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http断点续传简单实现(java)

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/* Io1j%T#ZT  
**SiteFileFetch.java %_ibe  
*/ jYHnJ}<  
package NetFox; \8`7E1d  
import java.io.*; QB*,+u4  
import java.net.*; i6WH^IQM  
n m-  
2.D2 o  
public class SiteFileFetch extends Thread { wq$$. .E  
tk&AZb,sP  
;xZ+1 zmL0  
SiteInfoBean siteInfoBean = null; //文件信息Bean _MBhwNBxZ  
long[] nStartPos; //开始位置 hOY@vm&  
long[] nEndPos; //结束位置 >}+{;d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 fg^AEn1i  
long nFileLength; //文件长度 #ibwD:{  
boolean bFirst = true; //是否第一次取文件 fp)SZu_*  
boolean bStop = false; //停止标志  ]n!V  
File tmpFile; //文件下载的临时信息 Mu\V3`j  
DataOutputStream output; //输出到文件的输出流 T/_u;My;  
=AIFu\9#a`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  E^1yU  
public SiteFileFetch(SiteInfoBean bean) throws IOException  }QFL  
{ *;fTiL  
siteInfoBean = bean; i#[8I-OtN/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); g8<ODU0[g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q)?%END  
if(tmpFile.exists ()) ?UtKu  
{ A2|Bbqd  
bFirst = false; >)kKP8l7  
read_nPos(); V<QpC5  
} 1 l,fK)z  
else )|~&(+Q?]  
{ qyz%9 9  
nStartPos = new long[bean.getNSplitter()]; B\J[O5},  
nEndPos = new long[bean.getNSplitter()]; j&8YE7  
} 6}^x#9\  
y2A\7&7  
@t%da^-HS"  
.U!EA0B  
} uY]';Ot G  
7=P)`@  
4uXGp sL  
public void run() K4Q{U@ZJ  
{ OrkcY39"~a  
//获得文件长度 &FXf]9 _X  
//分割文件 gP% <<yl  
//实例FileSplitterFetch 3:,%># "  
//启动FileSplitterFetch线程 !>sA.L&=  
//等待子线程返回 ~7: q+\  
try{ `<YMkp[  
if(bFirst) QVT0.GzR  
{ D!`[fjs6A  
nFileLength = getFileSize(); ef)RlzL Oq  
if(nFileLength == -1) TGJz[Ny  
{ Wg|6{'a  
System.err.println("File Length is not known!"); REh"/d  
} 8W&1"h`  
else if(nFileLength == -2) K *@?BE  
{ k79OMf<v  
System.err.println("File is not access!"); 3f`Uoh+  
} K)'[^V Xh  
else )I%M]K]F  
{ 0~nX7  
for(int i=0;i<nStartPos.length;i++) 6s@!Yn|?  
{ v}DNeIh~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 7ys' [G|}r  
} @K"$M>n$Z  
for(int i=0;i<nEndPos.length-1;i++) YEv\!%B  
{ If&))$7u  
nEndPos = nStartPos[i+1]; h% -=8l,  
} @/#G2<Vp1  
nEndPos[nEndPos.length-1] = nFileLength; awzlLI<2p  
} u>'0Xo9R  
} +3))G  
02]HwsvZ  
<aPZE6z  
//启动子线程 D[>:az `  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =v3o)lU  
for(int i=0;i<nStartPos.length;i++) 7J9<B5U  
{ #VhdYDbW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y;az&T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [Q T ;~5  
nStartPos,nEndPos,i); \n}%RD-Ce  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,LBj$U]e|E  
fileSplitterFetch.start(); R~=c1bpdq  
} z(A60b}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fHaF9o+/b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {L$$"r,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (6fD5XtS  
nEndPos = " + nFileLength); -c>3|bo  
// fileSplitterFetch[nPos.length-1].start(); ndQw>  
PcsYy]Q/  
Wps^wY  
//等待子线程结束 DcxT6[  
//int count = 0; *$cx7yJ  
//是否结束while循环 %R5- 6  
boolean breakWhile = false; e/4C` J-  
myo4`oH  
H ezbCwsx&  
while(!bStop) U%F a.bL~  
{ +=W(c8~P  
write_nPos(); BiU>h.4=\(  
Utility.sleep(500); P*k n}:  
breakWhile = true; 3uw3 [ SR1  
N!7?D'y   
3ko h!q+  
for(int i=0;i<nStartPos.length;i++) 5B%KiE&p  
{ LDegJer-v  
if(!fileSplitterFetch.bDownOver) o"qxR'V  
{ O}C*weU  
breakWhile = false; 6EY\  
break; tO&n$$  
} ^4IJL",  
} I!!cA?W  
if(breakWhile) ;Q t%>Uo8  
break; @CM5e!  
