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http断点续传简单实现(java)

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/* rK r2 K'  
**SiteFileFetch.java jS'hs>Ot  
*/ E K#ib  
package NetFox; eVB.g@%T  
import java.io.*; p="K4E8~H  
import java.net.*; {uji7TB  
u}BN)%`B  
hP26Bb1  
public class SiteFileFetch extends Thread { atWB*kqI  
6Rc%P)6  
Z'|A>4\  
SiteInfoBean siteInfoBean = null; //文件信息Bean QE%|8UFY  
long[] nStartPos; //开始位置 ts~$'^K[-  
long[] nEndPos; //结束位置 iMXK_O%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SM8m\c  
long nFileLength; //文件长度 TCS^nBEE  
boolean bFirst = true; //是否第一次取文件 +)QA!g$  
boolean bStop = false; //停止标志 a@U0s+V&a0  
File tmpFile; //文件下载的临时信息 v}-jls  
DataOutputStream output; //输出到文件的输出流 {GM8}M~D&  
SWM6+i p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ]#Q'~X W  
public SiteFileFetch(SiteInfoBean bean) throws IOException FAP1Bm  
{ hV>@qOl '  
siteInfoBean = bean; et0yS%7+?@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z]F4Z'(e.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 32ae? d  
if(tmpFile.exists ()) m=p<.%a  
{ NP5;&}uv*!  
bFirst = false; >"z&KZKI  
read_nPos(); \J?5K l[*c  
} 4E.K6=k|=a  
else Il,^/qvIY  
{ C*fSPdg?  
nStartPos = new long[bean.getNSplitter()]; b6~MRfx`7  
nEndPos = new long[bean.getNSplitter()]; {glRX R  
} &+>)H$5  
6 &)fZt  
xtP=/B/  
5Pu F]5  
} )XAD#GYM  
t(F] -[  
4*aNdh[t.  
public void run() @C fxPA  
{ ~ E|L4E  
//获得文件长度 yNu%D$6u7  
//分割文件 J>Uzd, /  
//实例FileSplitterFetch i&dMX:fRd  
//启动FileSplitterFetch线程 %*wOJx  
//等待子线程返回 x#s=eeP1  
try{ VIjsz42C  
if(bFirst) 58 Rmq/6s  
{ W9ewj:4\0  
nFileLength = getFileSize(); ,"!P{c  
if(nFileLength == -1) 6X.lncE@p  
{ !rMl" Y[  
System.err.println("File Length is not known!"); 4$<-3IP,  
} ^>fjURR  
else if(nFileLength == -2) 7,N>u8cTh  
{ #Zy-X_r  
System.err.println("File is not access!"); DG $._  
} d^<a)>5h  
else ,Cckp! 6  
{ wf8GH}2A  
for(int i=0;i<nStartPos.length;i++) 7VwLyy  
{ M1f ^Lx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); StuDtY  
} \PB~ 6  
for(int i=0;i<nEndPos.length-1;i++) 044*@a5f  
{ {%;KkC8=R  
nEndPos = nStartPos[i+1]; jW-j+ WGSM  
} (SlrV8;  
nEndPos[nEndPos.length-1] = nFileLength; gB?~!J?  
} ~CB6+t>  
} iEf6oM  
Eb<iR)e H=  
= ?hx+-'  
//启动子线程 t $+46**  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; OgTE^W@  
for(int i=0;i<nStartPos.length;i++) Ur]~>-Z  
{ ]d@@E_s]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~4~-^ t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Sr`gQ#b@r}  
nStartPos,nEndPos,i); ;=.QT  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ .%\czO  
fileSplitterFetch.start(); M7(vI4V  
} 0Up@+R2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G/Xa`4"_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2\z"6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pe !eID8  
nEndPos = " + nFileLength); i7[CqObzc  
// fileSplitterFetch[nPos.length-1].start(); Q\~4J1  
[k9aY$baT^  
$z+iB;x  
//等待子线程结束 [z:bnS~yiD  
//int count = 0; $3! j1  
//是否结束while循环 Aghcjy|j  
boolean breakWhile = false; cmIAWFj-)e  
^#R-_I  
3d.JV'C'c  
while(!bStop) @awaN  
{ _|ucC$*  
write_nPos(); WRJ+l_81  
Utility.sleep(500); ?zKVXK7}0  
breakWhile = true; Xz=MM0o  
w49Wl>M  
v?yHj-  
for(int i=0;i<nStartPos.length;i++) )T:{(v7 d`  
{ OH28H),}  
if(!fileSplitterFetch.bDownOver) &DFe+y~PR  
{ $;_'5`xs  
breakWhile = false; S #X$QD  
break; 2oAPJUPOJ  
} daaEN(  
} QY2!.a^q  
if(breakWhile) sa`7_KB  
break; KLXv?4!  
