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http断点续传简单实现(java)

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/* _Ml?cT/J.O  
**SiteFileFetch.java [p'2#Et  
*/ ?yAb=zI1b  
package NetFox; e:-pqZT`  
import java.io.*; 4ZUtK/i+r  
import java.net.*; ~N9k8eT  
"Fmq$.$%  
M/W9"N[ta  
public class SiteFileFetch extends Thread { *sp")h#Z  
yj_/:eX  
2*`kkS  
SiteInfoBean siteInfoBean = null; //文件信息Bean &#C&0f8PnD  
long[] nStartPos; //开始位置 r|}Pg}O  
long[] nEndPos; //结束位置 7<70\ 6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5,XEN$^  
long nFileLength; //文件长度 Z*3RI5)dx  
boolean bFirst = true; //是否第一次取文件 W!ug^2"  
boolean bStop = false; //停止标志 r:o9:w:  
File tmpFile; //文件下载的临时信息 hO> q|+mC  
DataOutputStream output; //输出到文件的输出流 ~ a 2A"#f  
]v:,<=S  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) TVvE0y(9  
public SiteFileFetch(SiteInfoBean bean) throws IOException 'g<{l&u  
{ [r 7Hcb  
siteInfoBean = bean; n,2p)#?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .sit5BX  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nl2Lqu1  
if(tmpFile.exists ()) t5l<Lm)  
{ DHn\ =M  
bFirst = false; w;$elXP|  
read_nPos(); dAG@'A\f  
} a{7*um  
else >j]Gz-wC  
{ tC1'IE-h  
nStartPos = new long[bean.getNSplitter()]; %Jl6e}!  
nEndPos = new long[bean.getNSplitter()]; >N! Xey  
} E5S(1Z}]p{  
gF9GU5T:  
@+~URIG)  
'U&]KSzxv  
} ;LC|1_ '  
?-&k?I  
?7CdJgJp  
public void run() 2vUcSKG7  
{ D3g5#.$,}>  
//获得文件长度 G@D8 [  
//分割文件 (oiQ5s^f  
//实例FileSplitterFetch '#A_KHD  
//启动FileSplitterFetch线程 9BOn8p;yz  
//等待子线程返回 p79QEIbk=  
try{ >nehyo:#  
if(bFirst) D{8B;+  
{ Ro$*bN6p  
nFileLength = getFileSize(); G1X73qoHT<  
if(nFileLength == -1) )qX.!&|I  
{ yAGQD[ih  
System.err.println("File Length is not known!"); =?Co<972Z  
} Q!-"5P X  
else if(nFileLength == -2) yWc%z6dXC  
{ DZESvIES  
System.err.println("File is not access!"); ~<IQe-Q 5  
} N>L)2WKFT  
else )=glN<*?  
{ ?:GrM!kq76  
for(int i=0;i<nStartPos.length;i++) zBI2cB8;P  
{ R ^@`]dX$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p `oB._ R  
} ,lCFe0>k!=  
for(int i=0;i<nEndPos.length-1;i++) +c]D2@ctG  
{ S~z$ =IiB  
nEndPos = nStartPos[i+1]; Y -BZV |  
} KvPLA{  
nEndPos[nEndPos.length-1] = nFileLength; H^B,b !5i  
} xV`)?hEXFh  
} hms Aim9i  
"{S4YA  
*.$ov<E.  
//启动子线程 &j'k9C2p  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kMzDmgoxNg  
for(int i=0;i<nStartPos.length;i++) * kL>9  
{  k_^ 4NU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p8s%bPjK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }7%ol&<@  
nStartPos,nEndPos,i); # NK{]H$fd  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |tY6+T}  
fileSplitterFetch.start(); S:2 xm8 i  
} ]t17= Lr?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1G(wESe  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2,|@a\H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G'HLnx}Yi  
nEndPos = " + nFileLength); GXv2B%i8  
// fileSplitterFetch[nPos.length-1].start(); h52+f  
Pa; *%7  
Cx) N;x  
//等待子线程结束 `x L@%  
//int count = 0; 2mx }bj8  
//是否结束while循环 &&}c R:U,  
boolean breakWhile = false; Pqvj0zUo$  
EO",|V-  
O9N%dir  
while(!bStop) S]&i<V1qX  
{ Jx&+e,OST  
write_nPos(); x41t=E](  
Utility.sleep(500); "1P2`Ep;  
breakWhile = true; _ -ec(w~/  
(d <pxx  
-%VFC^'5  
for(int i=0;i<nStartPos.length;i++) k]TJL9Q  
{ tJGPkeA  
if(!fileSplitterFetch.bDownOver) N7s9"i  
{ k[1[Y{n.  
