http断点续传简单实现（java)

/* .~/;v~bL  
**SiteFileFetch.java k@X As  
*/ CX@HG)l  
package NetFox; gcY~_'&u  
import java.io.*; Ffqn|}gb  
import java.net.*; sZ(Q4)r  
/:];2P6#X  
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public class SiteFileFetch extends Thread { t3kh]2t  
Y K62#;  
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SiteInfoBean siteInfoBean = null; //文件信息Bean B=qRZA!DQ?  
long[] nStartPos; //开始位置 SX<>6vH&  
long[] nEndPos; //结束位置 zK]%qv]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l=G#gKE  
long nFileLength; //文件长度 Pxu
z {  
boolean bFirst = true; //是否第一次取文件 >5Rw~  
boolean bStop = false; //停止标志 oZ>]8vw  
File tmpFile; //文件下载的临时信息 `rFGSq$9  
DataOutputStream output; //输出到文件的输出流 `E%d
$
 
5|H(N}S_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Le+8s LE`Y  
public SiteFileFetch(SiteInfoBean bean) throws IOException uaMmiR  
{ C3 c|@7FU  
siteInfoBean = bean; K>E!W!-PJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L ~'N6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q+=@kXs>+  
if(tmpFile.exists ()) _p^ "!  
{ I;PO$T  
bFirst = false; {.[,ee-)9  
read_nPos(); WN?`Od:y  
} PbC>v  
else |Szr=[  
{ `e:RZ
  
nStartPos = new long[bean.getNSplitter()]; F973U  
nEndPos = new long[bean.getNSplitter()]; iK23`@&%_  
} I>\?t4t  
Ho*RLVI0U  
(B4A$t  
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} @Pg@ltUd  
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public void run() ~ZIRCTQ"  
{ jtJ8r5j 1  
//获得文件长度 Q>Q}/{8!  
//分割文件 = nN*9HRD  
//实例FileSplitterFetch *y$ry]  
//启动FileSplitterFetch线程 0p2O8>w^%  
//等待子线程返回 Jm^jz  
try{ tAn6pGp  
if(bFirst) DccsVR`7  
{ Oc=PJf%D#  
nFileLength = getFileSize();  K8we*  
if(nFileLength == -1) \d`S
z *  
{ ?Gu>!7  
System.err.println("File Length is not known!"); y6yseR!  
} r\D8_S_  
else if(nFileLength == -2) T`G"2|ISS  
{ S}I=i>QB  
System.err.println("File is not access!"); JQ4>S<ttJ  
} Z*B(L@H  
else vG}oo  
{ |a\TUzq  
for(int i=0;i<nStartPos.length;i++) SZ){1Hu  
{ \5_^P{p7<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,_-*/- 7;8  
} (ytkq(  
for(int i=0;i<nEndPos.length-1;i++) N#ObxOE6T"  
{ |`/uS;O  
nEndPos = nStartPos[i+1]; qa?y lR"kA  
} U$Z}<8  
nEndPos[nEndPos.length-1] = nFileLength; ,6L>f.V^(U  
} fe/6JV  
} G-<~I#k  
3S?+G)qKo  
{P+[CO  
//启动子线程 (o\~2e:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u{z{3fW_  
for(int i=0;i<nStartPos.length;i++) %q^]./3p  
{ EC/R|\d?Un  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3!W&J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DVH><3FF  
nStartPos,nEndPos,i); }5Uf`pM8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mAa]Et.  
fileSplitterFetch.start(); EUqG"h5#A{  
} bS<p dOX_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]42l:at  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); E(#2/E6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .IU+4ENSy4  
nEndPos = " + nFileLength); RJD3o_("K  
// fileSplitterFetch[nPos.length-1].start(); D$;/ l}s?  
