【郭林专刊】万能 dao 层

2011-08-30 05:13 189人阅读 评论(3) 收藏 举报

packageheima.shawn.utils;

importjava.beans.Introspector;
importjava.beans.PropertyDescriptor;
importjava.sql.Connection;
importjava.sql.PreparedStatement;
importjava.sql.ResultSet;
importjava.util.ArrayList;
importjava.util.List;

publicclassBaseDao<T>{
publicObjectopreatorObj(Class<T>tClazz,Stringsql,Object...params)
throwsException{
Connectionconn=null;
PreparedStatementpst=null;
ResultSetrs=null;
try{
List<T>list=newArrayList<T>();
conn=DBUtils.getInstance().getConnection();
pst=conn.prepareStatement(sql);
if(params!=null){
for(inti=1;i<=params.length;i++){
pst.setObject(i,params[i-1]);
}
}
if(pst.execute()){
rs=pst.getResultSet();
while(rs.next()){
Tt=resultSet2Bean(rs,tClazz);
list.add(t);
}
returnlist;
}else{
introws=pst.getUpdateCount();
if(rows>0)
returntrue;
returnfalse;
}
}finally{
DBUtils.getInstance().release(conn,pst,rs);
}
}

publicTresultSet2Bean(ResultSetrs,Class<T>clazz)throwsException{
Tt=clazz.newInstance();
PropertyDescriptor[]props=Introspector.getBeanInfo(clazz)
.getPropertyDescriptors();
for(inti=0;i<props.length;i++){
if(props[i].getName().equals("class"))
continue;
props[i].getWriteMethod().invoke(t,
rs.getObject(props[i].getName()));
}
returnt;
}
}

package heima.shawn.utils;

import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class BaseDao<T> {
	public Object opreatorObj(Class<T> tClazz, String sql, Object... params)
			throws Exception {
		Connection conn = null;
		PreparedStatement pst = null;
		ResultSet rs = null;
		try {
			List<T> list = new ArrayList<T>();
			conn = DBUtils.getInstance().getConnection();
			pst = conn.prepareStatement(sql);
			if (params != null) {
				for (int i = 1; i <= params.length; i++) {
					pst.setObject(i, params[i - 1]);
				}
			}
			if (pst.execute()) {
				rs = pst.getResultSet();
				while (rs.next()) {
					T t = resultSet2Bean(rs, tClazz);
					list.add(t);
				}
				return list;
			} else {
				int rows = pst.getUpdateCount();
				if (rows > 0)
					return true;
				return false;
			}
		} finally {
			DBUtils.getInstance().release(conn, pst, rs);
		}
	}

	public T resultSet2Bean(ResultSet rs, Class<T> clazz) throws Exception {
		T t = clazz.newInstance();
		PropertyDescriptor[] props = Introspector.getBeanInfo(clazz)
				.getPropertyDescriptors();
		for (int i = 0; i < props.length; i++) {
			if (props[i].getName().equals("class"))
				continue;
			props[i].getWriteMethod().invoke(t,
					rs.getObject(props[i].getName()));
		}
		return t;
	}
}

packageheima.shawn.utils;

importjava.io.IOException;
importjava.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjava.sql.Statement;
importjava.util.Properties;

importcom.mysql.jdbc.Driver;

publicclassDBUtils{
privatePropertiesprop=newProperties();

privateDBUtils(){
try{
prop.load(DBUtils.class.getClassLoader().getResourceAsStream(
"DB.properties"));
}catch(IOExceptione){
thrownewRuntimeException(e);
}
}

privatestaticDBUtilsinstance=newDBUtils();

publicstaticDBUtilsgetInstance(){
returninstance;
}

publicConnectiongetConnection(){
Connectionconn=null;
try{
Class.forName(prop.getProperty("driver"));
//Driverdriver=newDriver();
conn=DriverManager.getConnection(prop.getProperty("url"),prop
.getProperty("user"),prop.getProperty("password"));
}catch(Exceptione){
thrownewRuntimeException(e);
}
returnconn;
}

publicvoidrelease(Connectionconn,Statementst,ResultSetrs){
if(rs!=null)
try{
rs.close();
}catch(SQLExceptione){
thrownewRuntimeException(e);
}
if(st!=null)
try{
st.close();
}catch(SQLExceptione){
thrownewRuntimeException(e);
}
if(conn!=null)
try{
conn.close();
}catch(SQLExceptione){
thrownewRuntimeException(e);
}
}
}

package heima.shawn.utils;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import com.mysql.jdbc.Driver;

public class DBUtils {
	private Properties prop = new Properties();

	private DBUtils() {
		try {
			prop.load(DBUtils.class.getClassLoader().getResourceAsStream(
					"DB.properties"));
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	private static DBUtils instance = new DBUtils();

	public static DBUtils getInstance() {
		return instance;
	}

	public Connection getConnection() {
		Connection conn = null;
		try {
			Class.forName(prop.getProperty("driver"));
			//Driver driver = new Driver();
			conn = DriverManager.getConnection(prop.getProperty("url"), prop
					.getProperty("user"), prop.getProperty("password"));
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		return conn;
	}

	public void release(Connection conn, Statement st, ResultSet rs) {
		if (rs != null)
			try {
				rs.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
		if (st != null)
			try {
				st.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
		if (conn != null)
			try {
				conn.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
	}
}