breakWhile = false; O1]XoUH<  
break; 9 771D  
} aO<H!hK  
} cwUor}<|  
if(breakWhile) !VfVpi+-  
break; )pey7-P7g5  
`AdHyE  
ybB<AkYc  
//count++; d?CU+=A&|  
//if(count>4) DEv,!8  
// siteStop(); }u5J<*:bZ  
} 7w0=i Z>K  
,.gI'YPQC  
4x/u$Ixzh=  
System.err.println("文件下载结束!"); H/G;hk  
} 3bugVJ9 3  
catch(Exception e){e.printStackTrace ();} )4+uM'2%  
} ."q8 YaW  
@ 6b;sv1W  
6& 9q6IIy  
//获得文件长度 ?N%5c%oF  
public long getFileSize() mvtuV`  
{ } 4>#s$.2  
int nFileLength = -1;  Z\$!:  
try{ 61TL]S8  
URL url = new URL(siteInfoBean.getSSiteURL()); S7hfwu&7F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ! }awlv;  
httpConnection.setRequestProperty("User-Agent","NetFox"); h/l?,7KHI  
N4 _V  
W?@+LQa??  
int responseCode=httpConnection.getResponseCode(); YGq-AB  
if(responseCode>=400) tkix@Q!;\  
{ 9+>%U~U<  
processErrorCode(responseCode); KEr?&e  
return -2; //-2 represent access is error k .F(*kh  
} IZ_ B $mo  
9l7 youZ]  
Q[Tbdc%1EG  
String sHeader; VqB9^qJ]!  
&cx]7:;  
w?c~be$  
for(int i=1;;i++) 4_Rv}Y d  
{ k1WyV_3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]0p*EB=C*  
//Utility.log(in.readLine()); 23UXOY0BW  
sHeader=httpConnection.getHeaderFieldKey(i); vf_pEkx*wD  
if(sHeader!=null) @] {:juD~  
{ bNz2Uo!0K  
if(sHeader.equals("Content-Length")) _ID =]NJ_  
{ /^Lo@672  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,PyPRPk  
break; 6HR*)*>z_  
} ]h&?^L<.  
} z:W1(/W~  
else QjUojHz%Z  
break; ;W#/;C _h  
} '#8;bU  
} 7)3cq}]O  
catch(IOException e){e.printStackTrace ();} c6pGy%T-  
catch(Exception e){e.printStackTrace ();} S4X['0rX!  
7otqGE\2  
["?WVXCF8|  
Utility.log(nFileLength); fm,:8%  
V=H}Ecd  
2HvzMo-4  
return nFileLength; OBp/:]  
} %O&C\{J  
p$%g$K  
 PYYO-Twg  
//保存下载信息(文件指针位置) _:;j)J0  
private void write_nPos() - e"XEot~  
{ 1HNX 6  
try{ z0&I>PG^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]r1 C  
output.writeInt(nStartPos.length); W.U|mNJ$  
for(int i=0;i<nStartPos.length;i++) \~q cYp  
{ o!t1EPJE*  
// output.writeLong(nPos); -wV0Nv(V8  
output.writeLong(fileSplitterFetch.nStartPos);  wZUR  
output.writeLong(fileSplitterFetch.nEndPos); 3H47 vm(`  
} [ w1"  
output.close(); \ 8X8N CM  
} 32V,25 (`5  
catch(IOException e){e.printStackTrace ();} FwGMrJW  
catch(Exception e){e.printStackTrace ();} c'6$`nC  
} F1o"H/:n  
NBZ>xp[U  
j k}m  
//读取保存的下载信息(文件指针位置) #8jH_bi  
private void read_nPos() >pl*2M&  
{ oE4hGt5x{  
try{ 7dU7cc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0=J69Yd  
int nCount = input.readInt(); k-vxKrjZ/  
nStartPos = new long[nCount]; ;R?9|:7  
nEndPos = new long[nCount]; |tS~\_O/  
for(int i=0;i<nStartPos.length;i++) r\66]u[  
{ ?|9$o/Q}  
nStartPos = input.readLong(); /L"&'~  
nEndPos = input.readLong(); ;42D+q=s  
} ;w}5:3+  
input.close(); KBFAV&  
} DWH)<\?  