>d\I*"C+d  
VCO/s9AL  
//等待子线程结束 DAi[3`C  
//int count = 0; rJ>8|K[kt  
//是否结束while循环 {'(8<n5
7  
boolean breakWhile = false; jEIL(0_H  
5$X{{j2  
t,_[nu(~8%  
while(!bStop) EK_^#b  
{ rg\w!L(  
write_nPos(); P9vROzXK  
Utility.sleep(500); c
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breakWhile = true; )
3  
+L6d$+  
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for(int i=0;i<nStartPos.length;i++) da@ .J9  
{ ! ZEKvW  
if(!fileSplitterFetch.bDownOver) 6s;x@g]  
{ <*P1Sd.  
breakWhile = false; &PX'=UT  
break; hkG<I';M?M  
} ??PpHBJ')  
} MZ'HMYed   
if(breakWhile) ~WSC6Bh@9  
break; G)Y!aX  
KMV!Hqkk  
4~4Hst#^  
//count++; *6L^A`_1]  
//if(count>4) UpILr\3U  
// siteStop(); _ sd?l  
} K4"as9oFP  
SW7%SX,xM  
V|= 1<v  
System.err.println("文件下载结束！"); 0U'r ia:$  
} UWHC]V?  
catch(Exception e){e.printStackTrace ();} s6I]H  
} ]+AI:  
t
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15COwc*k  
//获得文件长度 e(Verd:c  
public long getFileSize() ?k#%AM  
{ PA E)3  
int nFileLength = -1; \xt!b^d0  
try{ yAOC<d9 E  
URL url = new URL(siteInfoBean.getSSiteURL()); (w*$~p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]#nAld1cmy  
httpConnection.setRequestProperty("User-Agent","NetFox"); (<12&=WxE  
a <3oyY'  
p: o*=  
int responseCode=httpConnection.getResponseCode(); 04s N4C  
if(responseCode>=400) vI-KH:r"{  
{ T*oH tpFj#  
processErrorCode(responseCode); ~'ovJ46tx  
return -2; //-2 represent access is error *jYwcW"R{z  
} bnlL-]]9z  
o}T]f(>}  
0t) IWD  
String sHeader; 7cC$)  
;RU)Q)a)  
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for(int i=1;;i++) _u>+H#  
{ L2 I/h`n"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); A#T;Gi  
//Utility.log(in.readLine()); \ .:CL?m#  
sHeader=httpConnection.getHeaderFieldKey(i); q+K`+& @\  
if(sHeader!=null) !%Ak15o  
{ :A[ Gtc(_  
if(sHeader.equals("Content-Length")) $1axZ~8sS  
{ w(vf>L6(
 
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .N%$I6w
 
break; IcA]<}0!"v  
} TqWvHZX  
} c6e?)(V>  
else 9U+^8,5  
break; C. Sb4i*  
} V@$B>HeK  
} b&LhydaJ  
catch(IOException e){e.printStackTrace ();} 1Ao"DxZHy7  
catch(Exception e){e.printStackTrace ();} f`?|A  
*6uiOtH  
&B))3WFy  
Utility.log(nFileLength); tvd/Y|bV=  
6ds&n#n  
$hA[vi\5  
return nFileLength; +ux,cx.U"  
} a+]@$8+  
vZ*593C8  
b+{yF  
//保存下载信息（文件指针位置） >:Rc%ILym  
private void write_nPos() %cBJ haR{(  
{ 6CCM7  
try{ J&lQ,T!?B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {~Phc 2z  
output.writeInt(nStartPos.length); f9;M"Pd  
for(int i=0;i<nStartPos.length;i++) `TA
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{ CA{c-kG  
// output.writeLong(nPos); dD#A.C,Rz  
output.writeLong(fileSplitterFetch.nStartPos); _m;Y'  
output.writeLong(fileSplitterFetch.nEndPos); J.~$^
-&!  
