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http断点续传简单实现(java)

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/* @va{&i`%A7  
**SiteFileFetch.java #{7=  
*/ VBR@f<2L  
package NetFox; l)D18  
import java.io.*; Y{Kpopst  
import java.net.*; o1"U'y-9V  
;&e5.K+.Z  
VuFM jY  
public class SiteFileFetch extends Thread { LfyycC2E  
gwQL9 UYx  
lJoMJS;S]}  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1YR;dn  
long[] nStartPos; //开始位置 ^ef:cS$;  
long[] nEndPos; //结束位置 K @"m0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &q1(v3cOO  
long nFileLength; //文件长度 cRz7.9-<  
boolean bFirst = true; //是否第一次取文件 5R4h9D5  
boolean bStop = false; //停止标志 $=iz&{9  
File tmpFile; //文件下载的临时信息 UV)[a%/SB&  
DataOutputStream output; //输出到文件的输出流 =Y|TShKk  
6k"Wy3/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xXH%7%W'f  
public SiteFileFetch(SiteInfoBean bean) throws IOException Nt67Ye3;  
{ e.G&hJ r  
siteInfoBean = bean; 4nkH0dJQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k='sI^lF  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {.SN  
if(tmpFile.exists ()) e%x$Cb:znn  
{ 0 sVCTJ@  
bFirst = false; MdU_zY(c  
read_nPos(); K"eR 6_ k  
} $;7?w-.  
else aGNt?)8WPZ  
{ eB/3MUz1  
nStartPos = new long[bean.getNSplitter()]; VJD$nh #M5  
nEndPos = new long[bean.getNSplitter()]; N::_JH? ^=  
} `y0ZFh1>X  
5ejdf  
*gHOH!K,S  
BMU~1[r  
} ~FH''}3:3  
]eb9Fq:N7  
E& T9R2Y  
public void run() 9C[3w[G~C  
{ Zp@p9][C  
//获得文件长度 Rb<aCX  
//分割文件 3s\2 9gq  
//实例FileSplitterFetch hnL"f[p@gC  
//启动FileSplitterFetch线程 LYGFE jS[  
//等待子线程返回 V!c{%zd  
try{ Ia)wlA02S  
if(bFirst) j9%u&  
{ U/yYQZ\)  
nFileLength = getFileSize(); 0KnlomuH2  
if(nFileLength == -1) ckP&N:tC  
{ ko im@B  
System.err.println("File Length is not known!"); c;w cgU  
} Y%p"RB[  
else if(nFileLength == -2) 4a>z]&s  
{ !OPK?7   
System.err.println("File is not access!"); _.J{U0N  
} y&lj+j  
else P\iw[m7O  
{ P^v`5v  
for(int i=0;i<nStartPos.length;i++) .,l ?z  
{ !fwLC"QC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Xo(K*eIN  
} &xr?yd  
for(int i=0;i<nEndPos.length-1;i++) )Be}Ev#)Zx  
{ 6h}f^eJ:K,  
nEndPos = nStartPos[i+1]; : i3-7k  
} LB? evewu  
nEndPos[nEndPos.length-1] = nFileLength; T'\ lntN  
} (o{QSk\  
} vb9G_Pfz  
.zlUN0oe  
; z:}OD  
//启动子线程 h_?D%b~5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; h\C  
for(int i=0;i<nStartPos.length;i++) |=l;UqB  
{ -DX|[70  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y!i4P#4+q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e.\d7_T+  
nStartPos,nEndPos,i); H h$D:ZO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); | g> K$m^  
fileSplitterFetch.start(); fcr\XCG7U  
} !K'kkn,h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :b^tu 8E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (BMFGyE3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Cf<i"   
nEndPos = " + nFileLength); ~c! XQJ  
// fileSplitterFetch[nPos.length-1].start(); =B*,S#r  
J.?6a:#bU/  
M ,e_=aq  
//等待子线程结束 1P3^il7  
//int count = 0; W: cOzJ  
//是否结束while循环 i4'?/UPc  
boolean breakWhile = false; .2!'6;K  
%l,p />r  
O9=vz%  
while(!bStop) #p*{p)]HiA  
{ p[hA?dXn  
write_nPos(); H1 n`A#6?  
