The JDBC ( Java Database Connectivity) API defines interfaces and classes for writing database applications in Java by making database connections. Using JDBC you can send SQL, PL/SQL statements to almost any relational database. JDBC is a Java API for executing SQL statements and supports basic SQL functionality. It provides RDBMS access by allowing you to embed SQL inside Java code. Because Java can run on a thin client, applets embedded in Web pages can contain downloadable JDBC code to enable remote database access. You will learn how to create a table, insert values into it, query the table, retrieve results, and update the table with the help of a JDBC Program example.
Although JDBC was designed specifically to provide a Java interface to relational databases, you may find that you need to write Java code to access non-relational databases as well.
JDBC Architecture
Java application calls the JDBC library. JDBC loads a driver which talks to the database. We can change database engines without changing database code.
JDBC Basics – Java Database Connectivity Steps
Before you can create a java jdbc connection to the database, you must first import the
java.sql package.
import java.sql.*; The star ( * ) indicates that all of the classes in the package java.sql are to be imported.
1. Loading a database driver,
In this step of the jdbc connection process, we load the driver class by calling Class.forName() with the Driver class name as an argument. Once loaded, the Driver class creates an instance of itself. A client can connect to Database Server through JDBC Driver. Since most of the Database servers support ODBC driver therefore JDBC-ODBC Bridge driver is commonly used.
The return type of the Class.forName (String ClassName) method is “Class”. Class is a class in
java.lang package.
try {
Class.forName(”sun.jdbc.odbc.JdbcOdbcDriver”); //Or any other driver
}
catch(Exception x){
System.out.println( “Unable to load the driver class!” );
}
2. Creating a oracle jdbc Connection
The JDBC DriverManager class defines objects which can connect Java applications to a JDBC driver. DriverManager is considered the backbone of JDBC architecture. DriverManager class manages the JDBC drivers that are installed on the system. Its getConnection() method is used to establish a connection to a database. It uses a username, password, and a jdbc url to establish a connection to the database and returns a connection object. A jdbc Connection represents a session/connection with a specific database. Within the context of a Connection, SQL, PL/SQL statements are executed and results are returned. An application can have one or more connections with a single database, or it can have many connections with different databases. A Connection object provides metadata i.e. information about the database, tables, and fields. It also contains methods to deal with transactions.
JDBC URL Syntax:: jdbc: <subprotocol>: <subname>
JDBC URL Example:: jdbc: <subprotocol>: <subname>•Each driver has its own subprotocol
•Each subprotocol has its own syntax for the source. We’re using the jdbc odbc subprotocol, so the DriverManager knows to use the sun.jdbc.odbc.JdbcOdbcDriver.
try{
Connection dbConnection=DriverManager.getConnection(url,”loginName”,”Password”)
}
catch( SQLException x ){
System.out.println( “Couldn’t get connection!” );
}
3. Creating a jdbc Statement object,
Once a connection is obtained we can interact with the database. Connection interface defines methods for interacting with the database via the established connection. To execute SQL statements, you need to instantiate a Statement object from your connection object by using the createStatement() method.
Statement statement = dbConnection.createStatement();
A statement object is used to send and execute SQL statements to a database.
Three kinds of Statements
Statement: Execute simple sql queries without parameters.
Statement createStatement()
Creates an SQL Statement object.
Prepared Statement: Execute precompiled sql queries with or without parameters.
PreparedStatement prepareStatement(String sql)
returns a new PreparedStatement object. PreparedStatement objects are precompiled
SQL statements.
Callable Statement: Execute a call to a database stored procedure.
CallableStatement prepareCall(String sql)
returns a new CallableStatement object. CallableStatement objects are SQL stored procedure call statements.
4. Executing a SQL statement with the Statement object, and returning a jdbc resultSet.
Statement interface defines methods that are used to interact with database via the execution of SQL statements. The Statement class has three methods for executing statements:
executeQuery(), executeUpdate(), and execute(). For a SELECT statement, the method to use is executeQuery . For statements that create or modify tables, the method to use is executeUpdate. Note: Statements that create a table, alter a table, or drop a table are all examples of DDL
statements and are executed with the method executeUpdate. execute() executes an SQL
statement that is written as String object.
ResultSet provides access to a table of data generated by executing a Statement. The table rows are retrieved in sequence. A ResultSet maintains a cursor pointing to its current row of data. The next() method is used to successively step through the rows of the tabular results.
ResultSetMetaData Interface holds information on the types and properties of the columns in a ResultSet. It is constructed from the Connection object.