KEy8EB  
5Y;&L!T  
//count++; hvI#D>Z!Yp  
//if(count>4) mBL?2~M  
// siteStop(); g8/ ,E-u  
} eJf]"-  
8A0a/ 7Lj  
wtbN @g0  
System.err.println("文件下载结束!"); 26}3  
} q"269W:  
catch(Exception e){e.printStackTrace ();} ~;b}_?%o  
} 9<&*iIrM  
_o w7E\70  
\Ec*Gq?.  
//获得文件长度 [$} \Gv  
public long getFileSize() _gH$ ,.j/  
{ -V2f.QE%  
int nFileLength = -1; bRggt6$z  
try{ 0[H />%3O  
URL url = new URL(siteInfoBean.getSSiteURL()); {*;K>%r\o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P*[wB_^&UP  
httpConnection.setRequestProperty("User-Agent","NetFox"); }x|q*E\  
9y[U\[H  
iYiTkq  
int responseCode=httpConnection.getResponseCode(); &CQ28WG X  
if(responseCode>=400) ]fDb|s48  
{ _|;d D  
processErrorCode(responseCode); ;P' 5RCqj  
return -2; //-2 represent access is error Y{~`g(~9_A  
} <0Y<9+g!  
K:13t|  
,5U[#6^  
String sHeader; k v_t6(qd  
{^Q,G x(  
M:.+^.h  
for(int i=1;;i++) O=LW[h!  
{ ZG+FX:v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); P@bPdw!JA  
//Utility.log(in.readLine()); K20Hh7cVJ  
sHeader=httpConnection.getHeaderFieldKey(i); h}tC +_"D  
if(sHeader!=null) {ZdF6~+H(!  
{ WNeBthq6  
if(sHeader.equals("Content-Length")) \ (`2@  
{ Y9-F\t=~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >tkz%;6  
break; yFd.tQs  
} .p Mwa  
} :W>PKW`^  
else J(8?6&=ck  
break; 4C?4M;  
} )Ft+eMYti[  
} ?c8( <_I+  
catch(IOException e){e.printStackTrace ();} Wm{ebx  
catch(Exception e){e.printStackTrace ();} \FX"A#  
n2_;:=  
yIr0D 6L  
Utility.log(nFileLength); /]0SF_dZ  
l['p^-I  
M*cF'go  
return nFileLength; Oc,HnyV+  
} OVxg9  
*Ej;}KSv  
0nBDF79  
//保存下载信息(文件指针位置) }%c>Hh  
private void write_nPos() |Y6;8e`H  
{ _B^X3EOc  
try{ Xk'Pc0@a  
output = new DataOutputStream(new FileOutputStream(tmpFile)); pyX:$j2R+%  
output.writeInt(nStartPos.length); B[h^]k  
for(int i=0;i<nStartPos.length;i++) LN.*gG l  
{ \N-3JOVy  
// output.writeLong(nPos); x|AND]^Q  
output.writeLong(fileSplitterFetch.nStartPos); .nNZ dta&=  
output.writeLong(fileSplitterFetch.nEndPos); $y.0h(  
} mJ(ElDG  
output.close(); 7;Lv_Y"b  
} Xf"< >M  
catch(IOException e){e.printStackTrace ();} O8>&J-+2  
catch(Exception e){e.printStackTrace ();} raSga'uT;  
} rtbV*@Z  
p(="73  
_E8Cvaob  
//读取保存的下载信息(文件指针位置) :.=j)ljTx  
private void read_nPos() Gj%q:[r  
{ 4i&Rd1#0dI  
try{ 8mLW^R:`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $0OOH4  
int nCount = input.readInt(); &PApO{#Q  
nStartPos = new long[nCount]; S[hyN7sI  
nEndPos = new long[nCount]; +e.w]\}  
for(int i=0;i<nStartPos.length;i++) T~L V\}h  
{ q$b 4S4Z7  
nStartPos = input.readLong(); _NwHT`O[  
nEndPos = input.readLong(); br TP}A  
} 9@IL547V  
input.close(); NX8hFwR  
} 2"shB(:z>  
catch(IOException e){e.printStackTrace ();} QBi]gT@&g  
catch(Exception e){e.printStackTrace ();} }CZw'fhVWO  
} JC9$"0d7  
g]N'6La  
tcRJ1:d  
private void processErrorCode(int nErrorCode) a9 q:e  
