Programming

[Java] How to Convert XMLGregorianCalendar to java.util.Date and The Other Way Around

This is a simple code snippet on how to convert XMLGregorianCalendar into java.util.Date and java.util.Date into javax.xml.datatype.XMLGregorianCalendar. Usually i found XMLGregorianCalendar everytime im trying to convert java bean into webservice using wsdl2java.

But there are some time when i need to convert those XMLGregorianCalendar objects and change them into java.util.Date so i could do a much more various process on them. So this is how i convert XMLGregorianCalendar into java.util.Date,

            
            XMLGregorianCalendar calendar = responseMessage.getDate();
            java.util.Date date = calendar.toGregorianCalendar().getTime();

and this is how i convert java.util.Date into XMLGregorianCalendar

            GregorianCalendar gregorianCalendar = new GregorianCalendar();
            gregorianCalendar.setTime(new Date());
            responseMessage.setDate(new XMLGregorianCalendarImpl(gregorianCalendar));

For example, im using XMLGregorianCalendar value “2012-10-15T00:00:00”. Hope it would help others (H)

How To Change Apache Tomcat’s Server Name

On this tutorial, i’ll show you how to change Apache Tomcat’s server name. This is the screenshot from a regular Apache Tomcat,

And with a simple configuration on server.xml,

 <Connector port="8080" protocol="HTTP/1.1"
         connectionTimeout="20000"
	 server="Why So Serious"
         redirectPort="8443" />

It will change my Tomcat’s server name into,

Not hard actually 😉

A Simple Caching Example on MyBatis using EhCache

Today i will show a simple example on how to combine ehcache caching framework with MyBatis ORM. I use Maven as my build tool, and Netbeans as my IDE.

Okay, here is my pom.xml,

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.edw.ehcache</groupId>
    <artifactId>MyBatisEhCache</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>MyBatisEhCache</name>
    <url>http://maven.apache.org</url>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.2.2</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.caches</groupId>
            <artifactId>mybatis-ehcache</artifactId>
            <version>1.0.2</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>      
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
            <version>2.7.0</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.5</version>
        </dependency>     
    </dependencies>
</project>

And i create a simple mysql table,

CREATE TABLE `testing` (
  `Id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(30) NOT NULL DEFAULT '',
  `address` varchar(255) NOT NULL DEFAULT '',
  PRIMARY KEY (`Id`),
  UNIQUE KEY `ix` (`name`)
) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=latin1;

and a simple bean and xml representation from my table,

package com.edw.mybatisehcache.bean;

import java.io.Serializable;

public class Testing implements Serializable  {

    private Integer id;
    private String name;
    private String address;

    // setter and getter

    @Override
    public String toString() {
        return "testing{" + "id=" + id + ", name=" + name + ", address=" + address + '}';
    }            
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.edw.mybatisehcache.mapper.TestingMapper" >
  
     <cache type="org.mybatis.caches.ehcache.EhcacheCache"/>
    
    <resultMap id="Testings" type="com.edw.mybatisehcache.bean.Testing" >
        <id column="id" property="id" jdbcType="BIGINT" />
        <result column="name" property="name" jdbcType="VARCHAR" />
        <result column="address" property="address" jdbcType="VARCHAR" />
    </resultMap>  

    <select id="select" resultMap="Testings">
        select 
        *
        from testing    
    </select>   
</mapper>

An xml configuration to load my database connection,

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <environments default="development">
       <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="UNPOOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost/test"/>
                <property name="username" value="root"/>
                <property name="password" value=""/>
            </dataSource>
        </environment>          
    </environments>
     <mappers>        		
        <mapper resource="com/edw/mybatisehcache/xml/TestingMapper.xml" />  
    </mappers>              		
</configuration>

