½{”：Collection FrameWork如下åQ?br /> Collection
├List
│├LinkedList
│├ArrayList
│└Vector
�/span>　└Stack
â””Set
Map
├Hashtable
├HashMap
â””WeakHashMap
2.抽象¾cÖM¸ŽæŽ¥å£åQ?/span>
½{”：抽象¾cÖM¸ŽæŽ¥å£éƒ½ç”¨äºŽæŠ½è±¡ï¼Œä½†æ˜¯æŠ½è±¡¾c?/span>(JAVAä¸?/span>)å¯ä»¥æœ‰è‡ªå·Þqš„部分实现åQŒè€ŒæŽ¥å£åˆ™å®Œå…¨æ˜¯ä¸€ä¸ªæ ‡è¯?/span>(åŒæ—¶æœ‰å¤šé‡ç‘ô承的功能)ã€?br />
3.
STRING�/span>STRINGBUFFER的区别�/span>
½{”：STRING的长度是ä¸å¯å˜çš„åQ?/span>STRINGBUFFER的长度是å¯å˜çš„ã€‚å¦‚æžœä½ å¯¹å—½W¦ä¸²ä¸çš„内容¾l常˜q›è¡Œæ“作åQŒç‰¹åˆ«æ˜¯å†…容è¦ä¿®æ”ÒŽ—¶åQŒé‚£ä¹ˆä‹Éç”?/span>StringBufferåQŒå¦‚果最åŽéœ€è¦?/span>StringåQŒé‚£ä¹ˆä‹Éç”?/span>StringBufferçš?/span>toString()æ–ÒŽ³•
]]>
package com.test;public class OuterClass
{
static int a ; int b ; private class InnerClass
{
public InnerClass() { System.out.println("InnerClass create:" + a);
} } public OuterClass() { InnerClass ic = new InnerClass(); System.out.println("OuterClass create"); } public static void main(String[] args) { OuterClass oc = new OuterClass(); }
}一.é™æ€å†…部类å¯ä»¥æœ‰é™æ€æˆå‘˜ï¼Œè€Œéžé™æ€å†…部类则ä¸èƒ½æœ‰é™æ€æˆå‘˜ã€?
äº?é™æ€å†…部类的éžé™æ€æˆå‘˜å¯ä»¥è®¿é—®å¤–部类的é™æ€å˜é‡ï¼Œè€Œä¸å¯è®¿é—®å¤–部类的éžé™æ€å˜é‡ï¼›
ä¸?éžé™æ€å†…部类的éžé™æ€æˆå‘˜å¯ä»¥è®¿é—®å¤–部类的éžé™æ€å˜é‡?/span>
]]>
package com.test;public class Parent{ //1 static int a = 1; //2 static { a = 10; System.out.println("parent static code"); } //4 public Parent() { System.out.println("Parent constructor"); System.out.println("Parent a=" + a); } public static void main(String[] args) { System.out.println("***************"); Parent c = new Child(); }}class Child extends Parent{ static int a = 2; //3 static { a = 20; System.out.println("child static code"); } //5 public Child() { System.out.println("Child constructor"); System.out.println("Child var a=" + a); } }输出¾l“æžœ:
parent static codechild static code***************Parent constructorParent a=10Child constructorChild var a=20ç”±æ¤å¯çœ‹å‡ºåœ¨˜q˜æ²¡æœ‰å®žä¾‹åŒ–¾cÈš„æ—¶å€?注æ„*å?å·²ç»æ‰§è¡Œäº†static代ç å—ã€?br /> ™åºåºæ˜¯å…ˆçˆ¶ç±»åŽå¾c?
然åŽæ‰è°ƒç”¨çˆ¶¾cÈš„æž„é€ æ–¹æ³?å†è°ƒç”¨å¾cÈš„æž„é€ æ–¹æ³?ž®±æ˜¯˜q™ä¸ª™åºåºäº?
