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http断点续传简单实现(java)

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/* YKlYo~fGN9  
**SiteFileFetch.java Rt}H.D #  
*/ L'iENZ I$  
package NetFox; KmG*`Es  
import java.io.*; 4V@raI-  
import java.net.*; c |.~f+  
@GNNi?EY  
.B_LQ;0:   
public class SiteFileFetch extends Thread { >4b:`L  
'[Ap/:/UY  
;x^WPY Ej  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3#<b!Yz  
long[] nStartPos; //开始位置 ">_<L.,I  
long[] nEndPos; //结束位置 Xn@\p5<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ta8;   
long nFileLength; //文件长度 '#LbIv4  
boolean bFirst = true; //是否第一次取文件 +i HZ*  
boolean bStop = false; //停止标志 h8B:}_Cu  
File tmpFile; //文件下载的临时信息 'Z5l'Ac  
DataOutputStream output; //输出到文件的输出流  `S$zwot  
wFI2 (cQ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "*UN\VV+s  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5#|D1A  
{ Jmg<mjq/G  
siteInfoBean = bean; u5zL;C3O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cetHpU ,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Lu?MRF f  
if(tmpFile.exists ()) 5ar2Y$bY  
{ W}jel}:  
bFirst = false; mqe83 k%  
read_nPos(); \vwsRT 1  
} M~/7thP{  
else w1U2cbCr/  
{ 9BR/zQ2  
nStartPos = new long[bean.getNSplitter()]; XK#~w:/fB  
nEndPos = new long[bean.getNSplitter()]; ,'!x 9 `  
} X% JQ_Z  
u*}[fQ`aF  
st4z+$L  
^V6cx2M  
} y950Q%B]  
J34/rL/s  
>I*)0tE  
public void run() 3T1t !q4/5  
{ <9f;\+zA  
//获得文件长度 X;:qnnO  
//分割文件 =f~8"j  
//实例FileSplitterFetch Odn`q=  
//启动FileSplitterFetch线程 G42J  
//等待子线程返回 }`fFzb  
try{ k65V5lb  
if(bFirst) y-#{v.|L  
{ ~t=73 fwB  
nFileLength = getFileSize(); 1F|e/h%^  
if(nFileLength == -1) ^lvYj E  
{ ?58,Ja  
System.err.println("File Length is not known!"); G.{)#cR  
} r< MW8  
else if(nFileLength == -2) E^s<5BC;  
{ Kx4_`;>  
System.err.println("File is not access!"); s8:-*VR9  
} #!.26RM:P  
else ;bYS#Bid{V  
{ sOVbz2 \yb  
for(int i=0;i<nStartPos.length;i++) FH3^@@Y%  
{ %>io$o  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s2Rg-:7  
} y,/Arl}yc  
for(int i=0;i<nEndPos.length-1;i++) PP*',D3  
{ {)`tN&\  
nEndPos = nStartPos[i+1]; r+RFDg/  
} @LyCP4   
nEndPos[nEndPos.length-1] = nFileLength; b}APD))*H!  
