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http断点续传简单实现(java)

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/* P9/Bc^5'  
**SiteFileFetch.java $MPh\T  
*/ KbP( ;  
package NetFox; @_ Q  
import java.io.*; +^0Q~>=VD  
import java.net.*; y53f73Cg  
YrRD3P.P  
7F!(60xY  
public class SiteFileFetch extends Thread { l]wjH5mz=i  
2qQG  
n9p_D  
SiteInfoBean siteInfoBean = null; //文件信息Bean S( nZ]QEG  
long[] nStartPos; //开始位置 g4"0:^/  
long[] nEndPos; //结束位置 { t1|6R0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dY6A)[dAH'  
long nFileLength; //文件长度 ^S]-7>Yyr  
boolean bFirst = true; //是否第一次取文件 S>y(3E]I  
boolean bStop = false; //停止标志 #x^dR-@   
File tmpFile; //文件下载的临时信息 _pZaVx  
DataOutputStream output; //输出到文件的输出流 F]L$xU  
L UitY  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) S, g/2k*  
public SiteFileFetch(SiteInfoBean bean) throws IOException M!Hn`_E  
{ dd=' ;%?  
siteInfoBean = bean; G,]%dZH e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RqnT*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p#fd+  
if(tmpFile.exists ()) Kx[u9MD  
{ C>bd HB7  
bFirst = false; tn@MOOP l  
read_nPos(); eq<giHJM  
} P}dhpU  
else vsDR@Y}k  
{ h0v4!`PQ-  
nStartPos = new long[bean.getNSplitter()]; XC NM  
nEndPos = new long[bean.getNSplitter()]; aOWfu^&H:  
} ImnN&[Cu  
IC[iCrB  
{y0`p1  
s1/:Ts[3i  
} %8N=4vTJ  
_Vj uQ  
|}YeQl  
public void run() 2wKW17wj,  
{ b7nER]R  
//获得文件长度 &F xw19[G  
//分割文件 E,fG<X{  
//实例FileSplitterFetch iR`c/  
//启动FileSplitterFetch线程 e.<y-b?  
//等待子线程返回 p"lTZ7c:Y  
try{ 4Z"JC9As  
if(bFirst) vi :IO  
{ V< ]l=JOd  
nFileLength = getFileSize(); _0uFe7sIZ  
if(nFileLength == -1) CG -^}xE:  
{ ={GYJ. *Ah  
System.err.println("File Length is not known!"); ejID5NqG  
} t(,_  
else if(nFileLength == -2) Ry+Ax4#+(y  
{ Ie14`'  
System.err.println("File is not access!"); >^!qx b-  
} K/OE;;<IA  
else P{{pp<tX*&  
{ 8T2iqqG/1  
for(int i=0;i<nStartPos.length;i++) kS@6'5U  
{ pMfP3G7V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S9'8rn!_  
} $cUTe  
for(int i=0;i<nEndPos.length-1;i++) X=Th  
{ 'Itsu~fza  
nEndPos = nStartPos[i+1]; >#j f Z5t  
} Ba]J3Yp,z  
nEndPos[nEndPos.length-1] = nFileLength; uBPxMwohR  
} l-GQ AI8  
} /%'>?8/  
@&7|Laa  
zURob MpE#  
//启动子线程 6)QJms  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |KM<\v(A{  
for(int i=0;i<nStartPos.length;i++) p? q~.YY  
{ R>05MhA+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qit D{;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), y&$mN  
nStartPos,nEndPos,i); S<+/Ep 2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AZi|85rN  
fileSplitterFetch.start(); K:i{us`  
} mROXwzL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c,\!<4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \vU1*:3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Wg3\hv29  
nEndPos = " + nFileLength); ~S='~ g)  
// fileSplitterFetch[nPos.length-1].start(); 6tKm'`^z4  
~jqG  
0A7 qO1%xw  
//等待子线程结束 I`O)I&KH  
//int count = 0; tk"+PTGJT  
//是否结束while循环 4IW7^Pq`P  
boolean breakWhile = false; :=I@<@82W  
-X)KY_Xn@/  
XehpW}2\  
while(!bStop) @7C?]/8#  
{ `k>h2(@9S  
write_nPos(); FK8G BkQ!  
