introduction to ibatis by rohit

IBatis

Get to know iBatis

Author: Rohit Prabhakar

http://rohitprabhakar.com

Get to know iBatis from Rohit @ http://rohitprabhakar.com

iBatis

Topics:• Introduction• Installation• Environment• Spring-iBatis Integration• SQL Mappings• Conclusion

iBatis:Introduction

iBATIS is a Data Persistence Framework.

iBATIS in other words is an additional layer of indirection between the classes and the tables allowing it in more flexibility in how classes and tables are mapped with out making any changes to the Data model and the Object model. The layer of indirection here is the SQL.

This enables mapping SQL queries to POJOs-Plain Old Java Objects.

This works like the same as JPA[Hibernate/Spring framework] but faster than that.

The main advantages are-

1. Reduces the amount of Java code to access a DataBase with the use of XML files containing SQL queries. 2.Faster than JPA. 3.Uses existing SQL Stored Procedures.


iBatis: Installation

iBATIS is delivered in a single JAR file: ibatis-version.build.jar and should be copied and made available at runtime via the application's class path.

This can be downloaded from iBatis homepage.


iBatis:Environment Configuration

Using Spring - iBATIS with a stand-alone application:• You should place the ibatis-x.x.x.x.jar in the application's classpath. • Define and place the following three configuration files in the classpath

1. Spring config - This file defines the database connection parameters, the location of the SQL Map config file, and one or more Spring beans for use within the application. ( applicationContext.xml).

2. SQL Map config - This file defines any iBATIS-specific configuration settings that you may need and declares the location for any SQL Map files that should be accessible through this config file. (SqlMapConfig.xml)

3. SQL Map(s) One or more SQL Map files are declared in the SQL Map config and typically mapped to a single business entity within the application ,often represented by a single Java class (domainObject.xml).

Using Spring - iBATIS with a web application• Same as the above ,but just need one more xml (web.xml).


Spring-iBatis Integration

• Add to the iBatis jar to the project classpath• Create a package “com.test.ibatis”• Create a class “Student “

package com.test.ibatis;

public class Student {

private long studentId;

private String firstName;

private String lastName;

private String address;

}• Generate Getters and Setters for all the items in the Bean



• Create a table “STUDENT” with a table-per-class relationship

CREATE TABLE STUDENT(

STUDENT_ID NUMBER (6, 0) NOT NULL,

FIRST_NAME VARCHAR(50) NOT NULL,

LAST_NAME VARCHAR(50) ,

ADDRESS VARCHAR(200) NOT NULL,

PRIMARY KEY (STUDENT_ID)

)


Spring-iBatis Integration: applicationContext.xml

Add the following<bean id="dataSource"

class="org.apache.commons.dbcp.BasicDataSource"

destroy-method="close">

<property name="driverClassName"

value="oracle.jdbc.driver.OracleDriver" />

<property name="url"

value="jdbc:oracle:thin:@127.0.0.1:1521:orcl" />

<property name="username" value="scott" />

<property name="password" value="tiger" />

</bean>

<bean id="sqlMap"

class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">

<property name="configLocation">

<value>classpath:SqlMapConfig.xml</value>

</property>

<property name="dataSource" ref="dataSource" />

</bean>

<bean id="studentService"

class="com.test.ibatis.StudentServiceImpl">

<property name="sqlMapClient" ref="sqlMap" />

</bean>



SqlMapConfig.xml

As for the configLocation property, it should be configured with the path to an XML file that enumerates the locations of the iBATIS SQL maps.

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE sqlMapConfig PUBLIC "-//iBATIS.com//DTD SQL MAP Config 2.0//EN"

"http://www.ibatis.com/dtd/sql-map-config-2.dtd">

<sqlMapConfig>

<settings useStatementNamespaces="true" />

<sqlMap resource="StudentSQLMap.xml" />

</sqlMapConfig>


Spring-iBatis IntegrationStudentSQLMap.xml<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE sqlMap PUBLIC "-//iBATIS.com//DTD SQL MAP 2.0//EN"

"http://www.ibatis.com/dtd/sql-map-2.dtd">

<sqlMap namespace="student">

<typeAlias alias="student" type="com.test.ibatis.Student"/>

<resultMap id="studentResult" class="Student">

<result property="studentId" column="STUDENT_ID"/>

<result property="firstName" column="FIRST_NAME"/>

<result property="lastName" column="LAST_NAME"/>

<result property="address" column="ADDRESS"/>

</resultMap>

<select id="getTrade" parameterClass="long" resultMap="studentResult">

SELECT

STUDENT_ID,

FIRST_NAME,

FIRST_NAME,

ADDRESS

FROM

STUDENT

WHERE

STUDENT_ID = #id#

</select>

</sqlMap>



Create an Interface StudentService


public interface StudentService {

public Student getStudent(long studentId) throws Exception;

}



Create an Implementation Classpackage com.test.ibatis;

import com.ibatis.sqlmap.client.SqlMapClient;

public class StudentServiceImpl implements StudentService {

protected SqlMapClient sqlMapclient=null;

public void setSqlMapclient(SqlMapClient sqlMapclient) {this.sqlMapclient = sqlMapclient;

}

public Student getStudent(long studentId) throws Exception {

return (Student) sqlMapclient.queryForObject("student.getStudent", studentId);

}

}


Spring-iBatis Integration: Student Client


import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

public class StudentClient {

public static void Main(String[] args)

{// load spring beans

ApplicationContext ctx= new ClassPathXmlApplicationContext("applicationContext.xml");

StudentService studentService= (StudentService) ctx.getBean("studentService");

//get Object Student

int studentId=1;

try {

System.out.println("**********************************");

System.out.println(studentService.getStudent(studentId));

System.out.println("**********************************");

} catch (Exception e) {e.printStackTrace();}

}

}


Spring-iBatis Integration: Execute

Run the Client and check what it prints?


iBatis: Tools

Ibator

Ibator is a code generator and Eclipse plugin. It can be used to get a head start on your project by generating your Beans, Mappings and SQL from an existing database schema.


introduction to ibatis by rohit

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