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http断点续传简单实现(java)

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/* MCQ>BP  
**SiteFileFetch.java oO @6c%  
*/ xpyb&A  
package NetFox; *NV`6?o@6  
import java.io.*; K_`*ZV{r  
import java.net.*; w;QDQ fx0  
$E|W|4N  
#`GW7(M  
public class SiteFileFetch extends Thread { G"MpA[a_  
zx(j6  
Kggf!\MR8  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1:7>Em<s  
long[] nStartPos; //开始位置 XoSjYG(>,  
long[] nEndPos; //结束位置 p"H8;fPA0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r_xo>y~S  
long nFileLength; //文件长度 fY=iQ?{/[  
boolean bFirst = true; //是否第一次取文件 &X+V}  
boolean bStop = false; //停止标志 EyNI]XEj  
File tmpFile; //文件下载的临时信息 EhB9M!Y`@  
DataOutputStream output; //输出到文件的输出流 QY+#Vp<`  
#2ZXYH}  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0&/1{Dk*n  
public SiteFileFetch(SiteInfoBean bean) throws IOException z9HQFRbo[  
{ A&9l|b-"  
siteInfoBean = bean; CR934TE+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (53dl(L?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ? z=>n  
if(tmpFile.exists ()) =AL95"cH~  
{ * {4cc  
bFirst = false; <O5;w  
read_nPos(); RMC|(Q<  
} `N(.10~  
else 8<n8joO0  
{ 9,`mH0jP  
nStartPos = new long[bean.getNSplitter()]; 2+=|!+f  
nEndPos = new long[bean.getNSplitter()]; HC{|D>x.  
} />ob*sk/Y  
.?I!/;=[  
iZMsN*9[  
#-'}r}1ZT  
} |B`-chK  
C2<y(GU[Bh  
NYP3uGH]  
public void run() -&)^|Atm  
{ ,;+\!'lS  
//获得文件长度 7Wb.(` a<  
//分割文件 A^,(Vyd  
//实例FileSplitterFetch 6S6nE%.3  
//启动FileSplitterFetch线程 d`~#uN {  
//等待子线程返回 1xguG7  
try{ !-.-!hBN  
if(bFirst) v9inBBC q  
{ ,dVCbAS@  
nFileLength = getFileSize(); (la<X <w  
if(nFileLength == -1) hsqUiB tc6  
{ W$'pUhq\H  
System.err.println("File Length is not known!"); /kw4":{]  
} yN>"r2   
else if(nFileLength == -2) MT6kJDyLu  
{ ,o9)ohw  
System.err.println("File is not access!"); !5B9:p~-  
} G4x.''r&Sl  
else Z;>~<#!4  
{ J`RNik*>  
for(int i=0;i<nStartPos.length;i++) IN%>46e`  
{ }2NH>qvY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =fsaJ@q ,R  
} d:pp,N~2o  
for(int i=0;i<nEndPos.length-1;i++) h.?[1hT4R  
{ "L8V!M_e  
nEndPos = nStartPos[i+1]; )D[ypuM&  
} BB%(!O4Dl  
nEndPos[nEndPos.length-1] = nFileLength; LpmspIPvf  
} 9d{W/t?NH  
} =k$d8g ez  
Q%eBm_r;  
^1~/FU  
//启动子线程 pM46I"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !r LHPg  
for(int i=0;i<nStartPos.length;i++) Hzj*X}X#K  
{ $AXz/fGV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %x927I>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O]Kb~jkd  
nStartPos,nEndPos,i); }TF<C !]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6U&Uyd)  
fileSplitterFetch.start(); P);Xke  
} )K?GAj]Pq  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ! 4oIx`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5t<]|-i!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #>- rKv.A  
nEndPos = " + nFileLength); ^m+W  
// fileSplitterFetch[nPos.length-1].start(); ,gOQI S56  
;etQ  
ttsB'|p s  
//等待子线程结束 8uT6QCf  
//int count = 0; .|aSGv E  
//是否结束while循环 aDOH3Ri0K!  
boolean breakWhile = false; 1|nB\xgu  
E{fnh50^Q.  
