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http断点续传简单实现(java)

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/* ZS>}NN  
**SiteFileFetch.java zhHQJcQ.  
*/ Z(/jQ=ozQ  
package NetFox; vB/MnEKR  
import java.io.*; ua`2 & ;T=  
import java.net.*; e{To&gy~  
E^A9u |x  
+c}fDrr)  
public class SiteFileFetch extends Thread { ;OPzT9  
ws?p2$Cla  
}(op;7  
SiteInfoBean siteInfoBean = null; //文件信息Bean g3LAi#m  
long[] nStartPos; //开始位置 N=tyaS(YJ  
long[] nEndPos; //结束位置 uO,90g[C/R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3<m"z9$  
long nFileLength; //文件长度 HQ/PHUg2  
boolean bFirst = true; //是否第一次取文件 TeHL=\L-^  
boolean bStop = false; //停止标志 lG%oqxJ+ L  
File tmpFile; //文件下载的临时信息 o \b8lwA,  
DataOutputStream output; //输出到文件的输出流 CN\s,. ]  
1ReO.Dd`R  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9WtTUk  
public SiteFileFetch(SiteInfoBean bean) throws IOException OR1XQij  
{ +P}'2tE~'  
siteInfoBean = bean; hkHMBsNi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :V}8a!3h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,6i67!lb  
if(tmpFile.exists ()) .s7o$u~l  
{ (yc$W9  
bFirst = false; y ?4|jN  
read_nPos(); +r4US or  
} _P,fJ`w   
else dlJkxEh 2  
{ cg1<  
nStartPos = new long[bean.getNSplitter()]; <wj2:Z0  
nEndPos = new long[bean.getNSplitter()];  fJc,KZy  
} Gp; [WY\  
il5WLi;{  
3_^w/-7`B  
dE/Vl/:  
} 5_G7XBvD/w  
lG fO  
|=jgrm1yj  
public void run() RL.%o?<&?  
{ ,0lRs   
//获得文件长度 EJdq"6S  
//分割文件 2$qeNy  
//实例FileSplitterFetch *v l_3S5_  
//启动FileSplitterFetch线程 _f^q!tP&d  
//等待子线程返回 *=^_K`y  
try{ w V2 7  
if(bFirst) #\%Gr tM  
{ ^row=5]E  
nFileLength = getFileSize(); ~z32%k  
if(nFileLength == -1) T_v  
{ \&ERSk2  
System.err.println("File Length is not known!"); z7HC6{g%X  
} (Clf]\_II  
else if(nFileLength == -2) ScZ$&n  
{ PJO;[: .I  
System.err.println("File is not access!"); cX *  
} 1;.}u= 8  
else uZ<Bfrc  
{ gJ vc<]W8!  
for(int i=0;i<nStartPos.length;i++) IK~ur\3  
{ ,2&'8:B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <XCH{Te1  
} /*r MveT  
for(int i=0;i<nEndPos.length-1;i++) xv4nYm9  
{ yMX4 f  
nEndPos = nStartPos[i+1]; nez5z:7F  
} Nm OQ7T  
nEndPos[nEndPos.length-1] = nFileLength; (:-DuUt  
} "TN}=^A\F  
} ,!sAr;Rk`  
P5] cEZ n  
ag|d_;  
//启动子线程 U?xl%qF`)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "UVV/&`o  
for(int i=0;i<nStartPos.length;i++) BtU,1`El5  
{ LoBKR c2t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !X[lNt O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q'  _  
nStartPos,nEndPos,i); :4(7W[r6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Kq-y1h]7H  
fileSplitterFetch.start(); *2;w;(-s  
