ThS. Nguyn Nghim 0913.745.789

nghiemn@fpt.edu.vn

songlong2k@fpt.edu.vn

Write Once, Run Anywhere

String

Regular Expression

Date

SimpleDateFormat

String l

L dy k t lin nhau.

L kiu d liu c s dng nhiu nht trong lp trnh

To String

String s = hello world;

String s = new String(hello world);

String s = String.valueOf(123);

String s = new String(byte[] data)

String s = new String(char[] data)

K t c bit

Cc thao tc chui thng dng So snh chui

Tm v tr ca chui con

Thay th chui chon

Tch v hp chui

Chuyn i hoa thng

Ly di

V d String s = hello world;

String sub = s.substring(3, 6);

Phng thc so snh kim tra boolean equals (String anotherString) boolean equalsIgnoreCase (String anotherString)

Khng phn bit hoa thng

int compareTo (String anotherString) int compareToIgnoreCase (String anotherString)

Khng phn bit hoa thng

boolean contains (String substr) boolean startsWith (String prefix) boolean endsWith (String postfix) boolean matches (String regex)

Tm v tr ca chui con int indexOf (String substr, int fromIndex) int lastIndexOf (String substr, int fromIndex)

Thao tc chui String toLowerCase ()

String toUpperCase ()

String replaceAll (String regex, String replacement)

String replaceFirst (String regex, String replacement)

String[] split (String regex)

String substring (int beginIndex, int endIndex)

char charAt (int index)

Cc phng thc khc int length ()

String trim ()

byte[] getBytes ()

ng nhp hp l khi m ti khon l hello v mt khu trn 6 k t

Qun l sinh vin Nhp mng h tn sinh vin

Xut (IN HOA) h v tn nhng sinh vin tn Tun hoc h Nguyn

Xut tn (ch tn thi) nhng sinh vin c tn lt l M

Tm kim v thay th chui

Tch v xut cc email trong CC

Nhp chui cha dy s phn cch bi (,; ) v xut cc s chn

Phng thc tin ch String.format() gip nh dng chui rt thun tin v d dng.

C php: String.format(String format, Objectargs) Format l chui cha cc k t nh dng Args: l mng cha cc gi tr cn nh dng

V d: String name = M L; int age = 40; double salary = 500.8; String format = Lng ca %s (%d tui) l %.3f la; String s = String.format(format , name, age, salary) Kt qu:

Lng ca M L (40 tui) l 500.800 la

static String valueOf(Object value)

V d: String s = String.valueOf(123);

static String format(String format, Object... args)

V d: String name = M L;

int age = 40;

double salary = 500.80;

String s = String.format(%d, %f, %s, age, salary, name)

String khng th thay i ni dung chui. Tt c cc thao tc vi lp String s cho kt qu l mt chui khc trong khi chui gc khng h thay i.

StringBuffer cho php thao tc trc tip ni dung chui. Cc thao tc thng gp nh:

B sung: append(String s)

Chn thm: insert(int index, String s)

Xa bt: delete(int start, int end)

Thay i k t: setCharAt(int index, char c)

Thay i kch thc: setLength(int length)

o ngc: reverse()

2 on m lnh sau s cho cng mt kt qu l 1 chui cha mt dy s rt di bng cch ghp 1 triu s u tin vi nhau. Hy so snh tc x l ca 2 on m lnh sau

S dng string String s = "";

for(long i=0;i

y l ci g

nnghiem@yahoo.com

54-P6-6661

0913745789

(083)1239876

XYZA-12ED-497H-DDF2

Cch no nhn dng ra chng?

RE l chui dng thc dng kim tra s so khp chui.