)I>rC%2P  
while(!bStop) )/U1; O  
{ I L\mFjZ'  
write_nPos(); i&HV8&KygN  
Utility.sleep(500); d#d~t[=  
breakWhile = true; `UI)H*GA8  
}fCM_w  
p!a%*LfND  
for(int i=0;i<nStartPos.length;i++) 19rUvgC{M  
{ ..T (9]h  
if(!fileSplitterFetch.bDownOver) z<fEJN  
{ _@p|A  
breakWhile = false; *Qf }4a0  
break; dXDD/8E  
} Yq Fzbm{\  
} b5|p#&YK~  
if(breakWhile) Q|1bF!#(1  
break; :I $2[K  
AFFLnLA<L  
\l2 s^7G_  
//count++; {DK:"ep  
//if(count>4) 3?XLHMxW  
// siteStop(); &\H5*A.HkA  
} =z/F=1^<  
D1n2Z :9  
2|=_kN8;  
System.err.println("文件下载结束!"); kwL) &@  
} Ih7Eq/iu  
catch(Exception e){e.printStackTrace ();} (lnQ!4LK  
} v wyDY%B"n  
qL P +@wbJ  
?>y-5B[K/(  
//获得文件长度 @ 7?_Yw  
public long getFileSize() m?j!0>  
{ wuk7mIJ  
int nFileLength = -1; U. aa iX7  
try{ -^b^6=#  
URL url = new URL(siteInfoBean.getSSiteURL()); JqUVGEg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ie(7m| .  
httpConnection.setRequestProperty("User-Agent","NetFox"); tTt3D]h(  
kOCxIJ!Xp=  
wuzz%9;@B  
int responseCode=httpConnection.getResponseCode(); =5ih,>>g  
if(responseCode>=400) MuobMD}jqe  
{ W/>?1+r.Z  
processErrorCode(responseCode); gQuw|u  
return -2; //-2 represent access is error +29\'w,  
} 32iI :u  
Hl;p>>n  
ymZ/(:3_  
String sHeader; hU 7fZl%yl  
#Qr4Ke$g[l  
Gme$FWa  
for(int i=1;;i++) H/k W :k  
{ @vYmkF`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @q/1m~t  
//Utility.log(in.readLine()); ak) -OL1  
sHeader=httpConnection.getHeaderFieldKey(i); mi<D bnou  
if(sHeader!=null) )$B+ 3f  
{ ,)$KS*f"*z  
if(sHeader.equals("Content-Length")) Yp]G)}'R  
{ (AG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =&pN8PEn\  
break; o0G`Xn  
} 8-a6Q|   
} A+*oT(`  
else A{I a21T7  
break; n2 mw@Ay!  
} aNC,ccm  
}  - 1  
catch(IOException e){e.printStackTrace ();} g>xUS_d>  
catch(Exception e){e.printStackTrace ();} %hbLT{w  
kc'0NE4oq  
/iy*3P,`  
Utility.log(nFileLength); 1?RCJ]e5  
A dEbyL  
OgN1{vRFx  
return nFileLength; iM|"H..  
} 4 l}M i  
$U1kP?pR  
cNo4UZvr  
//保存下载信息(文件指针位置) \678Nx  
private void write_nPos() 9G&l qfX:  
{ SxZ^ "\H  
try{ bsi q9$F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tnF9Vj[#%_  
output.writeInt(nStartPos.length); '}+X,Usm  
for(int i=0;i<nStartPos.length;i++) y8hg8J|  
{ [du>ff  
// output.writeLong(nPos); j]B $(pt  
output.writeLong(fileSplitterFetch.nStartPos); {QS@Ugf  
output.writeLong(fileSplitterFetch.nEndPos); mu6xL QdA  
} 3.<6;?  
output.close(); \8*,&ak%  
} ^s@*ISY  
catch(IOException e){e.printStackTrace ();} an=+6lIl  
catch(Exception e){e.printStackTrace ();} } C{}oLz  
} ;WS7.  
