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http断点续传简单实现(java)

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/* $7bux 1L  
**SiteFileFetch.java _ hs\"W  
*/ D``>1IA]  
package NetFox; O,?aVgY  
import java.io.*; j-wz7B  
import java.net.*; JM Ikr9/$  
S*?x|&a  
+ +G %~)S:  
public class SiteFileFetch extends Thread { P(Ve' wOaf  
XpibI3:<  
xzTF| Z\  
SiteInfoBean siteInfoBean = null; //文件信息Bean Z^yhSbE{5  
long[] nStartPos; //开始位置 .?p\=C@C+  
long[] nEndPos; //结束位置 };@J)}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IRl(H_.  
long nFileLength; //文件长度 +~1~f'4J  
boolean bFirst = true; //是否第一次取文件 \t@4)+s/)  
boolean bStop = false; //停止标志 #[ch?K  
File tmpFile; //文件下载的临时信息 7.tEi}O&_g  
DataOutputStream output; //输出到文件的输出流 gVI2{\a  
d]w%zo,yr  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) yaKw/vV  
public SiteFileFetch(SiteInfoBean bean) throws IOException bcC+af0L  
{ n 0CS =  
siteInfoBean = bean; r&c31k]E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z7Xic5PI{4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~Y'j8W  
if(tmpFile.exists ()) YR}By;Bq  
{ L% ?3VW  
bFirst = false; 9V( esveq  
read_nPos(); ?br4 wl  
} YUsMq3^&  
else m kHcGB!~  
{ %t<ba[9F  
nStartPos = new long[bean.getNSplitter()]; UV8K$n<  
nEndPos = new long[bean.getNSplitter()]; W05>\Rl  
} &[|P/gj#>  
dt|f4 XWF  
~ 6-6aYhe  
qb1[-H  
} g?d*cwtU  
Seb J}P1x  
>*cg K}!@  
public void run() JW-!m8  
{ 5D%gDw+"  
//获得文件长度 AV*eGzz`  
//分割文件 m5rJY/  
//实例FileSplitterFetch !_SIq`5]@  
//启动FileSplitterFetch线程 #Bgq]6G2  
//等待子线程返回  _F9O4Q4  
try{ *QT|J6ng  
if(bFirst) kw.IVz<  
{ mFXkrvOf,  
nFileLength = getFileSize(); K7N.gT*4  
if(nFileLength == -1) [.`%]Z(  
{ q^k]e{PD  
System.err.println("File Length is not known!"); Ps_q\R  
} Z-B b,8  
else if(nFileLength == -2) &b7i> ()  
{ +Jv*u8T'  
System.err.println("File is not access!"); C ^hCT  
} DRw;.it2  
else Oe[qfsdW  
{ jJDY l([  
for(int i=0;i<nStartPos.length;i++) .&Ok53]b  
{ xRU ~h Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); du k:: |{F  
} KGoHn6jM  
for(int i=0;i<nEndPos.length-1;i++) I_h{n{,sr  
{ 81<0B @E  
nEndPos = nStartPos[i+1]; +|=5zWI /  
} 7yK1Q_XY>  
nEndPos[nEndPos.length-1] = nFileLength; 8${Yu  
} `Ufv,_n  
} Vdz(\-}ao  
#RA3 T[A  
qTl/bFD  
//启动子线程 U\\nSU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0{ ;[k  
for(int i=0;i<nStartPos.length;i++) +\O[)\  
{ q"Z!}^{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6Y[|xu:N8Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WDdp(<  
nStartPos,nEndPos,i); $=-Q]ld&]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ']]&<B}mz  
fileSplitterFetch.start(); GXE6=BO  
} @\UoZv(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qm&Z_6Pw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4/B n9F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %g<J"/  
nEndPos = " + nFileLength); _%$(D"^j  
// fileSplitterFetch[nPos.length-1].start(); Y[yw8a  
/-W-MP=Wd  
BLvI[b|3gn  
//等待子线程结束 r\-25F<e5  
//int count = 0; hIr$^%  
//是否结束while循环 yw( E}   
boolean breakWhile = false; k v}<u  
+.b@rU6H  
)5Bkm{v3  
while(!bStop) a}w%k  
{ _2,eS[wP  
write_nPos(); <?I s~[2  
Utility.sleep(500); H~P"uYKIZ  
breakWhile = true; pM i w9}  
C,!}WB@VME  
E(&GZ QE  
for(int i=0;i<nStartPos.length;i++) G2,r %|7ta  
{ ) -C9W7?I  
if(!fileSplitterFetch.bDownOver) XI*_ti  
{ DB>Y#2j4h  
breakWhile = false; {&Bpf K;`)  
break; @-ma_0cZQ  
} /@.c 59r  
} !^|%Z  
if(breakWhile) VnJ-nfA  
break; ab=s+[r1  
hR$lX8  
%YaUc{.%  
//count++; ^3-Wxn9&  
//if(count>4) ;^,2 QsM  
// siteStop(); L8~nx}UP5  
} O&:0mpRZ  
7Pc0|Z/  
w$5N6  
System.err.println("文件下载结束!"); Vd{h|=J  
} #NVqS5  
catch(Exception e){e.printStackTrace ();} ] _/d  
} YW}1iT/H  
Qjj:r~l  
Qn7l-:`?  
