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http断点续传简单实现(java)

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/* 9R2"(.U  
**SiteFileFetch.java  \m~p;B  
*/ *sZH3:  
package NetFox; 6-uLK'E  
import java.io.*; ?G,gPb  
import java.net.*; !zm;C@}ln  
4;W{#jk  
M| j=J{r  
public class SiteFileFetch extends Thread {  BdiV  
~ +>e hU  
P[-do  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?pfr^ !@$  
long[] nStartPos; //开始位置 _9t1 aP5  
long[] nEndPos; //结束位置 XXhN; -p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n-xdyJD  
long nFileLength; //文件长度 122s 7A  
boolean bFirst = true; //是否第一次取文件 dCS f$5  
boolean bStop = false; //停止标志 ]jm:VF]4  
File tmpFile; //文件下载的临时信息 ez!W0  
DataOutputStream output; //输出到文件的输出流 ^H7xFd|>  
Ef?hkq7X<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7)Vbp--b#  
public SiteFileFetch(SiteInfoBean bean) throws IOException a;^lOU|L{  
{ i\l}M]Z#  
siteInfoBean = bean; $/|) ,n  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HzKY2F(,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :fwtPvLo  
if(tmpFile.exists ()) UKZ )Boo  
{ z6l'v~\  
bFirst = false; 8PH4v\tJEK  
read_nPos(); ;Vc|3  
} In?#?:Q@&  
else {:("oK6w  
{ QRK\74'uY  
nStartPos = new long[bean.getNSplitter()]; oQ,<Yx%E3  
nEndPos = new long[bean.getNSplitter()]; @tY]=pqn_  
} 'fGKRd|)  
UOf\pG  
})P!7t  
)gSqO{Z  
} !`RMXUV  
Osm))Ua(  
Eyjsbj8  
public void run() nDX Em6|e  
{ 9]w?mHslE  
//获得文件长度 NU?<bIQ  
//分割文件 ^g|cRI_"  
//实例FileSplitterFetch >;hAw!|#  
//启动FileSplitterFetch线程 !&hqj$>-}  
//等待子线程返回  U-4F  
try{ mB"I(>q*M  
if(bFirst) {ri={p]l  
{ jLt3jN  
nFileLength = getFileSize(); ni%)a  
if(nFileLength == -1) d6'G 7'9  
{ ,!@MLn  
System.err.println("File Length is not known!"); &Q;sbI}  
} Y8]@y0(  
else if(nFileLength == -2) 2vLun   
{ 72"H#dy%U  
System.err.println("File is not access!"); Dqii60  
} |u^S}"@3sU  
else @-L]mLY  
{ ltDohm?  
for(int i=0;i<nStartPos.length;i++) :&TM0O  
{ aK - x{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C$PS@4'U  
} 'UWkJ2:!  
for(int i=0;i<nEndPos.length-1;i++) {9}CU~R  
{ oC49c~`8  
nEndPos = nStartPos[i+1]; -u'"l(n)~  
} 2;WbXc!#!  
nEndPos[nEndPos.length-1] = nFileLength; 8$A0q%n  
} ls:oC},p*  
} ^M6lF5  
e 9RYk:O  
[V:~j1{3  
//启动子线程 $8UW^#Bpq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; kt)Et  
for(int i=0;i<nStartPos.length;i++) +sjzT[ Dn  
{ l;@+=uVDHm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6{ ]F#ig=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0>7Ij7\[8  
nStartPos,nEndPos,i); ;J,(YNI 1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [UZ r|F  
fileSplitterFetch.start(); rf%lhBv  
} Rh|9F yN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "%Y=+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c_*w<vJ-'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -'d:~:1f  
nEndPos = " + nFileLength); yiC7)=  
// fileSplitterFetch[nPos.length-1].start(); s. A}ydtt  
EUuSN| a  
>x;\H(g  
//等待子线程结束 aF^N  Ye  
//int count = 0; 94ruQ/  
//是否结束while循环 Oa~ThbX7  
boolean breakWhile = false; 2.niB>  
,GYQ,9:  
 )^{}ov  
while(!bStop) G]f|?  
