Java实例---简单的数据库操作

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

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 ;
}
}
}
}

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 ;
}
}

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 ;
}
}

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 ;
}
}

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 ;
}

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) ;
}
}
}

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()) ;
}
}
}