Google App EngineのStruts 2。 レシピの設定

人気のあるクラウドプラットフォームであるGoogle AppEngineで Java用の最も便利なWebフレームワークの1つを使用するには、いくつかのアクションを実行する必要があります。 この記事は私の長い実験の結果として登場しました。 コメントでGAEプラットフォーム上のお気に入りのフレームワークと経験を共有していただければ幸いです:-)

使用するライブラリ

通常、次のライブラリセットを使用します。

• commons-fileupload-1.2.1.jar
• commons-io-1.3.2.jar
• commons-logging-1.0.4.jar
• commons-logging-api-1.1.jar
• freemarker-2.3.13.jar
• ognl-2.6.11.jar
• struts2-core-2.1.6.jar
• xwork-2.1.2.jar

IntelliJ Idea 9を使用し、プロジェクトの作成時にStruts 2の使用を指定した後、依存関係を自動的に交換します。 また、特別なIDEメニューを介してクラウドプラットフォームにアプリケーションをデプロイすることもでき、一般にAppEngineサポートは非​​常に良いレベルです。



次に、Appengineはスレッド、ファイル、その他多くのリソースへの直接アクセスを禁止しているため、クラウドプラットフォームの制限を回避するか、それに適応する必要があります。

Ognl SecurityManagerを構成する

アプリケーションの起動時にOgnl SecurityManagerを設定するリスナーを作成する必要があります。

1. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
   
   
   
   
3. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
   
   
   
   
5. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
   
   
   
   
6. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
   
   
   
   
8. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
   
   
   
   
9. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
   
   
   
   
10. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
    
    
    
    
11. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
    
    
    
    
13. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
    
    
    
    
14. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
    
    
    
    
15. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
    
    
    
    
16. package su.mvc.util; import ognl.OgnlRuntime; import javax.servlet.ServletContextEvent; import javax.servlet.ServletContextListener; public class GaeContextListener implements ServletContextListener { public void contextInitialized(ServletContextEvent servletContextEvent) { OgnlRuntime.setSecurityManager( null ); } public void contextDestroyed(ServletContextEvent servletContextEvent) { // } }
    
    
    
    

そして、web.xmlアプリケーションのデプロイメント記述子で接続します：

1. <？ xml version = "1.0" encoding = "UTF-8" ？ >
2. < web-app xmlns = "http://java.sun.com/xml/ns/javaee"
3. xmlns：xsi = "http://www.w3.org/2001/XMLSchema-instance"
4. xsi：schemaLocation = "http://java.sun.com/xml/ns/javaee java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
5. バージョン = "2.5" >
7. <！-リスナー->
8. < リスナー >
9. < リスナークラス > su.mvc.util.GaeContextListener </ リスナークラス >
10. </ リスナー >
11. <！-...->
13. </ web-app >

テストとキータイプの変換

次のタイプはAppengineで広く使用されています。

• 大きなテキストデータを管理するためのcom.google.appengine.api.datastore.Text
• com.google.appengine.api.datastore.Keyは 、エンティティのIDとして使用されます。 残念ながら、AppEngineでは、 IDとしてキーを使用する場合にのみ、エンティティの関係を正しく操作できます。

Webフォームでこれらのタイプを使用するには、これらのタイプの文字列への直接および逆変換を定義する必要があります。

1. パッケージsu.mvc.util.converters;
3. import com.google.appengine.api.datastore.Text;
4. import ognl.DefaultTypeConverter;
6. import java.util.Map;
8. パブリック クラス TextConverterはDefaultTypeConverterを拡張します{
9. @Override
10. public Object convertValue（マップマップ、オブジェクトo、クラスtoType）{
11. if （toType == Text。class）{
12. 文字列 値 =（（ 文字列 []）o）[0];
13. 新しいテキスト（ 値 ）を返します。
14. } else if （toType == String。class）{
15. テキストtext =（テキスト）o;
16. return text.getValue（）;
17. }
19. nullを 返し ます 。
20. }
21. }