{ 8CZfz!2  
write_nPos(); O;<wD h)Yt  
Utility.sleep(500); M['O`^  
breakWhile = true; 77O$^fG2  
3PU_STSix  
/"?DOsJ.  
for(int i=0;i<nStartPos.length;i++) W<pr Y  
{ 8(\}\4G_  
if(!fileSplitterFetch.bDownOver) s<F*kLib  
{ Zyz#xMmM  
breakWhile = false; {+WY,%e  
break; e6j1Fa9  
} #Z2 'Y[@.  
} ?QT6q]|d0+  
if(breakWhile) w/m@(EBK  
break; '?veMX  
w/nohZF6H  
~h3G}EH  
//count++; ?<!q F:r:  
//if(count>4) W^ L ^7  
// siteStop(); /_qq(,3  
} r3g^ 0|)  
Ia#!T"]@W6  
FHr)xqo=~  
System.err.println("文件下载结束!"); /o;L,mcx*  
} W"vLCHTh  
catch(Exception e){e.printStackTrace ();} tjx8 UgSi  
} hXjZ>n``  
1 6zxPSTr}  
Ie. on)  
//获得文件长度 fasW b&~z  
public long getFileSize() +112{v=!i  
{ ]64}Xob87_  
int nFileLength = -1; B~Kx Up  
try{ AuXUD9 -  
URL url = new URL(siteInfoBean.getSSiteURL()); z.cDbkf}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H1kI+YJ@  
httpConnection.setRequestProperty("User-Agent","NetFox"); B&a{,.m&q6  
FFcCoPX_  
Z2$_9.  
int responseCode=httpConnection.getResponseCode(); `;6M|5G  
if(responseCode>=400) ?CQE6ch  
{ H<_Tn$<zH.  
processErrorCode(responseCode); /@ @F nQ++  
return -2; //-2 represent access is error M co:eE  
} vzg^tJ  
Hloe7+5UD  
^}-l["u`  
String sHeader; cRnDAn#42  
KNAvLcg  
dRron_'  
for(int i=1;;i++) Jj \ nye+  
{ Ea@0>_U|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _  Lh0  
//Utility.log(in.readLine()); _C/|<Ot:  
sHeader=httpConnection.getHeaderFieldKey(i); M?h{'$T  
if(sHeader!=null) G7 UUx+X  
{ ['}|#3*w  
if(sHeader.equals("Content-Length")) ML12&E>  
{ |KYl'"5\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); kzZgNv#G;  
break; o&1mX  
} })-V,\  
} HqWWWCWal  
else Zmyq6.1q~  
break; kS-BB[T  
} I_ZJnu<  
} w"9h_;'C_  
catch(IOException e){e.printStackTrace ();} Z5q%L!4G  
catch(Exception e){e.printStackTrace ();} ~JL qh  
_VT{2`|})  
b \}a   
Utility.log(nFileLength); caQ1SV^{9  
d%P2V>P  
FSQB{9,H  
return nFileLength; \|Af26  
} .z,-ThTH@\  
ElW\;C:K*  
MeBTc&S<  
//保存下载信息(文件指针位置) DS(>R!bb  
private void write_nPos() mKe6rEUs|  
{ =T[P  
try{ daKZ*B|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Bo "9;F  
output.writeInt(nStartPos.length); 3%)cUkD  
for(int i=0;i<nStartPos.length;i++) &s`)_P[  
{ bPFGQlmIO  
// output.writeLong(nPos); B9"o Ru^}  
output.writeLong(fileSplitterFetch.nStartPos); HKJCiQ|k  
output.writeLong(fileSplitterFetch.nEndPos); ejV`W7U  
} YdCl  
output.close(); (sKg*G2  
} oYw?kxRZ  
catch(IOException e){e.printStackTrace ();} R1LirZlzJ  
catch(Exception e){e.printStackTrace ();} y ~  K8  
} 0OHXg=  
jo"nK,r  
#!Cg$6%x9  
//读取保存的下载信息(文件指针位置) 3~P$p<  
private void read_nPos() SdlO]y9E  
{ O<s7VHj  
try{ . \a+m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |^8ND #x  
int nCount = input.readInt(); 55O}SUs!P  
nStartPos = new long[nCount]; VjWJx^ZL#  
nEndPos = new long[nCount]; Hi[lN7ma8  
for(int i=0;i<nStartPos.length;i++) q<E7q Y+  
{ c/K#W$ l  
nStartPos = input.readLong(); HHx:s2G  
nEndPos = input.readLong(); 6h/!,j0:t_  
} ^ZsIQ4@`  
input.close(); tQzbYzGb7  
} @M\JzV4 A[  
catch(IOException e){e.printStackTrace ();} !6|_`l>G,  
catch(Exception e){e.printStackTrace ();} j4i$2ZT'  
} K;"H$0 !9  
WDY\Fj   
k H65k (  
private void processErrorCode(int nErrorCode) )2).kL>  
{ <o()14  
System.err.println("Error Code : " + nErrorCode); _]*[TGap  
} Mt4]\pMUb  
#6@hVR.  
