这一段代码只要一运行就会空指针的错误,但是我觉着应该没啥问题啊。。求指点
package Java5;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class Java5_14 extends JFrame{
JMenuBar menubar;//JMenuBar不参与布局
JMenu jm1,jm2,jm3,jm4,jm5,jmej;//JMenu有下一级菜单
JMenu [] menugroup={jm1,jm2,jm3,jm4,jm5};
JMenuItem jmi1,jmi2,jmi3,jmi4,jmej1,jmej2;//JMenuItem没有下一级菜单
JMenuItem [] menuitemgroup={jmi1,jmi2,jmi3,jmi4};
JToolBar toolbar;
JButton jb1,jb2,jb3,jb4,jb5,jb6;
JButton buttongroup[]={jb1,jb2,jb3,jb4,jb5,jb6};
JTextArea jta;
JScrollPane js;
public JButton setToolBar(JButton button,String s1,String s2){
button=new JButton(s1);
button.setToolTipText(s2);
return button;
}
public JMenu setMenuBar(JMenu menu,String s,char c){
menu=new JMenu(s);
menu.setMnemonic(c);
return menu;
}
public Java5_14(){
jb1=setToolBar(jb1,"new","新建");
jb2=setToolBar(jb2,"open","打开");
jb3=setToolBar(jb3,"save","保存");
jb4=setToolBar(jb4,"cut","剪切");
jb5=setToolBar(jb5,"paste","粘贴");
jb6=setToolBar(jb6,"copy","复制");
jm1=setMenuBar(jm1,"文件(F)",'F');
jm2=setMenuBar(jm2,"编辑(E)",'E');
jm3=setMenuBar(jm3,"格式(O)",'O');
jm4=setMenuBar(jm4,"查看(V)",'V');
jm5=setMenuBar(jm5,"帮助(H)",'H');
jmej=setMenuBar(jmej,"新建(N)",'N');
jmej1=new JMenuItem("文件");
jmej2=new JMenuItem("模板");
jmi1=new JMenuItem("打开");
jmi2=new JMenuItem("保存");
jmi3=new JMenuItem("另存为");
jmi4=new JMenuItem("页面设置");
jta=new JTextArea();
js=new JScrollPane();
js.add(jta);
toolbar=new JToolBar();
for(int i=0;i<buttongroup.length;i++){
toolbar.add(buttongroup[i]);
}
jmej.add(jmej1);
jmej.add(jmej2);
for(int i=0;i<menuitemgroup.length;i++){
jm1.add(menuitemgroup[i]);
if(i==1){
jm1.addSeparator();
}
}
menubar=new JMenuBar();
for(int i=0;i<menugroup.length;i++){
menubar.add(menugroup[i]);
}
this.add(menubar);
this.add(toolbar,BorderLayout.NORTH);
this.add(js);
this.setSize(500,300);
this.setLocation(500,300);
this.setVisible(true);
//this.setResizable(false);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
Java5_14 j=new Java5_14();
}
}