} W%vh7>.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W=F?+Kg L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  0A pvuf1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0FEb[+N  
nEndPos = " + nFileLength); Y;-"Z  
// fileSplitterFetch[nPos.length-1].start(); $t}L|"=8X  
*dUnP{6g  
7J$ ^R6rh  
//等待子线程结束 j q1qj9KZ  
//int count = 0; J fsCkS  
//是否结束while循环 tb0s+rb  
boolean breakWhile = false; L$7v;R3  
Q?[k>fu0  
&y Vii^  
while(!bStop) wond>m 3  
{ /V&$SRdL*  
write_nPos(); N;Hf7K  
Utility.sleep(500); xwK<f6H!y  
breakWhile = true; o^DiIo or  
F_V~UX1D  
U R@'J@V#:  
for(int i=0;i<nStartPos.length;i++) v,p/r )E  
{ vQBfT% &Q-  
if(!fileSplitterFetch.bDownOver) WdIr 3  
{ hnE@+(d=qJ  
breakWhile = false; Ev$?c9*>  
break; o`G'E&  
} {#Gr=iv~N  
} `[o^w(l:5@  
if(breakWhile) 8a-[Q  
break; A!iV iX &y  
C7qbofoV  
of{wZU\J+9  
//count++; 8?I(wn  
//if(count>4) Q&n  
// siteStop(); /!7m@P|&D  
} #C !8a  
{u9VHAXCf  
}Qg9l|  
System.err.println("文件下载结束!"); !>t |vgW  
} ^dqyX(  
catch(Exception e){e.printStackTrace ();} M-|4cd]6  
} ,h>0k`J:a  
N],A&}30  
`n5|4yaG~  
//获得文件长度 R<k4LHDy  
public long getFileSize() dc%+f  
{ npbNUKdz  
int nFileLength = -1; WW==  
try{ 8$3Tu "+;  
URL url = new URL(siteInfoBean.getSSiteURL()); 5 QMu=/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,v)@&1Wh:  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ij{{Z;o3  
+J+]P\:  
pD`7N<F 3  
int responseCode=httpConnection.getResponseCode(); dwJ'hg  
if(responseCode>=400) s*(Y<Ap7d  
{ KvktC|~?  
processErrorCode(responseCode); .c~;/@{  
return -2; //-2 represent access is error c%i/ '<Afr  
} Pi)`[\{  
$IB@|n  
R.> /%o  
String sHeader; >JC.qjA  
`iQyKZS/+  
J/RUKhs/  
for(int i=1;;i++) QD / | zi  
{ pm<<!`w"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u4+)lvt  
//Utility.log(in.readLine()); S>cT(q_&  
sHeader=httpConnection.getHeaderFieldKey(i); f N t  
if(sHeader!=null) D2?~03c  
{ 1N:eM/a  
if(sHeader.equals("Content-Length")) G 7zfyw}W  
{  "FG6R'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VWbgusxJ  
break; % J+'7'g  
} ^R K[-tVV  
} 3H4p$\; C  
else +J.^JXyp0  
break; l2n>Wce9  
} I>ofSaN  
} 0]i#1Si~@  
catch(IOException e){e.printStackTrace ();} a)`h*P5@  
catch(Exception e){e.printStackTrace ();} NaAq^F U  
|$6Gp Aq!  
uQpV1o5iA  
Utility.log(nFileLength); _Se>X=  
Xo]FOJ 5  
d{9jd{ _#G  
return nFileLength; 7J0 PO}N  
} (K0FWTmm  
KOw Ew~  
,uDB ]  
//保存下载信息(文件指针位置) 64>Zr  
private void write_nPos() bpKb<c  
{ !f_Kq$.{  
try{ ]lm9D@HMC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z2nDD6N  
output.writeInt(nStartPos.length); ?i9LqHL  
for(int i=0;i<nStartPos.length;i++) zb:p,T@5  
{ g($y4~#  
// output.writeLong(nPos); N2q'$o  
