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rs.getString("USER_NAME").trim()什么意思
da2121211
2006-08-30 02:16:23
trim()是什么意思
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rs.getString("USER_NAME").trim()什么意思
trim()是什么意思
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da2121211
2006-08-30
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学习中public static String trimAndConvertNull(String s) {
String str = (s == null ? "" : s.trim());
return str;
}
Netself
2006-08-30
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同意楼上
pipinews
2006-08-30
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rs.getString("USER_NAME")==null?null:rs.getString("USER_NAME").trim();
好像这样写才对,万一为空了,不就有一个Exception..or Null..Exception
flyforlove
2006-08-30
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这样写
rs.getString("USER_NAME")==null?null:rs.getString("USER_NAME").trim();
caac9999
2006-08-30
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如果该字段为null的时候调用trim()会抛出异常,这个有点麻烦,还不能随便加trim()
suncheng_hong
2006-08-30
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去掉首尾空格后留下的字符串
为了防止用户输入用户名和密码时多出个空格,不好辨别
china2001ok
2006-08-30
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去掉二楼的小鸡几
哈哈
peleduy
2006-08-30
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1
从结果集中取出名称为USER_NAME的值并去掉该值的首尾空格
ldg_2
2006-08-30
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去掉首尾空格,一般这个方法在处理输入判断时候用的比较多,因为人在输入时候有可能不自觉输入空格但是又不显示,采用这个方法限制这种情况,通常做判断还加上一个toUpperCase(),统一转化大小写。
zhangj0571
2006-08-30
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去掉首尾空格后留下的字符串
OnlyFor_love
2006-08-30
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楼上正解trim()方法是自带的
rs.getString("USER_NAME")表示通过执行sql语句后返回一个结果集rs getString("USER_NAME")就是取表中字段为“USER_NAME”的值
kevinliuu
2006-08-30
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去首尾空格
java 数据库 课程设计 图书馆管理信息系统
java 数据库 重点是实现了预约 违章等功能 public static int checkIt(
String
name,
String
password,
String
purview)// 验证用户名 密码 { interFace s = new interFace();
String
temp = "select * from
user
_info " + "where
user
_name='" + name + "'" + " and " + "
user
_psw='" + password + "'" + " and " + "
user
_purview='" + purview + "'"; s.search(temp); int i = 0; try { while (s.C.next()) { i++; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return i; } public static void update_book_number(
String
s4){
String
sql="update book_info set book_num_in=book_num_in+1 where book_info.book_id='"+s4+"'"; try{ interFace.edit(sql); }catch(Exception e){ e.printStackTrace(); } } public static int book_num_in(
String
s){
String
sql="select book_num_in from book_info where book_name= '"+s+"'"; int count=0; try{
rs
=B.executeQuery(sql); if(
rs
.next()){ count=Integer.pa
rs
eInt(
rs
.get
String
(1)); } } catch(Exception e){ e.printStackTrace(); } return count; } public static void day_number(
String
s1,
String
s2,int s3){ float days=0;
String
s=null; int mum=0; try{ SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd"); s = df.format(new Date());
String
date=s1; Date d1 = df.pa
rs
e(s); Date d2 = df.pa
rs
e(date); long diff = d1.getTime() - d2.getTime(); days= diff / (1000 * 60 * 60 * 24); }catch(Exception e){ e.printStackTrace(); }System.out.println(days); days=days-30; if(s2.equals("是")){ days=days-30; } if(days>0){ days=days/10;} else{ days=0; } if(days>0){ write_dirty(s3,days);//写入不良信息 } try{//把borrow 中的borrow_returned 将return 改成"是"
String
ss="是";
String
sql="update borrow_info set borrow_returned='"+ss+ "' , borrow_info.return_date= '"+s+"'where borrow_info.borrow_id='"+s3+"'"; interFace.edit(sql); }catch(Exception e ){ e.printStackTrace(); } } public static void write_dirty(int s,float days){ try{ int count=0;
rs
=B.executeQuery("select count(*) from dirty_info "); if(
rs
.next()) count=Integer.pa
rs
eInt(
rs
.get
String
(1)); count++;
String
des="过期"+days*10+"天,罚款"+days+"元"; interFace.edit("insert into dirty_info values('"+ count+"','"+s+"','"+des+"') "); JOptionPane.showMessageDialog(null,des,"提示!",JOptionPane.PLAIN_MESSAGE);
String
descri=Adminfrm.jTextArea.getText(); if(descri.
