//数据库连接池，用集合保存一大批connection,用户-servlet-dao-db
//-->改为用户-servlet-dao-connectionpool--db
public class jdbcpool implements DataSource {
//连接池里面先保存多个连接，供dao取出连接，要增删改查连接用linkedlist
private static LinkedList<Connection>list=new LinkedList<Connection>();
static{
Properties p=new Properties();
InputStream in=jdbcpool.class.getClassLoader().getResourceAsStream("db.properties");
try {
p.load(in);
for(int i=0;i<10;i++)//为数据库创建10个连接，放到连接池
{
Class.forName(p.getProperty("driver"));
Connection con=DriverManager.getConnection(p.getProperty("url"), p.getProperty("username"), p.getProperty("password"));
list.add(con);
}
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public Connection getConnection() throws SQLException {
//从连接池里面取出数据
if(list.size()<=0)
{
throw new RuntimeException();
}
Connection con=list.removeFirst();
//每次都移除第一个连接，连接池里减少一个，相当于取出了一个连接
//conn.Close();这样释放资源的话只会释放到数据库中，不会释放到连接池中
//相当于我们可以增强con.close()方法，当close()的时候，归还到连接池中去
MyConnection my=new MyConnection(con);
return my;
}
//增强方法有3种方法
//1:写一个connction子类，覆盖close()方法，增强close()方法
//2:用包装设计模式
//3:动态代理
//使用包装设计模式增强才，close()方法，包装设计模式步奏
/*
* 1:定义一个类，实现与增强相同的接口
* 2:在类中定义一个变量，记住被增强对象
* 3:定义一个构造函数，接受被增强对象
* 4:覆盖想增强方法
* 5:对于不想增强的方法，直接调用目标对象的方法
*/
class MyConnection implements Connection
{
private Connection con;
public MyConnection(Connection con)
{
this.con=con;
}
@Override
public void close() throws SQLException {
list.add(con);//释放数据库资源的时候，直接释放到连接池中去
}
@Override
public <T> T unwrap(Class<T> iface) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public boolean isWrapperFor(Class<?> iface) throws SQLException {
// TODO Auto-generated method stub
return false;
}
@Override
public Statement createStatement() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PreparedStatement prepareStatement(String sql) throws SQLException {
// TODO Auto-generated method stub
return this.con.prepareStatement(sql);
}
@Override
public CallableStatement prepareCall(String sql) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public String nativeSQL(String sql) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void setAutoCommit(boolean autoCommit) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public boolean getAutoCommit() throws SQLException {
// TODO Auto-generated method stub
return false;
}
@Override
public void commit() throws SQLException {
// TODO Auto-generated method stub
}
@Override
public void rollback() throws SQLException {
// TODO Auto-generated method stub
}
@Override
public boolean isClosed() throws SQLException {
// TODO Auto-generated method stub
return false;
}
@Override
public DatabaseMetaData getMetaData() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void setReadOnly(boolean readOnly) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public boolean isReadOnly() throws SQLException {
// TODO Auto-generated method stub
return false;
}
@Override
public void setCatalog(String catalog) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public String getCatalog() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void setTransactionIsolation(int level) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public int getTransactionIsolation() throws SQLException {
// TODO Auto-generated method stub
return 0;
}
@Override
public SQLWarning getWarnings() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void clearWarnings() throws SQLException {
// TODO Auto-generated method stub
}
@Override
public Statement createStatement(int resultSetType, int resultSetConcurrency)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PreparedStatement prepareStatement(String sql, int resultSetType,
int resultSetConcurrency) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public CallableStatement prepareCall(String sql, int resultSetType,
int resultSetConcurrency) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Map<String, Class<?>> getTypeMap() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void setTypeMap(Map<String, Class<?>> map) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public void setHoldability(int holdability) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public int getHoldability() throws SQLException {
// TODO Auto-generated method stub
return 0;
}
@Override
public Savepoint setSavepoint() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Savepoint setSavepoint(String name) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void rollback(Savepoint savepoint) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public void releaseSavepoint(Savepoint savepoint) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public Statement createStatement(int resultSetType,
int resultSetConcurrency, int resultSetHoldability)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PreparedStatement prepareStatement(String sql, int resultSetType,
int resultSetConcurrency, int resultSetHoldability)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public CallableStatement prepareCall(String sql, int resultSetType,
int resultSetConcurrency, int resultSetHoldability)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PreparedStatement prepareStatement(String sql, int autoGeneratedKeys)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PreparedStatement prepareStatement(String sql, int[] columnIndexes)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PreparedStatement prepareStatement(String sql, String[] columnNames)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Clob createClob() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Blob createBlob() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public NClob createNClob() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public SQLXML createSQLXML() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public boolean isValid(int timeout) throws SQLException {
// TODO Auto-generated method stub
return false;
}
@Override
public void setClientInfo(String name, String value)
throws SQLClientInfoException {
// TODO Auto-generated method stub
}
@Override
public void setClientInfo(Properties properties)
throws SQLClientInfoException {
// TODO Auto-generated method stub
}
@Override
public String getClientInfo(String name) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Properties getClientInfo() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Array createArrayOf(String typeName, Object[] elements)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public Struct createStruct(String typeName, Object[] attributes)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
}
@Override
public Connection getConnection(String username, String password)
throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public PrintWriter getLogWriter() throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public void setLogWriter(PrintWriter out) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public void setLoginTimeout(int seconds) throws SQLException {
// TODO Auto-generated method stub
}
@Override
public int getLoginTimeout() throws SQLException {
// TODO Auto-generated method stub
return 0;
}
@Override
public <T> T unwrap(Class<T> iface) throws SQLException {
// TODO Auto-generated method stub
return null;
}
@Override
public boolean isWrapperFor(Class<?> iface) throws SQLException {
// TODO Auto-generated method stub
return false;
}
}
package com.mysql;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import org.junit.Test;
public class insertData {
@Test
public void testInsert() throws SQLException
{
Connection con=null;
try{
jdbcpool p=new jdbcpool();
con=p.getConnection();
String sql="insert into login value('jack','456')";
PreparedStatement ps=con.prepareStatement(sql);
int i=ps.executeUpdate();
if(i>0)
{
System.out.println("insert success");
}
}
catch (Exception e) {
}
finally{
con.close();//释放资源到连接池
}
}
}