Java 当对应的JTextfield为空时,如何填充JTable中的所有项
我正在用NetBeans中的Java 当对应的JTextfield为空时,如何填充JTable中的所有项,java,swing,jdbc,jtable,jtextfield,Java,Swing,Jdbc,Jtable,Jtextfield,我正在用NetBeans中的sqlite在Java项目中设计一个高级搜索选项。 有5个不同的JTextfields和5列,我想用相应的匹配条件填充JTable。如果JTextfield为空,则应选择该列的所有项目 我使用的查询是: String val1 = txt_billing2.getText(); String val2 = txt_station2.getText(); String val3 = txt_invoice2.getText(); String val4 = txt_am
sqlite
在Java项目中设计一个高级搜索选项。
有5个不同的JTextfields
和5列,我想用相应的匹配条件填充JTable
。如果JTextfield
为空,则应选择该列的所有项目
我使用的查询是:
String val1 = txt_billing2.getText();
String val2 = txt_station2.getText();
String val3 = txt_invoice2.getText();
String val4 = txt_amonth2.getText();
String val5 = txt_umonth2.getText();
String sql = "SELECT * from airindia_sqlite WHERE BILLING = '"+val1+"' and STATION = '"+val2+"' and INVOICE = '"+val3+"' and AMONTH = '"+val4+"' and UMONTH = '"+val5+"'";
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
Table_airindia.setModel(DbUtils.resultSetToTableModel(rs));
但是当我将JTextfield
留空时,它在JTable
中不显示任何数据。
我知道的唯一方法是使用
if-else
条件,但这会生成5!=120个条件。首先请注意,您的查询容易受到攻击。要避免这些问题,您需要正确使用:
String val1 = txt_billing2.getText();
...
String val5 = txt_umonth2.getText();
String sql = "SELECT * from airindia_sqlite WHERE BILLING = ? and STATION = ? and INVOICE = ? and AMONTH = ? and UMONTH = ?";
ps = con.prepareStatement(sql);
ps.setObject(1, val1);
...
ps.setObject(5, val5);
说到这里,我将使用一个辅助类来编写WHERE
子句,给出一些参数。比如:
public class WhereClause {
private Integer currentIndex = 0;
private Map<Integer, Object> parameters = new HashMap<>();
private StringBuilder whereClause = null;
public void addParameter(String columnName, Object value) {
if(whereClause == null) {
whereClause = new StringBuilder(" WHERE ");
} else if (currentIndex > 0) {
whereClause.append(" AND ");
}
whereClause.append(columnName).append(" = ?");
paramenters.put(++currentIndex, value);
}
public String getWhereClause() {
return whereClause != null ? whereClause.toString() : "";
}
public Map<Integer, Object> getParamenters() {
return parameters;
}
}
public class子句{
私有整数currentIndex=0;
私有映射参数=new HashMap();
private StringBuilder whereClause=null;
public void addParameter(字符串列名、对象值){
if(whereClause==null){
whereClause=新的StringBuilder(“WHERE”);
}否则如果(当前索引>0){
其中第条。附加(“和”);
}
whereClause.append(columnName).append(=?);
参数put(++currentIndex,value);
}
公共字符串getWhere子句(){
return whereClause!=null?whereClause.toString():“”;
}
公共映射getParameters(){
返回参数;
}
}
然后,您可以执行以下操作以获得适当的SQL语句:
WhereClause whereClause = new WhereClause();
if(!(txt_billing2.getText().trim().isEmpty())) {
whereClause.addParameter("BILLING", txt_billing2.getText().trim());
}
...
if(!(txt_umonth2.getText().trim().isEmpty())) {
whereClause.addParameter("UMONTH ", txt_umonth2.getText().trim());
}
String sql = "SELECT * FROM airindia_sqlite" + whereClause.getWhereClause();
ps = con.prepareStatement(sql);
Map<Integer, Object> parameters = whereClause.getParameters();
for (Integer key : parameters.keySet()) {
ps.setObject(key, parameters.get(key));
}
rs = ps.executeQuery();
WhereClause WhereClause=新WhereClause();
if(!(txt_billing2.getText().trim().isEmpty()){
whereClause.addParameter(“BILLING”,txt_billing2.getText().trim());
}
...
if(!(txt_umonth2.getText().trim().isEmpty()){
whereClause.addParameter(“UMONTH”,txt_month2.getText().trim());
}
String sql=“SELECT*FROM airnia_sqlite”+whereClause.getWhereClause();
ps=con.prepareStatement(sql);
映射参数=whereClause.getParameters();
for(整数键:parameters.keySet()){
ps.setObject(key,parameters.get(key));
}
rs=ps.executeQuery();
离题
当心数据库调用是耗时的任务,可能会阻塞(又称EDT),导致GUI无响应。EDT是一个单独的特殊线程,Swing组件在其中创建和更新。为了避免阻塞,该线程考虑使用A在后台线程中执行数据库调用,并更新EDT中的Swing组件。请首先注意,您的查询容易受到攻击。要避免这些问题,您需要正确使用:
String val1 = txt_billing2.getText();
...