//获得文件长度 |m%M$^sZ}  
public long getFileSize() &E{5k{Y  
{ ')9%eBaeK  
int nFileLength = -1; @x@w<e%  
try{ ItTIU  
URL url = new URL(siteInfoBean.getSSiteURL()); J L9d&7-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J9LS6~ 7  
httpConnection.setRequestProperty("User-Agent","NetFox"); I@=h|GM  
X'&$wQ6,K  
,qRSB>5c  
int responseCode=httpConnection.getResponseCode(); 3"gifE  
if(responseCode>=400) RTSR-<{z  
{ {}3kla{  
processErrorCode(responseCode); bmAgB}Ior  
return -2; //-2 represent access is error sK:,c5^  
} {I |k@  
xX'Uq_ Jv  
ndm19M8Y|  
String sHeader; gKZ{O  
|<.b:e\4  
|7Q8WjCQ{m  
for(int i=1;;i++) R0<ka[+  
{ n;"4`6L~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J{mP5<8>b  
//Utility.log(in.readLine()); 4:}`X  
sHeader=httpConnection.getHeaderFieldKey(i); QD:0iD?  
if(sHeader!=null) 0<L@f=i  
{ lO9{S=N  
if(sHeader.equals("Content-Length")) %f;(  
{ ~MY (6P  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;f-|rC_"  
break;  W4CI=94  
} Z"gllpDr$  
} oQDOwM,  
else co3H=#2a  
break; \i-jME(sN  
} =tcPYYD  
} *eXO?6f%s^  
catch(IOException e){e.printStackTrace ();} ^c]Sl  
catch(Exception e){e.printStackTrace ();} 2LYd # !i  
ZZC= 7FB  
dW7dMx  
Utility.log(nFileLength); q rbF@{  
}bznx[4?I  
fC3IxlG  
return nFileLength; ud:?~?j&w  
} K23_1-mbe  
~rCnST  
cM4?G gn  
//保存下载信息(文件指针位置) !E_uQ?/w]Z  
private void write_nPos() savz>E &  
{ ID+'$u &  
try{ g}^ /8rW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YY!(/<VI  
output.writeInt(nStartPos.length); zF i+6I$  
for(int i=0;i<nStartPos.length;i++) A?}OOjA  
{ 0h shHv-  
// output.writeLong(nPos); 0]oQ08  
output.writeLong(fileSplitterFetch.nStartPos); J-PzIFWd  
output.writeLong(fileSplitterFetch.nEndPos); ^y6Pkb P  
} 0K3FH&.%  
output.close(); 6 qKIz{;  
} e3>Re![_.  
catch(IOException e){e.printStackTrace ();} 8)POEY4  
catch(Exception e){e.printStackTrace ();} )Elr8XLw  
} }2c}y7B,_  
Br~%S?4"o  
jZ D\u%  
//读取保存的下载信息(文件指针位置) vWkKNB  
private void read_nPos() @B9|{[P  
{ 4\OELU  
try{ C-Fp)Zs{0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ee|+uQ981>  
int nCount = input.readInt(); W=EO=}l#  
nStartPos = new long[nCount]; f[}SS]d:E  
nEndPos = new long[nCount]; <Ab:yD`K!  
