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http断点续传简单实现(java)

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/* |-vn,zpe  
**SiteFileFetch.java SBG.t:  
*/ Lq5Eu$;r  
package NetFox; zT _[pa)O`  
import java.io.*; 77zDHq=  
import java.net.*; )Yw m_f-N  
X>s'_F?  
! d" i  
public class SiteFileFetch extends Thread { 8$6^S{M3  
!K_ ke h  
vA@\V)s  
SiteInfoBean siteInfoBean = null; //文件信息Bean EY.Z.gMZI(  
long[] nStartPos; //开始位置 P&8QKX3 j^  
long[] nEndPos; //结束位置 #,\qjY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c_.4~>qw  
long nFileLength; //文件长度 vsCy?  
boolean bFirst = true; //是否第一次取文件 &UoQ8&  
boolean bStop = false; //停止标志 L]Dl}z  
File tmpFile; //文件下载的临时信息 7T9Mo .  
DataOutputStream output; //输出到文件的输出流 9uA2M!~i2  
Zd[6-/-:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) )?,X\/5  
public SiteFileFetch(SiteInfoBean bean) throws IOException WH0$v#8`v  
{ . ^JsnP  
siteInfoBean = bean; *bTR0U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `1U?^9Nf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rtgu{m02  
if(tmpFile.exists ()) CXhE+oS5z'  
{ 4qLH3I[Y  
bFirst = false; pksF| VS  
read_nPos(); )\Ay4 d  
} c=\H&x3X  
else .VfBwTh7q8  
{ gye'_AR?k  
nStartPos = new long[bean.getNSplitter()]; \y0uGnmCj  
nEndPos = new long[bean.getNSplitter()]; ]tDuCZA  
} ?Y#x`DMh  
@m(ja@YC  
;kiL`K  
%:7fAB,PA  
} YA4;gH+  
*Z=:?4u  
v`KYhqTUl  
public void run() A@k`$xevVj  
{ aMycvYzH  
//获得文件长度 wT+b|K  
//分割文件 |c5r&oM&m  
//实例FileSplitterFetch dd@-9?6M  
//启动FileSplitterFetch线程 8X2NEVH]  
//等待子线程返回 _^"0"<,  
try{ -H(\[{3{V  
if(bFirst) x $ oId{;  
{ d#]XyN>  
nFileLength = getFileSize(); 9Fv VM9  
if(nFileLength == -1) lDm0O)Dh!  
{ SLMnEtyTS  
System.err.println("File Length is not known!"); Z4'8x h)-  
} O &De!Gx  
else if(nFileLength == -2) @ wJ|vW_.  
{ j_2yTz"G-  
System.err.println("File is not access!"); 2n8spLZYGY  
} ley: =(  
else auV<=1<zJ  
{ pSlosv(6  
for(int i=0;i<nStartPos.length;i++) g4 G?hv`R  
{ C Nt  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @u}1 S1  
} h TY7`m">  
for(int i=0;i<nEndPos.length-1;i++) aR}L- -m  
{ 1'>wrGr  
nEndPos = nStartPos[i+1];  b"C1  
} [N4#R  
nEndPos[nEndPos.length-1] = nFileLength; ^;]Q,*Q  
} vfZ.js/  
} )"Vd8*e  
,Rh6( I  
ekx~svcC&A  
//启动子线程 Pn[R.u(l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lYt|C^  
for(int i=0;i<nStartPos.length;i++) <; (pol|  
{ AqHH^adzA:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kX)Xo`^Ys  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pAd 8-a  
nStartPos,nEndPos,i); &6mXsx$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M@b:~mI[sw  
fileSplitterFetch.start(); J$X{4  
} _9Zwg+oO[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +vh 4I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :_y}8am;H~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bW9a_myE  