package com.test;public class Parent{ //1 static int a = 1; //2 static { a = 10; System.out.println("parent static code"); } //4 public Parent() { System.out.println("Parent constructor"); System.out.println("Parent a=" + a); } public static void main(String[] args) { System.out.println("***************"); Parent c = new Child(); }}class Child extends Parent{ static int a = 2; //3 static { a = 20; System.out.println("child static code"); } //5 public Child() { System.out.println("Child constructor"); System.out.println("Child var a=" + a); } }]]>
¾l¼åˆé¢?/span>
1ã€ä½œç”¨åŸŸpublic,private,protected,以åŠä¸å†™æ—¶çš„区别
½{”：区别如下åQ?br />
作用åŸ?nbsp; 当剾c?nbsp; åŒä¸€package å噾c?nbsp; 其他package
public √ √ √ √
protected √ √ √ ×
friendly √ √ × ×
private √ × × ×
ä¸å†™æ—‰™»˜è®¤äØ“friendly
2ã€ArrayListå’ŒVector的区åˆ?HashMapå’ŒHashtable的区åˆ?br />
½{”：ž®±ArrayList与Vector主è¦ä»ŽäºŒæ–šw¢æ¥è¯´.
一.åŒæ¥æ€?Vector是线½E‹å®‰å…¨çš„åQŒä¹Ÿž®±æ˜¯è¯´æ˜¯åŒæ¥çš„，而ArrayList是线½E‹åºä¸å®‰å…¨çš„åQŒä¸æ˜¯åŒæ¥çš„
äº?æ•°æ®å¢žé•¿:当需è¦å¢žé•¿æ—¶,Vector默认增长为原æ¥ä¸€åŸ¹ï¼Œè€ŒArrayListå´æ˜¯åŽŸæ¥çš„一å?br />
ž®±HashMap与HashTable主è¦ä»Žä¸‰æ–šw¢æ¥è¯´ã€?br />
一.历å²åŽŸå› :Hashtable是基于陈旧的Dictionary¾cÈš„åQŒHashMap是Java 1.2引进的Map接å£çš„一个实çŽ?br />
äº?åŒæ¥æ€?Hashtable是线½E‹å®‰å…¨çš„åQŒä¹Ÿž®±æ˜¯è¯´æ˜¯åŒæ¥çš„，而HashMap是线½E‹åºä¸å®‰å…¨çš„åQŒä¸æ˜¯åŒæ¥çš„
ä¸?å€û|¼šåªæœ‰HashMapå¯ä»¥è®©ä½ ž®†ç©ºå€ég½œä¸ÞZ¸€ä¸ªè¡¨çš„æ¡ç›®çš„key或value
3ã€charåž‹å˜é‡ä¸èƒ½ä¸èƒ½å˜è´®ä¸€ä¸ªä¸æ–‡æ±‰å?ä¸ÞZ»€ä¹?
½{”：是能够定义æˆä¸ÞZ¸€ä¸ªä¸æ–‡çš„åQŒå› 为javaä¸ä»¥unicode¾~–ç åQŒä¸€ä¸ªcharå?(16bit)个å—节，所以放一个ä¸æ–‡æ˜¯æ²¡é—®é¢˜çš„
4ã€å¤š¾U¿ç¨‹æœ‰å‡ ¿U实现方æ³?都是什ä¹?åŒæ¥æœ‰å‡ ¿U实现方æ³?都是什ä¹?
½{”：多线½E‹æœ‰ä¸¤ç§å®žçŽ°æ–ÒŽ³•åQŒåˆ†åˆ«æ˜¯¾l§æ‰¿Thread¾cÖM¸Žå®žçŽ°Runnable接å£
åŒæ¥çš„实现方é¢æœ‰ä¸¤ç§åQŒåˆ†åˆ«æ˜¯synchronized,wait与notify.
]]>
public class Test2{ public static void main(String[] args) { Float a = new Float(3.4); System.out.println(a.SIZE); a = new Float(34000); System.out.println(a.SIZE); }}
让我们æ¥çœ‹çœ‹æ¤ç¨‹åºä¼šè¾“出什么呢?我们先æ¥çœ‹çœ‹JDK的解释å§.
æ„æ€æ˜¯è¯?通常åŽÀL˜qîC¸€ä¸ªfloat值的ä½æ•°.