BY4  R@)  
[B ~zoB(  
//读取保存的下载信息(文件指针位置) ]PzTl {]  
private void read_nPos() o;VkoYV  
{ KBr5bcm4u  
try{ < k+fKl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T]nR=uK6LL  
int nCount = input.readInt(); _.OMjUBZT  
nStartPos = new long[nCount]; ^?6 W<  
nEndPos = new long[nCount]; 1>@]@ST[:  
for(int i=0;i<nStartPos.length;i++) YZBzv2'\x  
{ V^ fGRA  
nStartPos = input.readLong(); kg?T$}O  
nEndPos = input.readLong(); cPx ~|,)l  
} 7/&C;"  
input.close(); 6t_ 3%{  
} B15O,sL&W  
catch(IOException e){e.printStackTrace ();} r%TLv  
catch(Exception e){e.printStackTrace ();} P )t]bS  
} T+K` ^xv_L  
T3G/v)ufd  
#0?"J)  
private void processErrorCode(int nErrorCode) 1=/doo{^  
{ [>$\s=` h  
System.err.println("Error Code : " + nErrorCode); qD(fYOX{C  
} #}/cM2m  
BP[CR1Gs  
G>=9gSLM  
//停止文件下载 _OJ0 < {E  
public void siteStop() 3yHb!}F  
{ _'!N q  
bStop = true;  ko=aa5c  
for(int i=0;i<nStartPos.length;i++) 6z9R1&~%  
fileSplitterFetch.splitterStop(); BaWQ<T8p8  
0<]$v"`I  
< v|%K.yd  
} aPD?Bh>JU  
} VM-qVd-  
//负责部分文件的抓取 lL:KaQ0E  
**FileSplitterFetch.java L _vblUDq  
*/ 7oZ@<QP'  
package NetFox; saGRP}7?  
C<[d  
Iz6ss(UJ  
import java.io.*; 22)0zY%\  
import java.net.*; iEiu%T>  
zyaW3th  
&u+yM D  
public class FileSplitterFetch extends Thread { =d go!k  
|. J,8~x  
8g<Q5(  
String sURL; //File URL %/UV_@x&  
long nStartPos; //File Snippet Start Position +<pVf%u5  
long nEndPos; //File Snippet End Position M0cd-Dn  
int nThreadID; //Thread's ID +<S9E'gT3V  
boolean bDownOver = false; //Downing is over u|(Ux~O  
boolean bStop = false; //Stop identical 6N9 c<JC  
FileAccessI fileAccessI = null; //File Access interface qq OxTG]  
8h*t55  
tl DY k  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1S+;ZMk  
{ nAIH`L"X  
this.sURL = sURL; _,DO~L  
this.nStartPos = nStart; ?TIV2m^?  
this.nEndPos = nEnd; WHp97S'd  
nThreadID = id; ki\B!<uv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mfZ)^X  
} t";{1.  
"Owct(9  
FXS^^p P  
public void run() $[[?;g  
{ *3;UAfHv  
while(nStartPos < nEndPos && !bStop) 8jRs =I  
{ ]53O}sH>  
}x]&L/  
a*D,*C5}  
try{ cI2Fpf`2Wj  
URL url = new URL(sURL); q^5yk=2fq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %Nj #0YF]  
httpConnection.setRequestProperty("User-Agent","NetFox"); +fM&su=wl  
String sProperty = "bytes="+nStartPos+"-"; 0|ZVA+  
httpConnection.setRequestProperty("RANGE",sProperty); W$r^  
Utility.log(sProperty); VKy5=2&  
XlVc\?  
bMsECA&  
InputStream input = httpConnection.getInputStream(); &M[MEO`t8  
//logResponseHead(httpConnection); F$i$a b  
Zb."*zL  
fmFzW*,E  
byte[] b = new byte[1024]; k=?^){[We  
int nRead; (%bE~Q2P*<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b4 CF`BG  
{ q]TqI' o  
nStartPos += fileAccessI.write(b,0,nRead); FqwIJ|ct  
//if(nThreadID == 1) fYB*6Xb,w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .Rvf/-e  
} &iNS?1a%f=  
}%$OU =T  
Q/py qe G  
Utility.log("Thread " + nThreadID + " is over!"); DVh)w}v  
bDownOver = true; ox[ .)v  
//nPos = fileAccessI.write (b,0,nRead); /g@^H/DO  
} +"8}R~`!  