} [^aow-4z  
output.close(); KpSHf9!&[  
} %h3CQk  
catch(IOException e){e.printStackTrace ();} \vKMNk;kz  
catch(Exception e){e.printStackTrace ();} tM~R?9OaJ  
} 1
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~Q5L)}8N  
//读取保存的下载信息（文件指针位置） z~Gi/L
n  
private void read_nPos() ,LG6py&aT  
{ K o,O!T.  
try{ IEHAPt'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @ 3FTf"#Y  
int nCount = input.readInt(); c}lUP(Ss  
nStartPos = new long[nCount]; h%pgdix  
nEndPos = new long[nCount]; EZa
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for(int i=0;i<nStartPos.length;i++) ?PLf+S  
{ S$ dFz  
nStartPos = input.readLong(); ShFSBD\M#  
nEndPos = input.readLong(); gTm[<Y  
} G,%R`Xns  
input.close(); v-EcJj%  
} ?~hC.5  
catch(IOException e){e.printStackTrace ();} a//<S?d$:  
catch(Exception e){e.printStackTrace ();} j$siCsF  
} ,{=#
  
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private void processErrorCode(int nErrorCode) o{lR_  
{ d A[I  
System.err.println("Error Code : " + nErrorCode); `VwZDU~6  
} {IJ,y27  
):31!IC  
5_9mA4gs@  
//停止文件下载 FTsvPLIv"  
public void siteStop() Rra<MOR  
{ 0ERA(=w5  
bStop = true; jIaAx_  
for(int i=0;i<nStartPos.length;i++) 1!~=8FTv  
fileSplitterFetch.splitterStop(); +QGZ2_vW  
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fczId"   
} M3!A?!BU  
} jTH,GF  
//负责部分文件的抓取 uzr(gFd  
**FileSplitterFetch.java Vf:/Kokq  
*/ 0[/>> !ws  
package NetFox; <k+dJ=f  
\]1qAF
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2x<,R/}  
import java.io.*; w3WBgH  
import java.net.*; qwM71B!r  
a<*q+a(*W  
xp7`[.  
public class FileSplitterFetch extends Thread { i=j
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?S9? ?y/  
String sURL; //File URL wc`UcGO  
long nStartPos; //File Snippet Start Position [|.IXdJ!  
long nEndPos; //File Snippet End Position ?Dm={S6  
int nThreadID; //Thread's ID P
|*c7+q  
boolean bDownOver = false; //Downing is over '_oWpzpe  
boolean bStop = false; //Stop identical f9ux+XQk9  
FileAccessI fileAccessI = null; //File Access interface @)k/t>r(  
Mtq\xF,/+  
W<| M0S{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?gD^K,A Hd  
{ tqbYrF)  
this.sURL = sURL; >%LZ|*U  
this.nStartPos = nStart; "%]<Co<S  
this.nEndPos = nEnd; wr>[Eo@%\  
nThreadID = id; n<q1itjD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 W cOyOv  
} 0])D)%B k  
_[F(8Qx"  
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public void run() ISa}Km>Q  
{ ,^wjtA3j8  
while(nStartPos < nEndPos && !bStop) :`Kv\w.  
{ lEAf\T7  
5?l8;xe`{f  
JX!z,X?r4  
try{ 'aV])(Wm>  
URL url = new URL(sURL); vo(riHH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a=_+8RyVQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;Qn)~b~  
String sProperty = "bytes="+nStartPos+"-";  N$ oQK(  
httpConnection.setRequestProperty("RANGE",sProperty); uvG'Kx  
Utility.log(sProperty); UA4="/  
nMM:Tr  
*? V boyU  
InputStream input = httpConnection.getInputStream(); @=<B8VPJd  
//logResponseHead(httpConnection); h4ozwVA  
P*6h$T  
>:J7u*>$'  
byte[] b = new byte[1024]; L`3;9rO  
int nRead; M:M"7>:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DyPHQ}G  
{ QJ\+u  
nStartPos += fileAccessI.write(b,0,nRead); '2z1$zst,#  
//if(nThreadID == 1) t7-6A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;IOM3'5T@  
} F,8?du]  
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Nn#;Kjul.  