1. パッケージsu.mvc.util.converters;
3. import com.google.appengine.api.datastore.Key;
4. import com.google.appengine.api.datastore.KeyFactory;
5. import ognl.DefaultTypeConverter;
7. import java.util.Map;
9. パブリック クラス KeyConverterはDefaultTypeConverterを拡張します{
10. @Override
11. public Object convertValue（マップマップ、オブジェクトo、クラスtoType）{
12. if （toType == Key。class）{
13. 文字列 s =（（ 文字列 []）o）[0];
14. Return KeyFactory.stringToKey（s）;
15. } else if （toType == String。class）{
16. キーk =（キー）o;
17. return KeyFactory.keyToString（k）;
18. }
20. nullを 返し ます 。
21. }
22. }

xwork-conversion.propertiesファイルで作成されたコンバーターを宣言することは残ります。

1. com.google.appengine.api.datastore.Text = su.mvc.util.converters.TextConverter
2. com.google.appengine.api.datastore.Key = su.mvc.util.converters.KeyConverter

コンベンションプラグインの使用

私の愛するコンベンションプラグインは、Convention-Over-Configurationの概念を実装するために使用され、アプリケーションを構成する時間を大幅に短縮します。 残念ながら、Struts 2を使用する場合、このプラグインを忘れる必要があります。

TextBlockのパッチFreemarker

Freemarkerを使用してUIを実装しない場合でも、Straem JSP Freemarkerタグを使用する場合は、パッチを適用する必要があります。 これを行うには、アプリケーションで次のコンテンツを使用してfreemarker.core.TextBlockクラスを作成します。

//

//Workaround for groups.google.com/group/google-appengine-java/browse_thread/thread/186c3fc515e6f6ae

//



/*

* Copyright (c) 2003 The Visigoth Software Society. All rights

* reserved.

*

* Redistribution and use in source and binary forms, with or without

* modification, are permitted provided that the following conditions

* are met:

*

* 1. Redistributions of source code must retain the above copyright

* notice, this list of conditions and the following disclaimer.

*

* 2. Redistributions in binary form must reproduce the above

copyright

* notice, this list of conditions and the following disclaimer in

* the documentation and/or other materials provided with the

* distribution.

*

* 3. The end-user documentation included with the redistribution, if

* any, must include the following acknowledgement:

* "This product includes software developed by the

* Visigoth Software Society (http://www.visigoths.org/)."

* Alternately, this acknowledgement may appear in the software

itself,

* if and wherever such third-party acknowledgements normally

appear.

*

* 4. Neither the name "FreeMarker", "Visigoth", nor any of the names

of the

* project contributors may be used to endorse or promote products

derived

* from this software without prior written permission. For written

* permission, please contact visigo...@visigoths.org.

*

* 5. Products derived from this software may not be called

"FreeMarker" or "Visigoth"

* nor may "FreeMarker" or "Visigoth" appear in their names

* without prior written permission of the Visigoth Software

Society.

*

* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED

* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

* DISCLAIMED. IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR

* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF

* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,

* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT

* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

* SUCH DAMAGE.

*

====================================================================

*

* This software consists of voluntary contributions made by many

* individuals on behalf of the Visigoth Software Society. For more

* information on the Visigoth Software Society, please see

* www.visigoths.org

*/



package freemarker.core;



import java.io.IOException;



/**

* A TemplateElement representing a block of plain text.

* @version $Id: TextBlock.java,v 1.17 2004/01/06 17:06:42 szegedia

Exp $

*/

public final class TextBlock extends TemplateElement {

private static final char [] EMPTY_CHAR_ARRAY = new char [0];

static final TextBlock EMPTY_BLOCK = new TextBlock

(EMPTY_CHAR_ARRAY, false );

// We're using char[] instead of String for storing the text block because

// Writer.write(String) involves copying the String contents to a char[]

// using String.getChars(), and then calling Writer.write(char[]). By

// using Writer.write(char[]) directly, we avoid array copying on each

// write.

private char [] text;

private final boolean unparsed;



public TextBlock( String text) {

this (text, false );

}



public TextBlock( String text, boolean unparsed) {

this (text.toCharArray(), unparsed);

}



private TextBlock( char [] text, boolean unparsed) {

this .text = text;

this .unparsed = unparsed;

}



/**

* Simply outputs the text.