l{4=La{?j  
^)b*"o  
//count++; buRXzSR  
//if(count>4) )Xa`LG =|  
// siteStop(); X9nt;A2TU+  
} <GShm~XD2  
j8@YoD5o  
DFs J}` $  
System.err.println("文件下载结束!"); uKqN  
} J! >HT'M  
catch(Exception e){e.printStackTrace ();} )}?'1ciHI  
} &j/ WjZPF  
+b] g;  
M"K$81  
//获得文件长度 :eI .E:/'  
public long getFileSize() QzIK580%t  
{ 4T6dju  
int nFileLength = -1; }Xs=x6Mj  
try{ j?6%=KuX<  
URL url = new URL(siteInfoBean.getSSiteURL()); v'.?:S&m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xt /T0.I  
httpConnection.setRequestProperty("User-Agent","NetFox"); iLy }G7h  
UUv&X+ Y  
3skq%;%Wsk  
int responseCode=httpConnection.getResponseCode(); vI ]| W  
if(responseCode>=400) r]km1SrS  
{ PDX^MYoN  
processErrorCode(responseCode); O!sZMGF$p  
return -2; //-2 represent access is error .*D~ .!  
} E/(:\Cm^  
/Z>#lMg\.  
:9c QK]O6  
String sHeader;  KEsMes(*  
~,Q+E8  
K(Otgp+zb  
for(int i=1;;i++) #HB]qa  
{ !l_ 1r$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _p7c<$ ;  
//Utility.log(in.readLine()); p[&'*"o!/  
sHeader=httpConnection.getHeaderFieldKey(i); IQdiVj  
if(sHeader!=null) GFx >xQk  
{ v4(!~S  
if(sHeader.equals("Content-Length")) ~LHG  
{ Qm,|'y:Tg  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^MUtmzh  
break; Ol"p^sqwj  
} gOO\` #  
} .0#?u1gXsX  
else b}o^ ?NtA  
break; 6+FmYp  
} mN_RB{g{  
} 1I KDp]SN  
catch(IOException e){e.printStackTrace ();} iO3@2J  
catch(Exception e){e.printStackTrace ();} Tm[IOuhM'?  
j$zw(EkN  
,jbj-b(  
Utility.log(nFileLength); vhZpYW8  
d/- f]   
O} QTg  
return nFileLength; +=Crfvt  
} ,/|"0$p2x  
Q9X_aB0  
GKtG#jZ&  
//保存下载信息(文件指针位置) sBq @W4  
private void write_nPos() qJVW :$1q  
{ <"AP&J'H  
try{ J^ryUO o}b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4'?kyTO~  
output.writeInt(nStartPos.length); Z|uUE   
for(int i=0;i<nStartPos.length;i++) e!ar:>T  
{ V;~W,o!  
// output.writeLong(nPos); D^I%tn=F  
output.writeLong(fileSplitterFetch.nStartPos); Wze\z  
output.writeLong(fileSplitterFetch.nEndPos); }Hrm/Ni  
} Dx/?0F7V  
output.close(); S*IF/ fu  
} `K~300-hOb  
catch(IOException e){e.printStackTrace ();} 1N1MD@C?P  
catch(Exception e){e.printStackTrace ();} ; @-7'%(C  
} zy8W8h(?  
d>)*!l2,C  
R.!'&<Svq  
//读取保存的下载信息(文件指针位置) Q~#udEajI  
private void read_nPos() |OUr=b  
{ 65\'(99y U  
try{ 55 Y BO$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7<mY{!2iF?  