catch(IOException e){e.printStackTrace ();} Uyyw'Ni  
catch(Exception e){e.printStackTrace ();} k||DcwO  
} J#W>%2 "s  
&hYjQ&n  
)Z 3fytY  
private void processErrorCode(int nErrorCode) t| zLR  
{ 6Gs,-Kb:  
System.err.println("Error Code : " + nErrorCode); Cx/duod p  
} ^5~[G%G4  
S.OGLLprp  
$T0|zPK5  
//停止文件下载 $rC`)"t  
public void siteStop() ]g; K_>@  
{ W}1h~rNy  
bStop = true; h@D4~(r  
for(int i=0;i<nStartPos.length;i++) 9?W38EF  
fileSplitterFetch.splitterStop(); ;nJCd1H  
)FqE8oN-  
-Q8pWtt  
} 4[&6yHJ^  
} " ,rA  
//负责部分文件的抓取 u$[T8UqF  
**FileSplitterFetch.java ),6Z1 K1  
*/ c$'UfW  
package NetFox; *WgP+"h  
{:enoV"  
6A/|XwfE/v  
import java.io.*; K~WwV8c9;  
import java.net.*; Ja#idF[V  
/qL&)24  
qQ6NxhQo  
public class FileSplitterFetch extends Thread { 9aC>gye!  
|T"{q  
\ca4X{x  
String sURL; //File URL E%-&!%_>D@  
long nStartPos; //File Snippet Start Position BWX&5""  
long nEndPos; //File Snippet End Position <s#}`R.#2  
int nThreadID; //Thread's ID ;@ d<*  
boolean bDownOver = false; //Downing is over ZdH WSfO)O  
boolean bStop = false; //Stop identical 5y"yd6O]O5  
FileAccessI fileAccessI = null; //File Access interface MJX m7<(  
aV(*BE/@F  
lv ^=g  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException I/)dXk~  
{ /HDX[R   
this.sURL = sURL; {+t'XkA  
this.nStartPos = nStart; ~ab"q %  
this.nEndPos = nEnd; oci-[CI,  
nThreadID = id; <ZrZSt+<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M=N`&m\  
} "5jZS6A]  
si nG $=  
l>&)_:\  
public void run() a4: PufS  
{ *G~c6B Z  
while(nStartPos < nEndPos && !bStop) d*>M<6b-  
{ n(f&uV_):  
a3lo;Cfp  
:({lXGc}4?  
try{ p-; ]O~^  
URL url = new URL(sURL); 65J'u N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x{ZVq 4  
httpConnection.setRequestProperty("User-Agent","NetFox"); uX0wg  
String sProperty = "bytes="+nStartPos+"-"; cdIy[ 1  
httpConnection.setRequestProperty("RANGE",sProperty); xSOL4  
Utility.log(sProperty); {@ , L  
@,aL'2G  
$~~=SOd0  
InputStream input = httpConnection.getInputStream(); 3.d=1|E  
//logResponseHead(httpConnection); ,.}PZL  
uV 6f~cQ  
cW GU?cv}  
byte[] b = new byte[1024]; 3iEcLhe"4  
int nRead; ) L{Tn 8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {U(h]'  
{ $uLzC]  
nStartPos += fileAccessI.write(b,0,nRead); tc,7yo\".  
//if(nThreadID == 1) QX]tD4OH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (I~,&aBr  
} m#;:%.Rm  
MA-$aN_(  
"?9fL#8f*!  