Utility.sleep(500); `(RQh@H  
breakWhile = true; RH=Tu6i  
BgzER[g|q{  
\8I>^4t'/  
for(int i=0;i<nStartPos.length;i++) C9`J6Uu  
{ K1F,M9 0]  
if(!fileSplitterFetch.bDownOver) &?-LL{W{  
{ -}h+hS50F  
breakWhile = false; vw'`t6  
break; NvZ )zE  
} axRzn:f  
} k>N >_{\  
if(breakWhile) PhS`,I^Z  
break; NVTNjDF%s  
-RSPYQjz  
]lKQ wpX3  
//count++; *TjolE~o  
//if(count>4) T2nbU6H  
// siteStop(); 7H1 ii   
} E27N1J+1  
;U +;NsCH  
yWs_Z6b  
System.err.println("文件下载结束!"); ~"Pu6-\VT  
} `@Q%}J  
catch(Exception e){e.printStackTrace ();} ~B NLzt3%O  
} w_gPX0N}3n  
!_EaF`oh(  
i&r56m<  
//获得文件长度 3E!#?N|v  
public long getFileSize() XYKWOrkQqa  
{ 7*7Z&1*3  
int nFileLength = -1; j:yQP# U  
try{ rt7Ma2tK  
URL url = new URL(siteInfoBean.getSSiteURL()); ]aqHk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qo4+=^(  
httpConnection.setRequestProperty("User-Agent","NetFox"); k{fCU%  
z)Y<@2V*C  
wW7W+,{o  
int responseCode=httpConnection.getResponseCode(); pP4i0mO{Dv  
if(responseCode>=400) 3lyk/',  
{ N}Ol`@@#h  
processErrorCode(responseCode); JY\8^}'9  
return -2; //-2 represent access is error h48JpZ"  
} :J3ZTyjb  
8-N8v *0  
RaK fYLw  
String sHeader; 4{:W5eT!/  
$II[b-X?S  
YH VJg?H3  
for(int i=1;;i++) O};U3=^0f  
{ AnbY<&OC1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o@?3i+%}8  
//Utility.log(in.readLine()); d(>7BV  
sHeader=httpConnection.getHeaderFieldKey(i); mulK(mp  
if(sHeader!=null) <p48?+K9  
{ ~zklrBn&  
if(sHeader.equals("Content-Length")) +\`D1d@  
{ UF[2Rb8?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sckyG  
break; 58H[sM4>  
} w1J&c'-  
} wff&ci28  
else &&0,;r, -)  
break; |(gq:O  
} t'uZho~^F  
} Lp; {&=PIo  
catch(IOException e){e.printStackTrace ();} c2}?[\U]  
catch(Exception e){e.printStackTrace ();} dOm#NSJVd  
f`5e0;zm  
vG(Gs=.U  
Utility.log(nFileLength); iOB]72dh  
|~mi6 lJ6  
M DnT  
return nFileLength; })V9d  
} ^A8'YTl  
or_x0Q  
qll)  
//保存下载信息(文件指针位置) ckqU2ETpD}  
private void write_nPos() \*}JdEHB  
{ pV:c`1\`  
try{ d}K"dr:W5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); SRl:+!@.  
output.writeInt(nStartPos.length); }5H3DavW  
for(int i=0;i<nStartPos.length;i++) 6#xP[hlR[  
{ 7xP>AU)y  
// output.writeLong(nPos); 0`=#1u8  
output.writeLong(fileSplitterFetch.nStartPos); *P_ 3A:_  
output.writeLong(fileSplitterFetch.nEndPos); DLYk#d: q?  
