Connect to Oracle Database

1. Write a connection directly in a fixed way in a Java class, for example:

 
Import Java. SQL. connection; import Java. SQL. drivermanager; import Java. SQL. sqlexception;/*** encapsulate Common Database Operations * @ author administrator **/public class dbutil {/*** get connection * @ return */public static connection getconnection () {connection conn = NULL; try {class. forname ("oracle. JDBC. driver. oracledriver "); string url =" JDBC: oracle: thin: @ 192.168.26.3: 1521: bjpowernode "; string username =" test "; string Password =" test "; Conn = drivermanager. getconnection (URL, username, password);} catch (classnotfoundexception e) {e. printstacktrace ();} catch (sqlexception e) {e. printstacktrace ();} return conn;} public static void main (string [] Arges) {system. out. println (dbutil. getconnection ());}}
 

2. Use the xml configuration file to flexibly connect to the database (easier to modify). For example:

Import Java. SQL. connection; import Java. SQL. drivermanager; import Java. SQL. sqlexception;/*** encapsulate Common Database Operations * @ author administrator **/public class dbutil {/*** get connection * @ return */public static connection getconnection () {connection conn = NULL; try {jdbcconfig = xmlconfigreader. getinstance (). getjdbcconfig (); Class. forname (jdbcconfig. getdrivername (); string url = jdbcconfig. geturl (); string username = jdbcconfig. getUserName (); string Password = jdbcconfig. getPassword (); Conn = drivermanager. getconnection (URL, username, password);} catch (classnotfoundexception e) {e. printstacktrace ();} catch (sqlexception e) {e. printstacktrace ();} return conn;} public static void main (string [] Arges) {system. out. println (dbutil. getconnection ());}}
 

Jdbcconfig. Java class (the tostring () method is also rewritten here)

/*** JDBC configuration information ** @ author administrator **/public class jdbcconfig {private string drivername; private string URL; private string username; private string password; Public String getdrivername () {return drivername;} public void setdrivername (string drivername) {This. drivername = drivername;} Public String geturl () {return URL;} public void seturl (string URL) {This. url = URL;} Public String GetUserName () {return username;} public void setusername (string username) {This. username = username;} Public String GetPassword () {return password;} public void setpassword (string password) {This. password = password;} @ overridepublic string tostring () {return this. getclass (). getname () + "{drivername:" + drivername + ", URL:" + URL + ", Username:" + username + ", password: "+ password + "}";}}
 

Xmlconfigreader. Java class (the singleton mode is used to read xml configuration information)

Import Java. io. inputstream; import Org. dom4j. document; import Org. dom4j. extends entexception; import Org. dom4j. element; import Org. dom4j. io. saxreader;/*** parse the sys-config.xml file in the standalone mode * @ Param ARGs */public class xmlconfigreader {// hungry (preloaded) // Private Static xmlconfigreader instance = new xmlconfigreader (); // Private xmlconfigreader () {//} // public static xmlconfigreader getinstance () {// return instance; // lazy (delayed loading) Private Static xmlconfigreader instance = NULL; // save JDBC-related configuration information private jdbcconfig = new jdbcconfig (); Private xmlconfigreader () {saxreader reader = new saxreader (); inputstream in = thread. currentthread (). getcontextclassloader (). getresourceasstream ("sys-config.xml"); try {document DOC = reader. read (in); // get the JDBC-related configuration element drivernameelt = (element) Doc. selectObject ("/config/DB-info/driver-name"); element urlelt = (element) Doc. selectObject ("/config/DB-info/url"); element usernameelt = (element) Doc. selectObject ("/config/DB-info/user-name"); element passwordelt = (element) Doc. selectObject ("/config/DB-info/password"); // set JDBC-related configuration jdbcconfig. setdrivername (drivernameelt. getstringvalue (); jdbcconfig. seturl (urlelt. getstringvalue (); jdbcconfig. setusername (usernameelt. getstringvalue (); jdbcconfig. setpassword (passwordelt. getstringvalue ();} catch (incluentexception e) {e. printstacktrace () ;}} public static synchronized xmlconfigreader getinstance () {If (instance = NULL) {instance = new xmlconfigreader ();} return instance ;} // return JDBC-related configuration information public jdbcconfig getjdbcconfig () {return jdbcconfig;} public static void main (string [] ARGs) {jdbcconfig = xmlconfigreader. getinstance (). getjdbcconfig (); system. out. println (jdbcconfig );}}

Sys-config.xml (profile)

 
<? XML version = "1.0" encoding = "UTF-8"?> <Config> <DB-Info> <driver-Name> oracle. JDBC. driver. oracledriver </driver-Name> <URL> JDBC: oracle: thin: @ 192.168.26.3: 1521: bjpowernode </URL> <user-Name> test </user-Name> <password> test </password> </DB-Info> </config>