catch(Exception e){e.printStackTrace ();} 3 CM^j<9  
} 3rNc1\a;  
} i6Qb[\;  
-w]/7cH  
hsz^rZ  
//打印回应的头信息 e[{mVhg4E  
public void logResponseHead(HttpURLConnection con) p x#suy  
{ r+S;B[Vd  
for(int i=1;;i++) 4&{!M _  
{ 1HbFtU`y~  
String header=con.getHeaderFieldKey(i); O9^T3~x[V  
if(header!=null) b9uBdo@o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^I`a;  
Utility.log(header+" : "+con.getHeaderField(header)); ]g,lRG  
else >b48>@~bY  
break; jO8X:j09A  
} q@l(Qol  
} DnFjEP^  
k!3 cq)  
{<K=*r rZ  
public void splitterStop() fx)KNm8Lx  
{ xS8,W  
bStop = true; oa`#RC8N  
} dZ]Rqr _!  
g jxS  
,lm=M 5b  
} $UvPo0{  
W~ruN4q.  
:(, mL2[  
/* vHcqEV|P/n  
**FileAccess.java 3^wC<ZXcD  
*//文件访问(定位,写) 0<.R A%dj  
package NetFox; `}fw1X5L  
import java.io.*; @i LIU}+  
% frfSGf.#  
|PP.<ce\-  
public class FileAccessI implements Serializable{ =&vFVIhWcf  
{( tHk_q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _<*Hv*Zm  
RandomAccessFile oSavedFile; O{]9hm(tN  
long nPos; 57Z-  
I7(?;MpI  
P^)q=A8Z#  
public FileAccessI() throws IOException :iPy m}CE  
{ Y; ) .+si  
this("",0); vmX"+sHz$]  
} Eu,`7iQ?(  
_O]xey^r  
_}gtcyx  
public FileAccessI(String sName,long nPos) throws IOException Vf $Dnu@}z  
{ A''pS  
oSavedFile = new RandomAccessFile(sName,"rw"); PaWr[ye  
this.nPos = nPos; rwf^,r"r  
oSavedFile.seek(nPos); )rtomp:X  
} GTl xq%?b  
s?C&s|'.  
j !H^-d}q  
public synchronized int write(byte[] b,int nStart,int nLen) n<7q`tM#  
{ Jxl6a:  
int n = -1; A1i!F?X  
try{ _NZ@4+aW  
oSavedFile.write(b,nStart,nLen); #,NvO!j<4  
n = nLen; O7G"sT1Dv  
} }} ZY  
catch(IOException e) )> a B  
{ ('[TLHP  
e.printStackTrace (); fAZiC+  
} V8=Y@T,  
Z%Z9oJ:  
B7\k< Nit0  
return n; *%Qn{x  
} {%w!@-  
, n !vsIN  
2/,0iwj-  
} OS7R Qw1  
B< ;==|  
a#(U2OP  
/* c;!g  
**SiteInfoBean.java E1q%gi4Q%  
*/ (}H ,ng'4  
package NetFox; 4KIWb~0Y  
IlZu~B9c  
N_'+B+U?  
public class SiteInfoBean { @6.]!U4w  
]S /G\z  
{Bs+G/?o/  
private String sSiteURL; //Site's URL $+VgDe5{S  
private String sFilePath; //Saved File's Path r5Wkc$  
private String sFileName; //Saved File's Name xz="|HD);  
private int nSplitter; //Count of Splited Downloading File kU>#1 He  
"1\(ZKG8^Q  
0rGj|@+;  
public SiteInfoBean() XZ; *>(  
{//nSplitter的缺省值为5 vN' VDvVM  
//default value of nSplitter is 5 ,%.:g65%  
this("","","",5); ?F!W#   
} &~42T}GTWG  
S54gqc1S]  
9k*^\@\\x  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yr (g~MQ  
{ z`;&bg\8  
sSiteURL= sURL; ]kzv8#  
sFilePath = sPath; Am]2@ESUP  
sFileName = sName; (xjqB{U  
this.nSplitter = nSpiltter; #I bS  
J,.j_ii`!  
