
               //用FileOutputSteam包装文件，并设置文件可追加
           OutputStream out2 =new FileOutputStream(f,true);
try {
out2 = new FileOutputStream(f,true);
// int j=0;
//for(j=0;j<arr.length;j++){                out2.write(arr[0].getBytes()); //向文件中写入数据
              out2.write('\r'); // \r\n表示换行
              out2.write('\n'); 
               
  out2.close(); //关闭输出流
     // System.out.println("写入成功！");
//out2.clear();
                    //out2 = pageContext.pushBody();


// }
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}            
            %>
           
     <%
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        }
       
    } catch (SQLException ex) {
        System.out.println(ex);
    }
%>