Utility.log("Thread " + nThreadID + " is over!"); x?7z15\  
bDownOver = true; $;pHv<  
//nPos = fileAccessI.write (b,0,nRead); 1'B&e)  
} ZS<`.L6B3  
catch(Exception e){e.printStackTrace ();} SPT?Tt  
} tdsfCvF=a  
} QQ,V35Vp[  
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^ItL_4  
//打印回应的头信息 x,NV{uG$n  
public void logResponseHead(HttpURLConnection con) V]Rt[l]  
{ vw6>eT  
for(int i=1;;i++) mY[*(a  
{ g43(N!@g  
String header=con.getHeaderFieldKey(i); W m&*  
if(header!=null) '=0l{hv@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); + )n}n5  
Utility.log(header+" : "+con.getHeaderField(header)); ZaYUf  
else 5?Ukf$)x  
break; _lDNYpv  
} p\P)    
} /_X`i[  
7,s5Gd-  
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public void splitterStop() _+j#
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{ Cg(&WJw(ep  
bStop = true; Zts1BWL[  
} M._;3_)%/  
LJ6L#es2  
.}5qi;CA  
} AJ3%Z$JJ;s  
;F_P<b 2  
w^9< I]  
/* ^(s(4|  
**FileAccess.java D\Y,2!I  
*//文件访问(定位，写) _pmo 6O  
package NetFox; "G^TA:O:=  
import java.io.*; GYg.B<Q.  
+z[+kir  
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public class FileAccessI implements Serializable{ (_]!}N  
CpB,L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -u7NBtgUh  
RandomAccessFile oSavedFile; z%1e>`\E  
long nPos; l3*GQ~m7  
PCHKH  
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public FileAccessI() throws IOException !"o\H(siT  
{ UM`{V5NG#  
this("",0); M.xZU\'ty  
} R
58NTPm  
dVk(R9 8  
d"@ /{O^1  
public FileAccessI(String sName,long nPos) throws IOException ExQ\qp3  
{ QT5pn5+ z  
oSavedFile = new RandomAccessFile(sName,"rw"); =av0a!  
this.nPos = nPos; 2;j<{'  
oSavedFile.seek(nPos); `*elzW  
} Mna yiJl  
9^9-\DG  
&4+|{Zx0  
public synchronized int write(byte[] b,int nStart,int nLen) {bADMj1  
{ ZJenwo  
int n = -1; Aix6O=K6  
try{ `qYii
c%  
oSavedFile.write(b,nStart,nLen); g$jTP#%b  
n = nLen; &AOGg\  
} '6})L  
catch(IOException e) 8{QCW{K  
{ ks\q^ten  
e.printStackTrace (); E#_2t)20  
} h_{f_GQ"  
Q"B8l[  
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return n; \|9B:y'y  
} @0s' (  
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`^,E4Qy  
} h]L.6G|hEN  
$,J}w%A  
0O,;[l  
/* C0KFN  
**SiteInfoBean.java oe.Jm#?2.  
*/ U65l o[  
package NetFox; deArH5&!  
uS,?oS  
Z$g'h1,zW  
public class SiteInfoBean { /&
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)D
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\Cu=Le^  
private String sSiteURL; //Site's URL xEurkR  
private String sFilePath; //Saved File's Path QNINn>2  
private String sFileName; //Saved File's Name #O!2
 
private int nSplitter; //Count of Splited Downloading File Z{BK@Q4z  
M9A1 8d|  
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public SiteInfoBean() .%{B=_7  
{//nSplitter的缺省值为5 S*=^I2;  
//default value of nSplitter is 5 OblHN*  
this("","","",5); R[
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} ULxQyY;32  
\XmplG:  
/KWdIP#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) krFp q;  
{ p<H_]|7$7U  
sSiteURL= sURL; s|H7;.3gp  
sFilePath = sPath; :0Jn`Ds4o  
sFileName = sName; s`H|o'0  
this.nSplitter = nSpiltter; L=qhb;  
l"E{ ?4  
s7sd(f]=  
} lAM)X&}0  
HBR/" m  
BHAFO E  
public String getSSiteURL() 8tR6.09'  
{ y>0 @.  