trim
().equals(null)){ //do nothing } else{ count++; descri=descri+"罚款一元"; interFace.edit("insert into dirty_info values('"+ count+"','"+s+"','"+descri+"') "); JOptionPane.showMessageDialog(null,descri,"提示!",JOptionPane.PLAIN_MESSAGE); } } catch(Exception e ){ e.printStackTrace(); } } public int
user
_num(){ interFace s = new interFace();
String
temp = "select * from
user
_info " ; s.search(temp); int i1 = 0; try { while (s.C.next()) { i1++; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return i1; } public static int sum_borrow(){ int count=0; try{
String
sql1="select max(borrow_id) from borrow_info";
rs
=null;
rs
=B.executeQuery(sql1); while(
rs
.next()){ count= Integer.pa
rs
eInt(
rs
.get
String
(1)); } } catch (Exception e ){ e.printStackTrace(); } count++; return count; } public static void edit(
String
command) { interFace s=new interFace (); s.C=s.search(command); return; } public static void book_inquire(Object [] [] data,
String
string
1,
String
sql){ try{
rs
=null;
rs
=B.executeQuery(sql); int i=0; initialize(data,30,9); while(
rs
.next()){ s1=
rs
.get
String
("book_id"); data[i][0]=s1; s2=
rs
.get
String
("book_name");data[i][1]=s2; s3=
rs
.get
String
("book_price").
trim
(); data[i][2] =s3; s4=
rs
.get
String
("book_publishing").
trim
();data[i][3]=s4; s5=
rs
.get
String
("book_author").
trim
();data[i][4]=s5; s6=
rs
.get
String
("book_date").
trim
();data[i][5]=s6; s7=
rs
.get
String
("book_num").
trim
();data[i][6]=s7; s8=
rs
.get
String
("book_num_in").
trim
();data[i][7]=s8; s9=
rs
.get
String
("lib_name");data[i][8]=s9; i++; } } catch(Exception e ){ e.printStackTrace(); } } public static
String
[][] doSearch(
String
command,
String
[] colName) { interFace s = new interFace();
String
temp = command; s.C = s.search(temp); int col = colName.length, i = 0; s.rec = new
String
[100][col]; try { while (s.C.next()) { for (int j = 1; j <= col; j++) { s.rec[i][j - 1] = s.C.get
String
(j); } i++; s.i++; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); }
String
[][] result = new
String
[s.i][col]; for (int k = 0; k < s.i; k++) { for (int l = 0; l < col; l++) result[k][l] = s.rec[k][l]; } return result; } public static void inquire_history(
String
string
1){
String
m=
string
1;
String
sql="select * from borrow_info ,book_info,
user
_info where borrow_info.borrow_bid=book_info.book_id and borrow_uid=
user
_id and
user
_name='"+m+"'"; try{
rs
=null;
rs
=B.executeQuery(sql); // System.out.println(
rs
); int i=0; initialize(
User
frm.rowData1,30,9); while(
rs
.next()){ if(!
rs
.get
String
("borrow_returned").
trim
().equals("否")){ s1=
rs
.get
String
("borrow_id");
User
frm.rowData1[i][0]=s1; s2=
rs
.get
String
("borrow_uid");
User
frm.rowData1[i][1]=s2; s3=
rs
.get
String
("borrow_bid").
trim
();
User
frm.rowData1[i][2]=s3; s4=
rs
.get
String
("book_name").
trim
();
User
frm.rowData1[i][3]=s4; s5=
rs
.get
String
("borrow_time").
trim
();
User
frm.rowData1[i][4]=s5; s6=
rs
.get
String
("borrow_reborrow").
trim
();
User
frm.rowData1[i][5]=s6; s7=
rs
.get
String
("borrow_returned").
trim
();
User
frm.rowData1[i][6]=s7; s8=
rs
.get
String
("return_date").
trim
();
User
frm.rowData1[i][7]=s8;} else{ continue; } i++; } } catch(Exception e ){ e.printStackTrace(); } } public static void inquire_current_history(
String
string
1){
String
m=
string
1;
String
sql="select * from borrow_info ,book_info,
user
_info where borrow_info.borrow_bid=book_info.book_id and borrow_uid=
user
_id and
user
_name='"+m+"'"; try{
rs
=null;
rs
=B.executeQuery(sql); // System.out.println(
rs
); int i=0; initialize(
User
frm.rowData4,30,9); while(
rs
.next()){ if(
rs
.get
String
("borrow_returned").
