Ajax简单示例应用，小片段，随意下载

package dao; 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 po.Student; public class StudentDao { public final static String DRIVER = "com.microsoft.jdbc.sqlserver.SQLServerDriver"; // 数据库驱动 public final static String URL = "jdbc:microsoft:sqlserver://localhost:1433;DataBaseName=shangji"; // url public final static String USER = "sa"; // 数据库用户名 public final static String PSWD = "sa123"; // 数据库密码 private Connection conn = null; public void initConnection(){//初始化数据库连接 try{ Class.forName(DRIVER); conn = DriverManager.getConnection(URL, USER, PSWD); }catch(Exception ex){ex.printStackTrace();} } public ArrayList queryStuByName(String sname){ ArrayList stus = new ArrayList(); String sql = "SELECT number,name,sex,bir,address FROM student WHERE name LIKE '%" + sname + "%'"; try{ this.initConnection(); ResultSet rs = conn.createStatement().executeQuery(sql); while(rs.next()){ Student stu = new Student(); stu.setStuId(rs.getString("number")); stu.setStuName(rs.getString("name")); stu.setStuSex(rs.getString("sex")); stu.setStuBir(rs.getString("bir")); stu.setStuAdd(rs.getString("address")); stus.add(stu); } }catch(Exception ex){ex.printStackTrace();} finally{ this.closeConnection(); } return stus; } public boolean add(Object obj){ Student stu=(Student)obj; boolean flag=false; PreparedStatement pstm=null; try { this.initConnection(); pstm=conn.prepareStatement("INSERT INTO student(number,name,sex,bir,address)VALUES(?,?,?,?,?)"); pstm.setString(1,stu.getStuId()); pstm.setString(2,stu.getStuName()); pstm.setString(3,stu.getStuSex()); pstm.setString(4,stu.getStuBir()); pstm.setString(5,stu.getStuAdd()); if(pstm.executeUpdate()>0){ flag=true; } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally{ this.closeConnection(); } return flag; } public String getNameById(String stuId){ String sql = "SELECT name FROM student WHERE number='"+stuId+"'"; try{ this.initConnection(); ResultSet rs = conn.createStatement().executeQuery(sql); if(rs.next()){ return rs.getString("name"); } }catch(Exception ex){ ex.printStackTrace(); } finally{ this.closeConnection(); } return null; } public void closeConnection(){ try{ if(conn!=null){ conn.close(); conn = null; } }catch(Exception ex){ex.printStackTrace();} } }