Java模糊查询方法详解

// 模糊查询方法  public List<person> query() {    List<person> 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<Object> list1 = new ArrayList<Object>();    //使用 commons-lang包    if (StringUtils.isNotEmpty(name)) {      sql += " and title like ?";      list1.add("%" + name + "%");    }    if (!StringUtils.isEmpty(id)) {      sql += " and content like ?";      list1.add("%" + id + "%");    }    if (!StringUtils.isEmpty(tel)) {      sql += " and addr like ?";      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?的值      for (int i = 0; i < list1.size(); i++) {        pst.setObject(i + 1, list.get(i));      }      ResultSet rs = pst.executeQuery();      while (rs.next()) {        person p = new person();        p.setId(rs.getString("id"));        p.setName(rs.getString("name"));        p.setTel(rs.getString("tel"));        p.setSex(rs.getString("sex").equals("1") ? "男" : "女");        list.add(p);      }      rs.close();      pst.close();    } catch (Exception e) {      e.printStackTrace();    } finally {      try {        con.close();      } catch (SQLException e) {        e.printStackTrace();      }    }    return list;  }

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<m.length();j++)//{//if (hashtable.containsValue(Integer.parseInt(j)+"*")//hashtable.put(j,//}}}public void valueChanged(ListSelectionEvent event){System.out.println(list.getSelectedIndex());}}