还能改进，，，但是已经觉得比hibernate好用了！！！你懂的·········

packageheima.shawn.utils;

importjava.beans.Introspector;
importjava.beans.PropertyDescriptor;
importjava.sql.Connection;
importjava.sql.PreparedStatement;
importjava.sql.ResultSet;
importjava.util.ArrayList;
importjava.util.List;

publicclassBaseDao<T>{
publicObjectopreatorObj(Class<T>tClazz,Stringsql,Object...params)
throwsException{
Connectionconn=null;
PreparedStatementpst=null;
ResultSetrs=null;
try{
List<T>list=newArrayList<T>();
conn=DBUtils.getInstance().getConnection();
pst=conn.prepareStatement(sql);
if(params!=null){
for(inti=1;i<=params.length;i++){
pst.setObject(i,params[i-1]);
}
}
if(pst.execute()){
rs=pst.getResultSet();
while(rs.next()){
Tt=resultSet2Bean(rs,tClazz);
list.add(t);
}
returnlist;
}else{
introws=pst.getUpdateCount();
if(rows>0)
returntrue;
returnfalse;
}
}finally{
DBUtils.getInstance().release(conn,pst,rs);
}
}

publicTresultSet2Bean(ResultSetrs,Class<T>clazz)throwsException{
Tt=clazz.newInstance();
PropertyDescriptor[]props=Introspector.getBeanInfo(clazz)
.getPropertyDescriptors();
for(inti=0;i<props.length;i++){
if(props[i].getName().equals("class"))
continue;
props[i].getWriteMethod().invoke(t,
rs.getObject(props[i].getName()));
}
returnt;
}
}

package heima.shawn.utils;

import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.ArrayList;
import java.util.List;

public class BaseDao<T> {
	public Object opreatorObj(Class<T> tClazz, String sql, Object... params)
			throws Exception {
		Connection conn = null;
		PreparedStatement pst = null;
		ResultSet rs = null;
		try {
			List<T> list = new ArrayList<T>();
			conn = DBUtils.getInstance().getConnection();
			pst = conn.prepareStatement(sql);
			if (params != null) {
				for (int i = 1; i <= params.length; i++) {
					pst.setObject(i, params[i - 1]);
				}
			}
			if (pst.execute()) {
				rs = pst.getResultSet();
				while (rs.next()) {
					T t = resultSet2Bean(rs, tClazz);
					list.add(t);
				}
				return list;
			} else {
				int rows = pst.getUpdateCount();
				if (rows > 0)
					return true;
				return false;
			}
		} finally {
			DBUtils.getInstance().release(conn, pst, rs);
		}
	}

	public T resultSet2Bean(ResultSet rs, Class<T> clazz) throws Exception {
		T t = clazz.newInstance();
		PropertyDescriptor[] props = Introspector.getBeanInfo(clazz)
				.getPropertyDescriptors();
		for (int i = 0; i < props.length; i++) {
			if (props[i].getName().equals("class"))
				continue;
			props[i].getWriteMethod().invoke(t,
					rs.getObject(props[i].getName()));
		}
		return t;
	}
}

packageheima.shawn.utils;

importjava.io.IOException;
importjava.sql.Connection;
importjava.sql.DriverManager;
importjava.sql.ResultSet;
importjava.sql.SQLException;
importjava.sql.Statement;
importjava.util.Properties;

importcom.mysql.jdbc.Driver;

publicclassDBUtils{
privatePropertiesprop=newProperties();

privateDBUtils(){
try{
prop.load(DBUtils.class.getClassLoader().getResourceAsStream(
"DB.properties"));
}catch(IOExceptione){
thrownewRuntimeException(e);
}
}

privatestaticDBUtilsinstance=newDBUtils();

publicstaticDBUtilsgetInstance(){
returninstance;
}

publicConnectiongetConnection(){
Connectionconn=null;
try{
Class.forName(prop.getProperty("driver"));
//Driverdriver=newDriver();
conn=DriverManager.getConnection(prop.getProperty("url"),prop
.getProperty("user"),prop.getProperty("password"));
}catch(Exceptione){
thrownewRuntimeException(e);
}
returnconn;
}

publicvoidrelease(Connectionconn,Statementst,ResultSetrs){
if(rs!=null)
try{
rs.close();
}catch(SQLExceptione){
thrownewRuntimeException(e);
}
if(st!=null)
try{
st.close();
}catch(SQLExceptione){
thrownewRuntimeException(e);
}
if(conn!=null)
try{
conn.close();
}catch(SQLExceptione){
thrownewRuntimeException(e);
}
}
}

package heima.shawn.utils;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import com.mysql.jdbc.Driver;

public class DBUtils {
	private Properties prop = new Properties();

	private DBUtils() {
		try {
			prop.load(DBUtils.class.getClassLoader().getResourceAsStream(
					"DB.properties"));
		} catch (IOException e) {
			throw new RuntimeException(e);
		}
	}

	private static DBUtils instance = new DBUtils();

	public static DBUtils getInstance() {
		return instance;
	}

	public Connection getConnection() {
		Connection conn = null;
		try {
			Class.forName(prop.getProperty("driver"));
			//Driver driver = new Driver();
			conn = DriverManager.getConnection(prop.getProperty("url"), prop
					.getProperty("user"), prop.getProperty("password"));
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		return conn;
	}

	public void release(Connection conn, Statement st, ResultSet rs) {
		if (rs != null)
			try {
				rs.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
		if (st != null)
			try {
				st.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
		if (conn != null)
			try {
				conn.close();
			} catch (SQLException e) {
				throw new RuntimeException(e);
			}
	}
}

还能改进，，，但是已经觉得比hibernate好用了！！！你懂的·········