涓寮濮嬩互涓烘槸鎴戜滑閭歡鏈嶅姟鍣↖P琚玝lacklist浜嗘垨瀵規柟鎶婃垜浠殑IP緇欑浜嗐備簬鏄氨璇曚簡涓嬬敤telnet SMTP嫻嬭瘯涓嬶細
telnet #customer.domain.com# 25
EHCO sdfa
MAIL FROM: <from@xxx.com>
RCPT TO: <to@xxxxxx.com>
DATA
.
QUIT
緇撴灉嫻嬭瘯鎴戜滑鏄彲浠elnet鍒板鏂圭殑SMTP server鐨勶紝榪欐牱鍙戞槸鍙互鍙戦佹垚鍔熺殑錛屽嵆鎺掗櫎浜嗗鏂規妸鎴戜滑紱佷簡鐨勫彲鑳姐傚彲濡傛灉telnet鍒版垜浠嚜宸辯殑SMTP server鐨勮瘽錛屽氨澶辮觸浜嗐?br />
telnet #own.domain.com# 25
...
鍚庢潵鏌ヤ簡寰堜箙錛屽師鏉ユ槸鍥犱負timeout鐨勫師鍥狅細鎴戜滑鐢ㄧ殑IMSS gateway鏈塼imeout鏈哄埗銆傛煡Log鍙戠幇錛岃繛鎺ュ鏂筍MTP SERVER鏃犻棶棰橈紝MAIL FROM command涔熸棤闂錛屽彲灝卞湪RCPT TO 榪欎釜command瓚呮椂浜嗭紝瓚呰繃30s閮芥病鏈塺esponse浠庡鏂筍MTP SERVER鍥炴潵錛屼及璁″鏂圭殑SMTP SERVER涓嶆庝箞濂斤紝parse鍜屾煡鎵句釜email address (end user: to@xxxx.com)閮借鑺卞緢闀挎椂闂淬傚悗鏉ユ垜浠氨timeout鐨勫弬鏁幫紝浠?0s璋冨埌60s錛屾灉鐒跺氨鍙互浜嗭紝浼拌瀵規柟SMTP server涔嬭RCPT TO榪欎釜鍛戒護閮借姳浜?0錛?0s銆?br />
闂瑙ｅ喅
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vi /etc/vim/vimrc.tiny
set compatible -> change to set nocompatible
And add set backspace=2
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2. Always initialize data.
3. Don't use too many basic types in a class.
4. Not all fields need individual field accessors and mutators.
5. Use a standard form for class definitions.
6. Break up classes with too many responsibilities.
7. Make the names of your classes and methods reflect their responsibilities.
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The javac compiler always looks for files in the current directory, but the java interpreter only looks into the current directory if the "." directory is on the class path. If you have no class path set, this is not a problem鈥攖he default class path consists of the "." directory. But if you have set the class path and forgot to include the "." directory, then your programs will compile without error, but they won't run.
Features tagged as public can be used by any class. Private features can be used only by the class that defines them. If you don't specify either public or private, then the feature (that is, the class, method, or variable) can be accessed by all methods in the same package.
Comment Extraction
Here, docDirectory is the name of the directory where you want the HTML files to go. Follow these steps:
|
1.
|
Change to the directory that contains the source files you want to document. If you have nested packages to document, such as com.horstmann.corejava, you must be working in the directory that contains the subdirectory com. (This is the directory that contains the overview.html file if you supplied one.)
|
|
2.
|
Run the command
|
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鏃ユ湡鏍煎紡璁劇疆鍙傝僀ore Java, Volumn 1鐨凱55欏碉紝璁稿鏍煎紡鍖栬鍒欎笌鏈湴鐜鏈夊叧銆?br />
java.util.Arrays綾誨寘鍚簡鐢ㄦ潵鎿嶄綔鏁扮粍(渚嬪鎺掑簭涓庢悳绱?鐨勫悇縐嶆柟娉曪紝甯哥敤鏂規硶濡備笅:
static String toString(type[] a)
static void sort(type[] a) //Quick Sort
static int binarySearcch(type[] a, type v)
static void fill(type[] a, type v) //灝嗘暟緇勭殑鎵鏈夋暟鎹厓绱犲艱涓簐
....