˜q™ä¸ªæ˜¯ä¸€ä¸ªå¸¸é‡?æ¥çœ‹çœ‹æºç å§:
final int å˜é‡ä¸€æ—¦è¢«å®šä¹‰ž®×ƒ¸èƒ½è¢«æ”¹å˜~
]]>
public class Test2{ public static void main(String[] args) { float a = 3.4; }}
˜q™ä¸ª½Ž€å•çš„½E‹åºèƒ½ä¸èƒ½ç¼–译通过呢？其实是ä¸èƒ½çš„ã€?br /> åŽŸå› æ˜¯ç²¾åº¦é—®é¢˜ï¼Œåº”è¯¥ç”¨å¼ºåˆ¶ç±»åž‹è{æ?
float a = (float)3.4;å†æ¥çœ‹çœ‹˜q™ä¸ªèƒ½ä¸èƒ½ç¼–译通过
public class Test2{ public static void main(String[] args) { Float a = new Float(3.4); }} public Float(double value) { this.value = (float)value; }å…¶ä¸æœ‰ä¸€ä¸ªæž„é€ æ–¹æ³•åœ¨æ–ÒŽ³•é‡Œå·²¾l进行了å‘下转型ã€?br /> æ‰€ä»¥è¿™æ ·å†™æ˜¯æ²¡æœ‰é—®é¢˜çš„.
]]>
Which two are equivalent? (Choose two)A. <%= YoshiBean.size%>B. <%= YoshiBean.getSize()%>C. <%= YoshiBean.getProperty("size")%>D. <jsp:getProperty id="YoshiBean" param="size"/>E. <jsp:getProperty name="YoshiBean" param="size"/>F. <jsp:getProperty id="YoshiBean" property="size"/>G. <jsp:getProperty name="YoshiBean" property="size"/>å…¶ä¸Cå’ŒG效果是一æ ïLš„åQ?br /> 所以æ¤é¢˜é€‰G.
7.
Which of the following statements regarding the lifecycle of a session bean are correct? 1. java.lang.IllegalStateException is thrown if SessionContext.getEJBObject() is invoked when a stateful session bean instance is passivated. 2. SessionContext.getRollbackOnly() does not throw an exception when a session bean with bean-managed transaction demarcation is activated. 3. An exception is not thrown when SessionContext.getUserTransaction() is called in the afterBegin method of a bean with container-managed transactions. 4. JNDI access to java:comp/env is permitted in all the SessionSynchronization methods of a stateful session bean with container-managed transaction demarcation. 5. Accessing resource managers in the SessionSynchronization.afterBegin method of a stateful session bean with bean-managed transaction does not throw an exception.½W¬äºŒéƒ¨åˆ†åQ?br /> 概念é¢?br /> 1åQ?span style="font: 7pt 'Times New Roman'"> æè¿°Struts体系¾l“æž„åQŸå¯¹åº”å„个部分的开å‘工作主è¦åŒ…括哪些？