int nCount = input.readInt(); h:<p EL  
nStartPos = new long[nCount]; !BP/#  
nEndPos = new long[nCount]; "D2 `=D!+  
for(int i=0;i<nStartPos.length;i++) ,*Tf9=z  
{ !TVlsm  
nStartPos = input.readLong(); G  2+A`\]  
nEndPos = input.readLong(); hoD (G X  
} ZTVX5"#Q  
input.close(); 4W*52*'F,  
} S j)&!  
catch(IOException e){e.printStackTrace ();} 0j7W\'!t  
catch(Exception e){e.printStackTrace ();} BYyR-m  
} p./zW )7+  
s6lo11  
EQ-r  
private void processErrorCode(int nErrorCode) T'  %TMA  
{ vtKQvQ  
System.err.println("Error Code : " + nErrorCode); :&HrOdz  
} _)yn6M'Dt  
vXAO#'4tm%  
6UG7lH!M  
//停止文件下载 (g`G(K_  
public void siteStop() d0"Hu^]  
{ %]h5\%@w  
bStop = true; c]v $C&FX  
for(int i=0;i<nStartPos.length;i++) (xBS~}e  
fileSplitterFetch.splitterStop(); |yx]TD{~P  
Q.>@w<[!L  
<[@AMdS  
} O[U^{~iM  
} |`1lCyV\tE  
//负责部分文件的抓取 mQhI"3! f  
**FileSplitterFetch.java 9i*t3W71]  
*/ casva;  
package NetFox; U}~SY  
z8G1[ElY  
}KEyJj3"DA  
import java.io.*; b lP@Cn2  
import java.net.*; k(pI5N}pJZ  
C}<j8a?  
3vfm$sx@  
public class FileSplitterFetch extends Thread { {~_X-g5|]  
>k"Z'9l  
7#SXqyP[  
String sURL; //File URL y4PR&^l?g  
long nStartPos; //File Snippet Start Position 'c*Q/C;  
long nEndPos; //File Snippet End Position OS;qb:;  
int nThreadID; //Thread's ID _HW~sz|  
boolean bDownOver = false; //Downing is over !}<d6&!py  
boolean bStop = false; //Stop identical S}f 3b N  
FileAccessI fileAccessI = null; //File Access interface rG|lRT3-K  
rkugV&BhV  
'G;y!<a  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9E5Ec~l  
{ !K-lO{Z^  
this.sURL = sURL; wmAZ {  
this.nStartPos = nStart; 0}C> e`<'  
this.nEndPos = nEnd; 0+L:+S  
nThreadID = id; D1rXTI$$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {4J:t_<nKO  
} zP$0B!9  
IL;JdIa  
kU{+@MA;  
public void run() j*+[=X/  
{ Tw *:Vw  
while(nStartPos < nEndPos && !bStop) YRa{6*M  
{ HX%lL }E  
F7P?*!dx  
cH%qoHgx  
try{ rp^= vfW  
URL url = new URL(sURL); 'APtY;x^{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bnHQvCO3$  
httpConnection.setRequestProperty("User-Agent","NetFox"); _<s[HGA`z  
String sProperty = "bytes="+nStartPos+"-"; un([3r  
httpConnection.setRequestProperty("RANGE",sProperty); a9]F.Jm  
Utility.log(sProperty); }N[|2n R'  
r@b M3V_o  
W^#HR  
InputStream input = httpConnection.getInputStream(); {9:[nqX  
//logResponseHead(httpConnection); B3|h$aKC  
P'%#B&LZo  
dO]N&'P7  
byte[] b = new byte[1024]; R+{QZ'K.qg  
int nRead; {w:*t)@j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) U4)x"s[CP  
{ <LL+\kfTZO  
nStartPos += fileAccessI.write(b,0,nRead); Sk7l&B  