{ oclU)f.,  
System.err.println("Error Code : " + nErrorCode); 9c*B%A8J  
} ")txFe  
oD9L5c)  
A n`*![  
//停止文件下载 CCt\[hl  
public void siteStop() <s\ZqL$ f  
{ h6IXD N  
bStop = true; fE)o-q6Z  
for(int i=0;i<nStartPos.length;i++) E`@Z9k1 `  
fileSplitterFetch.splitterStop(); 3O Ks?i3A  
z$d<ep{6  
\o72VHG66  
} ."O%pL]!/b  
} h 6?Z  
//负责部分文件的抓取 z$~F9Es9  
**FileSplitterFetch.java I S'Uuuz7g  
*/ %K=_  
package NetFox; .L;e:cvx  
<Uj9~yVN]  
{ J/Fp#  
import java.io.*; b5Q>e%i#  
import java.net.*; m__pQu:  
l1O"hd'~s  
IoK/2Gp  
public class FileSplitterFetch extends Thread { "lt5gu!`u  
:/Es%z D  
>mR8@kob<  
String sURL; //File URL v[8+fd)}S  
long nStartPos; //File Snippet Start Position T2.[iD!A  
long nEndPos; //File Snippet End Position ITn PF{N  
int nThreadID; //Thread's ID n|rKo<Y0  
boolean bDownOver = false; //Downing is over ~LOE^6C+~o  
boolean bStop = false; //Stop identical IFS_DW  
FileAccessI fileAccessI = null; //File Access interface q3h& V  
dT?3Q;>B?  
z5~W >r  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nfGI4ZE  
{ kQlwl9  
this.sURL = sURL; %.$7-+:7A  
this.nStartPos = nStart; t&[<Dl/L  
this.nEndPos = nEnd; Yc_(g0NK  
nThreadID = id; H=f| X<8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]b sabS?  
} M3|G^q:l  
dkCU U  
'6>*J  
public void run() <LXx_{=:  
{ SZ$WC8AX  
while(nStartPos < nEndPos && !bStop) v3XM-+Z4  
{ z,^~H  
p nI=  
)7 8T+7Kq  
try{ 0jjtx'F  
URL url = new URL(sURL); %+Z*-iX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BbC O K  
httpConnection.setRequestProperty("User-Agent","NetFox"); woP j>M  
String sProperty = "bytes="+nStartPos+"-"; t8xXGWk0  
httpConnection.setRequestProperty("RANGE",sProperty); .PR+_a-X  
Utility.log(sProperty); J,u-)9yBA<  
fG$LqzyqlK  
0{8L^ jB/  
InputStream input = httpConnection.getInputStream(); %-.;sO=g  
//logResponseHead(httpConnection); rvd%z7Z1o  
EEL3~H{(  
S7PWP< 9  
byte[] b = new byte[1024]; \#B<'J9.`  
int nRead; iQ2j ejd3(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S >CKm:7  
{ 6},[HpXRc4  
nStartPos += fileAccessI.write(b,0,nRead); |m ?ZE:  
//if(nThreadID == 1) ^w.]1x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G\;6n  
} NY^0$h  
i-5,* 0e6m  
/"u37f?[^  
Utility.log("Thread " + nThreadID + " is over!"); Rq[d\BN0.d  
bDownOver = true; Ur>1eN%9'  
//nPos = fileAccessI.write (b,0,nRead); uh2_Rzln  
} 73Jm  
catch(Exception e){e.printStackTrace ();} 7X/t2Vih@  
} #+ AQ:+  
} Q1?*+]  
y*-_  
 fPPP|  
//打印回应的头信息 SZHgXl3:  
public void logResponseHead(HttpURLConnection con) p WJ EFm  
{ *`Vmncv3  
for(int i=1;;i++) `V\?YS}  
{ =D Q :0w  
String header=con.getHeaderFieldKey(i); p&]V!O  
if(header!=null) {A:uy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DR:$urU$  
Utility.log(header+" : "+con.getHeaderField(header)); }AJoF41X  
else hp9U   
break; A!x&,<  
} a6e{bAuq  
} bSX/)')jU  
m Jk\$/Kh  
)(-;H|]?  
