Java实例---简单的数据库操作

源码分析

DAOFactory.java

 package cn.ftl.mysql ;
 public class DAOFactory {
     public static IEmpDAO getIEmpDAOInstance() throws Exception{
         return new EmpDAOProxy() ;
     }
 }

DatabaseConnection.java

 package cn.ftl.mysql ;
 import java.sql.Connection ;
 import java.sql.DriverManager ;
 public class DatabaseConnection {
     public static final String DBDRIVER= "com.mysql.jdbc.Driver";
     public static final String DBURL= "jdbc:mysql://localhost:3306/RUNOOB";
     public static final String DBUSER= "test";
     public static final String DBPASSWORD= "Changeme_123";

     private Connection conn ;
     public DatabaseConnection() throws Exception {
         Class.forName(DBDRIVER) ;
         this.conn = DriverManager.getConnection(DBURL,DBUSER,DBPASSWORD) ;
     }
     public Connection getConnection(){
         return this.conn ;
     }
     public void close() throws Exception {
         if(this.conn != null){
             try{
                 this.conn.close() ;
             }catch(Exception e){
                 throw e ;
             }
         }
     }
 }

Emp.java

 package cn.ftl.mysql ;
 import java.util.Date ;
 public class Emp {
     private int empno ;
     private String ename ;
     private String job ;
     private Date hiredate ;
     private float sal ;
     public void setEmpno(int empno){
         this.empno = empno ;
     }
     public void setEname(String ename){
         this.ename = ename ;
     }
     public void setJob(String job){
         this.job = job ;
     }
     public void setHiredate(Date hiredate){
         this.hiredate = hiredate ;
     }
     public void setSal(float sal){
         this.sal = sal ;
     }
     public int getEmpno(){
         return this.empno ;
     }
     public String getEname(){
         return this.ename ;
     }
     public String getJob(){
         return this.job ;
     }
     public Date getHiredate(){
         return this.hiredate ;
     }
     public float getSal(){
         return this.sal ;
     }
 }

EmpDAOImpl.java

 package cn.ftl.mysql;

 import java.util.* ;
 import java.sql.* ;

 public class EmpDAOImpl implements IEmpDAO {
     private Connection conn = null ;
     private PreparedStatement pstmt = null ;
     public EmpDAOImpl(Connection conn){
         this.conn = conn ;
     }
     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) ;
         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.getHiredate().getTime())) ;
         this.pstmt.setFloat(5,emp.getSal()) ;
         if(this.pstmt.executeUpdate() > 0){
             flag = true ;
         }
         this.pstmt.close() ;
         return flag ;
     }
     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.setHiredate(rs.getDate(4)) ;
             emp.setSal(rs.getFloat(5)) ;
             all.add(emp) ;
         }
         this.pstmt.close() ;
         return all ;
     }
     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) ;
         this.pstmt.setInt(1,empno) ;
         ResultSet rs = this.pstmt.executeQuery() ;
         if(rs.next()){
             emp = new Emp() ;
             emp.setEmpno(rs.getInt(1)) ;
             emp.setEname(rs.getString(2)) ;
             emp.setJob(rs.getString(3)) ;
             emp.setHiredate(rs.getDate(4)) ;
             emp.setSal(rs.getFloat(5)) ;
         }
         this.pstmt.close() ;
         return emp ;
     }
 }

EmpDAOProxy.java

 package cn.ftl.mysql;

 import java.util.* ;
 import java.sql.* ;

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

IEmpDAO.java

 package cn.ftl.mysql;
 import java.util.* ;
 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 ;
 }

TestDAOInsert.java

 package cn.ftl.mysql;
 public class TestDAOInsert{
     public static void main(String args[]) throws Exception{
         Emp emp = null ;
         for(int x=0;x<5;x++){
             emp = new Emp() ;
             emp.setEmpno(101 + x) ;
             emp.setEname("FTL - " + x) ;
             emp.setJob("JC - " + x) ;
             emp.setHiredate(new java.util.Date()) ;
             emp.setSal(5 * x) ;
             DAOFactory.getIEmpDAOInstance().doCreate(emp) ;
         }
     }
 }

TestDAOSelect.java

 package cn.ftl.mysql;
 import java.util.* ;
 public class TestDAOSelect{
     public static void main(String args[]) throws Exception{
         List<Emp> all = DAOFactory.getIEmpDAOInstance().findAll("") ;
         Iterator<Emp> iter = all.iterator() ;
         while(iter.hasNext()){
             Emp emp = iter.next() ;
             System.out.println(emp.getEmpno() + "、" + emp.getEname() + " --> " + emp.getJob()) ;
         }
     }
 }

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【更多参考】

Java学习---连接数据库操作

数据库建模工具 PD的使用

Linu下的Mysql学习详解_【all】