//if(nThreadID == 1) nb-]fa  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $WmB__  
} ^/@Z4(E  
t6u>_Sh e  
;e Iqxe>  
Utility.log("Thread " + nThreadID + " is over!"); x-27rGN  
bDownOver = true; &O8vI ,M  
//nPos = fileAccessI.write (b,0,nRead); riw0w  
} aT|SKb`  
catch(Exception e){e.printStackTrace ();} ]nPfIBoS  
} :{sy2g/+  
} >=Bl/0YH  
lw+Y_;  
ASGV3r (  
//打印回应的头信息 {zzc/!|  
public void logResponseHead(HttpURLConnection con) X!H[/b:1O  
{ @jh\yjrW  
for(int i=1;;i++) ]JDKoA{S0  
{ <14,xYpE  
String header=con.getHeaderFieldKey(i); ^4MRG6G  
if(header!=null) Q /D?U[G  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); TwPp Z@  
Utility.log(header+" : "+con.getHeaderField(header)); D)shWJRlvW  
else wavyREK   
break; a(.q=W  
} &[ oW"Q{  
} ?e=3G4N  
oF'_x,0  
pQ~Y7  
public void splitterStop() s Zn@ye^  
{ N"/J1   
bStop = true; Pgug!![  
} `r#]dT[g  
hk*@<ff  
1fgO3N  
} i ZU 1w7Z  
C2e.RTxc  
ZG(.Q:1  
/* <TN+-)H6  
**FileAccess.java *2,tGZ  
*//文件访问(定位,写) 7QSr C/e  
package NetFox; ,:[\h\5m  
import java.io.*; 0G; b+  
gvzBV +3'  
w-{a>ZU0  
public class FileAccessI implements Serializable{ ~ eNKu  
Q*jNJ^IW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `@<>"ff#F  
RandomAccessFile oSavedFile; y@XE! L  
long nPos; 9U]3B)h%m  
TmviYP gb  
(V(8E%<c  
public FileAccessI() throws IOException mETGYkPUa  
{ C[ma!he  
this("",0); hqDnmzG  
} \u4`6EYF?  
yC&u^{~BC  
+HDfEo T  
public FileAccessI(String sName,long nPos) throws IOException =Ju%3ptH0  
{ 5,_DM  
oSavedFile = new RandomAccessFile(sName,"rw"); JnE\z*NB  
this.nPos = nPos; w;b;rHAZ\  
oSavedFile.seek(nPos); (e"\%p`  
} P>}OwW  
bU4l|i;j  
Z Jgy!)1n  
public synchronized int write(byte[] b,int nStart,int nLen) ;$.^  
{ ee2k..Tq#  
int n = -1; N({0"7  
try{ BbIg]E/G  
oSavedFile.write(b,nStart,nLen); q2+`a;_S  
n = nLen; MA1y@  
} sq rY<@%  
catch(IOException e) S7v# `#  
{ #1)#W6 h\  
e.printStackTrace (); 4`Ib wg6"B  
} V=d~}PJ>  
~'#yH#o  
M o?y4X  
return n; |=u }1G?  
} rtxG-a56Q  
\yhj{QS.k  
1xTNrLW  
} FZBdQhYF  
L#k`>Qn2  
]q`'l_O  
/* cj;k{ Moc  
**SiteInfoBean.java $Wn!vbL  
*/ @ JfQ}`  
package NetFox; GT 5J`  
b3.}m[]  
?Gnx!3Q  
public class SiteInfoBean { 6s.>5}M!  
7`J= PG$A  
]?*'[  
private String sSiteURL; //Site's URL wh2Ljskda8  
private String sFilePath; //Saved File's Path b"JX6efnN  
private String sFileName; //Saved File's Name GHR r+  
private int nSplitter; //Count of Splited Downloading File XXg~eu?  
4+B&/}FDLo  
tk\)]kj  
public SiteInfoBean() ;9;jUQ]MyG  
{//nSplitter的缺省值为5 bLsN?_jy  
//default value of nSplitter is 5 7pO/!Lm  
this("","","",5); >&[q`i{  
} O0_kLH$.  