A java code to load my xml configuration,

package com.edw.mybatisehcache.config;

import java.io.Reader;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisSqlSessionFactory {

    private static final SqlSessionFactory FACTORY;

    static {
        try {
            Reader reader = Resources.getResourceAsReader("com/edw/mybatisehcache/xml/Configuration.xml");
            FACTORY = new SqlSessionFactoryBuilder().build(reader);
        } catch (Exception e){
            throw new RuntimeException("Fatal Error.  Cause: " + e, e);
        }
    }

    public static SqlSessionFactory getSqlSessionFactory() {
        return FACTORY;
    }
}

A java interface to do handle queries,

package com.edw.mybatisehcache.mapper;

import com.edw.mybatisehcache.bean.Testing;
import java.util.List;

public interface TestingMapper {
    public List<Testing> select();    
}

And this is my ehcache.xml configuration,

<?xml version="1.0" encoding="UTF-8"?>
<!--
    caching configuration
-->
<ehcache>
    
    <diskStore path="F:\\cache" />
    
    <defaultCache eternal="true" maxElementsInMemory="1000"
                   overflowToDisk="true" diskPersistent="true" timeToIdleSeconds="0"
                   timeToLiveSeconds="0" memoryStoreEvictionPolicy="LRU" statistics="true" />
</ehcache>

This is my main java class, as you can see i try to do a repeated simple select queries,

package com.edw.mybatisehcache.main;

import com.edw.mybatisehcache.bean.Testing;
import com.edw.mybatisehcache.config.MyBatisSqlSessionFactory;
import com.edw.mybatisehcache.mapper.TestingMapper;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.log4j.Logger;

public class Main {

    private static Logger logger = Logger.getLogger(Main.class);

    public static void main(String[] args) {

        for (int i = 0; i < 3; i++) {
            SqlSessionFactory sqlSessionFactory = MyBatisSqlSessionFactory.getSqlSessionFactory();
            SqlSession sqlSession = sqlSessionFactory.openSession();
            TestingMapper testingMapper = sqlSession.getMapper(TestingMapper.class);

            List<Testing> testings = testingMapper.select();
            for (Testing testing : testings) {
                logger.debug(testing);
            }
            sqlSession.close();

            try {
                Thread.sleep(3000);
            } catch (Exception e) {
                logger.error(e, e);
            }
        }
    }
}

This is what is written on my netbeans’ console,

2013-07-25 15:30:10,648 [Segment] DEBUG net.sf.ehcache.store.disk.Segment:779 - fault removed 0 from heap
2013-07-25 15:30:10,648 [Segment] DEBUG net.sf.ehcache.store.disk.Segment:796 - fault added 0 on disk
2013-07-25 15:30:13,722 [Cache] DEBUG net.sf.ehcache.Cache:1970 - Cache: com.edw.mybatisehcache.mapper.TestingMapper store hit for 2026218237:1652924294:com.edw.mybatisehcache.mapper.TestingMapper.select:0:2147483647:select 
        *
        from testing
2013-07-25 15:30:13,722 [Main] DEBUG com.edw.mybatisehcache.main.Main:24 - testing{id=1, name=edw, address=Ciledug}
2013-07-25 15:30:13,722 [Main] DEBUG com.edw.mybatisehcache.main.Main:24 - testing{id=2, name=kamplenk, address=Cikokol}
2013-07-25 15:30:13,722 [Main] DEBUG com.edw.mybatisehcache.main.Main:24 - testing{id=3, name=nugie, address=Pamulang}
2013-07-25 15:30:13,722 [Main] DEBUG com.edw.mybatisehcache.main.Main:24 - testing{id=4, name=tebek, address=Karawaci}

Here is my Netbeans project structure

Have fun (K)

Set Isolation Level on MyBatis

On this example, im trying to set mybatis default isolation level, but before i go further let me explain a little why we need to setup an isolation level.

In a typical application, multiple transactions run concurrently, often working with the same data to get their job done. Concurrency, while necessary, can lead to the following problems:

Dirty read—Dirty reads occur when one transaction reads data that has been written but not yet committed by another transaction. If the changes are later rolled back, the data obtained by the first transaction will be invalid.

