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：
1 package fafa.vo; 2 import java.util.*; 3 //前面的大写I 表示是接口 4 public interface IempDAO { 5 public boolean doCreate(Emp emp) throws Exception ; 6 public List<Emp> findAll(String keyword) throws Exception ; 7 public Emp findById(int empno) throws Exception ; 8 }
2、定义实现接口类 EmpDAOImpl 实现数据库CRUD
1 package fafa.vo; 2 import java.sql.*; 3 import java.util.*; 4 public class EmpDAOImpl implements IempDAO { 5 private Connection conn = null ; 6 private PreparedStatement pstmt = null ; 7 8 public EmpDAOImpl (Connection conn){ 9 this.conn = conn ; 10 } 11 12 //创建 13 public boolean doCreate(Emp emp) throws Exception { 14 boolean flag = false ; 15 String sql = "INSERT INTO emp(empno, ename, job, hiredate,sal) VALUES(?,?,?,?,?)" ; 16 this.pstmt = this.conn.prepareStatement(sql) ; //sql预处理 17 18 //赋值 19 this.pstmt.setInt(1, emp.getEmpno()) ; 20 this.pstmt.setString(2, emp.getEname()) ; 21 this.pstmt.setString(3, emp.getJob()) ; 22 this.pstmt.setDate(4, new java.sql.Date(emp.getHirdate().getTime())) ; 23 this.pstmt.setFloat(5, emp.getSal()) ; 24 //执行更新判断 25 if (this.pstmt.executeUpdate() > 0){ 26 flag = true ; 27 } 28 //关闭 29 this.pstmt.close() ; 30 return flag ; 31 } 32 33 //查询全部 34 public List<Emp> findAll(String keyword) throws Exception { 35 List<Emp> all = new ArrayList<Emp>() ; 36 String sql = "SELECT empno,ename,job,hiredate,sal FROM emp WHERE ename LIKE ? OR job LIKE ?" ; 37 this.pstmt = this.conn.prepareStatement(sql) ; 38 39 this.pstmt.setString(1, "%"+keyword+"%") ; 40 this.pstmt.setString(2, "%"+keyword+"%") ; 41 42 ResultSet rs = this.pstmt.executeQuery() ; 43 Emp emp = null ; 44 while (rs.next()){ 45 emp = new Emp() ; 46 emp.setEmpno(rs.getInt(1)) ; 47 emp.setEname(rs.getString(2)) ; 48 emp.setJob(rs.getString(3)) ; 49 emp.setHirdate(rs.getDate(4)) ; 50 emp.setSal(rs.getFloat(5)) ; 51 all.add(emp) ; 52 } 53 this.pstmt.close() ; 54 return all ; 55 } 56 57 //查询一个(ID) 58 public Emp findById(int empno) throws Exception { 59 Emp emp = null ; 60 String sql = "SELECT empno,ename,job,hiredate,sal FROM emp WHERE empno = ?" ; 61 62 this.pstmt = this.conn.prepareStatement(sql) ; //sql预处理 63 this.pstmt.setInt(1, empno) ; //设置值 64 ResultSet rs = this.pstmt.executeQuery() ; //执行sql 65 if (rs.next()){ 66 emp = new Emp() ; 67 emp.setEmpno(rs.getInt(1)) ; 68 emp.setEname(rs.getString(2)) ; 69 emp.setJob(rs.getString(3)) ; 70 emp.setHirdate(rs.getDate(4)) ; 71 emp.setSal(rs.getFloat(5)) ; 72 } 73 this.pstmt.close() ; 74 return emp ; 75 } 76 }
3 、定义代理类EmpDAOproxy 实现接口 并调用实际实现类完成操作
1 package fafa.vo; 2 3 import java.util.*; 4 5 public class EmpDAOproxy implements IempDAO { 6 private DatabaseConnection dbc = null ; 7 private IempDAO dao = null ; 8 9 public EmpDAOproxy () throws Exception{ 10 this.dbc = new DatabaseConnection() ; 11 this.dao = new EmpDAOImpl(this.dbc.getConnection()) ; 12 } 13 14 public boolean doCreate(Emp emp) throws Exception { 15 boolean flag = false ; 16 try { 17 if (this.dao.findById(emp.getEmpno()) == null){ 18 this.dao.doCreate(emp) ; 19 flag = true ; 20 } 21 } catch (Exception e) { 22 e.printStackTrace() ; 23 } finally { 24 this.dbc.close() ; 25 } 26 return flag ; 27 } 28 29 public List<Emp> findAll(String keyword) throws Exception { 30 List<Emp> all = null ; 31 try { 32 all = this.dao.findAll(keyword) ; 33 } catch (Exception e) { 34 e.printStackTrace() ; 35 } finally { 36 this.dbc.close() ; 37 } 38 return all ; 39 } 40 41 public Emp findById(int empno) throws Exception { 42 Emp emp = null ; 43 try { 44 this.dao.findById(empno) ; 45 } catch (Exception e) { 46 e.printStackTrace() ; 47 } finally { 48 this.dbc.close() ; 49 } 50 return emp ; 51 } 52 53 }
4、定义工厂类 实例化 代理类 –> 调用实现接口类 完成操作
1 package fafa.vo; 2 3 public class DAOfactory { 4 public static IempDAO getIEmpDAOInstance() throws Exception { 5 return new EmpDAOproxy() ; 6 } 7 }
5、当然少不了数据库连接类 DatabaseConnection 和vo 类 emp
1 package fafa.vo; 2 3 import java.sql.Connection; 4 import java.sql.DriverManager; 5 6 public class DatabaseConnection { 7 private static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ; 8 private static final String DBURL = "jdbc:mysql://localhost:3306/test" ; 9 private static final String DBUSER = "root" ; 10 private static final String DBPASS = "123456" ; 11 12 private Connection conn ; 13 public DatabaseConnection() throws Exception { 14 Class.forName(DBDRIVER) ; 15 this.conn = DriverManager.getConnection(DBURL,DBUSER,DBPASS) ; 16 } 17 //取得连接 18 public Connection getConnection(){ 19 return this.conn ; 20 } 21 //关闭连接 22 public void close(){ 23 if (this.conn != null){ 24 try{ 25 this.conn.close() ; 26 }catch(Exception e){ 27 e.printStackTrace() ; 28 } 29 } 30 } 31 }
1 package fafa.vo; 2 3 import java.util.Date; 4 5 public class Emp { 6 private int empno ; 7 private String ename ; 8 private String job ; 9 private Date hirdate ; 10 private float sal ; 11 12 public int getEmpno() { 13 return empno; 14 } 15 public void setEmpno(int empno) { 16 this.empno = empno; 17 } 18 public String getEname() { 19 return ename; 20 } 21 public void setEname(String ename) { 22 this.ename = ename; 23 } 24 public String getJob() { 25 return job; 26 } 27 public void setJob(String job) { 28 this.job = job; 29 } 30 public Date getHirdate() { 31 return hirdate; 32 } 33 public void setHirdate(Date hirdate) { 34 this.hirdate = hirdate; 35 } 36 public float getSal() { 37 return sal; 38 } 39 public void setSal(float sal) { 40 this.sal = sal; 41 } 42 }
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