for(int i=0;i<nStartPos.length;i++) (Z"Xp{u  
{ ~$\j$/A8/  
nStartPos = input.readLong(); @J<B^_+Se  
nEndPos = input.readLong(); #8z\i2I  
} d}o1 j  
input.close(); `f'q/  
} fd,~Yj$R?  
catch(IOException e){e.printStackTrace ();} oM7^h3R  
catch(Exception e){e.printStackTrace ();} lwg.'<  
} ;W+-x] O  
Z],"<[E  
_5m }g!  
private void processErrorCode(int nErrorCode) b/K&8C,c  
{ ai`:HhE  
System.err.println("Error Code : " + nErrorCode); =!CuCV7$1O  
} yX~[yH+Pn  
m~U{ V9;*  
F>b6fUtR  
//停止文件下载 (&*F`\  
public void siteStop() '9/kDkt!  
{ blN1Q%m6  
bStop = true; Qx,G3m[}  
for(int i=0;i<nStartPos.length;i++) .4Ny4CMHZ  
fileSplitterFetch.splitterStop(); bp$jD  
}[DAk~  
z>0"T2W y  
} a,4g`?  
} V]O :;(W_  
//负责部分文件的抓取 Ur-^X(nL  
**FileSplitterFetch.java _N:h&uw  
*/ u=l(W(9=  
package NetFox; .)3 2WD%  
eLYFd,?9  
YQ)m?=+J  
import java.io.*; OWjZ)f/  
import java.net.*; 8 KkpXaz  
`?@7 KEl>  
\;6F-0  
public class FileSplitterFetch extends Thread { &rd(q'Vi  
YiCDV(prT  
$ B9=v  
String sURL; //File URL =@w:   
long nStartPos; //File Snippet Start Position xKr,XZu  
long nEndPos; //File Snippet End Position `SwnKg  
int nThreadID; //Thread's ID JgB# EoF  
boolean bDownOver = false; //Downing is over heKI<[8l  
boolean bStop = false; //Stop identical 2$o[  
FileAccessI fileAccessI = null; //File Access interface 0/ Ht;(  
b tu:@s8ci  
(Lo2fY5  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hjG1fgEj  
{ ,![=_d  
this.sURL = sURL; 7asq]Y}<  
this.nStartPos = nStart; XJzXxhk2  
this.nEndPos = nEnd; ".)_kt[  
nThreadID = id; %yMzgk[u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `-H:j:U{  
} Ax0,7,8y  
h0 Sf=[>z  
W =zG  
public void run() ??m7xH5u1  
{ 4PWr;&  
while(nStartPos < nEndPos && !bStop) S2R[vB4).  