End of Chapter 3
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鍦?/span>Java涓紝鏁村瀷鐨勮寖鍥翠笌榪愯java浠ｇ爜鐨勬満鍣ㄦ棤鍏熾傚湪C/C++紼嬪簭涓紝int綾誨瀷鍗犵敤鐨勫瓧鑺傚彲鑳戒細鍥犱笉鍚屾満鍣ㄤ笉鍚屾搷浣滅郴緇熻屼笉鍚岋紱鑰屽湪java涓紝鍚勭鏁村瀷鐨勫瓨鍌ㄩ渶姹傚凡緇忚鏄庣‘瀹氫箟(int: 4 bytes; short: 2 bytes; long: 8 bytes; byte: 1 byte)錛屼粠鑰屽疄鐜頒簡騫沖彴鏃犲叧鎬с?/span>
甯哥敤鏁村瀷銆佹誕鐐瑰瀷甯擱噺錛?/span>
l Integer.MAX_VALUE
l Ingeger.MIN_VALUE
l Double.POSITIVE_INFINITY (姝ｆ棤絀峰ぇ)
l Double.NEGATIVE_INFINITY (璐熸棤絀峰ぇ)
l Double.NaN (Not a number)
PS: 鍒ゆ柇涓涓壒瀹氬兼槸鍚︾瓑浜?/span>Double.NaN:
if (x == Double.NaN) //is never true
Should use:
if (Double.isNaN(x)) // check whether x is “Not a number”
char 綾誨瀷鐢ㄤ簬琛ㄧずUnicode緙栫爜鐨勫瓧絎﹀崟鍏冦?/span>Unicode鍙〃紺轟負16榪涘埗鍊鹼紝浠?/span>"u0000鍒?/span>"uffff銆?/span>
鍏充簬Unicode: 鍦?/span>Unicode鍑虹幇鍓嶏紝宸茬粡鏈変簡寰堝鐨勫瓧絎︾紪鐮佹爣鍑?/span>(濡傜編鍥界殑ASCII, 瑗挎鐨?/span>ISO 8859-1, 淇勭綏鏂殑KOI-8, 涓浗鐨?/span>GB118030鍜?/span>BIG-5錛?/span>etc)錛岃繖鏍烽犳垚浜嗕袱涓棶棰橈細a). 瀵逛簬緇欏畾鐨勪唬鐮佸鹼紝涓嶅悓鐨勭紪鐮佹柟妗堜笅鍙兘瀵瑰簲涓嶅悓鐨勫瓧姣?/span>; b). 閲囩敤澶у瓧絎﹂泦鐨勮璦鍏剁紪鐮侀暱搴﹀彲鑳戒笉鍚岋紝e.g., 鏈変簺甯哥敤鐨勫瓧絎﹂噰鐢ㄥ崟瀛楄妭緙栫爜錛岃屽彟涓浜涘瓧絎﹀垯闇瑕佷袱涓垨鏇村瀛楄妭銆?/span>璁捐Unicode灝辨槸涓轟簡瑙ｅ喅榪欎簺闂銆備絾閬楁喚鐨勬槸錛岀粡榪囦竴孌墊椂闂達紝Unicode瀛楃瓚呰繃浜?/span>65536涓紝鐜板湪錛岃繛16浣嶇殑char綾誨瀷涔熷凡緇忎笉鑳芥弧瓚蟲墍鏈?/span>Unicode瀛楃鐨勯渶姹備簡銆?span style="color: red">寮虹儓寤鴻涓嶈鍦ㄧ▼搴忎腑鐢?/span>char綾誨瀷銆?/span>
褰撳皢涓涓瓧絎︿覆鍜屼竴涓潪瀛楃涓茬殑鍊艱繘琛屾嫾鎺ユ椂錛屽悗鑰呰杞崲鎴愬瓧絎︿覆銆?/span>E.g:
int age = 24;
String s = “abce” + age; //age琚漿鎹㈡垚瀛楃涓詫紝緇撴灉涓?#8220;abcd24”銆?br />
StringBuilder builder = new StringBuilder();
builder.append(ch/str);
鍏跺墠韜槸StringBuffer銆係tringBuffer鏁堢巼紼嶄綆錛屼絾鏀寔澶氱嚎紼嬨係tringBuilder涓嶆敮鎸佸綰跨▼錛屼粠鑰屾晥鐜囦篃杈冮珮銆?
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Javac灝?java鏂囦歡緙栬瘧鎴?class鏂囦歡錛屽彂閫佸埌jvm, jvm鎵ц緙栬瘧鍣ㄥ瓨鏀懼湪.class鏂囦歡涓殑瀛楄妭鐮併?
榪愯applet錛?). 鐩存帴鐢ㄦ祻瑙堝櫒鎵撳紑html錛岃html閲屽寘鍚玜pplet銆?). appletviewer ***.html銆俛pplet宓屽叆鍒癶tml鐨勫啓娉曞涓?
<html>
<head></head>
<body>
......
<applet code = "WelcomeApplet.class" width="400" height="200">
<param name = "greeting" value="Welcome to core java!" />
</applet>
</body>
<html>
]]>
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浣嗗緢澶氭椂鍊欐垜浠篃浼氭妸鐢變竴浜涗笉鍙鐨勫瓧絎︾粍鎴愮殑String涔熷綋鎴愭槸絀哄瓧絎︿覆(e.g, space, tab, etc)錛岃繖鏃跺欏氨涓嶈兘鍗曠敤length鎴杋sEmpty()鏉ュ垽鏂簡錛屽洜涓簍echnically涓婃潵璇達紝榪欎釜String鏄潪絀虹殑銆傝繖鏃跺欏彲浠ョ敤String鐨勬柟娉晅rim()錛屽幓鎺夊墠瀵肩┖鐧藉拰鍚庡絀虹櫧錛屽啀鍒ゆ柇鏄惁涓虹┖銆?br />
渚嬪:
1
public class TestEmpty
2
{
3
public static void main(String[] args){
4
String a = " ";
5
6 // if (a.isEmpty())
7 if (a.trim().isEmpty())
8 {
9 System.out.println("It is empty");
10
}
11 else
12 {
13 System.out.println("It is not empty");
14 }
15 }
16
}
17
18
public class TestEmpty2
{
3
public static void main(String[] args){
4
String a = " ";5
6
// if (a.isEmpty())7
if (a.trim().isEmpty())8
{9
System.out.println("It is empty");10
}11
else 12
{13
System.out.println("It is not empty");14
}15
}16
}17
18
緇撴灉褰撶劧鏄細It is empty
PS錛欽ava Doc
public String trim()
Returns a copy of the string, with leading and trailing whitespace omitted.
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