Utility.sleep(500); MCe =RR  
breakWhile = true; "^zxq5u  
Z)|*mJ  
`DC)U1  
for(int i=0;i<nStartPos.length;i++) ~( -B%Az  
{ Pf]6'?kQ  
if(!fileSplitterFetch.bDownOver) 3VB{Qj  
{ ,8c`  
breakWhile = false; 0#G&8*FMN  
break; MJ8z"SKnV  
} wR@fB  
} +x-n,!(  
if(breakWhile) 4B-v\3Ff  
break; j?g{*M  
;wp)E nF  
i~ n>dc YW  
//count++; u <%,Ql  
//if(count>4) d.% Vm&3  
// siteStop(); hi*\5(uH  
} ;?yd;GOt)  
"[BuQ0(g  
87>\wUJ  
System.err.println("文件下载结束!"); K S,X$)9  
} G7M:LcX  
catch(Exception e){e.printStackTrace ();} Hl?\P6   
} #8%Lc3n  
'?v.O}  
^B1Q";# B^  
//获得文件长度 +*DXzVC  
public long getFileSize() }a'8lwF%I  
{ wP+wA}SN  
int nFileLength = -1; BB|w-W=Kd  
try{ d; oaG (e  
URL url = new URL(siteInfoBean.getSSiteURL()); H^B/ '#mO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "DjD"?/b  
httpConnection.setRequestProperty("User-Agent","NetFox"); }PK8[N  
y_Bmd   
y%cg  
int responseCode=httpConnection.getResponseCode(); z./u;/:  
if(responseCode>=400) Jf|J":S  
{  *9`@  
processErrorCode(responseCode); ]{0 2!  
return -2; //-2 represent access is error Zc{at}{  
} O6YYOmt3  
BQ)zm  
pI( OI>~3  
String sHeader; L@ql)Lc);  
s0E:hn:  
{&4+W=0 n  
for(int i=1;;i++) c9=;:E  
{ 7-'!XD!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b9%hzD,MR  
//Utility.log(in.readLine()); =eDVgOZ)  
sHeader=httpConnection.getHeaderFieldKey(i); ql2>C.k3L  
if(sHeader!=null) 2Af1-z^^K  
{ 3EI$tP@4  
if(sHeader.equals("Content-Length")) U9SByqa1  
{ <FRYt-+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); egYJ.ZzF0  
break; b=wc-n A  
} J3oH^  
} \.POb5]p0  
else aHXd1\6m  
break; p4fU/  
} |/Ggsfmby  
} (VI4kRj  
catch(IOException e){e.printStackTrace ();} qYl%v  
catch(Exception e){e.printStackTrace ();} f-k%P$"X&  
dK#:io[Nz  
lN<vu#  
Utility.log(nFileLength); TXv3@/>ZlG  
~N;kF.q&>&  
!eMz;GZ  
return nFileLength; q#xoM1  
} "S,,BjL  
>j4;{r+eQw  
MQG(n+c  
//保存下载信息(文件指针位置) -L NJ*?b  
private void write_nPos() Ww{bh -nyq  
{ 2!QJa=  
try{ [GyW1-p33w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YiTiJ9jf  
output.writeInt(nStartPos.length); ,_!pUal  
for(int i=0;i<nStartPos.length;i++) ;*BG{rkr  
{ Q=)$  
// output.writeLong(nPos); ey_3ah3x  
output.writeLong(fileSplitterFetch.nStartPos); ,ZHIXylZ  
output.writeLong(fileSplitterFetch.nEndPos); QgqR93Ic  
} $>hPB[[  
output.close(); D. fP Hq  
} "iMuA  
catch(IOException e){e.printStackTrace ();} [o<Rgq 4  
catch(Exception e){e.printStackTrace ();} Kyq/'9`  
} .D(H@3qA@  
t3}>5cAxy  
NoB)tAvw  
//读取保存的下载信息(文件指针位置) bE74Ui  
private void read_nPos() p`fUpARA!  