2TccIv  
E#n=aY~u-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /?%1;s:'  
{ *v#Z/RrrA  
sSiteURL= sURL; T+j-MR}{\  
sFilePath = sPath; &BxZ}JH=k  
sFileName = sName; je;|zfe]  
this.nSplitter = nSpiltter; ^wlo;.8Y  
cqG&n0zb  
K3^2;j1F Q  
} LEd@""h  
_ SJ Fuv/  
G-[.BWQ   
public String getSSiteURL() -Oplk*  
{ sTmdoqTK!  
return sSiteURL; ` InBhU>  
} p~yGp] yJ9  
YBupC!R  
9jI5bi)  
public void setSSiteURL(String value) b^q%p1  
{ `^df la  
sSiteURL = value; RjxFlKs8  
} PTH'-G  
, Y^GQ`~#  
lho0Xy gn  
public String getSFilePath() FT6~\9m(  
{ 2*@@Bw.XA  
return sFilePath; 5H2Ugk3  
} ],F@.pg  
,zOv-pH  
y_M,p?]^,  
public void setSFilePath(String value) P?|>, \t  
{ 5ajd$t  
sFilePath = value; tHmV4H$  
} "R0(!3  
1StaQUB  
b[^|.>b  
public String getSFileName() 8,L)=3m-  
{ 4W<8 u(  
return sFileName; JIXZI\Fk  
} ~\OZEEI  
%?PRBE'}'  
ldWrv7. P  
public void setSFileName(String value) i#%!J:_=  
{ '3]M1EP  
sFileName = value; k;f%OQsF_  
} M.K%;j`  
$D m|ol.Z  
A>C8whx  
public int getNSplitter() (/jZ &4T  
{ !h70<Q^  
return nSplitter; X< 4f7;]O  
} tY- `$U@  
aucG|}B  
% U|4%P  
public void setNSplitter(int nCount) [orS-H7^  
{ )\+1*R|H}  
nSplitter = nCount; "H|hN  
} lNx:_g:SrZ  
} *n_7~ZX  
|W*i'E   
Vi>`g{\  
/* <KrfM  
**Utility.java b,lIndj#  
*/ 8F/JOtkGMt  
package NetFox; 64l(ru<  
;uaZp.<um&  
MX s]3M  
public class Utility { I` q"  
6]fz;\DgP  
.&rL>A2U  
public Utility() N4u-tlA  
{ h 6juX'V  
;oWak`]f  
C!^[d  
} B qcFbY  
[4b_`L  
//线程睡眠 -5GRit1q?  
public static void sleep(int nSecond) 7;SI=  
{ '5}@# Mi  
try{ jd+ U+8r  
Thread.sleep(nSecond); 1? Im"  
} <CN+VXF  
catch(Exception e) - aQf( =  
{ Lz=GA?lk[\  
e.printStackTrace (); j'q Iq;y  
} 7i88iT  
} Q6hWHfS  
dReJ;x4  
//日志 $kxP{0u  
public static void log(String sMsg) `:kI@TPI_C  
{ HB9|AQ4K  
System.err.println(sMsg); ~JTp8E9kw  
} l [ Navw  
/EV _Y|(-  
O_^;wey0}?  
public static void log(int sMsg) frUO+  
{ nE=,=K~  
System.err.println(sMsg); A;gU@8m  
} '<Jqp7$dL  
} 1(jDBP!8  
c63yJqiW  
!1xX)XD4y  
/* M5c~-}Ay  
**TestMethod.java UJk/Lxv  
*/ -P-&]F5  
package NetFox; -P We  
{qb2!}FQ  
Kq;s${ |G  
public class TestMethod { lR0WDJv  
O_^t u?x  
_qsg2e}n  
public TestMethod() fl o9iifZ  
{ ///xx/weblogic60b2_win.exe -HUlB|Q8r  
try{ aLO'.5 ~^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %OAvhutS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ( !0fmL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %SJFuw"  
fileFetch.start(); P:fcbfH+  
} -gVsOX0  
catch(Exception e){e.printStackTrace ();} I3d!!L2ma  
LuvRxmQ`  
;lc/FV[/  
} >6 A8+=  
r"&VG2c0K  
.?)gn]#  
public static void main(String[] args) o((!3H{ D  
{ Qgxpq{y  
new TestMethod(); _7b' i6-  
} y8$I=  
} sU0W)c;  
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