Java模糊查询方法详解

// 模糊查询方法
  public List query() {
    List list = new ArrayList<>();
    Connection con = null;
    Scanner sc = new Scanner(System.in);
    System.err.println("enter name:");
    String name = sc.nextLine();
    System.err.println("enter id:");
    String id = sc.nextLine();
    System.err.println("enter tel:");
    String tel = sc.nextLine();
    System.err.println("enter sex:");
    String sex = sc.nextLine();
    String sql = "select id,name,tel,sex from students "
        // 技巧在此，合理拼接字符串
        + "where 1=1";
    List list1 = new ArrayList();
    //使用 commons-lang包
    if (StringUtils.isNotEmpty(name)) {
      sql += " and title like &＃63;";
      list1.add("%" + name + "%");
    }

    if (!StringUtils.isEmpty(id)) {
      sql += " and content like &＃63;";
      list1.add("%" + id + "%");
    }

    if (!StringUtils.isEmpty(tel)) {
      sql += " and addr like &＃63;";
      list1.add("%" + tel + "%");
    }
    try {
      con = DSUtlis.getConnection();
      // SQL语句组成完成以后，就生成pst对象
      PreparedStatement pst = con.prepareStatement(sql);
      // 设置&＃63;的值
      for (int i = 0; i 

create table students(
id varchar(32),
name varchar(30),
tel varcher(15),
sex char(1),
constraint stud_pk primary key(id)
);

import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.filechooser.*;
import java.util.*;
import java.util.regex.*;

 

//模糊查询

public class Media
{
public static void main(String args[])
{
JFrame frame=new MediaFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}

class MediaFrame extends JFrame implements ActionListener,ListSelectionListener
{
private JList list;
private DefaultListModel m;
private JButton btn;
private JButton btn1;
private JButton btn2;
private JButton btn3;
private JButton btn4;
private JFileChooser chooser;
private JTextField textField;
Map hashtable=new Hashtable();
private int i=0;
int s=0;

public MediaFrame()
{
setTitle("Media");
setSize(600,500);

JMenuBar menu=new JMenuBar();
setJMenuBar(menu);

JLabel label=new JLabel("查询的歌曲名:");
textField=new JTextField();
menu.add(label);
menu.add(textField);

JToolBar TB=new JToolBar();

m=new DefaultListModel();

list=new JList(m);
list.setFixedCellWidth(100);
list.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
list.addListSelectionListener(this);

JScrollPane pane=new JScrollPane(list);

chooser=new JFileChooser();

btn=new JButton("添加歌曲");
btn.addActionListener(this);

btn1=new JButton("删除歌曲");
btn1.addActionListener(this);

btn2=new JButton("清空列表");
btn2.addActionListener(this);

btn3=new JButton("查找曲目");
btn3.addActionListener(this);

btn4=new JButton("排序");
btn4.addActionListener(this);

JPanel panel=new JPanel();

panel.setLayout(new GridLayout(5,1));

panel.add(btn);
panel.add(btn1);
panel.add(btn2);
panel.add(btn3);
panel.add(btn4);

TB.setLayout(new GridLayout(1,2));

TB.add(pane);
TB.add(panel);

add(TB,BorderLayout.WEST);
}

public void actionPerformed(ActionEvent event)
{

if (event.getSource()==btn)
{
i++;
chooser.setCurrentDirectory(new File("."));

int result=chooser.showOpenDialog(MediaFrame.this);

if (result==JFileChooser.APPROVE_OPTION)
{
System.out.println(i);

String name=chooser.getSelectedFile().getPath();

String str1=name;

int str2=name.lastIndexOf("//");

String name1=name.substring(str2+1,str1.length());

//截取最后一个"/"之前的所有字符串

 

int str3=name1.lastIndexOf(".");

String name2=name1.substring(0,str3);

//截取"."后面所有字符串后缀

 

hashtable.put(i,name2);

m.add(0,hashtable.get(i));

System.out.println(hashtable);
}
}

if (event.getSource()==btn1)
{
m.removeElement(list.getSelectedValue());
System.out.println(m);
}

if (event.getSource()==btn2)
{
System.out.println(m);
i=0;
hashtable.clear();
m.clear();
}

if (event.getSource()==btn3)
{
int [] a=new int[m.getSize()];

try
{
int j;
String name=textField.getText();

System.out.println(m.getSize());

for (j=1;j<=m.getSize();j++)
{
Pattern p=Pattern.compile("^"+name+"+");//正则表达式选取以你填的单词为首的所有查询结果
Matcher match=p.matcher((String)hashtable.get(j));

if (match.find())
{
s++;

 

//记录索引结点到数组中a[]中
a[s]=a[s]+m.getSize()-j;
System.out.println(hashtable.get(j));
System.out.println(a[s]);
}

}

 

//可以选择不多个选项(因为前面设置了JList可以多项选择)

list.setSelectedIndices(a);

}
catch (Exception e)
{

}

}

if (event.getSource()==btn4)
{

//int j;
//for (j=0;j