Write Data Sources (not written during development) and use dynamic proxy to overwrite the clos of Connection

Importjava. io. printWriter; importjava. lang. reflect. invocationHandler; importjava. lang. reflect. method; importjava. lang. reflect. proxy; importjava. SQL. connection; importjava. SQL. SQLException; importjava. util. using list; importjavax. SQL. dataS

Import java. io. printWriter; import java. lang. reflect. invocationHandler; import java. lang. reflect. method; import java. lang. reflect. proxy; import java. SQL. connection; import java. SQL. SQLException; import java. util. export list; import javax. SQL. dataS

Import java. io. printWriter; import java. lang. reflect. invocationHandler; import java. lang. reflect. method; import java. lang. reflect. proxy; import java. SQL. connection; import java. SQL. SQLException; import java. util. export list; import javax. SQL. dataSource; import com. itheima. util. jdbcUtil; // standard database connection pool. Literally, it is called a data source (all with a pool, to improve efficiency) public class MyDataSource implements DataSource {private static tables list
 
  
Pool = new external list
  
   
(); Static {try {// pool initialization: 10 connections for (int I = 0; I <10; I ++) {pool. add (JdbcUtil. getConnection () ;}} catch (Exception e) {throw new ExceptionInInitializerError ("database connection pool initialization failed") ;}// return its packaging class, all methods in connection @ Overridepublic synchronized Connection getConnection () throws SQLException {if (pool. size ()> 0) {final Connection conn = pool. removeFirst (); // The connection Implementation of the original data. Encapsulated Connection proxyconn = (Connection) Proxy. newProxyInstance (conn. getClass (). getClassLoader (), conn. getClass (). getInterfaces (), new InvocationHandler () {public Object invoke (Object proxy, Method method, Object [] args) throws Throwable {System. out. println (method. getName (); if ("close ". equals (method. getName () {return pool. add (conn);} else {return method. invoke (conn, args) ;}}); return proxyconn ;}elsethrow new RuntimeException ("busy server") ;}@ Overridepublic PrintWriter getLogWriter () throws SQLException {return null ;} @ Overridepublic void setLogWriter (timed out) throws SQLException {}@ Overridepublic void limit (int seconds) throws SQLException {}@ Overridepublic int limit () throws SQLException {return 0;} @ Overridepublic
   
    
T unwrap (Class
    
     
Iface) throws SQLException {return null;} @ Overridepublic boolean isWrapperFor (Class
     Iface) throws SQLException {return false;} @ Overridepublic Connection getConnection (String username, String password) throws SQLException {return null ;}}
    
   
  
 

Package com. jxnu. util; import java. io. inputStream; import java. SQL. connection; import java. SQL. driverManager; import java. SQL. resultSet; import java. SQL. SQLException; import java. SQL. statement; import java. util. properties; // common tool class: public class JdbcUtil {private static String driverClass; private static String url; private static String username; private static String password; static {try {// load the configuration file In PutStream in = JdbcUtil. class. getClassLoader (). getResourceAsStream ("dbcfg. properties "); Properties props = new Properties (); props. load (in); driverClass = props. getProperty ("driverClass"); url = props. getProperty ("url"); username = props. getProperty ("username"); password = props. getProperty ("password"); Class. forName (driverClass);} catch (Exception e) {throw new ExceptionInInitializerError (e) ;}// obtain the database connection Public static Connection getConnection () throws Exception {Connection conn = DriverManager. getConnection (url, username, password); return conn;} // release the occupied resource public static void release (ResultSet rs, Statement stmt, Connection conn) {if (rs! = Null) {try {rs. close () ;}catch (SQLException e) {e. printStackTrace () ;}} if (stmt! = Null) {try {stmt. close () ;}catch (SQLException e) {e. printStackTrace () ;}} if (conn! = Null) {try {conn. close () ;}catch (SQLException e) {e. printStackTrace ();}}}}

Test:

Package com. jxnu. pool04; import java. SQL. connection; import java. SQL. SQLException; import java. SQL. statement; import org. junit. test; public class Dao1Impl {MyDataSource ds = new MyDataSource (); @ Testpublic void add () {Connection conn = null; Statement stmt = null; try {conn = ds. getConnection (); stmt = conn. createStatement (); // com. mysql. jdbc. connection: MySQL // com. oracle. jdbc. connection: Oracle //... system. out . Println (conn. getClass (). getName ();} catch (Exception e) {e. printStackTrace () ;} finally {if (conn! = Null) {try {conn. close (); // closes the connection. Should not be switched off. Put it back into the pool. How can I put it back into the pool? Connection Pool highlights} catch (SQLException e) {e. printStackTrace ();}}}}}