public void splitterStop() DyGls8<\!  
{ -YKy"   
bStop = true; ]FTi2B{}H  
} >5L_t   
IY#:v%U  
9N}\>L)_  
} 5Q"w{ n  
{o)pwM"@(  
ZDR@VYi+~  
/* C=r2fc~w  
**FileAccess.java Em@:Qm EN  
*//文件访问(定位,写) rHX^bcYK  
package NetFox; W_Y8)KxG:L  
import java.io.*; :Q3pP"H,}  
#m{*]mY@  
P%(9`A  
public class FileAccessI implements Serializable{ p,$N-22a  
{.{Wl,|7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 <c pck  
RandomAccessFile oSavedFile; tULGfvp  
long nPos; bP 9ly9FH  
@3O)#r}\  
"yaxHd  
public FileAccessI() throws IOException SXOAa<u5  
{ PLc5m5  
this("",0); D @*<O=_D(  
} f;zNNx< ;  
m3lz#Pm'0  
.=#j dc/  
public FileAccessI(String sName,long nPos) throws IOException CG=c@-"n/  
{ &9#m] Mz  
oSavedFile = new RandomAccessFile(sName,"rw"); 6- i.*!I 8  
this.nPos = nPos; _f^KP@^j  
oSavedFile.seek(nPos); r8Pd}ptPU  
} JL= cIH8  
chE!,gik  
hb5K"9Y  
public synchronized int write(byte[] b,int nStart,int nLen) '|^:,@8P9  
{ PWpt\g  
int n = -1; p1Zb&:+  
try{ ([u|j  
oSavedFile.write(b,nStart,nLen);  XTJD>  
n = nLen; |0y#} |/  
} U+)p'%f;  
catch(IOException e) y3dk4s77  
{ L EgP-s W  
e.printStackTrace (); FRrp@hE  
} \@:,A]  
YS9RfK/  
NFs5XpZ~  
return n; :-k|jt  
} `R[ZY!=+  
&&X,1/  
,JV0ib,  
} RU:Rt'  
@%R<3!3v  
'+cI W(F?  