output.writeLong(fileSplitterFetch.nStartPos); ~-'nEATE  
output.writeLong(fileSplitterFetch.nEndPos); MPM_/dn-  
} UW)k]@L  
output.close(); |A5]hL   
} gqG l>=.m  
catch(IOException e){e.printStackTrace ();} NV*t  
catch(Exception e){e.printStackTrace ();} ,4EE9 ?J  
} #[Ns\%Ri0  
\kC/)d  
]FsPlxk6  
//读取保存的下载信息(文件指针位置) 1/ j}VC  
private void read_nPos() ~e'FPVDn  
{ Eepy%-\  
try{ -C.eXR{s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $yc&f(Tv  
int nCount = input.readInt(); ^\Jg {9a  
nStartPos = new long[nCount]; h9SS o0]F  
nEndPos = new long[nCount]; z[CCgs&vqe  
for(int i=0;i<nStartPos.length;i++) `[CXxp  
{ /UM9g+Bb  
nStartPos = input.readLong(); W}JJaZR*X  
nEndPos = input.readLong(); ]TD]    
} vW YN?"d  
input.close(); wGb{O  
} +F4xCz7f  
catch(IOException e){e.printStackTrace ();} 9SMM%(3, r  
catch(Exception e){e.printStackTrace ();} rS6iZp,  
} MhJq~G p  
]$KH78MTW  
/5zzzaj {  
private void processErrorCode(int nErrorCode) -u)06C*39  
{ W\FKA vS  
System.err.println("Error Code : " + nErrorCode); WS2TOAya)  
} g[:5@fI#*  
a Se.]_  
T>W(Caelq  
//停止文件下载 .>h|e_E  
public void siteStop() ^VoQGP/cl  
{ >;0z-;k6  
bStop = true; 4[rD|  
for(int i=0;i<nStartPos.length;i++) !"p,9  
fileSplitterFetch.splitterStop(); #YhKAG@|  
saYn\o"m  
:t9(T?2  
} H6e ^" E  
} <>2QDI6_  
//负责部分文件的抓取 )3z.{.F  
**FileSplitterFetch.java ?Yz.tg  
*/ Fda<cS]  
package NetFox; (Tc ~  
1!BV]&,[  
yh lZdF  
import java.io.*; scN}eg:5  
import java.net.*; Vv6xVX  
4}#*M2wb  
ZtDHN L  
public class FileSplitterFetch extends Thread { z?FZu,h}  
)e]:T4*vo  
q;Qpd]H  
String sURL; //File URL r\_aux^z  
long nStartPos; //File Snippet Start Position 'VR5>r  
long nEndPos; //File Snippet End Position l.b  
int nThreadID; //Thread's ID e`8z1r  
boolean bDownOver = false; //Downing is over gY;N>Yq,C  
boolean bStop = false; //Stop identical vjbot^W9  
FileAccessI fileAccessI = null; //File Access interface 6 U# C  
;?%2dv2d  
0.&gm@A~c$  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yvNYYp2r  
{ RwT.B+Onuy  
this.sURL = sURL; d|DIq T~{W  
this.nStartPos = nStart; p 4(-  
this.nEndPos = nEnd; r|rV1<d  
nThreadID = id; cC WOG d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 }{E//o:Ta  
} [xM07%:  
-7;RPHJs  
~+^,o_hT  
public void run() rA{h/T"  
{ _czLKbcF  
while(nStartPos < nEndPos && !bStop) 4#4kfGoT  
{ OM2|c}]ZQ  
v }P~g  
;#f_e;  
try{ OJkPlDym  
URL url = new URL(sURL); ^!Bpev  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,gD30Pylz  
httpConnection.setRequestProperty("User-Agent","NetFox"); (}] 74Lc  
String sProperty = "bytes="+nStartPos+"-"; "ZT=[&2  
httpConnection.setRequestProperty("RANGE",sProperty); 1NJ*EzJ~?  