{ g=0`^APql  
try{ AU -,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j2#RO>`,I  
int nCount = input.readInt(); V`fp%7W  
nStartPos = new long[nCount]; }xk85*V  
nEndPos = new long[nCount];  _/;vsQB  
for(int i=0;i<nStartPos.length;i++) ve49m%NQ  
{ DI{VJ&n66  
nStartPos = input.readLong(); i+ ]3J/J  
nEndPos = input.readLong(); UMILAoR  
} bBk_2lg=4)  
input.close(); F{WV}o=MY  
} <wfPbzs-V  
catch(IOException e){e.printStackTrace ();} }^ +E S^~  
catch(Exception e){e.printStackTrace ();} <~@}r\  
} LUc!a4i"fO  
{ 0RwjPYp  
/H/@7>  
private void processErrorCode(int nErrorCode) -GJ~xcf0  
{ ~2PD%+e7]  
System.err.println("Error Code : " + nErrorCode); 0/5 a3-3{  
} w j !YYBH  
A=JPmsj.  
lD)ZMaaS3  
//停止文件下载 `d2 r5*<  
public void siteStop() /'' |bIPa  
{ "4NcszEN  
bStop = true; " R!,5HQF;  
for(int i=0;i<nStartPos.length;i++) Q"7vzri  
fileSplitterFetch.splitterStop(); Y&!-VW  
$9YAq/#Q  
.)59*'0  
} ,P ~jO  
} O_OgTa  
//负责部分文件的抓取 Q =9Ce@[  
**FileSplitterFetch.java @`xR1pXQ  
*/ 6|:K1bI)  
package NetFox; `yJ3"{uO  
iY?J3nxD-:  
@( p9}  
import java.io.*; K~Nx;{{d  
import java.net.*; 6l]jm j)/  
C$WUg<kcK'  
r&+8\/{  
public class FileSplitterFetch extends Thread { +i^@QNOa  
uE] HU  
2>TOC BB"  
String sURL; //File URL znnnqR0us  
long nStartPos; //File Snippet Start Position |`eHUtjH  
long nEndPos; //File Snippet End Position o]/*YaB2>  
int nThreadID; //Thread's ID IJ\4S  
boolean bDownOver = false; //Downing is over ^x2zMB\t  
boolean bStop = false; //Stop identical "QSmxr  
FileAccessI fileAccessI = null; //File Access interface /M!b3bmA  
m&vuBb3  
'^B[Krs'Z`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Cq8.^=}_  
{ O{^8dwg  
this.sURL = sURL; D8X~qt/  
this.nStartPos = nStart; JOwm|%>3a  
this.nEndPos = nEnd; D[/h7Ha  
nThreadID = id; M5 \flE2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 SG \6qE~  
} .ni<'  
!aQb Kp  
AS4mJ UU9  
public void run() Lmsc ~~  
{ fVf @Ngvu  
while(nStartPos < nEndPos && !bStop) |2ImitN0  
{ tVQq,_9C  
#1fL2nlP*E  
IVSOSl|  
try{ .fFXH  
URL url = new URL(sURL); 4j|IG/m  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IC"Z.'Ph  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^+p7\D/E(  
String sProperty = "bytes="+nStartPos+"-"; M h"X9-Ot  
httpConnection.setRequestProperty("RANGE",sProperty); 6mV-+CnYC  
Utility.log(sProperty); /U26IbJ  
6|uv+$  
*T6*Nxs0k  
InputStream input = httpConnection.getInputStream(); +~(SeTY  
//logResponseHead(httpConnection); ~aPe?{yIUa  
0:I[;Q t  
PH.g+u=v  
byte[] b = new byte[1024]; H^ 'As;R  
int nRead; or,:5Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~Y/:]&wF  
{ OEw#;l4 C  
nStartPos += fileAccessI.write(b,0,nRead); |PtfG2Ty?  