nEndPos = " + nFileLength); vw/L|b7G  
// fileSplitterFetch[nPos.length-1].start(); > R5<D'cEN  
:6r)HJ5sg  
Ckc4U. t|  
//等待子线程结束 AvS<b3EoN  
//int count = 0; #nOS7Q#uW  
//是否结束while循环 }pzUHl>  
boolean breakWhile = false; Fs,#d%4@%  
?UGA-^E1  
^YLk&A)X  
while(!bStop) VS{po:]A  
{ +jPs0?}s  
write_nPos(); Z*Fxr;)d  
Utility.sleep(500); zJ2dPp~u  
breakWhile = true; sAG#M\A6  
9nrH 6]  
LyB &u( )  
for(int i=0;i<nStartPos.length;i++) AQH\ ;L  
{ .0b$mSV[  
if(!fileSplitterFetch.bDownOver) dq&N;kk |  
{ d?uN6JH9  
breakWhile = false; 2MapB*  
break; n%J {Tcn6  
} !b0ANIp  
} ^+m6lsuA  
if(breakWhile) 1>BY:xZr  
break; -N3fhW#)  
G(~ s(r{%I  
L93&.d@m9  
//count++; MvLmEmKb}\  
//if(count>4) 6pHn%yE*  
// siteStop(); ~RRp5x _  
} g]hTz)8fF  
Xj^Hy"HC^~  
'8$*gIQ8  
System.err.println("文件下载结束!"); Y%B:IeF}  
} W".: 1ov#B  
catch(Exception e){e.printStackTrace ();} [Pnk@jIk4  
} _4]GP3`  
?Thh7#7LM  
o'8`>rb  
//获得文件长度 TNHkHR[&  
public long getFileSize() #:y h2y7a%  
{ X?'v FC  
int nFileLength = -1; wInJ!1  
try{ MY[QYBkn}  
URL url = new URL(siteInfoBean.getSSiteURL()); ,'E+f%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sl?@c/Ng  
httpConnection.setRequestProperty("User-Agent","NetFox"); m1mA:R\zM  
k_^| %xJ  
7vRFF@eq}  
int responseCode=httpConnection.getResponseCode(); $Z!$E,@c  
if(responseCode>=400) {O4y Y=G  
{ g=T !fF=  
processErrorCode(responseCode); gW[(gf.oo  
return -2; //-2 represent access is error k{?Pgf27  
} aOj(=s  
9F&s9(=\  
p%8v+9+h2  
String sHeader; h*2NFL~#  
y$f{P:!"{3  
xM dbS4&!  
for(int i=1;;i++) 3j]P\T  
{ }52]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a=m7pe ^  
//Utility.log(in.readLine()); xTy[X"sJ  
sHeader=httpConnection.getHeaderFieldKey(i); yMQZulCWE  
if(sHeader!=null) xzqgem`[\  
{ U=<d;2N#  
if(sHeader.equals("Content-Length")) X~`<ik{q  
{ *Z+8L*k97  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b xU13ESv  
break; PW[NW-S`c  
} Y 0f"}A1  
} ?-y!FD}m&  
else Ax9a5;5WM  
break; ] X9e|  
} Fjc4[ C  
} Hkcr+BQ  
catch(IOException e){e.printStackTrace ();} <K$X>&Ts  
catch(Exception e){e.printStackTrace ();} ? x*Ve2+]  
-t<8)9q(  
O[tOpf@s.  
Utility.log(nFileLength); b?p_mQKtZ  
IwE{Zvr  
[%8t~zg  
return nFileLength; V8aLPJ0_  
} eC9nOwp]xH  
h;^H*Y&`  
yK$.wd 2,  
//保存下载信息(文件指针位置) M7\; Y  
private void write_nPos() 1nt VM+  
{ cVg!"  
try{ _* xjG \!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tKnvNOhn  
output.writeInt(nStartPos.length); ,}("es\b  
for(int i=0;i<nStartPos.length;i++) (#dwIBBFt  
{ F|eKt/>e  
// output.writeLong(nPos); kiW|h)w_,v  
output.writeLong(fileSplitterFetch.nStartPos); ]/o0p  
output.writeLong(fileSplitterFetch.nEndPos); tP?pN]Q$,  
} t3~ZGOn  
output.close(); <`B4+:;w6  
} |Ew~3-u!  
catch(IOException e){e.printStackTrace ();} %[x oA)0!  