Utility.log(sProperty); Ya\G/R  
 0fNWI  
KGK8;Q,O  
InputStream input = httpConnection.getInputStream(); 8v(Xr}q,r  
//logResponseHead(httpConnection); '_(oa<g  
QZQ@C#PR;  
BAqu@F\):  
byte[] b = new byte[1024]; '!IX;OSjH  
int nRead; Fd|:7NRA<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B(b[Dbb  
{ F KL}6W:  
nStartPos += fileAccessI.write(b,0,nRead); M(oW;^B  
//if(nThreadID == 1) <2|x]b 8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5Ko "-  
} REFisH-  
f\/};a  
7_q"%xH  
Utility.log("Thread " + nThreadID + " is over!"); Uf_w o  
bDownOver = true; V@cRJ3ZF  
//nPos = fileAccessI.write (b,0,nRead); zXVQLz5  
} @/|sOF;8W  
catch(Exception e){e.printStackTrace ();} Z(U&0GH`  
} LnR3C:NO k  
} +wT,dUin_<  
7 yF#G9,  
S2j7(T;~YB  
//打印回应的头信息 iAup',AZg  
public void logResponseHead(HttpURLConnection con) [iL2c=_  
{ jY ^ndr0;  
for(int i=1;;i++) ]1D>3  
{ 7W}~c/%  
String header=con.getHeaderFieldKey(i); 6jF~zI^  
if(header!=null) kv`x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r!Mr\  
Utility.log(header+" : "+con.getHeaderField(header)); Q9W*)gBv n  
else a$9UUH-|  
break; h3O5DP6~  
} i_gS!1Z2  
} f_;3|i  
Eb{TKz?  
SOP= X-6f  
public void splitterStop() }3)$aI_  
{ KJ'MK~g  
bStop = true; HJ_xg6.x  
} ?A2EuvQH]  
=X% D;2  
;Oe6SNquT  
} hM>xe8yE  
vuw1ycy)  
?\^u},HnE|  
/* 4b7}Sr=`  
**FileAccess.java n7{1m$/  
*//文件访问(定位,写) !kmo% +  
package NetFox; (v(_ XlMK  
import java.io.*; C-4I e  
QRt(?96  
rV2}> k  
public class FileAccessI implements Serializable{ CGv(dE,G&]  
[nG/>Z]W  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 iW |]-Ba\  
RandomAccessFile oSavedFile; v SWqOv$  
long nPos; {/B) YR  
s'LG3YV-<  
R`s /^0  
public FileAccessI() throws IOException )NyGV!Zuu  
{ t'[vN~I'  
this("",0); i37W^9 R  
} !pDS*{)E  
D0"+E*   
CsuSg*#X+  
public FileAccessI(String sName,long nPos) throws IOException H<1C5-  
{ :()4eK/\  
oSavedFile = new RandomAccessFile(sName,"rw"); wBeOMA  
this.nPos = nPos; &dOV0y_  
oSavedFile.seek(nPos); Q[~O`Lz  
} p&ow\A O  
P#Eqe O  
1b_ ->_9  
public synchronized int write(byte[] b,int nStart,int nLen) z|pH>R?:  
{ hpAIIgn  
int n = -1; gvsS:4N"Nq  
try{ ZE}m\|$  
oSavedFile.write(b,nStart,nLen); L6Ynid.k  
n = nLen; pCpj#+|_)  
} aIqNNR  
catch(IOException e) dIM:U :c  
{ 7&HP2r  
e.printStackTrace (); HjV^6oP  
} 1f}S:Z  
jp[QA\  
tP3H7Yl! g  
return n; ?(g kk YI  
} 4&`66\p;  
I~q}M!v~  
%*jpQOw  
} %lV>Nc|iz=  
Odbjl[>k  
<GoE2a4Va  
/* n.7 $*9)#  
**SiteInfoBean.java Q jQJ "  
*/ sPd5f2'  
package NetFox; gHox{*hb[  
mZq*o<kTA  
=8tdu B  
public class SiteInfoBean { W^y F5  
L`"cu.l  
f_z2d+  
private String sSiteURL; //Site's URL czHO)uQ?d`  
private String sFilePath; //Saved File's Path G~m(&,:Mu  
private String sFileName; //Saved File's Name d628@~ Ekn  
private int nSplitter; //Count of Splited Downloading File  *riGi  
RmzK?muk  
MN1|k  
public SiteInfoBean() 9V"^F.>  
{//nSplitter的缺省值为5 *b.>pY?2|  
//default value of nSplitter is 5 ,eZ'pxt  
this("","","",5); x,p|n  
} | sQ5`lV?  
px-*uh<  
BwL: B\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 071w o7  
{ FPcgQ v;p  
sSiteURL= sURL; ?G8 D6  
sFilePath = sPath; kdoE)C   
sFileName = sName; wvUph[j}J  
this.nSplitter = nSpiltter; <-lz_  
`ZNjA},.  
pwu5Fxn)  
} g5T~%t5lo  
u6%56 %^f  
5Impv3qaZ  
public String getSSiteURL() u |f h!-  
{ !Noabt  
return sSiteURL; 8fDnDA.e  
} y"){?  