} k zhek >  
output.close(); x+zz:^yHYf  
} .*u, !1u  
catch(IOException e){e.printStackTrace ();} nXDU8|"  
catch(Exception e){e.printStackTrace ();} AZ)H/#be  
} @[0zZX2EE  
m~%\f8w-x  
p=U*4[9k  
//读取保存的下载信息(文件指针位置) ;z;O}<8s  
private void read_nPos() i,R<`K0  
{ fX).A`  
try{ \ajy%$;$}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7:U^Ki  
int nCount = input.readInt(); G#ov2  
nStartPos = new long[nCount]; <4z |"(  
nEndPos = new long[nCount]; B$aA=+<S  
for(int i=0;i<nStartPos.length;i++) ?Kw~O"L8  
{ {n8mE,;M  
nStartPos = input.readLong(); 'AN3{  
nEndPos = input.readLong(); "d'D:>z]%  
} 'rJkxU{  
input.close(); A4.Q \0  
} WJ$D]7  
catch(IOException e){e.printStackTrace ();} * B!uYP  
catch(Exception e){e.printStackTrace ();} YC#N],#  
} j  )6A  
fu3/n@L  
_}.BZ[i  
private void processErrorCode(int nErrorCode) MtC\kTW  
{ K!6k<  
System.err.println("Error Code : " + nErrorCode); G(F }o]  
} q/,>UtRr  
53d8AJ_@X  
{-IH?!&v  
//停止文件下载 5BCHW X*y  
public void siteStop() 12;"=9e!  
{ ^>02,X mk  
bStop = true; )Xxu-/-  
for(int i=0;i<nStartPos.length;i++) !6: kJL}U  
fileSplitterFetch.splitterStop(); RiC1lCE  
LutP&Ebt8  
{)]5o| Hx  
} GGcN aW'  
} 8%]o6'd4  
//负责部分文件的抓取 qc_c&  
**FileSplitterFetch.java 62~8>71;'  
*/ W'x/Kg,w-  
package NetFox; 7Z0fMk  
mt$0p|B8  
v'(p."g  
import java.io.*; bcFG$},k  
import java.net.*; e[f}Lxln  
E}K6Op;=v5  
>[;+QVr;  
public class FileSplitterFetch extends Thread { 2Z 4Ekq0@  
OnE#8*8  
iB1"aE3  
String sURL; //File URL pIBL85Xe  
long nStartPos; //File Snippet Start Position F)'kN2  
long nEndPos; //File Snippet End Position m,KG}KX  
int nThreadID; //Thread's ID XVcY?_AS#  
boolean bDownOver = false; //Downing is over (LzVWz m  
boolean bStop = false; //Stop identical Lu,72i0O ^  
FileAccessI fileAccessI = null; //File Access interface Tg|0!0qD]F  
9~i=Af@  
"w.gP8`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;5qZQ8`4  
{ oUrNz#U  
this.sURL = sURL; Vvk1 D(  
this.nStartPos = nStart; 'E FP/(2J  
this.nEndPos = nEnd; 555j@  
nThreadID = id;  ,83%18b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?5(Cwy ?  
} T$[50~  
w.w(*5[  
t]LOBy-Kv  
public void run() !5lb+%7  
{ gE$D#PZa  
while(nStartPos < nEndPos && !bStop) xi|T7,\X  
{ fz'@ON  
%O] ]La  
7M;7jI/C  
try{ yO\ .dp  
URL url = new URL(sURL); 8,unq3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8D3|}z?  
httpConnection.setRequestProperty("User-Agent","NetFox"); M?mPi 3  
String sProperty = "bytes="+nStartPos+"-"; M4[(.8iE  
httpConnection.setRequestProperty("RANGE",sProperty); ,@1rP55  
Utility.log(sProperty); ZoJ_I >uv  
[?z`XY_-  
~JhH ,E  
InputStream input = httpConnection.getInputStream(); T%|{Qo<j  
//logResponseHead(httpConnection); IiW*'0H:/  
~n9x ,  
E Dh$UB)  
byte[] b = new byte[1024]; vz'/]E  
int nRead; XFJGL!wWm[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) jpijnz{M  
{ @@->A9'L  
nStartPos += fileAccessI.write(b,0,nRead); i+rh&,  
//if(nThreadID == 1) ]\DZW4?'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [t #xX59  
} 8NCu;s  
66ULR&D8  
ejs_ ?  