Utility.log("Thread " + nThreadID + " is over!"); $qrr]U  
bDownOver = true; sy@k3wQ  
//nPos = fileAccessI.write (b,0,nRead); Vd1K{rH#  
} y?unI~4tC  
catch(Exception e){e.printStackTrace ();} 7T2W% JT-,  
} "+ Qh,fTt  
} #/jHnRrQ   
q2<J`G(tZ  
2.lnT{  
//打印回应的头信息 F9+d7 Y$  
public void logResponseHead(HttpURLConnection con)  vo(?[[  
{ X)&Z{ V>  
for(int i=1;;i++) wRiP5U,  
{ iN {TTy  
String header=con.getHeaderFieldKey(i); h.Dk>H_G  
if(header!=null) r?+u}uH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `Ys })Pl  
Utility.log(header+" : "+con.getHeaderField(header)); ~fUSmc  
else R$3JbR.  
break; p.}[!!m P  
} p4AXQuOP  
} e-K8K+7  
q-3KF  
<|`@K| N  
public void splitterStop() RYhdf  
{ Em]T.'y  
bStop = true; !KlSw,&=.6  
} CM#EA"9  
`k\1vum  
`i:0dVs  
} 7lj-Z~1  
7S7!  
Y}#^n7*w~  
/* f:Ja  
**FileAccess.java 'q^Gg;c>+  
*//文件访问(定位,写) D8#q.OR]  
package NetFox; &Egn`QU  
import java.io.*; %7@H7^s}9  
j bGH3 L  
E0h p%:  
public class FileAccessI implements Serializable{ .5ycO  
*h%G4M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KN`z68c4L  
RandomAccessFile oSavedFile; Q+Fw =Xw  
long nPos; ppD ~xg]  
A X#!9-m3  
U`Ag|R  
public FileAccessI() throws IOException A-u5  
{ =iQm_g  
this("",0);  0EB'!  
} X]*/]Xx  
.0-m=3mp2  
ykeUS zz2  
public FileAccessI(String sName,long nPos) throws IOException H44&u](8{  
{ ,+BgY4OY  
oSavedFile = new RandomAccessFile(sName,"rw"); c>!J@[,  
this.nPos = nPos; -:>#w`H  
oSavedFile.seek(nPos); 7EO&:b]  
} DnFl*T>  
q{ 1U  
}\{1`$*~  
public synchronized int write(byte[] b,int nStart,int nLen) vTEkh0Ys  
{ .%<&W1  
int n = -1; 4~Pto f@  
try{ Ft rw3OxN  
oSavedFile.write(b,nStart,nLen); C941 @I  
n = nLen; 5gEfhZQ  
} I}v#r8'!  
catch(IOException e) h3IkOh4|h  
{ `4q}D-'TF8  
e.printStackTrace (); kZ}u  
} PPO<{  
g DG m32  
NGs9Jke2  
return n; oI~Qo*4eh  
} zs:7!  
j1C.#-P[  
wg.fo:Q  
} {wXN kq  
$:N "*  
|P7f^0idk  
/* o)=VPUe  
**SiteInfoBean.java EI.Pk>ZIm  
*/ =*}Mymhk(  
package NetFox; +|<&#b0Xd  
aF"Z!HD  
Hc%\9{zH  
public class SiteInfoBean { =M#?*e  
-b}S3<15@  
X4G55]D$>  
private String sSiteURL; //Site's URL %Nl(Y@dD*  
private String sFilePath; //Saved File's Path 26VdRy{[  
private String sFileName; //Saved File's Name 2H+DT-hK  
private int nSplitter; //Count of Splited Downloading File :t S"sM  
WG luY>C;  
ee^_Dh4  
public SiteInfoBean() :*'?Ac ?  
{//nSplitter的缺省值为5 :+Ax3  
//default value of nSplitter is 5 gtGKV  
this("","","",5); aQ:f"0fL  
} )o</gt)  
z 2VCK@0  
32LB*zc  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <&%1pZ/6.  