{ <n\.S  
_6m3$k_[MJ  
rxK0<pWJhx  
try{ RF)B4D-W  
URL url = new URL(sURL); QC4T=E]` j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *jK))|%  
httpConnection.setRequestProperty("User-Agent","NetFox"); i-?zwVmn  
String sProperty = "bytes="+nStartPos+"-"; @;6}xO2  
httpConnection.setRequestProperty("RANGE",sProperty); y2R=%EFh6  
Utility.log(sProperty); j1 F+,   
%-l:_A  
|&Pl4P  
InputStream input = httpConnection.getInputStream(); m=MT`-:  
//logResponseHead(httpConnection); 0'hxw3#  
OkZ!ZS h  
psC7I E<v  
byte[] b = new byte[1024]; doc  
int nRead; aHC;p=RQ\A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .e"Qv*[^  
{ <dL04F  
nStartPos += fileAccessI.write(b,0,nRead); Y/0O9}hf  
//if(nThreadID == 1) .dCP8|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u =kSs  
} 2]9<%-=S  
U_- K6:tr  
kkBU<L2  
Utility.log("Thread " + nThreadID + " is over!"); l,u{:JC  
bDownOver = true; v$G*TR<2  
//nPos = fileAccessI.write (b,0,nRead); cf'}*$[S  
} C/waH[Yzan  
catch(Exception e){e.printStackTrace ();} UWp8I)p!\O  
} j#,M@CE  
} p^rX.?X  
~5uNw*H  
6wB>-/'Y  
//打印回应的头信息 0NtsFPO  
public void logResponseHead(HttpURLConnection con) _-\s[p5  
{ ZPsY0IzLo  
for(int i=1;;i++) ?0NSjK5ma  
{ Ro]IE|Fv  
String header=con.getHeaderFieldKey(i); %"Q!5qH&  
if(header!=null) <88}+j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); e H  
Utility.log(header+" : "+con.getHeaderField(header)); T(UYlLe  
else mzxvfXSF  
break; 2U'JzE^Do  
} |/^aL j^u  
} 1vs>2` DLa  
^Cn]+0G#C8  
ff1B)e  
public void splitterStop() HoE.//b  
{ R9/xC7l@  
bStop = true; K}`p_)(  
} b*F~%K^i$  
~|{)h^]@  
Vfm #UvA  
} Jf<yTAm  
"!Oh#Vf  
DUKmwKM"k  
/* yr9A0F0  
**FileAccess.java |C6(0fgWd  
*//文件访问(定位,写) ICbdKgLz  
package NetFox; Zmbz-##HQ  
import java.io.*; qV8\/7'A0a  
NE2sD  
jjwMvf.R  
public class FileAccessI implements Serializable{ ]a!; `m$  
T:%wX9W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 PnIvk]"Ab  
RandomAccessFile oSavedFile; #D/ }u./  
long nPos; y?z_^ppj  
gVA}?t;  
tD7C7m  
public FileAccessI() throws IOException 8^/Ek<Q b|  
{ O;BMwg_7  
this("",0); B Ff. Rd95  
} h"1"h.  
*!]Epb  
199hQxib:  
public FileAccessI(String sName,long nPos) throws IOException _2X6bIE  
{ 8wpwJs&V  
oSavedFile = new RandomAccessFile(sName,"rw"); renmz,dJ,  
this.nPos = nPos; .cT$h?+jyl  
oSavedFile.seek(nPos); m)|.:sj  
} ZYR,8y  
HvgK_'  
zHoO?tGf  
public synchronized int write(byte[] b,int nStart,int nLen) q8 xc70: R  
{ yCkW2p]s,K  
int n = -1; %{~mk[d3  
try{ -?w v}o  
oSavedFile.write(b,nStart,nLen); %Di 7u- x  
n = nLen; ds$\vSd  
} ssX6kgq_(  
catch(IOException e) @)Hbgkdi  
{ zGL<m0C  
e.printStackTrace (); 2mG&@E  
} hXQg=Sj  
?^48Zq6wM  
N7$DRG/<b  
return n; Z_V&IQo-7  
} w[ YkTv  
v`+n`DT  
_ 2gT1B  
} jU4)zN/`r  
Q$.V:#  
GkGC4*n  
/* "E ok;io  
**SiteInfoBean.java "l[ V%f E  
*/ COan) <Ku  
package NetFox; n L+YL  
W:{PBb"x8  
1_j<%1{sZ  
public class SiteInfoBean { Tu= eQS|'  
d%_78nOh"  
t=W$'*P0}  
private String sSiteURL; //Site's URL Ca5Sc, no  
private String sFilePath; //Saved File's Path kJ#[UCqzM  
private String sFileName; //Saved File's Name ^{fi^lL=  
private int nSplitter; //Count of Splited Downloading File 4-d99|mv  
zN)|g  
dW{o+9nw  
public SiteInfoBean() Xs%R]KOwt  
{//nSplitter的缺省值为5 #}t 1   
//default value of nSplitter is 5 (J^Lqh_  
this("","","",5); <^*+8{*  
} +6#%P  
OHtgn  
}W@#S_-e8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,Og[[0g  
{ J]|6l/i  
sSiteURL= sURL; K.#,O+-Kg`  
sFilePath = sPath; 1fO2)$Y  
sFileName = sName; `Dz]z_  
this.nSplitter = nSpiltter; mHI4wS>()+  
D?\"  
@\6nXf  
} %7C%`)T]  
nv_m!JG7  
STXqq[+Rf  
public String getSSiteURL() gf3u0' $  
{ <(#xOe  
return sSiteURL; `b^#quz  
} oA!5dpNhU  
- 5o<Q'(  
k}I5x1>&  
public void setSSiteURL(String value) C>JekPeM  
{ 7}#*3*]  
sSiteURL = value; y?*[}S  
} $/<"Si&(  
i)@U.-*5m  
<@U.   