0t!ZMH  
//停止文件下载 .'M.yE~5J  
public void siteStop() 5]*lH t  
{ bq7+l4CGTv  
bStop = true; mfZbo#KS#v  
for(int i=0;i<nStartPos.length;i++) |iJz[%  
fileSplitterFetch.splitterStop(); .K~V DUu  
Q)aoc.f!v  
:j+E]|d(~6  
} <T7@,_T  
} S<]k0bC  
//负责部分文件的抓取 Ia](CN*;6  
**FileSplitterFetch.java ek)rsxf1A  
*/ TSFrv8L  
package NetFox; BMAWjEr  
lJAzG,f  
`P\H{  
import java.io.*; *P *.'XM  
import java.net.*; :c]y/lQmV  
~*EipxhstJ  
a)2l9  
public class FileSplitterFetch extends Thread { %u%;L+0Q[  
ypM,i  
6 T4"m  
String sURL; //File URL 9Y2u/|!.3  
long nStartPos; //File Snippet Start Position ; ]% fFcy  
long nEndPos; //File Snippet End Position }%w;@[@L  
int nThreadID; //Thread's ID K_U`T;Z\  
boolean bDownOver = false; //Downing is over bzpi7LKN  
boolean bStop = false; //Stop identical $]?pAqU\  
FileAccessI fileAccessI = null; //File Access interface 27gHgz}}  
'*Y mYU  
|8}y?kAC  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0D4 4  
{ N''xdz3Z  
this.sURL = sURL; D`n<!"xg@$  
this.nStartPos = nStart; rMG[,:V  
this.nEndPos = nEnd; WClprSl8  
nThreadID = id; dh]Hf,OLF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =KR^0<2r  
} GX19GI@k  
~C 3 Y/}  
q#Otp\f  
public void run() q:up8-LAr  
{ !pe[H*Cy  
while(nStartPos < nEndPos && !bStop) VKXi*F9  
{ 7202N?a {  
LL:N/1ysG  
J8FzQ2  
try{ ,%m~OB #  
URL url = new URL(sURL); f(}&8~&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); si%V63^lN  
httpConnection.setRequestProperty("User-Agent","NetFox");  `&a8Wv  
String sProperty = "bytes="+nStartPos+"-"; Q >yj<DR  
httpConnection.setRequestProperty("RANGE",sProperty); iU0jv7}n  
Utility.log(sProperty); dh}"uM}a  
L9hL@  
_j$V[=kdM/  
InputStream input = httpConnection.getInputStream(); X%!?\3S  
//logResponseHead(httpConnection); ?>=vKU5  
lKQjG+YF  
:1'1 n  
byte[] b = new byte[1024]; r_ 9"^Er  
int nRead; zGO_S\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ( K-7z  
{ P[`>*C\9c  
nStartPos += fileAccessI.write(b,0,nRead); p^{yA"MQ  
//if(nThreadID == 1) 8oHIXnK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E]{0lG`l  
} ViOXmK"  
oM n'{+(w  
8f?o?c|  
Utility.log("Thread " + nThreadID + " is over!"); T}p|_)&y  
bDownOver = true; Rp zuSh  
//nPos = fileAccessI.write (b,0,nRead); 6EWCJ%_  
} HE4S%#bH>  
catch(Exception e){e.printStackTrace ();} `T2DGv  
} mV7_O//  
} |[V6R\l39  
wc6#C>=F  
muK)Y w[#N  
//打印回应的头信息 UWCm:eRQ  
public void logResponseHead(HttpURLConnection con) *}r6V"pH~  
{ 5U_ar   
for(int i=1;;i++) `ER#S_}  
{ kyB>]2  
String header=con.getHeaderFieldKey(i); T/L\|_:'  
if(header!=null) Odt<WG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]~m=b` o  
Utility.log(header+" : "+con.getHeaderField(header)); m&*0<N  
else UBwYwm0  
break; BhyLcUBuB  
} Pw Amnk !  