Utility.log("Thread " + nThreadID + " is over!"); L\;n[,.  
bDownOver = true; ndW]S7  
//nPos = fileAccessI.write (b,0,nRead); _{$eOwB  
} r"HQ>Wn  
catch(Exception e){e.printStackTrace ();} "u29| OY  
} pjG/`  
} (%p@G5GU  
f_\,H|zco)  
yhTC?sf<  
//打印回应的头信息 t5t!-w\M$+  
public void logResponseHead(HttpURLConnection con) FFC"rG  
{ ~)ut"4  
for(int i=1;;i++) VINb9W}G[  
{ 8NP|>uaj  
String header=con.getHeaderFieldKey(i); |.]sL0; 4Z  
if(header!=null) 3i\<#{  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mO#62e4C  
Utility.log(header+" : "+con.getHeaderField(header)); ,%Go.3i[  
else _=Y?' gHH  
break; 4v[Zhf4JM  
} ?rauhTVnJ  
} @J~hi\&`  
e'nhP  
/i:c!l9  
public void splitterStop() a ][t#`  
{ !i4/#H  
bStop = true; Lp1\vfU<+  
} sKu/VAh x  
+g.lLb*#  
g/3t@7*<  
} <D}yqq@|  
5N~JRq\  
'tJb(X!]q  
/* PvHX#wJ  
**FileAccess.java #!yW)RG  
*//文件访问(定位,写) ;q5.\m:  
package NetFox; pDYcsC{p  
import java.io.*; rf\/Y"D  
Kg8n3pLAX  
8bTE# 2+-  
public class FileAccessI implements Serializable{ gPJZpaS  
.#Vup{.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Al}D~6MD  
RandomAccessFile oSavedFile; Sv#S_jh  
long nPos; !_i;6UVG  
QZZt9rA;  
V'iT>  
public FileAccessI() throws IOException  Y%zYO  
{ [\BLb8  
this("",0); B!j7vXM2  
} #ULjK*)R  
$R&K-;D/8  
EX"o9'  
public FileAccessI(String sName,long nPos) throws IOException k`(Cwp{Oc  
{ V'M#."Of/  
oSavedFile = new RandomAccessFile(sName,"rw"); *!5X!\e_  
this.nPos = nPos; *4 HogC  
oSavedFile.seek(nPos); n.l7V<1  
} H*KZZTKd  
W ])Lc3X  
JmBe1"hs  
public synchronized int write(byte[] b,int nStart,int nLen) oVAY}q|wU  
{ 1`q>*S](  
int n = -1; n=iL6Yu(  
try{ qK-\`m  
oSavedFile.write(b,nStart,nLen); &x.n>O  
n = nLen; YQ$Wif:@(n  
} eeM$c`Y<  
catch(IOException e) YiGSFg  
{ c,L{Qv"n{  
e.printStackTrace (); Ljs4^vy <J  
} v!WkPvU  
=6O<1<[y  
zd0 [f3~  
return n; 38zG[c|X  
} /w/um>>K.  
GNX`~%3KYc  
-qs R,H  
} L"[>tY  
3uy^o  
GOU>j "5}2  
/* 5sZqX.XVF  
**SiteInfoBean.java vxZ :l  
*/ }}X<e  
package NetFox; N@x5h8  
W6&mXJ^3L  
g;-6Hg'  
public class SiteInfoBean { I&Z+FL&@f  
d>gN3}tT  
.|c=]_{  
private String sSiteURL; //Site's URL [,TK"  
private String sFilePath; //Saved File's Path o?`^ UG-   
private String sFileName; //Saved File's Name L7"B`oa(p  
private int nSplitter; //Count of Splited Downloading File ^@f-Ni\  
:=oIvSnh  
L)QAI5o:3  
public SiteInfoBean() ,sZ)@?e  
{//nSplitter的缺省值为5 m#|h22^H  
//default value of nSplitter is 5 /VHQ!Wi  
this("","","",5); 4NDT5sL  
} }!^`%\ %\  
t2_pwd*B  
B!AJ*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8;<3Tyjzu  
{ "NvB@>S  
sSiteURL= sURL; G_v^IM#B=  
