MVC.zip_学生系统mvc

package cie.model; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.ArrayList; public class ProccessBean { private Connection con; private Statement stmt; public ProccessBean(){ } private Connection getCon() throws ClassNotFoundException, SQLException{ if(con == null){ Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?user=root&password=123456&useUnicode=true&characterEncoding=utf8"); } return con; } private Statement getStat() throws SQLException, ClassNotFoundException{ if(stmt == null){ stmt = getCon().createStatement(); } return stmt; } private void closeDB(){ try { if(stmt != null){ stmt.close(); } if(con != null){ con.close(); } } catch (SQLException e) { e.printStackTrace(); } } private ResultSet query(String sql) throws SQLException, ClassNotFoundException{ ResultSet rs = getStat().executeQuery(sql); return rs; } public ArrayList<Student> getAllStudent() throws SQLException, ClassNotFoundException{ ArrayList<Student> stuList = new ArrayList<Student>(); String sql = "select * from student"; ResultSet rs = query(sql); Student stu; while(rs.next()){ stu = new Student( rs.getInt("id"), rs.getString("stuID"), rs.getString("stuName"), rs.getString("stuClass"), rs.getString("homeAddress") ); stuList.add(stu); } rs.close(); closeDB(); return stuList; } public void save(Student stu) throws SQLException, ClassNotFoundException{ String addSql = "insert into student (stuID,stuName,stuClass,homeAddress) values(?,?,?,?)"; String updateSql = "update student set stuID = ?,stuName=?,stuClass=?,homeAddress=? where id=?"; PreparedStatement pt ; if(stu.getId() == 0){ pt = getCon().prepareStatement(addSql); pt.setString(1, stu.getStuID()); pt.setString(2, stu.getStuName()); pt.setString(3, stu.getStuClass()); pt.setString(4, stu.getHomeAddress()); } else{ pt = getCon().prepareStatement(updateSql); pt.setString(1, stu.getStuID()); pt.setString(2, stu.getStuName()); pt.setString(3, stu.getStuClass()); pt.setString(4, stu.getHomeAddress()); pt.setInt(5, stu.getId()); } pt.executeUpdate(); } public Student getStuById(int id) throws SQLException, ClassNotFoundException{ String sql = "select * from student where id = " + id; ResultSet rs = query(sql); Student stu = new Student(); if(rs.next()){ stu.setId(id); stu.setStuID(rs.getString("stuID")); stu.setStuName(rs.getString("stuName")); stu.setStuClass(rs.getString("stuClass")); stu.setHomeAddress(rs.getString("homeAddress")); } return stu; } public void deleteById(int id) throws SQLException, ClassNotFoundException{ String sql = "delete from student where id = " + id; getStat().executeUpdate(sql); } }