{ %,cFX[D/)  
sSiteURL= sURL; A<5`[<x$  
sFilePath = sPath; ya L W(@  
sFileName = sName; xBfe8lor  
this.nSplitter = nSpiltter; LC\:xia{X  
J8BT%  
:_a]T-GL  
} /B\-DP3K  
tB=D&L3  
4`P2FnJ?  
public String getSSiteURL() O)JUY *&I5  
{ gNN" H#=2  
return sSiteURL; sg"D;b:X  
} Z"|P(]A  
9Pp|d"6]y  
M6*{#Y?  
public void setSSiteURL(String value) tZCe?n]  
{ ~y H>Ko9F}  
sSiteURL = value; [Um4\QvUx  
} H!.D2J   
%e7(HfW-U  
L(n/uQ :  
public String getSFilePath() kok^4VV  
{ H"rzRd; S  
return sFilePath; /+t[,  
} &:I +]G/W  
'b?.\Bm;  
|z]2KjF&w-  
public void setSFilePath(String value) n_n|^4 w  
{ @IY?DO  
sFilePath = value; xhkWKB/7  
} Rw\C0'  
_+ 04M)q0  
}t%>_  
public String getSFileName() _d| 62VS  
{ 7(~H77  
return sFileName; kTZx-7~  
} m?VRX .>  
<h_P+ nz  
:sVHY2x  
public void setSFileName(String value) 'cF%4F  
{ MhI)7jj`mt  
sFileName = value; IqCCfsf4  
} W _,;eyo  
,ANK3n\  
}t51U0b%  
public int getNSplitter() l \^nC2  
{ <VaMUm<2  
return nSplitter; %|(?!w7  
} {rvbo1t  
t0J5v;  
LJ(n?/z%  
public void setNSplitter(int nCount) 6=,#9C9  
{ V9E6W*IE  
nSplitter = nCount; Lkl|4L   
} 1.0!H.>q  
} }S vw,c  
.y7)XLC  
"?SOBA!vy  
/* U7"BlT!V\  
**Utility.java H : T N  
*/ xeHb89GnoQ  
package NetFox; F%#*U82  
!-5S8b  
3K#mF7)a  
public class Utility { IjDT'p_  
crNjI`%tw  
_MdZDhtm  
public Utility() xEiX<lguyN  
{ Sc'c$/  
II-$WJy  
B8UZ9I$n  
} 27a* H1iQ  
m@Ip^]9ry  
//线程睡眠 fNqmTRu  
public static void sleep(int nSecond) 7SK 3  
{ P*SCHe'  
try{ (H8C\%g:  
Thread.sleep(nSecond); 1O9p YW5J  
} qqe2,X?  
catch(Exception e) o3F|#op  
{ R#/?AD&  
e.printStackTrace (); e$Bf[F#;-  
} :6W^ S/pf  
} {M@@)27gW  
kPO6gdwq$  
//日志 `.>k)=F&  
public static void log(String sMsg)  L%WME8PB  
{ afY_9g!\  
System.err.println(sMsg); *^D@l%av;  
} |}M0,AS  
SH vaV[C  
;vJ\]T ml  
public static void log(int sMsg) 2Io6s '  
{ v\ %B  
System.err.println(sMsg); o9ctJf=qn  
} %GX uuE}mX  
} RVkU+7  
';b3Mm #  
Z cm<Fw  
/* JY2/YDJ  
**TestMethod.java }Kj Ju;  
*/ W-z90k4Z5  
package NetFox; zj>aaY  
*#1y6^  
tyEPU^PM  
public class TestMethod { I /On3"U%  
SE^j=1  
c~^CKgr~R9  
public TestMethod() H|;*_  
{ ///xx/weblogic60b2_win.exe 5{13 V*<  
try{ <&5m N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }!%JYG^!D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C,A!tj7@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &|.hkR2k  
fileFetch.start(); E dn[cH7  
} yB,{#nM>8  
catch(Exception e){e.printStackTrace ();} FxCZRo&  
PS=e\(6QC  
#wenX$UTh3  
} UvxSMD:A  
'qL5$zG  
!K3})& w  
public static void main(String[] args) r{\BbUnf)  
{ ?;|@T ty%  
new TestMethod(); wG1y,u'  
} ;} lT  
} KVB0IXZC~  
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