} a<pEVV\NB~  
A[88IMZs  
GO#eI]>/r  
public void splitterStop() w `M/0.)V  
{ ,;= S\  
bStop = true; iQh:y:Jo1&  
} p{V(! v|  
sYTToanA$?  
78mJ3/?rC  
} FP6Jf I8  
Zg])uM]\2i  
3v~}hV/RUy  
/* )6he;+  
**FileAccess.java w/0;N`YB  
*//文件访问(定位,写) 9 Xh<vh8&  
package NetFox; ,(yaWd6  
import java.io.*; n<[H!4  
-fz(]d  
,+_gx.H2j  
public class FileAccessI implements Serializable{ J:;nN-\j  
# b= *hi`E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 No/D"S#  
RandomAccessFile oSavedFile; Zvz}Z8jW  
long nPos; i\L7z)u  
^\PNjj*C i  
`? f sU  
public FileAccessI() throws IOException TsRbIq[  
{ R<>uCF0  
this("",0); YH[HJ#:7r  
} wlX K2D  
` \-m qe  
28,HZaXhc  
public FileAccessI(String sName,long nPos) throws IOException 6;\Tps;A  
{ hcD.-(-;)  
oSavedFile = new RandomAccessFile(sName,"rw"); iEBxBsz_  
this.nPos = nPos; fVBu?<=d  
oSavedFile.seek(nPos); 6[1lK8o  
} 0Szt^l7  
Fo| rRI2  
k:E+]5  
public synchronized int write(byte[] b,int nStart,int nLen) Bk4|ik}  
{ QtqE&j  
int n = -1; B\7 80p<  
try{ $5yH8JU  
oSavedFile.write(b,nStart,nLen); ^t)alNGos  
n = nLen; YcuHYf5  
} k{C|{m  
catch(IOException e) )0@&pEObm  
{ w3oe.hWP3N  
e.printStackTrace (); 9O#?r82  
} Ru`7Xd.  
oO,"B8a  
w 259':  
return n; 1A 9Gf  
} $QuSmA<4lS  
;ZLfb n3\  
T`^LWc"  
} IQ}YF]I;  
F|W(_llfM  
:j!N7c{  
/* +QFY. >KH  
**SiteInfoBean.java T_?,?  
*/ c:z<8#A}  
package NetFox; q0]Z` <w  
]a=Bc~g91  
!xZ`()D#  
public class SiteInfoBean { e;)&Hc:Z  
,n+~S^r  
E@$HO_;&  
private String sSiteURL; //Site's URL c`G~.paY|  
private String sFilePath; //Saved File's Path V4 Wn  
private String sFileName; //Saved File's Name |zSoA=7?  