catch(Exception e){e.printStackTrace ();} d:U2b"k=/u  
} V! sT2  
K%XQdMv  
RS$!TTeQ  
//读取保存的下载信息(文件指针位置) 9^;)~ G  
private void read_nPos() ^[7ZBmS  
{ ^x! N]  
try{ iK#5nY].  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q\P?[i]  
int nCount = input.readInt(); ^`W8>czi  
nStartPos = new long[nCount]; 5$v,%~$Xds  
nEndPos = new long[nCount]; '^T Q Ubw  
for(int i=0;i<nStartPos.length;i++) peA}/Jc  
{ OZ/P@`kN.f  
nStartPos = input.readLong(); Pl@3=s!~>~  
nEndPos = input.readLong(); :GXD-6}^|  
} \m>mE/N  
input.close(); QbF!V%+a's  
} h83;}>  
catch(IOException e){e.printStackTrace ();} 'u \my  
catch(Exception e){e.printStackTrace ();} Y7|R vLWoP  
} O#}'QZd'  
i; 8""A  
$R\D[`y|  
private void processErrorCode(int nErrorCode) ileqI/40f  
{ .,)C^hs@  
System.err.println("Error Code : " + nErrorCode); .pP{;:Avpn  
} mSw$? >  
AgOw{bJ%  
Fq]ht*  
//停止文件下载 }b// oe7  
public void siteStop() M![aty@  
{ (QO8_  
bStop = true; X3z$f(lF%)  
for(int i=0;i<nStartPos.length;i++) 7O_@b$Q  
fileSplitterFetch.splitterStop(); qjK'sge/  
eV?._-G  
 H %Cb  
} % R18  
} E3pnu.;U:_  
//负责部分文件的抓取 mfYY?]A*+  
**FileSplitterFetch.java (<= &#e?  
*/ .RI{\i`  
package NetFox; >)/,5VSE  
/rKdxsI*  
2D5S%27,  
import java.io.*; 9WXJz;  
import java.net.*; 5h"moh9tG  
: ryE`EhB  
-Y*"!8  
public class FileSplitterFetch extends Thread { iIOA54!o  
UStNUNCq  
fM[Qn*.  
String sURL; //File URL  aOS:rC  
long nStartPos; //File Snippet Start Position + _=&7  
long nEndPos; //File Snippet End Position a(+.rf;  
int nThreadID; //Thread's ID ?2Q9z-$  
boolean bDownOver = false; //Downing is over tBtG- X2  
boolean bStop = false; //Stop identical j@JhxCe1+R  
FileAccessI fileAccessI = null; //File Access interface uR|?5DK  
t0 [H_  
mA ^[S.!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y7K&@ Y  
{ hAPWEh^  
this.sURL = sURL; 8\z5*IPGs  
this.nStartPos = nStart; K$S:V=y%r7  
this.nEndPos = nEnd; 4LO U[D  
nThreadID = id; 5t` :=@u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '6^20rj  
} *Q?ZJS ~  
iKy_DV;J  
0!WF,)/T7i  
public void run() N5 BC<pu  
{ K~j&Q{yws@  
while(nStartPos < nEndPos && !bStop) 5dH}cXs  
{ 0KW@j>=jK  
zJp}JO  
1_D|;/aI  
try{ QZcdfJck=+  
URL url = new URL(sURL); ]9xuLJ)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '@Zau\xC  
httpConnection.setRequestProperty("User-Agent","NetFox"); RUJkfi=$  
String sProperty = "bytes="+nStartPos+"-"; /Iwnl   
httpConnection.setRequestProperty("RANGE",sProperty); >900I4]I  
Utility.log(sProperty); Cu5fp.OS7  
EXlmIY4  
vvJ{fi  
InputStream input = httpConnection.getInputStream(); w"s;R8  
//logResponseHead(httpConnection); Y{6vW-z_<  
_l?InNv  
(!-gX" <b  
byte[] b = new byte[1024]; -WDU~VSU  
int nRead; ]7 qn&(]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Uu~7+oaQ  
{ <h(KI Y9T  
nStartPos += fileAccessI.write(b,0,nRead); ^/|agQ7D2  
//if(nThreadID == 1) P8tpbdZE-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OH`| c  
} %9,:  
T3HAr9i%)  
<qG4[W,[  
Utility.log("Thread " + nThreadID + " is over!"); 08J[9a0[  
bDownOver = true; #) eI]  
//nPos = fileAccessI.write (b,0,nRead); 8]@)0q {r  
} k lLhi<*  
catch(Exception e){e.printStackTrace ();} ` ZO#n  
} Z(fXN$  
} ^[K3]*!@  
bRSE"B  
 U 6((  
//打印回应的头信息 k)Y}X)\36  
public void logResponseHead(HttpURLConnection con) t' )47k\  
{ i$~2pr  
for(int i=1;;i++) N=1zhI:VaQ  
{ 'H"wu /#  
String header=con.getHeaderFieldKey(i); P5u Y1(  
if(header!=null) dGxk ql  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r)ni;aP  
Utility.log(header+" : "+con.getHeaderField(header)); mR3)$!  