return sSiteURL; @}H'2V  
} `Wjq$*  
;"Qq/knVL  
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public void setSSiteURL(String value) eA
2*}"W  
{ Uz,P^\8^$  
sSiteURL = value; $peL1'Evo  
} F/lL1nTdK  
TM{m:I:Z*n  
*~6]IWN`  
public String getSFilePath() SaF0JPm4z  
{ hz;SDaBA  
return sFilePath; ~FYC'd  
} !p+rU
?  
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[_xOz4
`%  
public void setSFilePath(String value) #UymD-yII  
{ hlV(jz  
sFilePath = value; |tI{MztJ"c  
} k7*-v/*S  
6zU0 8z0-  
;:[P/eg  
public String getSFileName() 2BOH8Mp9  
{ 8q9^  
return sFileName; _?{KTgJG  
} 8i`T?KB  
@]X!#&2>  
 !vl1#@  
public void setSFileName(String value) 1iR\M4?Frf  
{ aMydeTCHi  
sFileName = value; u SZfim@Z7  
} AX@bM  
N/{=j  
jK6dI 7h  
public int getNSplitter() 6@^ ?dQ  
{ +gndW  
return nSplitter;  nSo.,72  
} e'npa*.e  
DPnrzV)  
u5qaLHoEP  
public void setNSplitter(int nCount) ZyC[w7$I2  
{ K~UT@,CS60  
nSplitter = nCount; ^|rzqXW  
} uh)f/)6  
} <Vyl*a{%  
YL;*%XmAG  
TffeCaBv  
/* {|zQ .sA  
**Utility.java * e,8o2C$  
*/ 9ys[xOh WM  
package NetFox; 2+(SR.oGq  
[F *hjGLc}  
K^AIqL8  
public class Utility { q4/P'.S  
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r)qow.+&  
public Utility() MGKSaP;x  
{ 'OYnLz`"6  
bq5?fPBrq  
v'y<}U  
} Q?m= a0g  
pi*?fUg!W  
//线程睡眠 :(jovse\  
public static void sleep(int nSecond) jvE&%|Ngw  
{ Dm;aTe  
try{ =p!Hl#  
Thread.sleep(nSecond); `@ Ont+  
} F,GG>(6c  
catch(Exception e) y7 W7270)  
{ )Oj%3  
e.printStackTrace (); *zPz)3;
 
} N*
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} j=b-Y  
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//日志 7LW%:0  
public static void log(String sMsg) %Zu+=IZ  
{ 'F8:|g  
System.err.println(sMsg); za4:Jdr  
} DVyxe
}  
AUkePp78  
_ <pO<S  
public static void log(int sMsg) {D8[pG%z  
{  A,|lDsvM  
System.err.println(sMsg); ?[Qxq34  
} M}F) P&Y  
} Nf{tC9l  
5l(NX  
_/[(&}M  
/* }W R?n  
**TestMethod.java >9]i#So^  
*/ ulnlRx  
package NetFox; !Ry4w|w  
'St\$X  
.3T#:Hl  
public class TestMethod { ?`D/#P  
'd 6z^Z6  
7j L.\O  
public TestMethod() Bso3Z ^X.  
{ ///xx/weblogic60b2_win.exe zINziAp{  
try{ MXU8QVSY"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V2|XcR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '&$xLZ8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }xM >F%  
fileFetch.start(); >)PcK  
} 6o/!H  
catch(Exception e){e.printStackTrace ();} y\
"Kur*O  
H-.8{8  
d$`NApr  
} N-Nq*  
(>\w8]  
nXOJ  
public static void main(String[] args) ^8yhx-mgb  
{ Os-sYaW  
new TestMethod(); YAf`Fnmw  
} XZFM|=%X  
} /Z*XKIU6v/  
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