我有以下代码：
package nypdapp;
import java.sql.*;
import javax.swing.*;
public class CaseFileAddFrame extends javax.swing.JFrame {
/**
* Creates new form CaseFileFrame
*/
private Connection Econn;
private int cfid;
private boolean wijzig;
private DefaultListModel DetectiveListModel = new DefaultListModel();
private DefaultListModel EmployeeTotListModel = new DefaultListModel();
private DefaultListModel WitnessModel = new DefaultListModel();
private DefaultListModel EvidenceModel = new DefaultListModel();
private DefaultListModel SuspectsModel = new DefaultListModel();
private DefaultComboBoxModel DistrictModel = new DefaultComboBoxModel();
private DefaultComboBoxModel LocationModel = new DefaultComboBoxModel();
SpinnerModel spmodel = new SpinnerNumberModel(2013,1950,2013,1);
public CaseFileAddFrame(int cfid, boolean wijzig) {
initComponents();
this.cfid = cfid;
this.wijzig=wijzig;
s1.setVisible(false);
s3.setVisible(false);
s4.setVisible(false);
YearSn.setModel(spmodel);
try
{
SimpleDataSource.init();
Econn = SimpleDataSource.getConnection();
}
catch(SQLException | ClassNotFoundException e)
{
System.out.println(e);
}
setDistricts();
getSelectedDistrict();
ClassCB.setEnabled(false);
if(wijzig == true)
{
setInformation();
}
}
private void setLocation(int lid)
{
try
{
Statement userStat = Econn.createStatement();
String userquery = "SELECT name, district_name FROM location l INNER JOIN district d ON l.distr_ic = d.district_id WHERE l_id = "+lid;
ResultSet result = userStat.executeQuery(userquery);
result.next();
String name = result.getString("district_name");
System.out.println("DBName: "+name);
int i = DistrictModel.getSize();
for(int p =0; p < i; p++)
{
System.out.println("Current:"+DistrictModel.getElementAt(p));
if(DistrictModel.getElementAt(p).equals(name))
{
//DistrictModel.setSelectedItem(p);
DistrictCB.setSelectedIndex(p);
System.out.println("Done<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<");
}
}
}
catch(SQLException e)
{
System.out.println(e);
}
}
private void setInformation()
{
try
{
Statement userStat = Econn.createStatement();
String userquery = "SELECT * FROM casefile WHERE cf_id = "+this.cfid;
ResultSet result = userStat.executeQuery(userquery);
result.next();
switch(result.getInt("crime"))
{
case 0:
{
CrimeCB.setSelectedIndex(0);
}
break;
case 1:
{
CrimeCB.setSelectedIndex(1);
}
break;
case 2:
{
CrimeCB.setSelectedIndex(2);
}
break;
default:
{
CrimeCB.setSelectedIndex(0);
}
}
if(CrimeCB.getSelectedIndex() == 2)
{
ClassCB.setEnabled(true);
switch (result.getInt("classtype"))
{
case 0:
{
ClassCB.setSelectedIndex(0);
}
break;
case 1:
{
ClassCB.setSelectedIndex(1);
}
break;
case 2:
{
ClassCB.setSelectedIndex(2);
}
break;
case 3:
{
ClassCB.setSelectedIndex(3);
}
break;
case 4:
{
ClassCB.setSelectedIndex(4);
}
break;
case 5:
{
ClassCB.setSelectedIndex(5);
}
break;
case 6:
{
ClassCB.setSelectedIndex(6);
}
break;
case 7:
{
ClassCB.setSelectedIndex(7);
}
break;
case 8:
{
ClassCB.setSelectedIndex(8);
}
break;
default:
{
ClassCB.setSelectedIndex(0);
}
}
}
else
{
ClassCB.setEnabled(false);
}
switch (result.getInt("type"))
{
case 0:
{
TypeCB.setSelectedIndex(0);
}
break;
case 1:
{
TypeCB.setSelectedIndex(1);
}
break;
case 2:
{
TypeCB.setSelectedIndex(2);
}
break;
case 3:
{
TypeCB.setSelectedIndex(3);
}
break;
case 4:
{
TypeCB.setSelectedIndex(4);
}
break;
case 5:
{
TypeCB.setSelectedIndex(5);
}
break;
case 6:
{
TypeCB.setSelectedIndex(6);
}
break;
case 7:
{
TypeCB.setSelectedIndex(7);
}
break;
case 8:
{
TypeCB.setSelectedIndex(8);
}
break;
default:
{
TypeCB.setSelectedIndex(0);
}
}
SubjectTF.setText(result.getString("subject"));
Date date = result.getDate("date");
int month = date.getMonth();
int day = date.getDate();
int year = date.getYear()+1900;
MonthCB.setSelectedIndex(month);
DayCB.setSelectedIndex(day);
spmodel.setValue(year);
AssignedDATF.setText(result.getString("assignedDA"));
FRNameTF.setText(result.getString("fr_id"));
DescriptionTA.setText(result.getString("description"));
setLocation(result.getInt("lid"));
}
catch(SQLException e)
{
System.out.println(e);
}
}
private void setDistricts()
{
try
{
Statement userStat = Econn.createStatement();
String userquery = "SELECT district_id, district_name FROM district";
ResultSet userResult = userStat.executeQuery(userquery);
while(userResult.next())
{
int ids = userResult.getInt("district_id");
