for(i=1i<=4i++)
{
这个小的for是打印每一行前边的空格
for(j=1j<=4-ij++)
System.out.print(" ")
这个是打印星星的
for(j=1j<=2*i-1j++)
System.out.print("*")
这个是打印完一行的换行
System.out.println("")
}
下边的是一样的 只不过每一行的空格和星星数 和上边是翻过来的
for(i=1i<=3i++)
{
for(j=1j<=ij++)
System.out.print(" ")
for(j=1j<=7-2*ij++)
System.out.print("*")
System.out.println("")
}
java.sql.SQLException: 无效的列索引
无效的列索引
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:111)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:145)
at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:207)
atoracle.jdbc.driver.OraclePreparedStatement.setStringInternal(OraclePreparedStatement.java:5328)
atoracle.jdbc.driver.OraclePreparedStatement.setString(OraclePreparedStatement.java:5320)
at untitled5.addreader1.validID(addreader1.java:128)
at untitled5.addreader1.jButton1_actionPerformed(addreader1.java:97)
at untitled5.addreader1_jButton1_actionAdapter.actionPerformed(addreader1.java:175)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
代码:String driverName = "oracle.jdbc.OracleDriver"
Driver driver = (Driver) Class.forName(driverName).newInstance()
//连接数据库
Connection con = DriverManager.getConnection(
"jdbc:oracle:thin:@LONG:1521:orcl", "sysman", "tongfang")
PreparedStatement pstmt = con.prepareStatement(
" insert into reader values(?)")
pstmt.setString(1, str1)
pstmt.setString(2,str2)
pstmt.setString(3,str3)
pstmt.setString(4,str4)
ResultSet res = pstmt.executeQuery()
public class PrintDiamond2{public static void main (String args[]){
int TotalLayer=9
for(int layer=1 layer<=TotalLayer layer++) {
for(int space=1 space<=Math.abs((TotalLayer+1)/2-layer) space++){
System.out.print(" ")
}
for(int b=1 b<=TotalLayer-2*Math.abs((TotalLayer+1)/2-layer) b++){
System.out.print("*")
}
System.out.println()
}
}
}
用3个for循环打出菱形,可以改变TotalLayer的值来改变菱形的大小
第一个for循环规定多少行
第二个for循环规定每行有多少个空格
第三个for循环规定每行有多少个星号
然后换行,重复2,3循环直到完成第一个循环
最后菱形完成
java打印菱形通过二维数组来打印,实例如下:
int hangshu = 11int yiban = hangshu / 2 + 1
int yibanduo = hangshu / 2
System.out.println("空心菱形:")
for(int k = 1k <= yibank++){
for(int i = 1i <= (yiban - k)i++){
System.out.print(" ")
}
System.out.print("*")
for(int i = 1i <= ( (k - 2) * 2 + 1)i++){
System.out.print(" ")
}
if(k != 1){
System.out.print("*")
}
System.out.println()
}
for(int k = yibanduok >=1k--){
for(int i = 1i <= (yiban - k)i++){
System.out.print(" ")
}
System.out.print("*")
for(int i = 1i <= ( (k - 2) * 2 + 1)i++){
System.out.print(" ")
}
if(k != 1){
System.out.print("*")
}
System.out.println()
}
System.out.println("实心菱形:")
for(int i = 1i <= hangshui++){
if(i <= hangshu/2 + 1){
for(int k = 1k <= hangshu/2 + 1- ik++){
System.out.print(" ")
}
for(int k = 1k <= ik++){
System.out.print("* ")
}
System.out.println()
}else{
for(int k =1k <= (i -(hangshu/2 + 1))k++){
System.out.print(" ")
}
for(int k = 1k <= (2 *(hangshu/2 + 1) - i)k++){
System.out.print("* ")
}
System.out.println()
}
}
结果如下: