用java寫一個程序，實現(xiàn)對SQL數(shù)據(jù)庫的動態(tài)表進(jìn)行定時查詢

你這跟struts2沒關(guān)系，需要一個定時器，定時去跑你的查詢庫表代碼就OK了。

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如果你的程序是需要將查詢結(jié)果展示在jsp頁面上，你需要在jsp頁面上使用js寫定時器代碼，參考SetInterval方法。

如果你的程序是桌面應(yīng)用程序，你可以使用java的定時器Timer。當(dāng)然，你的項目中如果使用了spring，那有更好的解決方案Quartz。

具體問題要具體分析了。

JAVA 動態(tài)搜索（查找） 在線等

我用的是oracle 數(shù)據(jù)庫。查詢String sql = "select EMPNO,ENAME,SAL,DEPTNO from emp where ENAME like ?";顯示4個字段

///主方法

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import javax.swing.JFrame;

public class TrendSearch extends JFrame {

private javax.swing.JScrollPane jScrollPane1;

private javax.swing.JTable jTable1;

private javax.swing.JTextField jTextField1;

private MyTableModel tableModel;

private ListObject list = new ArrayListObject();

private Staff staff;

private Connection connection = (Connection) OraSqlConnection

.getConnection();

ResultSet rs = null;

/**

* @param args

*/

public TrendSearch() {

initComponents();

}

private void initComponents() {

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

jTextField1 = new javax.swing.JTextField();

jScrollPane1 = new javax.swing.JScrollPane();

jTable1 = new javax.swing.JTable();

jTextField1.addKeyListener(new java.awt.event.KeyAdapter() {

public void keyReleased(java.awt.event.KeyEvent evt) {

jTextField1KeyReleased(evt);

}

});

setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

getContentPane().add(jTextField1, java.awt.BorderLayout.NORTH);

tableModel = new MyTableModel(new String[] { "EMPNO", "ENAME", "SAL",

"DEPTNO" }, new ArrayList());

jTable1.setModel(tableModel);

jScrollPane1.setViewportView(jTable1);

getContentPane().add(jScrollPane1, java.awt.BorderLayout.SOUTH);

pack();

}

private void jTextField1KeyReleased(java.awt.event.KeyEvent evt) {

// TODO add your handling code here:

String s = jTextField1.getText().trim();

list.removeAll(list);

if (s != null !"".equals(s)) {

PreparedStatement pstmt = null;

System.out.println(s);

String sql = "select EMPNO,ENAME,SAL,DEPTNO from emp where ENAME like ?";

try {

pstmt = connection.prepareStatement(sql);

pstmt.setString(1, s + "%");

rs = pstmt.executeQuery();

while (rs.next()) {

staff = new Staff();

staff.setEMPNO(rs.getString(1));

staff.setENAME(rs.getString(2));

staff.setSAL(rs.getString(3));

staff.setDEPTNO(rs.getString(4));

list.add(staff);

}

tableModel.data = list;

tableModel.fireTableDataChanged();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

private class MyTableModel extends BaseTableModel {

public MyTableModel(String[] cols, ListObject data) {

super(cols, data);

// TODO Auto-generated constructor stub

}

public Object getValueAt(int rowIndex, int columnIndex) {

// TODO Auto-generated method stub

Staff s = (Staff) list.get(rowIndex);

switch (columnIndex) {

case 0:

return s.getDEPTNO();

case 1:

return s.getENAME();

case 2:

return s.getSAL();

case 3:

return s.getDEPTNO();

default:

break;

}

return null;

}

}

public static void main(String[] args) {

// TODO Auto-generated method stub

TrendSearch ts = new TrendSearch();

ts.setVisible(true);

}

}

///tabel 類

import java.util.List;

import javax.swing.table.AbstractTableModel;

public abstract class BaseTableModel extends AbstractTableModel {

public String[] cols;

public ListObject data;

public BaseTableModel(String[] cols, ListObject data) {

this.cols = cols;

this.data = data;

}

public int getColumnCount() {

return cols.length;

}

public int getRowCount() {

return data.size();

}

public String getColumnName(int colIndex) {

return cols[colIndex];

}

}

//javabean 類

public class Staff {

private String EMPNO;

private String ENAME;

private String SAL;

private String DEPTNO;

public String getEMPNO() {

return EMPNO;

}

public void setEMPNO(String empno) {

EMPNO = empno;

}

public String getENAME() {

return ENAME;

}

public void setENAME(String ename) {

ENAME = ename;

}

public String getSAL() {

return SAL;

}

public void setSAL(String sal) {

SAL = sal;

}

public String getDEPTNO() {

return DEPTNO;

}

public void setDEPTNO(String deptno) {

DEPTNO = deptno;

}

}

///JDBC類

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.SQLException;

/**

* @author jiangzongshuai

*

*/

public class OraSqlConnection {

private static String className = "oracle.jdbc.driver.OracleDriver";

private static String url = "jdbc:oracle:thin:@localhost:1521:ORCL";

private static String username = "scott";

private static String password = "tiger";

private static Connection conn = null;

public static Connection getConnection() {

try {

if (conn !=null) return conn;

Class.forName(className);

conn = DriverManager.getConnection(url, username, password);

return conn;

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

}

如何在java里實現(xiàn)復(fù)雜的動態(tài)查詢功能？

根據(jù)選擇查詢內(nèi)容在后臺動態(tài)拼接sql，比如條件A，select * from A,條件B換成select * from B.

前端也可以動態(tài)的顯示要查詢的內(nèi)容。