empmodel.java

java课程的资料以及实验的代码

/*
 *EmpModel.java：建立职工实体类。
 *包括：与数据库进行增、删、改、查操作。
 */
 
import java.sql.*;
import java.math.*;

public class EmpModel {
   String empno;
   String ename;
   String position;
   String remarks;
   DbConn dbc;
   Connection conn;
   public EmpModel() {
   }
   public EmpModel(String n,String e,String p,String r) {
   	empno = n;
   	ename = e;
   	position = p;
   	remarks = r;
   }
   public void setAll(String e,String p,String r) {
   	ename = e;
   	position = p;
   	remarks = r;
   }
   public String getEmpno() {
   	return empno;
   }
   public String getEname() {
   	return ename;
   }
   public String getPosition() {
   	return position;
   }
   public String getRemarks() {
   	return remarks;
   }
   public void insert() {
      dbc = new DbConn();
      conn = dbc.getConnection();
      try {
      PreparedStatement pstmt = 
      conn.prepareStatement("insert into EMPLOYEE (EMPNO,ENAME,POSITION,REMARKS) values (?, ?, ?, ?)");
      pstmt.setInt(1, Integer.parseInt(empno)); 
      pstmt.setString(2, ename);   
      pstmt.setString(3, position);
      pstmt.setString(4, remarks);
      pstmt.execute();
      conn.commit();
      conn.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
   }
   
   public void select() {
      dbc = new DbConn();
      conn = dbc.getConnection();
      String sql;
      sql = "SELECT empno,rtrim(ename),rtrim(position),rtrim(remarks) FROM employee where empno = "+Integer.parseInt(empno);
      try {
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery (sql);
      while (rset.next()) {
        ename = rset.getString(2);
        position = rset.getString(3);
        remarks = rset.getString(4);
      }
      conn.commit();  
      rset.close();
      stmt.close();
      conn.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
    } 
    
    public void update() {
      dbc = new DbConn();
      conn = dbc.getConnection();
      try {
      PreparedStatement pstmt = 
      conn.prepareStatement("update EMPLOYEE set ENAME = ?,POSITION = ?,REMARKS = ? where empno = "+Integer.parseInt(empno));
      pstmt.setString(1, ename);   
      pstmt.setString(2, position);
      pstmt.setString(3, remarks);
      pstmt.execute();
      conn.commit();
      conn.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
   }
   
   public void delete() {
      dbc = new DbConn();
      conn = dbc.getConnection();
      try {
      PreparedStatement pstmt = 
      conn.prepareStatement("delete EMPLOYEE where empno = "+Integer.parseInt(empno));
      pstmt.execute();
      conn.commit();
      empno = "";
      ename = null;
      position = null;
      remarks = null;
      conn.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
   }
   
   public int selEmpCnt() {
      dbc = new DbConn();
      conn = dbc.getConnection();
      int cnt=0;
      if (conn == null) {
      	System.out.println("Can not connected yet!");
      	return -1;
      }
      try {
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery ("select count(empno) from employee");
      while (rset.next()) {
        cnt = rset.getInt(1);
      }
      rset.close();
      stmt.close();
      conn.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
      return cnt;
   } 
   
   public void selEmpNo(String [] scnt) {
      dbc = new DbConn();
      conn = dbc.getConnection();
      int k=0;
      String sql;
      if (conn == null) {
      	System.out.println("Can not connected yet!");
      	return;
      }
      try {
      sql = "select empno from employee";
      Statement stmt = conn.createStatement();
      ResultSet rset = stmt.executeQuery (sql);
      while (rset.next()) {
        scnt[k++] = rset.getString(1);
      }
      rset.close();
      stmt.close();
      conn.close();
      }
      catch (java.sql.SQLException s) {
	System.out.println("exception: " + s.getMessage());
      }
   }
}