package com. Zyj. School. Util. 

The import com. Alibaba. Druid. Pool. DruidDataSource; 
The import com. Alibaba. Druid. Pool. DruidDataSourceFactory; 

The import javax.mail. SQL. DataSource. 
Import the Java. IO. IOException; 
Import the Java. IO. InputStream; 
Import the Java. SQL. Connection; 
Import the Java. SQL. The ResultSet; 
Import the Java. SQL. SQLException; 
Import Java, SQL Statement; 
Import the Java. Util. Properties; 

Public class DruidUtil {
/* * 
* database connection pool has multiple connections 
* so will con change for the DataSource 
*/
//get a data connection source con 
Private static DruidDataSource datasource. 
Public static DataSource getDatasource () {
Return the datasource; 
} 
//static block decrease code optimization code 
The static {
Try {
The Properties of pro=readproperties (); 
System. The out. Println (" Druid + pro "); 
The datasource=(DruidDataSource) DruidDataSourceFactory. CreateDataSource (pro); 
System. Out.println (" database connection success!" ); 
} the catch (Exception e) {
e.printStackTrace(); 
System. Out.println (" database connection failed!" ); 
} 
} 
//read method reads ojdbc of hard disk. The properties file information 
Public static Properties readproperties () {
//by class loaders 
InputStream InputStream=DruidUtil. Class. GetClassLoader () getResourceAsStream (" DruidPool. Properties "); 
//data type 
The Properties of pro=new Properties (); 
Try {
Pro. The load (inputstream); 
} the catch (IOException e) {
e.printStackTrace(); 
} 
Return pro; 
} 
//for connecting the datasource connection 
Public static Connection getCon () {
The Connection Connection=null; 
Try {
The connection=datasource. GetConnection (); 
} the catch (SQLException e) {
e.printStackTrace(); 
System. The out. Println (e + "datasource get connection problems"); 
return null; 
} 
Return the connection; 
} 
//close the database related links 
Public static void closeConnection (ResultSet rs, Connection conn, the Statement state) throws the Exception {
if(rs!=null) {
rs.close(); 
//System. Out.println (" database rs close success!" ); 
} 

If (the state!=null) {
State. The close (); 
//System. Out.println (" database pstate close success!" ); 
} 

If (conn!=null) {
Conn. Close (); 
//System. Out.println (" database con close success!" ); 
} 
Shutdown System. Out.println (" success!" ); 
} 
} 

Java. Lang. NullPointerException
At Java. Util. The Properties of $LineReader. ReadLine (434). The Properties of Java:
The at Java. Util. Properties. Load0 (353). The Properties of Java:
The at Java. Util. Properties. The load (341). The Properties of Java:
At com. Zyj. School. Util. DruidUtil. Readproperties (DruidUtil. Java: 44)
At com. Zyj. School. Util. DruidUtil. & lt; Clinit> (DruidUtil. Java: 28)
At com. Zyj. School. Dao. LoginDaoImpl. & lt; init> (LoginDaoImpl. Java: 19)
At com. Zyj. School. Service. LoginServiceImpl. & lt; init> (LoginServiceImpl Java: 19)
At com. Zyj. School. Controller. LoginServlet. DoPost (LoginServlet. Java: 36)
At com. Zyj. School. Controller. LoginServlet. DoGet (LoginServlet. Java: 29)
The at Jakarta. Servlet. HTTP. HttpServlet. Service (HttpServlet. Java: 663)
The at Jakarta. Servlet. HTTP. HttpServlet. Service (HttpServlet. Java: 770)
The at org. Apache. Catalina. Core. ApplicationFilterChain. InternalDoFilter (ApplicationFilterChain. Java: 223)
The at org. Apache. Catalina. Core. ApplicationFilterChain. DoFilter (ApplicationFilterChain. Java: 158)
At org, apache tomcat, websocket server WsFilter. DoFilter (53) WsFilter. Java:
The at org. Apache. Catalina. Core. ApplicationFilterChain. InternalDoFilter (ApplicationFilterChain. Java: 185)
The at org. Apache. Catalina. Core. ApplicationFilterChain. DoFilter (ApplicationFilterChain. Java: 158)
At com. Zyj. School. Filter. SchoolFilter. DoFilter (SchoolFilter. Java: 24)
The at org. Apache. Catalina. Core. ApplicationFilterChain. InternalDoFilter (ApplicationFilterChain. Java: 185)
The at org. Apache. Catalina. Core. ApplicationFilterChain. DoFilter (ApplicationFilterChain. Java: 158)
The at org. Apache. Catalina. Core. StandardWrapperValve. Invoke (StandardWrapperValve. Java: 202)
The at org. Apache. Catalina. Core. StandardContextValve. Invoke (StandardContextValve. Java: 97)
The at org. Apache. Catalina. The authenticator. AuthenticatorBase. Invoke (AuthenticatorBase. Java: 543)
The at org. Apache. Catalina. Core. StandardHostValve. Invoke (StandardHostValve. Java: 127)
The at org. Apache. Catalina. Valves. ErrorReportValve. Invoke (ErrorReportValve. Java: 92)
The at org. Apache. Catalina. Valves. AbstractAccessLogValve. Invoke (AbstractAccessLogValve. Java: 690)
The at org. Apache. Catalina. Core. StandardEngineValve. Invoke (StandardEngineValve. Java: 78)
At org. Apache. Catalina. Connector. CoyoteAdapter. Service (353) CoyoteAdapter. Java:
At org. Apache. Coyote. Http11. Http11Processor. Service (374) Http11Processor. Java:
The at org. Apache. Coyote. AbstractProcessorLight. Process (AbstractProcessorLight. Java: 65)
The at org. Apache. Coyote. AbstractProtocol $ConnectionHandler. Process (AbstractProtocol. Java: 870)
At org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun NioEndpoint. Java: (1696)
The at org.apache.tomcat.util.net.SocketProcessorBase.run (SocketProcessorBase. Java: 49)
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