trim
().equals("否")){ s1=
rs
.get
String
("borrow_id");
User
frm.rowData4[i][0]=s1; s2=
rs
.get
String
("borrow_uid");
User
frm.rowData4[i][1]=s2; s3=
rs
.get
String
("borrow_bid").
trim
();
User
frm.rowData4[i][2]=s3; s4=
rs
.get
String
("book_name").
trim
();
User
frm.rowData4[i][3]=s4; s5=
rs
.get
String
("borrow_time").
trim
();
User
frm.rowData4[i][4]=s5; s6=
rs
.get
String
("borrow_reborrow").
trim
();
User
frm.rowData4[i][5]=s6; s7=
rs
.get
String
("borrow_returned").
trim
();
User
frm.rowData4[i][6]=s7; s8=
rs
.get
String
("return_date").
trim
();
User
frm.rowData4[i][7]=s8; } else{ continue; } i++; } } catch(Exception e ){ e.printStackTrace(); } } public static void inquire_weizhang(
String
string
1){
String
sql="select * from book_info ,borrow_info,dirty_info where book_info.book_id=borrow_info.borrow_bid " + "and borrow_info.borrow_id=dirty_info.dirty_borrow_id"; try{
rs
=null;
rs
=B.executeQuery(sql); int i=0; initialize(
User
frm.rowData2,13,6); /**if(
rs
==null){ System.out.println("恭喜您,没有不良记录,请继续保持"); }*/ while(
rs
.next()){ s1=
rs
.get
String
("dirty_id");
User
frm.rowData2[i][0]=s1; s2=
rs
.get
String
("borrow_id");
User
frm.rowData2[i][1]=s2; s3=
rs
.get
String
("borrow_bid");
User
frm.rowData2[i][2]=s3; s4=
rs
.get
String
("book_name");
User
frm.rowData2[i][3]=s4; s5=
rs
.get
String
("borrow_time");
User
frm.rowData2[i][4]=s5; s6=
rs
.get
String
("dirty_description");
User
frm.rowData2[i][5]=s6; i++; } } catch(Exception e ){ e.printStackTrace(); } } //得出uid号 public static void book_request(
String
string
1){ int count=0; int uid = 0;
String
s="是"; try{
String
sql="select count (*) from request_info ";
rs
=null;
rs
=B.executeQuery(sql); while(
rs
.next()){ count= Integer.pa
rs
eInt(
rs
.get
String
(1)); }
String
user
name=Login.jTextField.getText();
String
sql1="select
user
_id from
user
_info where
user
_name='"+
user
name+"'";
rs
=null;
rs
=B.executeQuery(sql1); //System.out.println(
rs
); while(
rs
.next()){ uid= Integer.pa
rs
eInt(
rs
.get
String
(1)); } Calendar cal=Calendar.getInstance();
String
date=Integer.to
String
(cal.get(Calendar.YEAR))+"-"+ Integer.to
String
(cal.get(Calendar.MONTH)+1)+"-"+ Integer.to
String
(cal.get(Calendar.DATE)); count++; sql="insert into request_info values ( '"+count+"','"+uid+"','"+
string
1+"','"+date+"','"+s+"' )"; interFace.edit(sql); } catch (Exception e){ e.printStackTrace(); } } public static void yuyue_history(){
String
user
name=Login.jTextField.getText(); int uid=0;
String
sql1="select
user
_id from
user
_info where
user
_name='"+
user
name+"'"; try{
rs
=null;
rs
=B.executeQuery(sql1); //System.out.println(
rs
); while(
rs
.next()){ uid= Integer.pa
rs
eInt(
rs
.get
String
(1)); }
String
sql="select * from request_info where request_uid ='"+uid+"'";
rs
=null;int i=0;
rs
=B.executeQuery(sql); initialize(
User
frm.rowData3,10,5); // System.out.println(
rs
); while(
rs
.next()){ s1=
rs
.get
String
("request_id");
User
frm.rowData3[i][0]=s1; s2=
rs
.get
String
("request_uid");
User
frm.rowData3[i][1]=s2; s3=
rs
.get
String
("request_description");
User
frm.rowData3[i][2]=s3; s4=
rs
.get
String
("request_date");
User
frm.rowData3[i][3]=s4; s5=
rs
.get
String
("request_finished");
User
frm.rowData3[i][4]=s5; i++; } } catch (Exception e){ e.printStackTrace(); } } public static void information(){ //System.out.println(Login.jTextField.getText());
String
m=Login.jTextField.getText();
String
sql="select * from
user
_info where
user
_name= '"+m+"'"; try{
rs
=null;
rs
=B.executeQuery(sql); while(