*/

public void accept(Environment env)

throws IOException

{

env.getOut().write(text);

}



public String getCanonicalForm() {

String text = new String ( this .text);

if (unparsed) {

return "<#noparse>" + text + "</#noparse>" ;

}

return text;

}



public String getDescription() {

String s = new String (text).trim();

if (s.length() == 0) {

return "whitespace" ;

}

if (s.length() > 20) {

s = s.substring(0,20) + "..." ;

s = s.replace( '\n' , ' ' );

s = s.replace( '\r' , ' ' );

}

return "text block (" + s + ")" ;

}



TemplateElement postParseCleanup(boolean stripWhitespace) {

if (text.length == 0) return this ;

int openingCharsToStrip = 0, trailingCharsToStrip=0;

boolean deliberateLeftTrim = deliberateLeftTrim();

boolean deliberateRightTrim = deliberateRightTrim();

if (!stripWhitespace || text.length == 0 ) {

return this ;

}

if (parent.parent == null && previousSibling() == null ) return

this ;

if (!deliberateLeftTrim) {

trailingCharsToStrip = trailingCharsToStrip();

}

if (!deliberateRightTrim) {

openingCharsToStrip = openingCharsToStrip();

}

if (openingCharsToStrip == 0 && trailingCharsToStrip == 0) {

return this ;

}

this .text = substring(text, openingCharsToStrip, text.length - trailingCharsToStrip);

if (openingCharsToStrip > 0) {

this .beginLine++;

this .beginColumn = 1;

}

if (trailingCharsToStrip >0) {

this .endColumn = 0;

}

return this ;

}



/**

* Scans forward the nodes on the same line to see whether there

is a

* deliberate left trim in effect. Returns true if the left trim

was present.

*/

private boolean deliberateLeftTrim() {

boolean result = false ;

for (TemplateElement elem = this .nextTerminalNode();

elem != null && elem.beginLine == this .endLine;

elem = elem.nextTerminalNode())

{

if (elem instanceof TrimInstruction) {

TrimInstruction ti = (TrimInstruction) elem;

if (!ti.left && !ti.right) {

result = true ;

}

if (ti.left) {

result = true ;

int lastNewLineIndex = lastNewLineIndex();

if (lastNewLineIndex >=0 || beginColumn == 1) {

char [] firstPart = substring(text, 0, lastNewLineIndex + 1);

char [] lastLine = substring(text, 1+lastNewLineIndex);

if (trim(lastLine).length == 0) {

this .text = firstPart;

this .endColumn = 0;

} else {

int i =0;

while (Character.isWhitespace(lastLine [i])) {

i++;

}

char [] printablePart = substring(lastLine, i);

this .text = concat(firstPart, printablePart);

}

}

}

}

}

if (result) {

}

return result;

}



/**

* Checks for the presence of at or rt directive on the

* same line. Returns true if the right trim directive was

present.

*/

private boolean deliberateRightTrim() {

boolean result = false ;

for (TemplateElement elem = this .prevTerminalNode();

elem != null && elem.endLine == this .beginLine;

elem = elem.prevTerminalNode())

{

if (elem instanceof TrimInstruction) {

TrimInstruction ti = (TrimInstruction) elem;

if (!ti.left && !ti.right) {

result = true ;

}

if (ti.right) {

result = true ;

int firstLineIndex = firstNewLineIndex() +1;

if (firstLineIndex == 0) {

return false ;

}

if (text.length > firstLineIndex

&& text[firstLineIndex-1] == '\r'

&& text[firstLineIndex] == '\n' )

{

firstLineIndex++;

}

char [] trailingPart = substring(text, firstLineIndex);

char [] openingPart = substring(text, 0, firstLineIndex);

if (trim(openingPart).length ==0) {

this .text = trailingPart;

this .beginLine++;

this .beginColumn=1;

} else {

int lastNonWS = openingPart.length -1;

while (Character.isWhitespace(text[lastNonWS])) {

lastNonWS--;

}

char [] printablePart = substring(text, 0,lastNonWS+1);

if (trim(trailingPart).length == 0) {

// THIS BLOCK IS HEINOUS! THERE MUST BE A BETTER WAY! REVISIT (JR)

boolean trimTrailingPart = true ;

for (TemplateElement te = this .nextTerminalNode();

te != null && te.beginLine == this .endLine;

te = te.nextTerminalNode())

{

if (te.heedsOpeningWhitespace())

{

trimTrailingPart = false ;

}

if (te instanceof TrimInstruction && ((TrimInstruction) te).left) {

trimTrailingPart = true ;

break ;

}

}

if (trimTrailingPart) trailingPart = EMPTY_CHAR_ARRAY;

}

this .text = concat(printablePart, trailingPart);

}

}

}

}

return result;

}

/*

private String leftTrim(String s) {

int i =0;

while (i<s.length()) {

if (!Character.isWhitespace(s.charAt(i)))

break;