} V|\dnVQ'-%  
} HuI?kLfj\  
x*#9\*@EI  
U0m 5Rc  
//启动子线程 )lh Pl  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #@UzOQ>  
for(int i=0;i<nStartPos.length;i++) aam6R/4  
{ 0rrNVaM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >OxSrc@A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ` W} Bc  
nStartPos,nEndPos,i); OF1fS\P<>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); af-  
fileSplitterFetch.start(); a(#aEbN?d  
} <rn26Gfr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gnthz0\]{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); EEJ OJ<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2kSN<jMr  
nEndPos = " + nFileLength); b+#A=Z+Pr  
// fileSplitterFetch[nPos.length-1].start(); y_:~  
3:g~@PB  
6%A_PP3Z  
//等待子线程结束 A. 5`+  
//int count = 0; i-FsA  
//是否结束while循环 b#[EkI 0@  
boolean breakWhile = false; SJ8CBxA  
HU1ZQkf  
PZ.q  
while(!bStop) WKvG|YRDq  
{ zL@FN sYVM  
write_nPos(); WV&grG|  
Utility.sleep(500); ;RzbPlkl  
breakWhile = true; vuoD~=z  
#qDMUN*i  
f&2f8@  
for(int i=0;i<nStartPos.length;i++) ym*oCfu=  
{ |aX1PC)o_  
if(!fileSplitterFetch.bDownOver) L ]Y6/Q   
{ 2tqj]i  
breakWhile = false; <$@*'i^7Ez  
break; lL;SP&  
} mx=2lL`  
} Ad)::9K?J  
if(breakWhile) vp4NH]fJ  
break; X:kr$  
I3hN7  
sNHxUI  
//count++; YwaWhBCIF  
//if(count>4) lN~V1(1B  
// siteStop(); xe@11/F  
} jnIf (a  
E (-@F%Q  
|w+N(wcJ  
System.err.println("文件下载结束!"); =-%10lOI  
} ?2nF1>1  
catch(Exception e){e.printStackTrace ();} T=,A pa  
} &rfl(&\oUi  
N 9cCfB\`  
V.|#2gC]t  
//获得文件长度 JU3to_Io  
public long getFileSize() 0BrAgv"3a_  
{ (~N[j;W,_W  
int nFileLength = -1; E+z"m|G  
try{ _?oofE:{  
URL url = new URL(siteInfoBean.getSSiteURL()); @8eQ|.q]Q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !]C=5~B BI  
httpConnection.setRequestProperty("User-Agent","NetFox"); $(fhO   
d6f+[<<  
{'a|$u+  
int responseCode=httpConnection.getResponseCode(); <`?V:};Q  
if(responseCode>=400) H&So Vi_V  
{ v}sk %f  
processErrorCode(responseCode); G$A=Tu~  
return -2; //-2 represent access is error h,zM*zA_  
} b6UpE`\z  
N~|Z@pU"  
@@V{W)r l  
String sHeader; iHKX#*  
<7 xX/Z}M  
wl/1~!  
for(int i=1;;i++) ^m ['VK#?  
{ r (KAG"5  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N|e#&  
//Utility.log(in.readLine()); ]sZ! -q'8  
sHeader=httpConnection.getHeaderFieldKey(i); UvF5u(o  
if(sHeader!=null) xG WA5[YV  
{ Q.,2G7[ <  
if(sHeader.equals("Content-Length")) x@3" SiC  
{ 26ae|2?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z\`tn z7>$  
break; Qs,4PPEg  
} } 89-U  
} B!1h"K5.($  
else &embAqW:  
break; G^V a$ike  
} $.x,[R aN  
} Xp[xO0  
catch(IOException e){e.printStackTrace ();} 2ElZ&(RZJF  
catch(Exception e){e.printStackTrace ();} h + <Jv   
PiN^/#D  
qLV3Y?S!L  
Utility.log(nFileLength); }<^QW't_Y  
;EQ7kuJQ?  
8j)*T9  
return nFileLength; _< KUa\  
} =&F~GC Z>  
4L_)@n}  
.(99f#2M:  
//保存下载信息(文件指针位置) e2yCWolmTS  
private void write_nPos() E>iN>  
{ !Ahxi);a  
try{ ERy=lP~gV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); HR ;I}J 9  
output.writeInt(nStartPos.length); =~>g--^U  
for(int i=0;i<nStartPos.length;i++) DTlId~Dyq  
{ GOOm] ]I  
// output.writeLong(nPos); 6Ey@)p..E  
output.writeLong(fileSplitterFetch.nStartPos); Tje(hnN  
output.writeLong(fileSplitterFetch.nEndPos); (K_{a+$[  
} oFGWI#]ts>  
output.close(); t.#ara{  
} 6Yl+IP];i  
catch(IOException e){e.printStackTrace ();} pI_dV44W  
catch(Exception e){e.printStackTrace ();} 2 w6iqLr?  