rs
.next()){ s1=
rs
.get
String
("
user
_name");
User
frm.jTextField3.setText(s1); s2=
rs
.get
String
("
user
_psw");
User
frm.jTextField4.setText(s2); s3=
rs
.get
String
("
user
_age");
User
frm.jTextField5.setText(s3); s4=
rs
.get
String
("
user
_sex");
User
frm.jTextField6.setText(s4); } } catch (Exception e){ e.printStackTrace(); } } public static void info_modify(
String
s1,int a ,
String
b){
String
m=Login.jTextField.getText();
String
sql="update
user
_info set
user
_psw='"+s1 +"',
user
_age='"+a+"' ,
user
_sex='"+b+"' where
user
_name='"+m+"'"; try{ interFace.edit(sql); } catch (Exception e ){ e.printStackTrace(); } } public static int whichlib(
String
s){ int w=0; try{
String
sql1="select * from lib_info where lib_name='"+s+"'";
rs
=null;
rs
=B.executeQuery(sql1); while(
rs
.next()){ w= Integer.pa
rs
eInt(
rs
.get
String
(1)); } } catch (Exception e ){ e.printStackTrace(); } return w; } public static int book_sum(){ int count=0; try{
String
sql1="select count(*) from book_info";
rs
=null;
rs
=B.executeQuery(sql1); while(
rs
.next()){ count= Integer.pa
rs
eInt(
rs
.get
String
(1)); } } catch (Exception e ){ e.printStackTrace(); } count++; return count; } public static void insert_book(
String
sql){ try{
rs
=null; interFace.edit(sql); } catch (Exception e ){ e.printStackTrace(); } } public static void
user
_inquire(
String
sql){ try{ int i=0;
rs
=B.executeQuery(sql); while(
rs
.next()){ s1=
rs
.get
String
(2); Adminfrm.rowdata1[i][0]=s1; s2=
rs
.get
String
(10); Adminfrm.rowdata1[i][1]=s2; s3=
rs
.get
String
(5); Adminfrm.rowdata1[i][2]=s3; s4=
rs
.get
String
(6); Adminfrm.rowdata1[i][3]=s4; s5=
rs
.get
String
(7); Adminfrm.rowdata1[i][4]=s5; s6=
rs
.get
String
(8); Adminfrm.rowdata1[i][5]=s6; i++; } } catch (Exception e ){ e.printStackTrace(); } } public static void weizhang(){
String
sql="select * from dirty_info"; try{ int i=0;
rs
=B.executeQuery(sql); initialize(Adminfrm.rowdata3,15,3); while(
rs
.next()){ s1=
rs
.get
String
(1); Adminfrm.rowdata3[i][0]=s1; s2=
rs
.get
String
(2);Adminfrm.rowdata3[i][1]=s2; s3=
rs
.get
String
(3).
trim
(); Adminfrm.rowdata3[i][2]=s3; i++; } } catch(Exception e ){ e.printStackTrace(); } } public static Boolean notrequest(
String
s){ Boolean re=false;
String
sql="select * from request_info where request_description='"+s+"' and request_finished='否'"; try{
rs
=B.executeQuery(sql); if(!(
rs
.next())){ re=true; } }catch(Exception e){ e.printStackTrace(); } return re; } public static void request(){
String
sql="select * from request_info"; try{ int i=0;
rs
=B.executeQuery(sql); initialize(Adminfrm.rowdata2,15,5); while(
rs
.next()){ s1=
rs
.get
String
(1); Adminfrm.rowdata2[i][0]=s1; s2=
rs
.get
String
(2);Adminfrm.rowdata2[i][1]=s2; s3=
rs
.get
String
(3).
trim
(); Adminfrm.rowdata2[i][2]=s3; s4=
rs
.get
String
(4).
trim
();Adminfrm.rowdata2[i][3]=s4; s5=
rs
.get
String
(5).
trim
();Adminfrm.rowdata2[i][4]=s5; i++; } } catch(Exception e ){ e.printStackTrace(); } } @SuppressWarnings("deprecation") public static void book_reborrow(
String
s){
String
sql=null;
String
sql1=null;
String
user
name=Login.jTextField.getText(); //得出用户ID号 int u_id=0;
String
b_id=null; sql="select book_id from book_info where book_name='"+s+"'"; sql1="select
user
_id from
user
_info where
user
_name='"+
user
name+"'"; try{
rs
=null;
rs
=B.executeQuery(sql1); //System.out.println(
rs
); while(
rs
.next()){ u_id= Integer.pa
rs
eInt(
rs
.get
String
(1)); }
rs
=null;
rs
=B.executeQuery(sql); if(
rs
.next()) b_id=
rs
.get
String
(1).