++i;

}

return s.substring(i);

}

*/

private int firstNewLineIndex() {

String content = new String (text);

int newlineIndex1 = content.indexOf( '\n' );

int newlineIndex2 = content.indexOf( '\r' );

int result = newlineIndex1 >=0 ? newlineIndex1 : newlineIndex2;

if (newlineIndex1 >=0 && newlineIndex2 >=0) {

result = Math .min(newlineIndex1, newlineIndex2);

}

return result;

}



private int lastNewLineIndex() {

String content = new String (text);

return Math .max(content.lastIndexOf( '\r' ), content.lastIndexOf

( '\n' ));

}



/**

* figures out how many opening whitespace characters to strip

* in the post-parse cleanup phase.

*/

private int openingCharsToStrip() {

int newlineIndex = firstNewLineIndex();

if (newlineIndex == -1 && beginColumn != 1) {

return 0;

}

++newlineIndex;

if (text.length > newlineIndex) {

if (newlineIndex >0 && text[newlineIndex-1] == '\r' && text[newlineIndex] == '\n' ) {

++newlineIndex;

}

}

if ( new String (text).substring(0, newlineIndex).trim().length() >0) {

return 0;

}

// We look at the preceding elements on the line to see if we should

// strip the opening newline and any whitespace preceding it.

for (TemplateElement elem = this .prevTerminalNode();

elem != null && elem.endLine == this .beginLine;

elem = elem.prevTerminalNode())

{

if (elem.heedsOpeningWhitespace())

{

return 0;

}

}

return newlineIndex;

}



/**

* figures out how many trailing whitespace characters to strip

* in the post-parse cleanup phase.

*/

private int trailingCharsToStrip() {

String content = new String (text);

int lastNewlineIndex = lastNewLineIndex();

if (lastNewlineIndex == -1 && beginColumn != 1) {

return 0;

}

String substring = content.substring(lastNewlineIndex +1);

if (substring.trim().length() >0) {

return 0;

}

// We look at the elements afterward on the same line to see if weshould

// strip any whitespace after the last newline

for (TemplateElement elem = this .nextTerminalNode();

elem != null && elem.beginLine == this .endLine;

elem = elem.nextTerminalNode())

{

if (elem.heedsTrailingWhitespace())

{

return 0;

}

}

return substring.length();

}



boolean heedsTrailingWhitespace() {

if (isIgnorable()) {

return false ;

}

for ( int i=0; i<text.length; i++) {

char c = text[i];

if (c== '\n' || c== '\r' ) {

return false ;

}

if (!Character.isWhitespace(c)) {

return true ;

}

}

return true ;

}



boolean heedsOpeningWhitespace() {

if (isIgnorable()) {

return false ;

}

for ( int i = text.length -1; i>=0; i--) {

char c = text[i];

if (c == '\n' || c == '\r' ) {

return false ;

}

if (!Character.isWhitespace(c)) {

return true ;

}

}

return true ;

}



boolean isIgnorable() {

if (text == null || text.length == 0) {

return true ;

}

if (!isWhitespace()) {

return false ;

}

// trick here

boolean atTopLevel = true ;

TemplateElement prevSibling = previousSibling();

TemplateElement nextSibling = nextSibling();

return ((prevSibling == null && atTopLevel) || nonOutputtingType(prevSibling))

&& ((nextSibling == null && atTopLevel) || nonOutputtingType(nextSibling));

}



private boolean nonOutputtingType(TemplateElement element) {

return (element instanceof Macro ||

element instanceof Assignment ||

element instanceof AssignmentInstruction ||

element instanceof PropertySetting ||

element instanceof LibraryLoad ||

element instanceof Comment);

}



private static char [] substring( char [] c, int from , int to) {

char [] c2 = new char [to - from ];

System.arraycopy(c, from , c2, 0, c2.length);

return c2;

}



private static char [] substring( char [] c, int from ) {

return substring(c, from , c.length);

}



private static char [] trim( char [] c) {

if (c.length == 0) {

return c;

}

return new String (c).trim().toCharArray();

}



private static char [] concat( char [] c1, char [] c2) {

char [] c = new char [c1.length + c2.length];

System.arraycopy(c1, 0, c, 0, c1.length);

System.arraycopy(c2, 0, c, c1.length, c2.length);

return c;

}



boolean isWhitespace() {

return text == null || trim(text).length == 0;

}



}