//if(nThreadID == 1) %lq[,6?>5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [s4|+  
} tn{YIp   
m^%@bu,  
bog3=Ig-  
Utility.log("Thread " + nThreadID + " is over!"); }#r awVe=  
bDownOver = true; {x{~%)-  
//nPos = fileAccessI.write (b,0,nRead); 7F2 WmMS  
} Gsn$r(m{K  
catch(Exception e){e.printStackTrace ();} 3D;?X@  
} t)|~8xpP  
} ]f{3_M[  
-w"$[XP  
4mjlat(d  
//打印回应的头信息 ]sTbEw.[  
public void logResponseHead(HttpURLConnection con) s<>d& W 0=  
{ sZx`u+  
for(int i=1;;i++) 2cEvsvw>  
{ k?Kt*T  
String header=con.getHeaderFieldKey(i); 7Q^p|;~a  
if(header!=null) D%}rQ,*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t!-\:8n  
Utility.log(header+" : "+con.getHeaderField(header)); {o SdVRI  
else Nj;5iy  
break; nuH=pIq6x  
} /:tzSKq}  
} 2##;[  
*8r^!(Kj  
`>0%Ha   
public void splitterStop() 577#A,O  
{ Yt[LIn-v:  
bStop = true; b)eoFc)lc  
} 1etT."  
%oB0@&!mS  
ZIN1y;dJ  
} [QFAkEJ--o  
WeJ=]7T'L  
IwXWtVL  
/* ,wf:Fr  
**FileAccess.java G2<$to~{  
*//文件访问(定位,写) 5S<Rz)1r  
package NetFox; #_eXybUV  
import java.io.*; E.%V 0}  
b(oe^jeGz  
wBDHhXi0  
public class FileAccessI implements Serializable{ 0!-'4+"  
:i4AkBNK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0K'{w]Q  
RandomAccessFile oSavedFile; 2?Y8hm  
long nPos; qV9}N-sS  
$PG(>1e  
\ZM5J  
public FileAccessI() throws IOException /qKA1-R}4  
{ eC"k-a8j+  
this("",0); |8pSMgN  
} denxcDFu/~  
{#st>%i  
NN#k^[i1  
public FileAccessI(String sName,long nPos) throws IOException Llkh kq_  
{ IQ$!y,VJ  
oSavedFile = new RandomAccessFile(sName,"rw"); SwsJ<Dq^z  
this.nPos = nPos; eR4ib-nS  
oSavedFile.seek(nPos); OK)>QGl  
} wz1nV}  
ul3~!9F5F  
Tw djBMte  
public synchronized int write(byte[] b,int nStart,int nLen) 8 :WN@  
{ w$IUm_~waa  
int n = -1; 4#{f8  
try{ t{g@z3  
oSavedFile.write(b,nStart,nLen); ^KdT,^6T  
n = nLen; fF(AvMsO  
} V:#rY5X  
catch(IOException e) gg.]\#3g  
{ z . Z  
e.printStackTrace (); Mq#m;v$E  
} @  R[K8  
`*cqT  
qdLzB  
return n; /O<~n%< G  
} 9 Jw, ls  
>yr;Y4y7K  
/lbj!\~  
} K\wu9z8M  
T;5VNRgpI  
?%`Ph ?BZl  
/* V@]SKbK}wN  
**SiteInfoBean.java GMg! 2CIU  
*/ 3$xpZm60  
package NetFox; ~r?tFE* +  
Zr1"'+-  
i6P}MtC1  
public class SiteInfoBean { g4=C]\1  
IqV" 4  
yKuZJXGVo  
private String sSiteURL; //Site's URL CcW3o"=4  
private String sFilePath; //Saved File's Path A +=#  
private String sFileName; //Saved File's Name VH4wsEH]  
private int nSplitter; //Count of Splited Downloading File i3mw.`7  
ZJW8S  
uB^"A ;0v  
public SiteInfoBean() %19~9Tw  
{//nSplitter的缺省值为5  pdm(7^  
//default value of nSplitter is 5 ,}\LC;31,  
this("","","",5); ^SsdM#E  
} U# [T!E  
[<5/s$,i  
yZ 7)|j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Vpp$yM&?  