else l@ +lUx8  
break; %4F Q~  
} 8(yZX4OH>  
} hu?Q,[+o  
g"k1O  
8>T#sO?+  
public void splitterStop() +D[|Mi  
{ ~vqVASUc,  
bStop = true; 5a$Q}!6E.Y  
} X9W'.s.[Q  
gZa/?[+  
]Gk;n/! B  
} \!!qzrq  
QucDIZ  
|Z]KF>S]  
/* L-B"P&  
**FileAccess.java $;kFuJF  
*//文件访问(定位,写) fkLI$Cl  
package NetFox; qOA+ao  
import java.io.*; K U 2LJ_~Y  
s}2TJa  
{FYWQ!L  
public class FileAccessI implements Serializable{ ;E Z5/"T  
9YpgzCx Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N$\'X<{  
RandomAccessFile oSavedFile; eWKFs)C]  
long nPos; 2nNBX2 o&_  
 8*nv+  
jZjWz1+  
public FileAccessI() throws IOException o!R.QI^2VT  
{ ,g69?w  
this("",0); r[doN{%  
} 75@!j[QL<  
cB$OkaG#  
#@ClhpLD  
public FileAccessI(String sName,long nPos) throws IOException ]><K8N3Z  
{ oRf.34  
oSavedFile = new RandomAccessFile(sName,"rw"); cyM9[X4rC  
this.nPos = nPos; zD#$]?@ b  
oSavedFile.seek(nPos); k|C~qe3E  
} icO$9c  
{e'P* j  
j,DF' h  
public synchronized int write(byte[] b,int nStart,int nLen) <x QvS^|[  
{ zKh^BwhO|X  
int n = -1; i-.]onR  
try{ myq@X(K  
oSavedFile.write(b,nStart,nLen); s$%t*T2J>  
n = nLen; Ro}7ERA  
} ~]sj.>P  
catch(IOException e) +8<|P&fH  
{ )b%t4~7  
e.printStackTrace (); Lud[.>i  
} f ZEyXb  
_xKIp>A  
7+N0$0w%r  
return n;  lu_kir~  
} 2 m"2>gX  
;mT|0&o>#  
kM:Z(Z7$  
} Z\lJE>1  
.Us)YVbk  
HZINsIm!?  
/* -_*ux!  
**SiteInfoBean.java 0W_olnZ  
*/ 2X X-  
package NetFox; ]\ ~s83?X  
(vR9vOpJ  
r\PO?1  
public class SiteInfoBean { ZVelKI8>  
c)*,">$#  
ojc m%yd  
private String sSiteURL; //Site's URL n-"(lWcp  
private String sFilePath; //Saved File's Path Arr(rM  
private String sFileName; //Saved File's Name ?|i C-7{8L  
private int nSplitter; //Count of Splited Downloading File qjBF]3%t%  
?l> <?i  
Vn=K5nm  
public SiteInfoBean() ?[Sac]h ys  
{//nSplitter的缺省值为5 0 ~a9gBG  
//default value of nSplitter is 5 1Yk!R9.  