Test JDBC Driver Installation
import javax.swing.JOptionPane;
public class TestJDBCDriverInstallation_Oracle {
public static void main(String[] args) {
StringBuffer output = new StringBuffer();
output.append(”Testing oracle driver installation \n”);
try {
String className = “sun.jdbc.odbc.JdbcOdbcDriver”;
Class driverObject = Class.forName(className);
output.append(”Driver : “+driverObject+”\n”);
output.append(”Driver Installation Successful”);
JOptionPane.showMessageDialog(null, output);
} catch (Exception e) {
output = new StringBuffer();
output.append(”Driver Installation FAILED\n”);
JOptionPane.showMessageDialog(null, output);
System.out.println(”Failed: Driver Error: ” + e.getMessage());
}
}
}
Download JDBC Sample Code
Java JDBC Connection Example, JDBC Driver Example
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.SQLException;
public class JDBCDriverInformation {
static String userid=”scott”, password = “tiger”;
static String url = “jdbc:odbc:bob”; static Connection con = null;
public static void main(String[] args) throws Exception {
Connection con = getOracleJDBCConnection();
if(con!= null){
System.out.println(”Got Connection.”);
DatabaseMetaData meta = con.getMetaData();
System.out.println(”Driver Name : “+meta.getDriverName());
System.out.println(”Driver Version : “+meta.getDriverVersion());
}else{
System.out.println(”Could not Get Connection”);
}
}
public static Connection getOracleJDBCConnection(){
try {
Class.forName(”sun.jdbc.odbc.JdbcOdbcDriver”); } catch(java.lang.ClassNotFoundException e) {
System.err.print(”ClassNotFoundException: “);
System.err.println(e.getMessage());
}
try {
con = DriverManager.getConnection(url, userid, password);
} catch(SQLException ex) {
System.err.println(”SQLException: ” + ex.getMessage());
}
return con;
}
}
分享到:
相关推荐
spring-data-jdbc-basic Spring Data JDBC基本介绍。 该项目尝试涵盖一对一和多对X关系。 该项目还包括使用DTO(Spring Data Core)进行投影的概念和客户行映射器(JDBC API)的概念
additional basic features of Java and JDBC supported by the Oracle JDBC drivers. Chapter 4, "Overview of JDBC 2.0 Support" This chapter presents an overview of JDBC 2.0 features and describes the ...
最新的Oracle 数据库 10g 10.2.0.1.0 第 2 版 JDBC 驱动程序 包含: ojdbc14.jar ojdbc14_g.jar ojdbc14dms.jar ojdbc14dms_g.jar
This book covers a lot of material about Oracle's implementation of JDBC. It provides both the beginner and the advanced Oracle or Java user with all the information needed to be successful. ...
Instant Client Package - Basic: All files required to run OCI, OCCI, and JDBC-OCI applications instantclient-basic-windows.x64-11.2.0.4.0.zip (54,956,947 bytes) Instant Client 程序包 — Basic(win64...
oracle-instantclient11.2-basic-11.2.0.4.0-1.x86_64.rpm --基础包,为了运行OCI、OCCI、JDBC-OCI 这几个应用程序; oracle-instantclient11.2-sqlplus-11.2.0.4.0-1.x86_64.rpm --补充包/文件,是为了运行sql*plus...
Instant Client Package - Basic: All files required to run OCI, OCCI, and JDBC-OCI applications oracle-instantclient12.2-basiclite-12.2.0.1.0-1.x86_64.rpm (52,826,628 bytes) (cksum - 888077889)
由于本地maven无法正常下载驱动包,只能手动下载后填加到本地maven仓库(无需导入,直接复制到仓库目录下),idea无法正常识别,用eclipse更新一次项目后,idea即可正常。
Basic Package - All files required to run OCI, OCCI, and JDBC-OCI applications Download instantclient-basic-windows.x64-12.2.0.1.0.zip (75,062,441 bytes) (cksum - 1462971172) The 12.2 Basic package ...
Instant Client Package - Basic: All files required to run OCI, OCCI, and JDBC-OCI applications 。 Instant Client 程序包 — Basic(win64位): 运行 OCI、OCCI 和 JDBC-OCI 应用程序所需的所有文件。
- basic:展示了Spring Data JDBC的基本用法。 - immutables:展示了使用Immutables的Spring Data JDBC用法。 4. Spring Data JPA: - eclipselink:展示了如何在Spring Boot和Eclipselink中使用Spring Data JPA...
instantclient-basic-win64是一款完全免费轻量级数据库客户端。用户无需安装标准 Oracle客户端或拥有ORACLE_HOME就可运行应用程序,当然OCI、OCCI、Pro*C、ODBC 和 JDBC应用程序也无需进行修改即可运行,同时使用的...
Portal-Basic Java Web应用开发框架(简称 Portal-Basic)是一套功能完备的高性能Full-Stack Web应用开发框架,内置稳定高效的MVC基础架构和DAO框架(已内置Hibernate、MyBatis和JDBC支持),集成 Action拦截、Form ...
Oracle 10.2 Instant Client Package - Basic: All files required to run OCI, OCCI, and JDBC-OCI applications . 其他版本资源可从...
oracle-instantclient11.2-jdbc-11.2.0.4.0-1.x86_64.rpm oracle-instantclient11.2-odbc-11.2.0.4.0-1.x86_64.rpm oracle-instantclient11.2-sqlplus-11.2.0.4.0-1.x86_64.rpm oracle-instantclient11.2-tools-11.2...
例如有如下的Access数据库student,表basic,以及6条记录,现在通过几种方式在Jsp中将他们的数据显示出来。如图所示: 对于几种连接Access数据库的方式,基本上都是基于JDBC-ODBC方式的,当然也有纯JDBC驱动的方式...
instantclient-basic-win32是一款完全免费轻量级数据库客户端。用户无需安装标准 Oracle客户端或拥有ORACLE_HOME就可运行应用程序,当然OCI、OCCI、Pro*C、ODBC 和 JDBC应用程序也无需进行修改即可运行,同时使用的...
Java web 项目,通过JDBC简单实现用户的增、删、改、查等功能,界面比较简洁。
#MyJdbcupdate:model & connection 支持async+awaitQuick StartInstalljava模块安装步骤请参考:$ npm install myjdbc$ npm install javaBasic Usage let MyJdbc=require('myjdbc'); MyJdbc(['./drivers/jconn4.jar']...
免费,轻量的Oracle数据库工具,库和SDK,用于构建应用程序并将其连接到Oracle数据库实例。 此为集合包,版本均为11.2.0.4.0,适用于64位的Linux系统,包含zip及rpm两种格式...JDBC Supplement SQL*Plus SDK ODBC WRC