} /;kSa}"Q  
M@o^V(j  
,m8mh)K?0>  
//读取保存的下载信息(文件指针位置) _+X-D9j(l  
private void read_nPos() ]GO=8$Z  
{ m VFo2^%v  
try{ .TCDv4?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bObsj]  
int nCount = input.readInt(); wr5v-_7r,  
nStartPos = new long[nCount]; *%Fu/  
nEndPos = new long[nCount]; _N=f&~T  
for(int i=0;i<nStartPos.length;i++) 6bPl(.(3  
{ {A'*3(8  
nStartPos = input.readLong(); &isKU 8n  
nEndPos = input.readLong(); - AU{Y`j  
} U(LLIyZv  
input.close(); e^'|<0J  
} yO}5.  
catch(IOException e){e.printStackTrace ();} x[0O*ty-*<  
catch(Exception e){e.printStackTrace ();} ITg<u?z_  
} ~Hu!iZ2]  
Xdw pn+7s  
VFzIBgJ3  
private void processErrorCode(int nErrorCode) 2WTOu x*  
{ BNj_f  
System.err.println("Error Code : " + nErrorCode); ~>HzAo9e  
} C$0g2X  
bAbR0)  
8NiR3*1  
//停止文件下载 u`&lTJgF/O  
public void siteStop() {VKFw=$8  
{  * k<@  
bStop = true; yYaoA/0  
for(int i=0;i<nStartPos.length;i++) 3%hq<  
fileSplitterFetch.splitterStop(); @Ns[qn;9  
1Qu@pb^  
loO"[8i.k  
} y$_@C8?H  
} Z %Ozzp/  
//负责部分文件的抓取 yIrJaS-  
**FileSplitterFetch.java JhfVm*,  
*/ bMGn&6QiP[  
package NetFox; x M(H4.<  
fx(h fz  
^lAM /  
import java.io.*; '3Lu_]I-  
import java.net.*; FY ms]bv  
z9*e%$+S  
d&[RfZ`  
public class FileSplitterFetch extends Thread { |1RVm?~i  
%IX)+ Lp`  
BBRL _6  
String sURL; //File URL wWy;dma#  
long nStartPos; //File Snippet Start Position Vv45w#w;  
long nEndPos; //File Snippet End Position X!p`|i  
int nThreadID; //Thread's ID qh:Bc$S  
boolean bDownOver = false; //Downing is over sVK?sBs]  
boolean bStop = false; //Stop identical qD4]7"9  
FileAccessI fileAccessI = null; //File Access interface Jsysk $R  
Y.\x.Hg  
tqZ+2c<W3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *y!O\-\S#>  
{ })H d]a  
this.sURL = sURL; !: ^q_q4  
this.nStartPos = nStart; %'yrIR  
this.nEndPos = nEnd; <;6{R#Tuh  
nThreadID = id; {]< G=]'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8o$rF7.-  
} ,|{`(y/v  
/{\ /e"5  
I I+y  
public void run() l6ym <V(1p  
{ ;^5k_\  
while(nStartPos < nEndPos && !bStop) yGdX>h  
{  ch8a  
=FrB{Eu  
Gv_~@MN  
try{ wQSye*ec  
URL url = new URL(sURL); #GE]]7:Na  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q$c6l[(g  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;:fW]5"R  
String sProperty = "bytes="+nStartPos+"-"; e@Lxduq  
httpConnection.setRequestProperty("RANGE",sProperty); FfdB%  
Utility.log(sProperty); 6 Rl[M+Q  
[OW <<6  
Do/R.Mgy*  
InputStream input = httpConnection.getInputStream(); YV<y-,Io  
//logResponseHead(httpConnection); |oi+|r  
#wI}93E  
?T/]w-q>  
byte[] b = new byte[1024]; YQn<CjZ8af  
int nRead; "XR=P> xk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wlT8|  
{ STp9Gh-  
nStartPos += fileAccessI.write(b,0,nRead); L~Gr,i  
//if(nThreadID == 1) #h5lz%2g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QQM:[1;RT  
} kAQ(8xV  
"lI-/ G  
V4:/LNq_]  
Utility.log("Thread " + nThreadID + " is over!"); Io1j%T#ZT  
bDownOver = true; 7nek,8b  
//nPos = fileAccessI.write (b,0,nRead); HIXAA?_eh=  
} P:"R;YCvE  
catch(Exception e){e.printStackTrace ();} YYv0cV{E  
} apo)cR  
} An{>39{  
/MGapmqV9  
]JrD@ Vy  
//打印回应的头信息 ~U0%}Bbh  
public void logResponseHead(HttpURLConnection con) Qt>K{ >9Cf  
{ l88=  
for(int i=1;;i++) 2R[v*i^S  
{ a!9'yc  
String header=con.getHeaderFieldKey(i); b=,B Le\  
if(header!=null) mn7I# ~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); R2,9%!iiX  
Utility.log(header+" : "+con.getHeaderField(header));  ]n!V  
else Mu\V3`j  
break; T/_u;My;  
} =AIFu\9#a`  
} Q K]P=pE'C  
Vu:ZG*^  
;W,* B.~  
public void splitterStop() [';o -c"!  
