Java 向JComboBox添加字符串数组
我的目标是从SQL表中获取一个值,并将该值添加到组合框中Java 向JComboBox添加字符串数组,java,swing,combobox,model,Java,Swing,Combobox,Model,我的目标是从SQL表中获取一个值,并将该值添加到组合框中 Connection con; Statement st; ResultSet rs; con=DriverManager.getConnection("jdbc:mysql://localhost/needed","arv",""); st=con.createStatement(); rs= st.executeQuery("SELECT
Connection con;
Statement st;
ResultSet rs;
con=DriverManager.getConnection("jdbc:mysql://localhost/needed","arv","");
st=con.createStatement();
rs= st.executeQuery("SELECT * FROM INVENTORY");
List<String> l = new ArrayList();
while(rs.next()){
l.add(rs.getString("CAT"));
}
String[] h = l.toArray(new String[l.size()]);
jComboBox1.setModel(new javax.swing.DefaultComboBoxModel(h));
连接con;
报表st;
结果集rs;
con=DriverManager.getConnection(“jdbc:mysql://localhost/needed","抗逆转录病毒药物","抗逆转录病毒药物",;
st=con.createStatement();
rs=st.executeQuery(“从库存中选择*);
列表l=新的ArrayList();
while(rs.next()){
l、 添加(rs.getString(“CAT”);
}
字符串[]h=l.toArray(新字符串[l.size()]);
setModel(新的javax.swing.DefaultComboxModel(h));
但我无法执行它,因为我在jcombox1.setModel(newjavax.swing.defaultcomboxmodel(h))获得了一个NPE强>
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at FilterTabs.<init>(FilterTabs.java:43)
线程“AWT-EventQueue-0”java.lang.NullPointerException中的异常
在FilterTabs(FilterTabs.java:43)
在这之后我该如何继续,我该如何解决这个NPE?给出这个代码片段,这是表达式
jcombox1.setModel(new javax.swing.defaultcomboxmodel(h))中唯一可以为null的东西代码>是JCombox1
确保在到达此代码段之前对其进行初始化。该行中唯一的取消引用是jcombox1.setModel
。因此,jcombox1
很可能是null