String name = userResult.getString("district_name");
DistrictModel.addElement(new DistrictItem(name,ids));
}
DistrictCB.setModel(DistrictModel);
}
catch(SQLException e)
{
System.out.println(e);
}
}
private void SubmitCaseFileButtonActionPerformed(java.awt.event.ActionEvent evt) {
if(validation() == false)
{
javax.swing.JOptionPane.showMessageDialog(null, "WARNING\nCheck the field validation!\nIf there is no Assigned DA Enter 'Unknown'");
}
else if(wijzig == false)
{
int crime = CrimeCB.getSelectedIndex();
int crimeclass;
if(ClassCB.isEnabled() == true)
{
crimeclass = ClassCB.getSelectedIndex();
}
else
{
crimeclass = 0;
}
String subject = SubjectTF.getText();
int month = MonthCB.getSelectedIndex()+1;
int day = DayCB.getSelectedIndex()+1;
int year = Integer.parseInt(spmodel.getValue().toString());
Date date = ToSQLClass.toSqlDate(year, month, day);
int crimetype = TypeCB.getSelectedIndex();
LocationSItem li = (LocationSItem)LocationCB.getSelectedItem();
int locationid = li.id;
String assignedDA = AssignedDATF.getText();
String description = DescriptionTA.getText();
String fr = FRNameTF.getText();
try
{
PreparedStatement addstat = Econn.prepareStatement("INSERT INTO casefile VALUES(cf_id,?,?,?,?,?,?,?,?,?,?)");
addstat.setString(1, subject);
addstat.setInt(2, crime);
addstat.setInt(3, crimetype);
addstat.setString(4, description);
addstat.setString(5, assignedDA);
addstat.setString(6, fr);
addstat.setNull(7,java.sql.Types.INTEGER);
addstat.setDate(8, date);
addstat.setInt(9, crimeclass);
addstat.setInt(10, locationid);
addstat.execute();
javax.swing.JOptionPane.showMessageDialog(null, "WARNING\nCasefile added!\n\nDon't forget to add suspects, witnesses, detectives and evidence!");
this.dispose();
}
catch(SQLException e)
{
System.out.println(e);
}
}
else
{
int crime = CrimeCB.getSelectedIndex();
int crimeclass;
if(ClassCB.isEnabled() == true)
{
crimeclass = ClassCB.getSelectedIndex();
}
else
{
crimeclass = 0;
}
String subject = SubjectTF.getText();
int month = MonthCB.getSelectedIndex()+1;
int day = DayCB.getSelectedIndex()+1;
int year = Integer.parseInt(spmodel.getValue().toString());
Date date = ToSQLClass.toSqlDate(year, month, day);
int crimetype = TypeCB.getSelectedIndex();
LocationSItem li = (LocationSItem)LocationCB.getSelectedItem();
int locationid = li.id;
String assignedDA = AssignedDATF.getText();
String description = DescriptionTA.getText();
String fr = FRNameTF.getText();
try{
Statement addstat = Econn.createStatement();
addstat.executeUpdate("UPDATE casefile SET subject = '" + subject
+ "' ,assignedDA = '" + assignedDA
+ "' ,description = '" + description
+ "' , fr_id = '" + fr
+"',date = '"+date
+"' ,crime = "+crime
+" ,crimeclass = " +crimeclass
+" ,crimetype = " +crimetype
+" ,lid = " +locationid
+ " WHERE cf_id = " + this.cfid);
}
catch(SQLException e) { System.out.println(e); }
}
}
private void getSelectedDistrict()
{
try
{
LocationModel.removeAllElements();
DistrictItem di = (DistrictItem)DistrictCB.getSelectedItem();
Statement userStat = Econn.createStatement();
String userquery = "SELECT l_id, name FROM location WHERE distr_ic = "+di.id;
ResultSet userResult = userStat.executeQuery(userquery);
while(userResult.next())
{
int ids = userResult.getInt("l_id");
String name = userResult.getString("name");
LocationModel.addElement(new LocationSItem(ids,name));
}
LocationCB.setModel(LocationModel);
}
catch(SQLException e)
{
System.out.println(e);
}
}
private void DistrictCBItemStateChanged(java.awt.event.ItemEvent evt) {
getSelectedDistrict();
}
private void CrimeCBItemStateChanged(java.awt.event.ItemEvent evt) {
if(CrimeCB.getSelectedIndex() == 2)
{
ClassCB.setEnabled(true);
}
else
{
ClassCB.setEnabled(false);
}
}
}
DistrictModel包含从setDistricts（）方法检索的每个区域。
我认为这是非常自我解释的。事实是，它永远不会进入if语句（即使它打印de districtmodel.getelementat中的所有项目），因此它可以通过for循环正确运行。
答案 0 :(得分：0)
行。现在答案很简单，我们可以看到代码。区模型包含DistrictItem：
DistrictModel.addElement(new DistrictItem(name,ids));
然后将此模型的每个元素与String进行比较。很明显，比较将始终为false，因为DistrictItem不能等于String。只有String可以等于String。
因此，假设区域名称是唯一的（但您应该使用ID而不是名称），您应该遍历这些元素并找到与您检索到的名称相同的元素：
int i = DistrictModel.getSize();
for (int p = 0; p < i; p++) {
DistrictItem currentDistrictItem = (DistrictItem) DistrictModel.getElementAt(p);
if (currentDistrictItem.getName().equals(name)) {
DistrictCB.setSelectedIndex(p);
break;
}
}
此外，您应该遵守Java命名约定：变量以lwoercase字母开头：districtModel而不是DistrictModel（对于所有其他变量也是如此）