trim
(); int count=book_num_in(s); if((count>0)||(count==0&¬request(s) )){
String
date; sql="select borrow_reborrow,return_date from borrow_info where borrow_bid='"+b_id+"' and borrow_uid='"+u_id+"'";
rs
=B.executeQuery(sql); if(
rs
.next()){ if (
rs
.get
String
(1).
trim
().equals("否")){ //System.out.println(
rs
.get
String
(1)); date=
rs
.get
String
("return_date"); SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); Date d=sdf.pa
rs
e(date); System.out.println(d.to
String
()); /*
String
date=Integer.to
String
(cal.get(Calendar.YEAR))+"-"+ Integer.to
String
(cal.get(Calendar.MONTH))+"-"+ Integer.to
String
(cal.get(Calendar.DATE));*/ Calendar cal = new GregorianCalendar(); cal.setTime(d);
String
d1=Integer.to
String
(cal.get(Calendar.YEAR))+"-"+ Integer.to
String
(cal.get(Calendar.MONTH)+2)+"-"+ Integer.to
String
(cal.get(Calendar.DATE)); //System.out.println(d.getYear()+" "+d.getDay()); System.out.println(d1); sql="update borrow_info set borrow_reborrow= '是' , return_date='"+d1+"' where borrow_bid='"+b_id+"' and borrow_uid='"+u_id+"'"; System.out.println(sql); interFace.edit(sql); JOptionPane.showMessageDialog(null,"续借成功","提示!",JOptionPane.PLAIN_MESSAGE); } else JOptionPane.showMessageDialog(null,"已经续借,不得续借","提示!",JOptionPane.PLAIN_MESSAGE); } } else{ JOptionPane.showMessageDialog(null,"不得续借"+count + notrequest(s),"提示!",JOptionPane.PLAIN_MESSAGE); } }catch(Exception e){ e.printStackTrace(); } } @SuppressWarnings("static-access") public static void book_borrow(
String
b_id,int u_id){ interFace s=new interFace();
String
sql="select count(*)from request_info where (request_finished='否' and request_uid<>'"+u_id+"' and " + " request_description in (select book_info.book_name " + "from book_info where book_id='"+b_id+"'))"; try{
rs
=null;int count=0;int count1=0;
rs
=B.executeQuery(sql); if(
rs
.next()){ count=
rs
.getInt(1);
rs
=B.executeQuery("select book_num_in from book_info where book_id='"+b_id+"'"); if(
rs
.next()) count1=Integer.pa
rs
eInt(
rs
.get
String
(1)); if(count>=count1||count1==0){System.out.println(count + " "+count1); JOptionPane.showMessageDialog(null,"全部书被预约或部借出","提示!",JOptionPane.PLAIN_MESSAGE); } else{ sql="update request_info set request_finished='是' where (request_uid='"+u_id+"' and " + "request_info.request_description=(select book_info.book_name " + "from book_info where book_id='"+b_id+"'))"; s.edit(sql); Calendar cal=Calendar.getInstance();
String
date=Integer.to
String
(cal.get(Calendar.YEAR))+"-"+ Integer.to
String
(cal.get(Calendar.MONTH)+1)+"-"+ Integer.to
String
(cal.get(Calendar.DATE)); cal.add(Calendar.DATE, 30);
String
date1=Integer.to
String
(cal.get(Calendar.YEAR))+"-"+ Integer.to
String
(cal.get(Calendar.MONTH)+1)+"-"+ Integer.to
String
(cal.get(Calendar.DATE)); int num=s.sum_borrow(); sql="insert into borrow_info values('"+num+"','"+u_id+"','"+b_id+"','"+date+"','否','否','"+date1+"')"; s.edit(sql); sql="update book_info set book_info.book_num_in=book_info.book_num_in-1 " + "where book_id='"+b_id+"'"; s.edit(sql); JOptionPane.showMessageDialog(null,"成功借出","提示!",JOptionPane.PLAIN_MESSAGE); } } } catch (Exception e){ e.printStackTrace(); } } 课程设计 图书馆管理信息系统
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