albert's blog

2011/04/07

Utilize Recursive Java Decompiler to Decompile Jar File

1. Download JD-GUI from http://java.decompiler.free.fr/?q=jdgui

2. Unzip jd-gui-0.3.3.windows.zip and execute jd-gui.exe

3. assign jar file which you want to do decompile

4. File --> Save All Sources

5. Download Doxygen from http://www.stack.nl/~dimitri/doxygen/download.html#latestsrc

6. Install Doxygen

7. Assign project name, source code directory, destination directory. And check "Scan

recursively"

8. Change to "Mode", and do some configuration

9. Change to "Output", and do some configuration

10. Change to "Diagram", and do some configuration

11. Click "Run" tab, and click "Run doxygen"

12. Check result

2011/04/01

Extract Method Refactoring Example

Extract Method is a refactoring operation that provides an easy way to create a new method from a code fragment in an existing member.

Using Extract Method, you can create a new method by extracting a selection of code from inside the code block of an existing member. The new, extracted method contains the selected code, and the selected code in the existing member is replaced with a call to the new method. Turning a fragment of code into its own method lets you quickly and accurately reorganize code for better reuse and readability.

Extract Method has the following benefits:

1. Encourages best coding practices by emphasizing discrete, reusable methods.

2. Encourages self-documenting code through good organization.

3. When descriptive names are used, high-level methods can read more like a series of comments.

4. Encourages the creation of finer-grained methods to simplify overriding.

5. Reduces code duplication.

實例說明
我們在Controller中，會撰寫新增、修改、刪除等method，其中在新增與修改的部份，會將前端form bean的value轉成entity class，然後再呼叫insert or update method，其code snippets如下：

Extract Method Refactoring三部曲

1. 選取要進行refactor的部分

2. 按右鍵-->Refactor-->Extract Method

3. 給予新的method name --> OK

檢查Refactor後的結果

Eclipse將原本set的動作抽離成一個獨立的method

insert與update的method中，原本重複的動作只要用covertBeanToEntity此method取代即可，避免code duplication

2011/03/25

Implementing a simple toString() with Apache Commons

我們在Web開發的時候，JSP頁面參數是透過form bean傳遞，有時候需要印出form bean裡頭的value來debug，大家可以在form bean中，override toString()，如以下寫法

public String toString() {

return ToStringBuilder.reflectionToString(this);

}

實作如下

public static void main(String[] args) {

// set value to value object

Nigw002PK vo = new Nigw002PK();

vo.setCarryDate("1");

vo.setCarrySeqNo("2");

vo.setCaseStus("3");

vo.setMtgTp("4");

// print value object by toString()

System.out.println(vo.toString());

}

印出結果入下：gov.fdc.nig.domain.Nigw002PK@63396339[mtgTp=4,caseStus=3,taxCd=,carryDate=1,carrySeqNo=2,vioNo=>]

Reference: http://blogs.bytecode.com.au/glen/2007/10/05/implementing-a-simple-tostring---with-apache-commons.html

2011/03/24

Apply MyEclipse to do entity class generation

Check out this SlideShare Presentation:

Apply MyEclipse to do entity class generation

View more presentations from Guo Albert.

NIG Project setup quickly tutorial

Nig project setup quickly tutorial from Guo Albert

2011/03/16

WTRN0037W: The transaction service encountered an error on an xa_recover operation

As I start up WAS(WebSphere Application Server) V7, it show error messages as bellows:

[2011/3/16 17:30:48:784 CST] 0000000b XARminst E WTRN0037W: The transaction service encountered an error on an xa_recover operation. The resource was com.ibm.ws.rsadapter.spi.WSRdbXaResourceImpl@702d702d. The error code was XAER_RMERR. The exception stack trace follows: javax.transaction.xa.XAException

at oracle.jdbc.xa.OracleXAResource.recover(OracleXAResource.java:709)

at com.ibm.ws.rsadapter.spi.WSRdbXaResourceImpl.recover(WSRdbXaResourceImpl.java:1044)

at com.ibm.ws.Transaction.JTA.XARminst.recover(XARminst.java:140)

at com.ibm.ws.Transaction.JTA.XARecoveryData.recover(XARecoveryData.java:571)

at com.ibm.tx.jta.PartnerLogTable.recover(PartnerLogTable.java:389)

at com.ibm.tx.jta.RecoveryManager.resync(RecoveryManager.java:1523)

at com.ibm.ws.tx.jta.RecoveryManager.performResync(RecoveryManager.java:126)

at com.ibm.tx.jta.RecoveryManager.run(RecoveryManager.java:2200)

at java.lang.Thread.run(Thread.java:735)

Solution

1. Shut down WAS(WebSphere Application Server) V7

2. Change directory to transaction logs foldler: [WebSphere Application Server_install_root]\profiles\[PROFILE_NAME]\tranlog\[CELL_NAME]\[NODE_NAME]\[SERVER_NAME]\transaction