sFilePath = sPath; ojbms>a  
sFileName = sName; i~ITRi@  
this.nSplitter = nSpiltter; 7*C>4Gs  
W%P$$x5&  
t2hI^J0y  
} <d~IdK'\x  
F x3X  
5c 69M5  
public String getSSiteURL() qk_YFR?R  
{ Z"N}f ,  
return sSiteURL; vT;~\,M  
} Cm%xI& Y  
7*(K%e"U  
9D{p^hd  
public void setSSiteURL(String value) ;.I,R NM  
{ lnWs cb3t  
sSiteURL = value; =y]F cxF  
} !f01.Tq8  
+z O.|`+  
|wkUnn4UB8  
public String getSFilePath() \xjI=P'-25  
{ %ou@Y`  
return sFilePath; <G /a-Z  
} cIQ e^C  
3Bbd2[<W  
4;)aGN{e  
public void setSFilePath(String value) Psw<9[  
{ NxrfRhaU3  
sFilePath = value; 3Q2z+`x'  
} TQ69O +  
H:4? sR3  
gV;9lpZ2  
public String getSFileName() H|s,;1#  
{ 5 NN`tv  
return sFileName; eD)@:K  
} :$^cY>o  
c3!YA"5  
r#\Lq;+-B  
public void setSFileName(String value) qs3V2lvYw{  
{ ; G4g;YHy|  
sFileName = value; OY,iz  
} |*JMCI@Mz  
GEJy?$9   
 ;GZ/V;S  
public int getNSplitter()  Fm`c  
{ fa 2hQJ02  
return nSplitter; f <LRM  
} aB2t/ua  
!"bU|a  
-^WW7 g`  
public void setNSplitter(int nCount) W3y9>]{x^  
{ [_1K1i"m  
nSplitter = nCount;  li  
} fT0+i nRG  
} cjc1iciZ  
>{ .|Ng4K  
Fh~ pB>t  
/* L%31>)8  
**Utility.java 6rh^?B  
*/ H57wzG{xG  
package NetFox; `8b4P>';O'  
n|) JhXQ  
p#>d1R1&  
public class Utility { MxLi'R=  
N6w!V]b  
i ?]`9z  
public Utility() }q=uI`  
{ #8i9@w  
)5Ofr-Y  
!f)^z9QX8  
} 4C`p`AQqpQ  
MOIMW+n  
//线程睡眠 _)-y&  
public static void sleep(int nSecond) 3?uah' D5  
{ O%m>4OdH  
try{ 3\H0Nkubts  
Thread.sleep(nSecond); OHK]=DH:M  
} Ry"N_Fb  
catch(Exception e) 905Lk>rB  
{ b&I{?'"%8  
e.printStackTrace (); mM\jU5P:^  
} hDD]Kc;G^1  
} O[\obi"}  
;]Ko7M(4  
//日志 ;\rKkH"K8n  
public static void log(String sMsg) {:ZsUnzm  
{ FSA"U9 w<  
System.err.println(sMsg); aJSBG|IC  
} 9 M!U@>  
K%3{a=1  
SoNT12>  
public static void log(int sMsg) QO <.l`F  
{  3;f}w g  
System.err.println(sMsg); 'FwNQzzt  
} uM@ve(8\  
} x|U[|i,;  
/}R*'y  
# mW#K  
/* TA>28/U#  
**TestMethod.java *IV_evgM7  
*/ TmUN@h  
package NetFox; 1 2J#}|  
"cx#6Bo|  
 :qrCqFl  
public class TestMethod { r"x/,!_E  
on)$y&lu  
BOWR}n!g  
public TestMethod() `m=u2kxY  
{ ///xx/weblogic60b2_win.exe 'h{| ]  
try{ :{M1]0 NH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X$9 "dL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +=g9T`YbE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (VB-5&b  
fileFetch.start(); NG\^>.8  
} ">!<OB  
catch(Exception e){e.printStackTrace ();} ILMXWw  
7N}==T89[  
faPgp  
} IT0 [;eqR  
\4"01:u'  
mH5[(?   
public static void main(String[] args) 95b65f  
{ kC=h[<'  
new TestMethod(); be+tAp`  
} D5jZ;z}  
} o 12w p  
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