{ hdPGqJE  
bStop = true; %Mda<3P  
} (S~kyU!)0  
cx\E40WD  
q Gk.7wf%  
} * Gg7(cnpw  
;m]V12  
GV0\+A"vD  
/* AxH;psj  
**FileAccess.java 6}^x#9\  
*//文件访问(定位,写) J,=K1>8s  
package NetFox; ?Mjs[|  
import java.io.*; uY]';Ot G  
\p4*Q}t  
$*C }iJsF  
public class FileAccessI implements Serializable{ w2s`9  
WLUgiW(0$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U% h.l  
RandomAccessFile oSavedFile; C'JI%HnQ  
long nPos; TO6F  
U,W OP7z  
N[_T3(  
public FileAccessI() throws IOException 7{#p'.nc5  
{ $--8%gh dG  
this("",0); q8{Bx03m6  
} TGJz[Ny  
Wg|6{'a  
REh"/d  
public FileAccessI(String sName,long nPos) throws IOException 8W&1"h`  
{ K *@?BE  
oSavedFile = new RandomAccessFile(sName,"rw"); k79OMf<v  
this.nPos = nPos; -wn-PB@r  
oSavedFile.seek(nPos); +~5Lo'^  
} o?a2wY^_  
L4po1  
/@`"&@W'  
public synchronized int write(byte[] b,int nStart,int nLen) G8repY  
{ 6s@!Yn|?  
int n = -1; v}DNeIh~  
try{ vPnS`&  
oSavedFile.write(b,nStart,nLen); MXA?rjd0  
n = nLen; y" =?l  
} 4@{;z4*`  
catch(IOException e) D$FTnY  
{ H:G``Vq;0m  
e.printStackTrace (); D <iG*I  
} (%^C}`|EA  
nAP*w6m0j  
K_M Ed1l  
return n; so` \e^d  
} Xe4   
3o rSk  
Hcf"u&%  
} gW~YB2 $  
s)\PY  
4-bM90&1t  
/* b'O/u."O  
**SiteInfoBean.java [r2V+b.C  
*/ >l0Qd1   
package NetFox; =d;a1AO{&  
{L$$"r,  
dw6ysOR@  
public class SiteInfoBean { zTue(Kr  
nk!uO^  
6PsT])*>DE  
private String sSiteURL; //Site's URL xhALJfv  
private String sFilePath; //Saved File's Path 5YrzOqg=  
private String sFileName; //Saved File's Name ~=yU%5 s@  
private int nSplitter; //Count of Splited Downloading File }oD^tU IK  
61_PSScSY  
Ja1`S+  
public SiteInfoBean() `@y~JNf!  
{//nSplitter的缺省值为5 TFHYB9vV  
//default value of nSplitter is 5 @kSfF[4H  
this("","","",5); .nY}_&  
} K-'uE)  
4l0>['K&{  
W(62.3d~}?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -']Idn6  
{ IfH/~EtX  
sSiteURL= sURL; fhg'4FO  
sFilePath = sPath; 1!zd#TX  
sFileName = sName; )7NK+k  
this.nSplitter = nSpiltter; /K2[`+-  
=o~mZ/ 7=M  
c6jVx_tt.  