public String getSFilePath() \N`fWh8&  
{ MAwC\7n+X  
return sFilePath; (^tr}?C  
} >Bh)7>`3c  
+ 4V1>e+  
=qV4Sje|q  
public void setSFilePath(String value) Wk\mgGn+  
{ `Ct'/h{  
sFilePath = value; ;<bj{#mMv  
} "o^bN 9=  
nl)_`8=  
"q9~ C  
public String getSFileName() WIEx '{  
{ a%MzNH  
return sFileName; >}dTO/  
} ]HJ{dcF  
vDK:v$g  
;Ch+X$m9  
public void setSFileName(String value) 0$xK   
{ B91S h`  
sFileName = value; Pp1zW3+Q  
} 1EC-e|M.  
`uIx/.L  
pPiYPfs  
public int getNSplitter() TZ&4  
{ n=<NFkeX  
return nSplitter; |dl0B26x  
} "t (1tWO1o  
! F0rd9  
+ AcKB82  
public void setNSplitter(int nCount) ?o(ZTlT  
{ Aj8l%'h[  
nSplitter = nCount; njy~   
} };|!Lhl+  
} *<`7|BH3  
TRs[~K)n  
LPq*ZZK  
/* ?r -\%_J_(  
**Utility.java `DgaO-Dg3  
*/ #Acon7R p  
package NetFox; (TT3(|v  
:DOr!PNA  
o9KyAP$2  
public class Utility { bc3|;O  
;=5@h!@R  
Qa,NGP.  
public Utility() itqQ)\W  
{ 90  
1KeJd&e  
egZyng pB  
} NqiB8hZ~  
JwN}Jm  
//线程睡眠 #d }0}7ue  
public static void sleep(int nSecond) 4o1Q7  
{ :0 W6uFNOU  
try{ tx^92R2/  
Thread.sleep(nSecond); jgk{'_ j  
} `FZ(#GDF  
catch(Exception e) K)<Wm,tON  
{ b\SXZN)Be  
e.printStackTrace (); {c v;w  
} 6V'wQqJ  
} /M0l p   
3[MdUj1y[  
//日志 :`:xP  
public static void log(String sMsg) RpHpMtvNo/  
{ <MPeh&_3#  
System.err.println(sMsg); :.C+?$iuX  
} ,|e}Y [  
Zij"/gx\  
Pk$}%;@v  
public static void log(int sMsg) kVV\*"9y  
{ fC=fJZU7$  
System.err.println(sMsg); <T(s\N5B=  
} =}~NRmmF  
} I["F+kt^^  
[:AB$l*  
5Z* b(R  
/* |$YyjYK  
**TestMethod.java BhqhyX\D&y  
*/ \w{@u)h  
package NetFox; xL9:4'I  
AyE%0KmraK  
pp/#Am  
public class TestMethod { J)-T:.i|0  
?F!EB4E\y}  
^dFh g_GhF  
public TestMethod() s9uL<$,'  
{ ///xx/weblogic60b2_win.exe E"Zb};}  
try{ }*?yHJ3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Lf5%M|o.)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); @)9REA(U  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \9046An  
fileFetch.start(); Ya~ "R#Uy  
} 99J+$A1  
catch(Exception e){e.printStackTrace ();} PPUEkvH W  
q $t&|{  
mG0L !5  
} uK$=3[;U/!  
dVvZu% DFp  
9OPK4-  
public static void main(String[] args) v2IEJ  
{ *y)4D[ z-  
new TestMethod(); #0}Ok98P  
} )J;ny!^2  
} 6a7vlo  
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