Mt s ng dng thng dng

Kim tra mt chui c khp vi regex khng boolean matches (String regex)

Tm kim v thay th String replaceAll (String regex, String replacement)

String replaceFirst (String regex, String replacement)

Tch chui String[] split (String regex)

K hiu M t

Chui i din cho chui

[] i din mt k t c lit k trong ngoc

[^] i din cho mt k t khng khng lit k trong ngoc

. i din cho k t bt k

\d vit tc ca [0-9]

\D khng phi \d

\w vit tc ca [a-zA-Z0-9_]

\W khng phi \w

\s i din cho k t trng (gm c tab, xung dng, v u

dng)

\S khng phi \s

K hiu M t

{min, max} xut hin t nht l min v nhiu nht l max ln

{n} xut hin ng bng n ln

? vit tc ca {0,1}

* vit tc ca {0,}

+ vit tc ca {1,}

^ bt u

$ kt thc

() Phn nhm

| La chn

\ loi b k t c bit

Dng thc email n gin: String regex = \\w+@\\w+\\.\\w+;

S CMND String regex = \\d{10};

S in thoi di ng: String regex = 0\\d{10,11};

S xe my si gn String regex = 5\\d-[A-Z]\\d-\\d{3}.{2};

a ch trang web: String regex = http://www\\.(\\w+\\.)\\.+\\w+;

Stri

ng

emai

l =

Stri

ng

ph

on

e=

Stri

ng

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l = r

eq

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st.g

etP

aram

eter

(tx

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ail

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Stri

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;

Nhp vo mt chui v xut cc thng tin sau Chui va nhp Chui o ngc Chui IN HOA Chui con cha 10 k t u tin S k t S nguyn m C cha t Vit nam hay khng C bt u bi Hello hay khng Thay VN thnh Vit nam Xa cc email khi trn chui

Sinh s seri ngu nhin cho phn mm theo dng: xxx-xxxx-xxxxx (3 s - 4 s - 5 s)

Nhp thng tin nhn vin v lu vo tp tin thuc tnh. Thng tin ca mi nhn vin phi tun theo cc rng buc sau

Xy dng RE so khp ni dung th ca Xy dng RE so khp thuc tnh href= ca cc th HTML

Thng tin Kim sot Biu thc chnh qui

M sinh vin 5 k t hoa [A-Z]{5}

Mt khu t nht 6 k t .{6,}

H v tn Ch dng alphabet v k t trng [a-zA-Z ]+

Ngy sinh Dng ngy-thng-nm \d{2}-\d{2}-\d{4}

Email ng dng email \w+@\w+\. \w+

in thoi in thoi Si gn 083\d{7}

S xe my S xe my Si gn 5\d-[A-Z]-\d{3}\.{2}

S CMND 10 ch s \d{10}

Website a ch website http://www\.\w+\.\w{2,4}

Date nm thng tin thi gian (nm, thng, ngy, gi, pht, giy)

Khi to ngy Date d = new Date(); // ly thi gian hin ti Date d2 = new Date(111, 12, 31); // 2011-12-31

c ghi cc thng s thi gian d.setDate(35); // thay i ngy d.setMonth(17); // thay i thng int year = d.getYear() + 1900; // ly nm int day = d.getDay(); // ly th (0-6: 0 l ch nht) long time = d.getTime(); // ly thi gian (tnh t 1/1/1970) if(d.after(d2)){ System.out.printf(%s sau %s, d, d2); }

SimpleDateFormat gip chuyn i gia Date v String

Date String

format() format()

parse() parse()

yy, yyyy, M, MM, MMM, , E,

, H, HH,

yy, yyyy, M, MM, MMM, MMMM, m, mm, d, dd, E, EE, EEE, EEE, h, hh, H, HH,

s, ss, SSS, t,tt

SimpleDateFormat

To SimpleDateFormat SimpleDateFormat df1 = new SimpleDateFormat(); SimpleDateFormat df2 = new SimpleDateFormat(dd-MM-yyyy);

Chuyn i sang ngy String s = 20-10-2011; try {

Date d = df2.parse(s);

} catch(Exception ex) {

System.out.printf(%s khng hp nh dng !);

}

Chuyn sang chui Date d = new Date(); df1.applyPattern(MMMM dd, yyyy); String s = df1.format(d);