private int nSplitter; //Count of Splited Downloading File <DM:YWNa  
i/WiSwh:  
8Ow0A  
public SiteInfoBean() GGwHz]1L  
{//nSplitter的缺省值为5 be{tyV  
//default value of nSplitter is 5 < {dV=  
this("","","",5); naKB2y]l  
} e$@azi1  
t12 xPtN1  
o.H(&ex|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oT27BK26?h  
{ p=U5qM.O  
sSiteURL= sURL; :Qra9; Y  
sFilePath = sPath; `]:&h'  
sFileName = sName; Nl`8Kcv  
this.nSplitter = nSpiltter; E; Z1HF R  
['n;e:*  
$3MYr5  
} 4 U`5=BI  
0?nm`9v6  
,=kQJ|  
public String getSSiteURL() Kzd)Z fnD0  
{ Fs EPM"&?h  
return sSiteURL; A `n:q;my  
} gcf EJN4'  
(t)a u  
K2R[u#Q  
public void setSSiteURL(String value) {n>W8sN<  
{ pI|H9  
sSiteURL = value; BWN[>H %S  
} S7 Tem:/  
(Q09$  
FO5'<G-  
public String getSFilePath() !EQMTF=(  
{ v(tr:[V  
return sFilePath; h .$3 jNU  
} C6C7*ks  
"ewB4F[  
q9&d24|  
public void setSFilePath(String value) ^g56:j~?  
{ 77I D 82  
sFilePath = value; h0fbc;l  
} GM<r{6Qy  
&<sN( ;%0R  
Q@lJ|  
public String getSFileName() 7 n=fB#!*3  
{ ( nH3  
return sFileName; U0:tE>3`  
} 2x7%6'  
m mj6YQ0a  
ES#K'Lf  
public void setSFileName(String value) }TCOm_Y/qL  
{ E|Lv_4lb=  
sFileName = value; `<L6Q2Y>j  
} { +%S{=j  
5'Fh_TXTD  
{s=$.Kg  
public int getNSplitter() JUlV$b.)J  
{ g2<xr;<t^  
return nSplitter; qeyBZ8BG  
} HEjrat;5  
m_z1|zM}o  
 ? h$>7|  
public void setNSplitter(int nCount) 7QlA/iKqK  
{ 5!PU+9Kh  
nSplitter = nCount; m{bw(+r  
} q)uq?sZe  
} @"m? #  
C9q`x2  
^vmyiF  
/* o|nj2.  
**Utility.java 5[|MO.CB$  
*/ 8L?35[]e  
package NetFox; ? 1g<] ?  
 R9->.eE  
Z=Oo%lM6B  
public class Utility { 2EOt.4cP  
;TK:D=p4  
av1*i3  
public Utility() dfo{ B/+  
{ {qm(Z+wcmb  
b7/1 ]  
Y24: D7Q  
} >4.{|0%ut  
^zv28Wq>  
//线程睡眠 )h ~MIpWR  
public static void sleep(int nSecond) SZCF db  
{ L`ZH.fN  
try{ W)F2X0D>  
Thread.sleep(nSecond); Vl!Z|}z  
} 7K`A2  
catch(Exception e) L44-: 3  
{ a<[@p  
e.printStackTrace (); 1@H3!V4  
} MdWT[  
} 0j1I  
FxC@KZG  
//日志 _wg6}3  
public static void log(String sMsg) LmLV2f  
{ @>J4K#"  
System.err.println(sMsg); AO9F.A<T5  
} X.,1SYG[  
L!-@dz  
4b8!LzKS  
public static void log(int sMsg) ,2)LH 'Xx  
{ EM*YN=So  
System.err.println(sMsg); Ftm%@S?  
} YXJjqH3  
} ()vxTTa  
v!ULErs  
gJ>?<F;  
/* O1@xF9<  
**TestMethod.java X+{4,?04+  
*/ cT8jG ,+"}  
package NetFox; =F ZvtcCa  
N`/6 By  
/r|^Dc Nx  
public class TestMethod { 6tM CpSJ  
zQ}:_  
im_W0tGvF  
public TestMethod() S >uzW #  
{ ///xx/weblogic60b2_win.exe EpeTfD  
try{ "j9,3yJT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JLRw`V,o7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X LPO_ tD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "!gd)^<e  
fileFetch.start(); L&lNpMT  
} i7}) VDsZ  
catch(Exception e){e.printStackTrace ();} u(SdjLf:  
\{n]&IjA  
v\t$. _at  
} LI?rz<H!D  
o\8yYX  
L^)&"6oSa  
public static void main(String[] args) 7 #_{UJ%  
{ x<"e} Oo  
new TestMethod(); &@A(8(%  
} dapQ5JT/  
} {y'c*NS  
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