总结学了 j2ee 一月半后的项目情况(1)

项目有三个，殊途同归：

1、MODEL1【jsp+javabean/dao】 或者 MODEL2 【jsp+servlet+javabean/dao】

2、三个项目所使用的模式分别是不同讲师所讲的，魔乐java、韩顺平j2ee 、java开放课程二期jsp，三者同时使用EL / JSTL 

源码：【魔乐 雇员管理系统（MODEL1） 】

1、定义IempDAO接口如下：

package fafa.vo;
import java.util.*;
//前面的大写I 表示是接口
public interface IempDAO {
    public boolean doCreate(Emp emp) throws Exception ;
    public List<Emp> findAll(String keyword) throws Exception ;
    public Emp findById(int empno) throws Exception ;
}

2、定义实现接口类 EmpDAOImpl 实现数据库CRUD

package fafa.vo;
import java.sql.*;
import java.util.*;
public class EmpDAOImpl implements IempDAO {
    private Connection conn = null ;
    private PreparedStatement pstmt = null ;
    
    public EmpDAOImpl (Connection conn){
        this.conn = conn ;
    }
    
    //创建
    public boolean doCreate(Emp emp) throws Exception {
        boolean flag = false ;
        String sql = "INSERT INTO emp(empno, ename, job, hiredate,sal) VALUES(?,?,?,?,?)" ;
        this.pstmt = this.conn.prepareStatement(sql) ; //sql预处理 
        
        //赋值
        this.pstmt.setInt(1, emp.getEmpno()) ;
        this.pstmt.setString(2, emp.getEname()) ;
        this.pstmt.setString(3, emp.getJob()) ;
        this.pstmt.setDate(4, new java.sql.Date(emp.getHirdate().getTime())) ;
        this.pstmt.setFloat(5, emp.getSal()) ;
        //执行更新判断
        if (this.pstmt.executeUpdate() > 0){
            flag = true ;
        }
        //关闭
        this.pstmt.close() ;
        return flag ;
    }

    //查询全部
    public List<Emp> findAll(String keyword) throws Exception {
        List<Emp> all = new ArrayList<Emp>() ;
        String sql = "SELECT empno,ename,job,hiredate,sal FROM emp WHERE ename LIKE ? OR job LIKE ?" ;
        this.pstmt = this.conn.prepareStatement(sql) ;
        
        this.pstmt.setString(1, "%"+keyword+"%") ;
        this.pstmt.setString(2, "%"+keyword+"%") ;
        
        ResultSet rs = this.pstmt.executeQuery() ;
        Emp emp = null ;
        while (rs.next()){
            emp = new Emp() ;
            emp.setEmpno(rs.getInt(1)) ;
            emp.setEname(rs.getString(2)) ;
            emp.setJob(rs.getString(3)) ;
            emp.setHirdate(rs.getDate(4)) ;
            emp.setSal(rs.getFloat(5)) ;
            all.add(emp) ;
        }
        this.pstmt.close() ;
        return all ;
    }

    //查询一个(ID)
    public Emp findById(int empno) throws Exception {
        Emp emp = null ;
        String sql = "SELECT empno,ename,job,hiredate,sal FROM emp WHERE empno = ?" ;
        
        this.pstmt = this.conn.prepareStatement(sql) ;    //sql预处理
        this.pstmt.setInt(1, empno) ;                    //设置值
        ResultSet rs = this.pstmt.executeQuery() ;        //执行sql
        if (rs.next()){
            emp = new Emp() ;
            emp.setEmpno(rs.getInt(1)) ;
            emp.setEname(rs.getString(2)) ;
            emp.setJob(rs.getString(3)) ;
            emp.setHirdate(rs.getDate(4)) ;
            emp.setSal(rs.getFloat(5)) ;
        }
        this.pstmt.close() ;
        return emp ;
    }
}

3 、定义代理类EmpDAOproxy 实现接口 并调用实际实现类完成操作

package fafa.vo;

import java.util.*;

public class EmpDAOproxy implements IempDAO {
    private DatabaseConnection dbc = null ;
    private IempDAO dao = null ;
    
    public EmpDAOproxy () throws Exception{
        this.dbc = new DatabaseConnection() ;
        this.dao = new EmpDAOImpl(this.dbc.getConnection()) ;
    }
    
    public boolean doCreate(Emp emp) throws Exception {
        boolean flag = false ;
        try {
            if (this.dao.findById(emp.getEmpno()) == null){
                this.dao.doCreate(emp) ;
                flag = true ;
            }
        } catch (Exception e) {
            e.printStackTrace() ;
        } finally {
            this.dbc.close() ;
        }
        return flag ;
    }

    public List<Emp> findAll(String keyword) throws Exception {
        List<Emp> all = null ;
        try {
            all = this.dao.findAll(keyword) ;
        } catch (Exception e) {
            e.printStackTrace() ;
        } finally {
            this.dbc.close() ;
        }
        return all ;
    }

    public Emp findById(int empno) throws Exception {
        Emp emp = null ;
        try {
            this.dao.findById(empno) ;
        } catch (Exception e) {
            e.printStackTrace() ;
        } finally {
            this.dbc.close() ;
        }
        return emp ;
    }

}

4、定义工厂类 实例化 代理类 --> 调用实现接口类 完成操作

package fafa.vo;

public class DAOfactory {
    public static IempDAO getIEmpDAOInstance() throws Exception {
        return new EmpDAOproxy() ;
    }
}

5、当然少不了数据库连接类 DatabaseConnection 和vo 类 emp

package fafa.vo;

import java.sql.Connection;
import java.sql.DriverManager;

public class DatabaseConnection {
    private static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ;
    private static final String DBURL = "jdbc:mysql://localhost:3306/test" ;
    private static final String DBUSER = "root" ;
    private static final String DBPASS = "123456" ;
    
    private Connection conn ;
    public DatabaseConnection() throws Exception {
        Class.forName(DBDRIVER) ;
        this.conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ;
    }
    //取得连接
    public Connection getConnection(){
        return this.conn ;
    }
    //关闭连接
    public void close(){
        if (this.conn != null){
            try{
                this.conn.close() ;
            }catch(Exception e){
                e.printStackTrace() ;
            }
        }
    }
}

package fafa.vo;

import java.util.Date;

public class Emp {
    private int empno ;
    private String ename ;
    private String job ;
    private Date hirdate ;
    private float sal ;
    
    public int getEmpno() {
        return empno;
    }
    public void setEmpno(int empno) {
        this.empno = empno;
    }
    public String getEname() {
        return ename;
    }
    public void setEname(String ename) {
        this.ename = ename;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public Date getHirdate() {
        return hirdate;
    }
    public void setHirdate(Date hirdate) {
        this.hirdate = hirdate;
    }
    public float getSal() {
        return sal;
    }
    public void setSal(float sal) {
        this.sal = sal;
    }
}