this("","","",5); {6I)6}w!k  
} r,43 gg  
0hN gr'  
0?$jC-@k:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /` ;rlH*  
{ ;L*Ku'6Mt  
sSiteURL= sURL; ]>9[}'u  
sFilePath = sPath; .4[\%r\i  
sFileName = sName; _J,lF-,  
this.nSplitter = nSpiltter; #\zC|%2+z  
Z|#G+$"QV  
h tuYctu`  
} :5'8MU  
#Dz. 58A  
4)Bk:K  
public String getSSiteURL() .5^7Jwh  
{ 5i0vli /L  
return sSiteURL; ]/#3 P  
} yI{4h $c  
`o4%UkBpM  
N,3 )`Vm  
public void setSSiteURL(String value) DqJzsk'd3  
{ ;hgRMkmz4<  
sSiteURL = value; c]/X >8;  
} B*@0l:  
S4Q fx6:~h  
e"d-$$'e  
public String getSFilePath() NiSybyR$  
{ _x`oab0@  
return sFilePath; 20,}T)}Tm  
} \H4$9lPk  
V;LV),R?  
1CR)1H  
public void setSFilePath(String value) F"^/R  
{ f-BPT2U+  
sFilePath = value; T;M4NGmvd  
} TFZxk  
"$I8EW/1  
FyhLMW3  
public String getSFileName() :!QT ,  
{ 5M&<tj/[a0  
return sFileName; 6no&2a|D  
} iw{rns  
BhzcimC)  
uj~(r=%  
public void setSFileName(String value) ~]Weyb[ N  
{ ["H2H rI2  
sFileName = value; cK1 Fv6V#  
} 4n0Iw  I  
Krd0Gc~\|  
+zg3/C4 S  
public int getNSplitter() 5v[2R.eT-  
{ Tr.u'b(  
return nSplitter; mhgvN-? "h  
} WB.w3w [f  
ZK4d;oa",  
7P bwCRg  
public void setNSplitter(int nCount) TtWWq5X|  
{ $/kZKoF{f  
nSplitter = nCount; fyF8RTm{  
} xyrlR;Sk  
} "=Cjm`9~j  
-KL5sK  
IMSLHwZ  
/* T0X+\&W  
**Utility.java O %1uBc  
*/ T(=Z0M  
package NetFox; EX/{W$ &K  
Gm[XnUR7V  
C/!7E:  
public class Utility { ' j\~> a3\  
bo-lT-I  
|Sv}/ P-  
public Utility() `hDH7u!U.  
{ #2dH2k\F  
.k"unclT0  
,: Ij@u>)  
} 6Zx)L|B  
97pfMk1_  
//线程睡眠 QT4&Ix,4T1  
public static void sleep(int nSecond) sdBB(  
{ 8^pu C  
try{ 2f5YkmGc";  
Thread.sleep(nSecond); KjK-#F,@  
} iBk1QRdn  
catch(Exception e) #'5{ ?Cb  
{ ODxCD%L  
e.printStackTrace (); eyuQ}R  
} 7 &iav2q  
} J|u_45<  
1oI2  
//日志 Z4dl'v)9  
public static void log(String sMsg) pwVaSnre`  
{ 39bw,lRPV  
System.err.println(sMsg); @2~;)*  
} I&f!>y?,Z  
Eih6?Lpu  
PU-L,]K  
public static void log(int sMsg) '3=@UBs  
{ LaYd7Oyf]  
System.err.println(sMsg); d^Rea8  
} 9z+ZFIf7d  
} +t8#rT ^B  
A3.*d:A  
|`pDOd  
/* O jH"qi  
**TestMethod.java dN@C)5pm5`  
*/ UHS "{%  
package NetFox; K$wxiGg8P  
6GoQJ  
@CS%=tE}U  
public class TestMethod { #kgLdd"  
0lU pil  
\s6 VOR/  
public TestMethod() *-&+;|mM  
{ ///xx/weblogic60b2_win.exe ~!P&LZ  
try{ F{E`MK~f_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j9R+;u/!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 24k;.o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Bo;{ QoB  
fileFetch.start(); E-deXY  
} \F14]`i  
catch(Exception e){e.printStackTrace ();} -d[Gy- J  
825 QS`  
jd.w7.8  
} X2`n&JE  
oK3PA  
s=Xg6D  
public static void main(String[] args) Ap> H-/C  
{ l6N"{iXU  
new TestMethod(); B D [<>Wm  
} s8;*Wt  
} A$rCo~Ek  
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