Nonrepeatable read—Nonrepeatable reads happen when a transaction performs the same query two or more times and each time the data is different. This is usually due to another concurrent transaction updating the data between the queries.

Phantom reads—Phantom reads are similar to nonrepeatable reads. These occur when a transaction (T1) reads several rows, and then a concurrent transaction (T2) inserts rows. Upon subsequent queries, the first transaction (T1) finds additional rows that were not there before.

That’s why on some mission critical application, i always set Isolation Level on Serializable. Why i use Serializable because this fully ACID-compliant isolation level ensures that dirty reads, nonrepeatable reads, and phantom reads are all prevented. This is the slowest of all isolation levels because it is typically accomplished by doing full table locks on the tables involved in the transaction.

Okay, here is how to achieve Serializable Isolation Level using MyBatis,

import com.edw.mybatis.bean.Testing;
import com.edw.mybatis.config.MyBatisSqlSessionFactory;
import com.edw.mybatis.mapper.TestingMapper;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.TransactionIsolationLevel;
import org.apache.log4j.Logger;

public class Main {

    private static Logger logger = Logger.getLogger(Main.class);

    public static void main(String[] args) {

        SqlSessionFactory sqlSessionFactory = MyBatisSqlSessionFactory.getSqlSessionFactory();
        SqlSession sqlSession = sqlSessionFactory.openSession(TransactionIsolationLevel.SERIALIZABLE);
        TestingMapper testingMapper = sqlSession.getMapper(TestingMapper.class);

        try {
            Testing testing = new Testing();
            testing.setName("name 1");
            testing.setAddress("address 1");

            int success = testingMapper.insert(testing);
            logger.debug(success);
            
            sqlSession.commit();
        } catch (Exception e) {
            logger.error(e, e);
            sqlSession.rollback();
        } finally {
            sqlSession.close();
        }
    }
}

Hope this piece of code could help others, have fun with other TransactionIsolationLevel parameters, such as READ_COMMITTED or REPEATABLE_READ. 😉

A java.lang.IllegalArgumentException when Using SpringMVC @PathVariable

Another exception happened to me today while im deploying my application to Tomcat 7, somehow the error (again) never happen on my IDE. The error is related to Spring MVC’s @PathVariable. Below is the complete stacktrace for the error.

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalArgumentException: Name for argument type [java.lang.String] not available, and parameter name information not found in class file either.
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:894)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
	com.opensymphony.module.sitemesh.filter.PageFilter.parsePage(PageFilter.java:119)
	com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:55)
	org.springframework.security.web.FilterChainProxy$VirtualFilterChain .doFilter(FilterChainProxy.java:330)
	org.springframework.security.web.access.intercept.FilterSecurityInterceptor .invoke(FilterSecurityInterceptor.java:118)
	org.springframework.security.web.access.intercept.FilterSecurityInterceptor .doFilter(FilterSecurityInterceptor.java:84)

And this is the suspected method which raise exception,

    @RequestMapping(value ="/baculsoft/news/view/{id}", method = RequestMethod.GET)
    public String newsView(ModelMap modelMap, 
                        @PathVariable String id) {
        modelMap.put("news", newsService.get(id);
        return "news/view";
    }

The workaround is actually simple, below is how to deal with it,

    @RequestMapping(value ="/baculsoft/news/view/{id}", method = RequestMethod.GET)
    public String newsView(ModelMap modelMap, 
                        @PathVariable("id") String id) {
        modelMap.put("news", newsService.get(id);
        return "news/view";
    }

Actually very simple workaround, but since i have hundreds of methods using @PathVariable, it’s not so simple anymore. And the weird thing is, the .war exported from Eclipse IDE run perfectly, only .war created from Netbeans that raise exception. I dont know why, but somehow Netbeans’ ant create a different war compared to Eclipse’s war file.

After sometimes googling, i found out that it happens due to javac’s debug parameter on Netbeans’ ant, changing “debug” default value into “on” on Netbeans’ build-impl.xml makes my war file run perfectly on Tomcat 7. Well i hope it hepled others, cheers (B)