{ .rG~\Ws  
sSiteURL= sURL; w_o+;B|I  
sFilePath = sPath; bl&9O  
sFileName = sName; YhNrg?nS  
this.nSplitter = nSpiltter; 45n.%*,  
)5n0P Zi  
:!l.ze{F  
} }cI-]|)|2  
vs$h&o>|  
qLN\>Z,3;  
public String getSSiteURL() R<gAxO%8  
{ y9?*H?f,  
return sSiteURL; Go1xyd:k  
} R<_VWPlj  
2q]ZI  
c7{s'ifG  
public void setSSiteURL(String value) ovOV&Zt  
{ J~xm[^0  
sSiteURL = value; `q\F C[W  
} /k ?l%AH  
 H{yBD xw  
kP}l"CN4  
public String getSFilePath() VRgckh m  
{ n|?sNM<J3  
return sFilePath; (SQGl!Lai0  
} *Gv:N6  
E.;Hm;  
n:B){'S  
public void setSFilePath(String value) jbq x7x  
{ y`8U0TE3R  
sFilePath = value; Ym"^Ds}  
} I L7kpH+y  
Du +_dr^4  
QHja4/  
public String getSFileName() WF*j^ %5  
{ xjF>AAM_Px  
return sFileName; ~:k r;n2  
} )7!,_r  
TghT{h@  
<$hv{a  
public void setSFileName(String value) 4YI6&  
{ c%O97J.5b  
sFileName = value; Ek_&E7  
} )MSCyPp5  
A$7K5   
@aN~97 H\  
public int getNSplitter() k"%JyO8Y  
{ Nt]nwae>A  
return nSplitter; hrD2 -S  
} X jxa 2D  
o3\^9-jmp  
f3n^Sw&Q(Q  
public void setNSplitter(int nCount) suIYfjh  
{ o<p4r}*AVJ  
nSplitter = nCount; %-fS:~$  
} p %.Adxx  
} p<h(  
bC"h7$3  
Ac{TqiIv  
/* ^b~ZOg[p  
**Utility.java _t;^\"\  
*/ -IVWkA)7  
package NetFox; OGLA1}k4  
G5OGyQp  
qhG2j;  
public class Utility { mJd8?d  
"[k>pzl6  
yMM2us#*+q  
public Utility() G;#xcld  
{ DF-PBVfpu  
Vv5T(~   
55TFBDc  
} pO fw *lD  
Het>G{  
//线程睡眠 6C<GYzzo  
public static void sleep(int nSecond) %XBTN  
{ /qwY/^  
try{ Z8/.I  
Thread.sleep(nSecond); ^V9|uHOJoq  
} Gg GjBt  
catch(Exception e) -R1;(n)  
{ gaNe\  
e.printStackTrace (); _,v?rFLE  
} B 5qy4MFWs  
} e2G;_:  
pRxVsOb  
//日志 ~*\ *8U@7  
public static void log(String sMsg) % jf|efxo  
{ 7rbw_m`12-  
System.err.println(sMsg); 'byTM?Sp{  
} (RrC<5"  
o(> #}[N}  
-OmpUv-O"  
public static void log(int sMsg) Ktt(l-e+  
{ )+Z.J]$O-  
System.err.println(sMsg); b&QI#w  
} C|g1:#0  
} FYu30  
wxBZ+UP_  
E@)'Z6r1  
/* vaHtWz!P  
**TestMethod.java ;gu4~LQw  
*/ |9.J?YP8 (  
package NetFox; H/Ql  
 Y%y  
B<Cg_C  
public class TestMethod { 2'OY,Ooe  
@qW$un:  
Unq~lt%2  
public TestMethod() nFI<Te^)  
{ ///xx/weblogic60b2_win.exe t5i58@{~  
try{ :kE*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -vc$I=b;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); = \oW {?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9C Ki$L  
fileFetch.start(); ,JbP~2M~%  
} m :~y:.  
catch(Exception e){e.printStackTrace ();} .X)Wb{7  
Ay^P #\VZ  
MT)q?NcG  
} ,Csjb1  
P*%P"g  
<tsexsw  
public static void main(String[] args) i| ,}y`C#  
{ H"Hl~~U  
new TestMethod(); l= Jw6F+5  
} 3fX _XH1Q  
} N7}3?wS  
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