3$y]#L  
Z#o o8  
public void setSSiteURL(String value) ~u3I=b  
{ . t~I[J\<  
sSiteURL = value; KUly"B  
} =B?uNoe  
@&2T0UB  
!\"C<*5  
public String getSFilePath() !CsoTW9C:  
{ SJy?^  
return sFilePath; f|b|\/.=  
} \(;5YCCE  
_`;6'}]s  
QY{f=  
public void setSFilePath(String value) b[u_r,b  
{ ,:,c kul  
sFilePath = value; ,q:6[~n  
} : ;d&m  
#s]]\  
#}B~V3UD  
public String getSFileName() KIuYWr7&  
{ Q2Q`g`*O:  
return sFileName; }>p)|Y T"/  
} 3g5i5 G\  
;Y)?6^"  
f[dwu39k  
public void setSFileName(String value) p?d Ma_ g  
{ v#nFPB=z  
sFileName = value; [u-~<80  
} g0ug:- R  
o}NKqA3  
;vd%=vR  
public int getNSplitter() @9QHv  
{ 0<o#;ZQ]  
return nSplitter; 1`h`-dqr#  
} OCR x|  
KK7Y"~ 9&-  
o+q 5:vJt  
public void setNSplitter(int nCount) ;f6G&>p  
{ Y$'fds4P  
nSplitter = nCount; 6}|/~n  
} r3iNfY b  
} blS*HKw  
?EYF61? rw  
K` U\+AE  
/* 1{u;-pg  
**Utility.java qOk4qbl[  
*/ 2{&|%1Jg  
package NetFox; IG#=}q  
g\X"E>X  
x.45!8Zb  
public class Utility { ~){*XJw6  
O >'o;0  
RtF_p {s  
public Utility() b@5bN\"x$  
{ /#Ew{RvW'  
!7}5"j ;A  
Oys.8%+ P  
} J.El&Dev  
.4?M.Z4[  
//线程睡眠 G19FSLrtA  
public static void sleep(int nSecond) _c%~\LOk  
{ q>H!?zi\Hy  
try{ (}Gl'.>\M  
Thread.sleep(nSecond); \8<bb<`  
} W]rXt,{ &  
catch(Exception e) ef|Y2<P  
{ -|V@zSKr3  
e.printStackTrace (); EJL45R>  
} iVmf/N@A|  
} fzw6VGTf  
b7"pm)6  
//日志 SHh g&~B  
public static void log(String sMsg) A #ZaXu/:X  
{ "\> <UJ  
System.err.println(sMsg); )Hw;{5p@  
} [q_Yf!(m-  
~6@~fhu  
auS$B %  
public static void log(int sMsg) AbfLV942  
{ u wf3  
System.err.println(sMsg); d~28!E+  
} Hm4lR{A  
} Tm` QZh3  
(VC_vz-  
mp@JsCU  
/* LfF<wDvXf  
**TestMethod.java Lmj?V1% V  
*/ N}s[0s  
package NetFox; %f, 9  
^DIN(0u)  
}g(aZ  
public class TestMethod { ?#]c{Tlpz  
>5]Xl*{H)  
vA+RZ  
public TestMethod() `W|2Xi=^5  
{ ///xx/weblogic60b2_win.exe "7gS*v,r  
try{ ;'cv?3Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A$|> Jt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >-oa`im+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [[TB.'k  
fileFetch.start(); xazh8X0P  
} zwAuF%U  
catch(Exception e){e.printStackTrace ();} YS~\Gls%  
!y*V;J  
e2Xx7*vS  
} m#8KCZS  
BNaZD<<  
in B}ydk  
public static void main(String[] args) KF7f<  
{ QmgwIz_  
new TestMethod(); l65'EO|  
} ]4hXK!^Uu  
} ,[~Ydth  
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