HIQ]"Hl  
} \=$EmHF  
t@l(xnsV  
(X0`1s  
public String getSSiteURL() Sa( yjF1  
{ rDK;6H:u{  
return sSiteURL; #_?426Wfs  
} ?r^ hm u"a  
.G7]&5s  
5@GD} oAn6  
public void setSSiteURL(String value) 8Pl+yiB/o`  
{ 'Wo?%n  
sSiteURL = value; hP,b-R9\  
} /8 e2dw: \  
2V#c[%vI  
/5L'9e  
public String getSFilePath() V[BY/<z)A  
{ 6M O|s1zk  
return sFilePath; YlZYS'_  
} u=_bM2;~Z  
,6S_&<{  
 '7S!6kd?  
public void setSFilePath(String value) )nf=eU4|  
{ ~%cSckE  
sFilePath = value; uW\@x4  
} EqNz L*E  
 ?.4yg(  
z 'vdC  
public String getSFileName() xI.Orpw  
{ Uxj<x`<1x  
return sFileName; 1kz9>;Ud6  
} A{DIp+  
.(P@Bl]XJ  
!q7;{/QM6  
public void setSFileName(String value) wHB Hkz  
{ XudH  
sFileName = value; p[af[!  
} }(f.uN_v  
n6}E4Eno  
O&rD4#  
public int getNSplitter() 'NG^HLD/  
{ [t "_}t=w  
return nSplitter; 34+)-\xt:  
} P0`>{!r6@  
=hOj8;2  
$,z[XM&9)  
public void setNSplitter(int nCount) I;Z`!u:+  
{ t9$AvE#a!=  
nSplitter = nCount; c|R3,<Q]  
} F=*BvI "+  
} pZ@W6}  
A^= Hu,"e  
8IT_mjj  
/* NejsI un%  
**Utility.java Q J(e*/  
*/ 6/V{>MTZg  
package NetFox; $&n240(  
n{qw ]/  
@LkW_  
public class Utility { ]X"i~$T1S  
J4 '!  
)z4kP09  
public Utility() WW8L~4Zy  
{ ?O.6r"  
go%X%Os]  
F|n$0vQ*  
} eqUn8<<s  
*`pec3"  
//线程睡眠 L2/<+ Zw  
public static void sleep(int nSecond) ]Xkc0E1  
{ Ie`SWg*WL  
try{ 6!Tf'#TV~!  
Thread.sleep(nSecond); i>kNz(*  
} Cn./Naq  
catch(Exception e) 9>$%F;JP44  
{ 3/SqXu  
e.printStackTrace (); 8 *(W |J  
} ETH#IM8J  
} UNZVu~WnF  
Velbq  
//日志 I!0$% ]F  
public static void log(String sMsg) omUl2C  
{ UgP=k){  
System.err.println(sMsg); vsr~[d=  
} Dk{nOvZu<  
XGrxzO|{  
 C>K"ZJ  
public static void log(int sMsg) B=RKi\K6a  
{ 0\ytBxL  
System.err.println(sMsg); iNrmhiql  
} ;uo|4?E:\(  
} QX~72X=(  
7QL) }b.H  
>,Swk3  
/* r@V(w`  
**TestMethod.java +iDz+3v(  
*/ eEds-&_  
package NetFox; 'w$we6f  
bA9dbe  
%^@0tT  
public class TestMethod { By"ul:.D  
gdn,nL`dP  
?B31 t9  
public TestMethod() 9lwo/(s  
{ ///xx/weblogic60b2_win.exe }j<_JI  
try{ 6 VJj(9%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [z t&8g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9Qm{\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); NZ? =pfK\s  
fileFetch.start(); Vh-h{  
} 5TW<1'u  
catch(Exception e){e.printStackTrace ();} y]z#??  
z&G3&?Z  
\Hx#p`B%  
} ?=o]Wx0(9  
si4=C  
vP;tgW9Qk  
public static void main(String[] args) +?eAaC7s  
{ "+"dALX{3K  
new TestMethod(); /u1zRw  
} ) W7H{#  
} R}mWHB_h"  
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