/* y~ =H`PAE  
**SiteInfoBean.java `um,S  
*/ ssi7)0  
package NetFox; MePD:;mm^  
$>XeC}"x68  
~t`s&t'c|  
public class SiteInfoBean { ?0VR2Yb${b  
yJm"vN  
c[dzO .~  
private String sSiteURL; //Site's URL ]yU"J:/  
private String sFilePath; //Saved File's Path HB/V4ki  
private String sFileName; //Saved File's Name WVbrbs4  
private int nSplitter; //Count of Splited Downloading File fSuykbZ  
hi0HEm\  
8vY-bm,e  
public SiteInfoBean() >d2Fa4u3  
{//nSplitter的缺省值为5 5~JT*Ny  
//default value of nSplitter is 5 `Z?wj@H1`  
this("","","",5); ;<AcW.jx  
} EiW|+@1  
/fr>Fd  
jmM|on!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6Dq4Q|C  
{ #.bW9j/  
sSiteURL= sURL; $"^K~5Q  
sFilePath = sPath; qos7u91z  
sFileName = sName; u*l|MIi6J  
this.nSplitter = nSpiltter; L_8zZ8 o  
Z'JS@dV  
B[t^u\Fk  
} S\e&xUA;|  
xAQtX=FoX+  
|W">&Rb<t#  
public String getSSiteURL() @c3xUK   
{ &_ekA44E  
return sSiteURL; |^pev2g  
} ]k0 jmE  
NK_|h %  
{m.$EoS  
public void setSSiteURL(String value) <>cS@V5j  
{ Ux [<g%F"  
sSiteURL = value; V2YK  T,5  
} M ?$[WS  
>Jz9wo`  
!~@GIr  
public String getSFilePath() UNdD2Fd9  
{ Y`|+sND  
return sFilePath; m~ tvuz I  
} >H2`4]4]  
RLB3 -=9t  
#%0V`BS7n  
public void setSFilePath(String value) ~C.*Vc?|  
{ 0+1wi4wy/  
sFilePath = value; 1uw#;3<L  
} E9HMhUe  
> VG  
H",B[ YK  
public String getSFileName() _'u]{X\k{J  
{ EdJL&*  
return sFileName; )D)5 `n)  
} ^QB[;g.O  
^PksXfk  
J3K=z  
public void setSFileName(String value) 7|P kc(O  
{ U@lc 1#  
sFileName = value; tT$OnZu&  
} l\HdB"nT  
aER|5!7(2\  
mP(3[a_Q  
public int getNSplitter() @fL ^I&++  
{ OZ,kz2SF#  
return nSplitter; /HC:H,"i  
} p5Q]/DhG  
f^WTsh]  
--$o$EP`  
public void setNSplitter(int nCount) v<qh;2  
{ '=\}dav!  
nSplitter = nCount; h~MV=7 lE  
} Y Y:Bw W:  
} Zo9<96I&  
JE?p'77C  
V|7YRa@  
/* L+%"e w  
**Utility.java vh9* >[i  
*/ =P- &dN  
package NetFox; `+J Fvn!  
1SQATUV  
gt&|T j  
public class Utility { ~}/Dl#9R!  
l^B.iB  
E_HB[ 9  
public Utility() o_b[*  
{ c PGlT"  
|m19fg3u  
PJnC  
} <P9fNBGa  
Y4T")  
//线程睡眠 "}]`64?  
public static void sleep(int nSecond) # kI>  
{ R#(0C(FI^  
try{ F /b`[  
Thread.sleep(nSecond); X>%nzY]m  
} 3P>gDQP  
catch(Exception e) _`$LdqgE  
{ uFd$*`jS  
e.printStackTrace (); q^@*{H  
} +)Te)^&v%  
} Z5{a7U4z_  
&dtk&P{  
//日志 <G"cgN#]  
public static void log(String sMsg) bRC243]g*A  
{ #%"q0"  
System.err.println(sMsg); 4 p_C+4  
} ]m]`J|%i  
bP,<^zA|X  
r@r%qkh(.@  
public static void log(int sMsg) ]AP1+ &9fN  
{ GnV0~?  
System.err.println(sMsg); <?jd NM  
} ,CO2d)}  
} vG&>- Z  
yev!Nw  
vL/ 3(Bo7  
/* X/]@EF  
**TestMethod.java C2LPLquD+  
*/ x "W~m.y$h  
package NetFox;  K +7  
e4X df>B  
N&8TG  
public class TestMethod { ?M2(8 0  
WxdQ^#AE  
)cf i@-J+#  
public TestMethod() myx/|-V"F  
{ ///xx/weblogic60b2_win.exe #kg`rrF r  
try{ ^<]'?4m]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tz1@s nes  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^Fk;t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Q&m85'r5X  
fileFetch.start(); Jx*cq;`Vee  
} c? ::l+  
catch(Exception e){e.printStackTrace ();} 77e*9/6@  
^df wWP  
Z['.RF'`  
} +^I0> \  
GqFx^dY4*  
;yH>A ;,K%  
public static void main(String[] args) CjdM*#9lW  
{  CB7dr&>  
new TestMethod(); =j]y?;7q  
} w+o5iPLX  
} ];r! M0  
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