String val5 = txt_umonth2.getText();
String sql = "SELECT * from airindia_sqlite WHERE BILLING = ? and STATION = ? and INVOICE = ? and AMONTH = ? and UMONTH = ?";
ps = con.prepareStatement(sql);
ps.setObject(1, val1);
...
ps.setObject(5, val5);
说到这里,我将使用一个辅助类来编写WHERE
子句,给出一些参数。比如:
public class WhereClause {
private Integer currentIndex = 0;
private Map<Integer, Object> parameters = new HashMap<>();
private StringBuilder whereClause = null;
public void addParameter(String columnName, Object value) {
if(whereClause == null) {
whereClause = new StringBuilder(" WHERE ");
} else if (currentIndex > 0) {
whereClause.append(" AND ");
}
whereClause.append(columnName).append(" = ?");
paramenters.put(++currentIndex, value);
}
public String getWhereClause() {
return whereClause != null ? whereClause.toString() : "";
}
public Map<Integer, Object> getParamenters() {
return parameters;
}
}
public class子句{
私有整数currentIndex=0;
私有映射参数=new HashMap();
private StringBuilder whereClause=null;
public void addParameter(字符串列名、对象值){
if(whereClause==null){
whereClause=新的StringBuilder(“WHERE”);
}否则如果(当前索引>0){
其中第条。附加(“和”);
}
whereClause.append(columnName).append(=?);
参数put(++currentIndex,value);
}
公共字符串getWhere子句(){
return whereClause!=null?whereClause.toString():“”;
}
公共映射getParameters(){
返回参数;
}
}
然后,您可以执行以下操作以获得适当的SQL语句:
WhereClause whereClause = new WhereClause();
if(!(txt_billing2.getText().trim().isEmpty())) {
whereClause.addParameter("BILLING", txt_billing2.getText().trim());
}
...
if(!(txt_umonth2.getText().trim().isEmpty())) {
whereClause.addParameter("UMONTH ", txt_umonth2.getText().trim());
}
String sql = "SELECT * FROM airindia_sqlite" + whereClause.getWhereClause();
ps = con.prepareStatement(sql);
Map<Integer, Object> parameters = whereClause.getParameters();
for (Integer key : parameters.keySet()) {
ps.setObject(key, parameters.get(key));
}
rs = ps.executeQuery();
WhereClause WhereClause=新WhereClause();
if(!(txt_billing2.getText().trim().isEmpty()){
whereClause.addParameter(“BILLING”,txt_billing2.getText().trim());
}
...
if(!(txt_umonth2.getText().trim().isEmpty()){
whereClause.addParameter(“UMONTH”,txt_month2.getText().trim());
}
String sql=“SELECT*FROM airnia_sqlite”+whereClause.getWhereClause();
ps=con.prepareStatement(sql);
映射参数=whereClause.getParameters();
for(整数键:parameters.keySet()){
ps.setObject(key,parameters.get(key));
}
rs=ps.executeQuery();
离题
当心数据库调用是耗时的任务,可能会阻塞(又称EDT),导致GUI无响应。EDT是一个单独的特殊线程,Swing组件在其中创建和更新。为了避免阻塞,该线程考虑使用A在后台线程中执行数据库调用,并更新EDT中的Swing组件。请首先注意,您的查询容易受到攻击。要避免这些问题,您需要正确使用:
String val1 = txt_billing2.getText();
...
String val5 = txt_umonth2.getText();
String sql = "SELECT * from airindia_sqlite WHERE BILLING = ? and STATION = ? and INVOICE = ? and AMONTH = ? and UMONTH = ?";
ps = con.prepareStatement(sql);
ps.setObject(1, val1);
...
ps.setObject(5, val5);
说到这里,我将使用一个辅助类来编写WHERE
子句,给出一些参数。比如:
public class WhereClause {
private Integer currentIndex = 0;
private Map<Integer, Object> parameters = new HashMap<>();
private StringBuilder whereClause = null;
public void addParameter(String columnName, Object value) {
if(whereClause == null) {
whereClause = new StringBuilder(" WHERE ");
} else if (currentIndex > 0) {
whereClause.append(" AND ");
}
whereClause.append(columnName).append(" = ?");
paramenters.put(++currentIndex, value);
}
public String getWhereClause() {
return whereClause != null ? whereClause.toString() : "";
}
public Map<Integer, Object> getParamenters() {
return parameters;
}
}
public class子句{
私有整数currentIndex=0;
私有映射参数=new HashMap();
private StringBuilder whereClause=null;
public void addParameter(字符串列名、对象值){
if(whereClause==null){
whereClause=新的StringBuilder(“WHERE”);
}否则如果(当前索引>0){
其中第条。附加(“和”);
}
whereClause.append(columnName).append(=?);
参数put(++currentIndex,value);
}
公共字符串getWhere子句(){
return whereClause!=null?whereClause.toString():“”;
}
公共映射getParameters(){
返回参数;
}
}
然后,您可以执行以下操作以获得适当的SQL语句:
WhereClause whereClause = new WhereClause();
if(!(txt_billing2.getText().trim().isEmpty())) {
whereClause.addParameter("BILLING", txt_billing2.getText().trim());
}
...
if(!(txt_umonth2.getText().trim().isEmpty())) {
whereClause.addParameter("UMONTH ", txt_umonth2.getText().trim());
}
String sql = "SELECT * FROM airindia_sqlite" + whereClause.getWhereClause();
ps = con.prepareStatement(sql);
Map<Integer, Object> parameters = whereClause.getParameters();
for (Integer key : parameters.keySet()) {
ps.setObject(key, parameters.get(key));
}
rs = ps.executeQuery();
WhereClause WhereClause=新WhereClause();
if(!(txt_billing2.getText().trim().isEmpty()){
whereClause.addParameter(“BILLING”,txt_billing2.getText().trim());
}
...
if(!(txt_umonth2.getText().trim().isEmpty()){
whereClause.addParameter(“UMONTH”,txt_month2.getText().trim());
}
String sql=“SELECT*FROM airnia_sqlite”+whereClause.getWhereClause();
ps=合同准备声明