} `"~GqFwy~  
|ghyH  
KEy8EB  
public String getSSiteURL() 5Y;&L!T  
{ /\e_B6pF<  
return sSiteURL; [#!Y7Ede  
} /sYr?b!/<6  
8}BM`@MG  
1#L%Q(G  
public void setSSiteURL(String value) P:Q&lnC  
{ dOaOWMrfdf  
sSiteURL = value; [m! P(o  
} e>_a (  
sC"w{_D@*4  
6# bTlmcg  
public String getSFilePath() otaRA  
{ ?yG[VW  
return sFilePath; "Pc}-&  
} JV,h1/a("  
8yIBx%"4MH  
7Tp +]"bL  
public void setSFilePath(String value) 3Z~_6P^ +N  
{ }S*]#jr&  
sFilePath = value; iYiTkq  
} &CQ28WG X  
:/gHqEC24  
#HP-ne; #  
public String getSFileName() Jr'a_ (~  
{ `#ff`j|a  
return sFileName; jBEW("4R  
} aQHR=.S]X  
;eo}/-a_Xw  
CY=lN5!J  
public void setSFileName(String value) I\Y N!  
{ ]*MVC/R,  
sFileName = value; %O!x rA{  
} F7<u1R x]  
3;jx Io$,  
'PrBa[%  
public int getNSplitter() GfSD% "  
{ h}tC +_"D  
return nSplitter; {ZdF6~+H(!  
} WNeBthq6  
*oLDy1<  
G'Wp)W;])\  
public void setNSplitter(int nCount) ]>Dbta.2 7  
{ Xn~\Vb  
nSplitter = nCount; rosD)]I7  
} 'pUJREb  
} 8 mOGEx  
o/&K>]8M  
gKQs:25  
/* iW2\;}y  
**Utility.java fVZ9 2Xw B  
*/ ^?0'\Z  
package NetFox; W8x&:5Fc)3  
'5Kj "aD%  
+2tFX  
public class Utility { 3_9CREZCl  
0)zJG |  
y5KeUMcu  
public Utility() } tBw<7fe  
{ <5Ll<0  
+BO kHXk1  
-awG1 4%  
} ' -9=>  
O> _ F   
//线程睡眠 qnQ".  
public static void sleep(int nSecond) y8C8~-&OK  
{ 'C`Ykjf  
try{ 4*o?2P$Q  
Thread.sleep(nSecond); IMM+g]#e  
} @d^DU5ats>  
catch(Exception e) RO3q!+a$/  
{ | Vlx:  
e.printStackTrace (); G{,DoCM5WL  
} pd`m//G  
} CAx eJ`Q  
r9! s@n  
//日志 9Nna-}e?W  
public static void log(String sMsg) uzmYkBv  
{ d@$bPQQ$,  
System.err.println(sMsg); m<k6oev$  
} $0OOH4  
b>i5r$S8G  
S[hyN7sI  
public static void log(int sMsg) +e.w]\}  
{ 8QL=%Pv  
System.err.println(sMsg); .v}|Tp&k  
} /ece}7M  
} IG\Cj7{K^  
aO(iKlZ$  
t,r:= '  
/* z Fj|E  
**TestMethod.java 8D@Jd  
*/ Sp?e!`|8  
package NetFox; /:{4,aX2  
RL\?i~'KH  
<}'=@a  
public class TestMethod { L<iRqayn  
9c*B%A8J  
Bxw(pACf  
public TestMethod() oP4+:r)LKD  
{ ///xx/weblogic60b2_win.exe f52P1V]  
try{ fI<d&5&g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gs/ocu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &%@O V:C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '/X]96Ci7  
fileFetch.start(); Ac*J;fI  
} $%'3w~h`  
catch(Exception e){e.printStackTrace ();} KZ#\ >  
`jr?I {m;  
RjgJIVm(  
} h~CLJoK<  
H[OgnnM  
TXyiCS3  
public static void main(String[] args) 0b n%L~KU  
{ goF87^M  
new TestMethod(); v@M^ukk'}  
} dkDPze9l  
} -/Wf iE  
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