在Struts的体¾pÈ»“æž„ä¸åQŒæ¨¡åž‹åˆ†ä¸ÞZ¸¤ä¸ªéƒ¨åˆ†ï¼š¾pÈ»Ÿçš„内部状æ€å’Œå¯ä»¥æ”¹å˜çŠ¶æ€çš„æ“作åQˆäº‹åŠ¡é€»è¾‘åQ‰ã€‚内部状æ€é€šå¸¸ç”׃¸€¾l„Actinform Beanè¡¨ç¤ºã€‚æ ¹æ®è®¾è®¡æˆ–应用½E‹åºå¤æ‚度的ä¸åŒåQŒè¿™äº›Beanå¯ä»¥æ˜¯è‡ªåŒ…å«çš„åƈå…ähœ‰æŒç®‹çš„状æ€ï¼Œæˆ–åªåœ¨éœ€è¦æ—¶æ‰èŽ·å¾—æ•°æ®ï¼ˆä»ŽæŸä¸ªæ•°æ®åº“åQ‰ã€‚大型应用程åºé€šå¸¸åœ¨æ–¹æ³•å†…部å°è£…事务逻辑åQˆæ“作）åQŒè¿™äº›æ–¹æ³•å¯ä»¥è¢«æ‹¥æœ‰çŠ¶æ€ä¿¡æ¯çš„bean调用。比如è´ç‰©èžRbeanåQŒå®ƒæ‹¥æœ‰ç”¨æˆ·è´ä¹°å•†å“çš„ä¿¡æ¯ï¼Œå¯èƒ½˜q˜æœ‰checkOut()æ–ÒŽ³•ç”¨æ¥‹‚€æŸ¥ç”¨æˆïLš„信用å¡ï¼Œòq¶å‘仓库å‘定货信æ¯ã€‚å°åž‹ç¨‹åºä¸åQŒæ“作å¯èƒ½ä¼šè¢«å†…嵌在Action¾c»ï¼Œå®ƒæ˜¯struts框架ä¸æŽ§åˆ¶å™¨è§’色的一部分。当逻辑½Ž€å•æ—¶˜q™ä¸ªæ–ÒŽ³•å¾ˆé€‚åˆã€‚å¾è®®ç”¨æˆ·å°†äº‹åŠ¡é€»è¾‘åQˆè¦åšä»€ä¹ˆï¼‰ä¸ŽAction¾cÀL‰€æ‰®æ¼”的角è‰ÔŒ¼ˆå†›_®šåšä»€ä¹ˆï¼‰åˆ†å¼€ã€‚　　
　　
2åQ‰è§†å›¾ï¼ˆViewåQ‰ã€€ã€€ã€€ã€€
视图主è¦ç”±JSP建立åQŒstruts包å«æ‰©å±•è‡ªå®šä¹‰æ ‡½{‘Öº“åQˆTagLibåQ‰ï¼Œå¯ä»¥½Ž€åŒ–创建完全国际化用户界é¢çš„过½E‹ã€‚ç›®å‰çš„æ ‡ç¾åº“包括：Bean Tagsã€HTML tagsã€Logic Tagsã€Nested Tags 以åŠTemplate Tags½{‰ã€‚　　
　　
3åQ‰æŽ§åˆ¶å™¨åQˆControlleråQ‰ã€€ã€€ã€€ã€€
在strutsä¸ï¼ŒåŸºæœ¬çš„控制器¾l„äšg是ActionServlet¾cÖM¸çš„实例serveltåQŒå®žé™…ä‹É用的servlet在酾|®æ–‡ä»¶ä¸ç”׃¸€¾l„æ˜ ž®„（由ActionMapping¾c»è¿›è¡Œæ˜qŽÍ¼‰˜q›è¡Œå®šä¹‰ã€‚对于业务逻辑的æ“作则主è¦ç”±Actionã€ActionMappingã€ActionForward˜q™å‡ 个组件å调完æˆçš„åQŒå…¶ä¸Action扮演了真æ£çš„业务逻辑的实现者，ActionMapping与ActionForward则指定了ä¸åŒä¸šåŠ¡é€»è¾‘或浽E‹çš„˜q行方å‘。struts-config.xml æ–‡äšgé…置控制器ã€?br />
2åQ?span> XML包括哪些解释技术，区别是什么？
包括åQšDOMåQˆDocument Object ModalåQ‰æ–‡æ¡£å¯¹è±¡æ¨¡åž‹ï¼ŒSAXåQˆSimple API for XMLåQ‰ã€‚DOM是一‹Æ¡æ€§å°†æ•´ä¸ªæ–‡æ¡£è¯Õd…¥å†…å˜æ“作åQŒå¦‚果是文档比较ž®ï¼Œè¯Õd…¥å†…å˜åQŒå¯ä»¥æžå¤§æ高æ“作的速度åQŒä½†å¦‚果文档比较大，那么˜q™ä¸ªž®±åƒåŠ›äº†ã€‚所以æ¤æ—¶SAX应用而生åQŒå®ƒä¸æ˜¯ä¸€‹Æ¡æ€§çš„ž®†æ•´ä¸ªæ–‡æ¡£è¯»å…¥å†…å˜ï¼Œ˜q™å¯¹äºŽå¤„ç†å¤§åž‹æ–‡æ¡£å°±æ¯”较ž®±åŠ›äº?
3åQ?nbsp; JSP有哪些内¾|®å¯¹è±¡å’ŒåŠ¨ä½œåQŸå®ƒä»¬çš„作用分别是什ä¹?/span>åQ?br />
JSP共有以下9¿U基本内¾|®ç»„ä»Óž¼š
request 用户端请求，æ¤è¯·æ±‚会包å«æ¥è‡ªGET/POSTè¯äh±‚çš„å‚æ•?br /> response ¾|‘é¡µä¼ å›žç”¨æˆ·ç«¯çš„å›žåº”
pageContext ¾|‘页的属性是在这里管ç?
session 与请求有关的会è¯æœ?
application servlet æ£åœ¨æ‰§è¡Œçš„内å®?br /> out 用æ¥ä¼ é€å›žåº”的输出
config servlet的构枉™ƒ¨ä»?br /> page JSP¾|‘页本èín
exception 针对错误¾|‘页åQŒæœªæ•æ‰çš„例å¤?
常用的组ä»Óž¼šrequestã€responseã€outã€sessionã€applicationã€exception
]]>
]]>