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http断点续传简单实现(java)

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/* W{;LI WsZ  
**SiteFileFetch.java B&H [z  
*/ _Hq)mF  
package NetFox; gr$H?|n l  
import java.io.*; )i>T\B  
import java.net.*; DZ|/#- k  
3bB%@^<  
gH/k}M7tA#  
public class SiteFileFetch extends Thread { ) $I"LyK)  
~bJ*LM?wOP  
gJBk&SDgtP  
SiteInfoBean siteInfoBean = null; //文件信息Bean W-ECmw(  
long[] nStartPos; //开始位置 rYr.mX  
long[] nEndPos; //结束位置 cNqw(\rr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :y[tZ&*<_?  
long nFileLength; //文件长度 Q|cA8Fn  
boolean bFirst = true; //是否第一次取文件 Ad`jV_z  
boolean bStop = false; //停止标志 1Aa=&B2  
File tmpFile; //文件下载的临时信息 Yy0m &3[  
DataOutputStream output; //输出到文件的输出流 <8/lHQ^\)  
w+ tO@  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) rx;zd?  
public SiteFileFetch(SiteInfoBean bean) throws IOException k$ } 6Qd  
{  WR"p2=  
siteInfoBean = bean; mdHC{sp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); aMjCqu05  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3836Di:{  
if(tmpFile.exists ()) Cqk6Igw  
{ LIHf]+  
bFirst = false; o>Z+=&BZ@a  
read_nPos(); $(%t^8{a~G  
} sQe>LNp,G  
else 5=Y\d,SS"  
{ bpe WK&  
nStartPos = new long[bean.getNSplitter()]; _Msaub!N  
nEndPos = new long[bean.getNSplitter()]; \Tj(]  
} bga2{<VF  
:dzam HbX9  
-n~VMLd?@  
1{S" axSL  
} K&noA  
b}r3x&)  
~UJ_Rr54  
public void run() wA}+E)x/C  
{ !xK`:[B  
//获得文件长度 ^UK6q2[  
//分割文件 nEm+cHHo?  
//实例FileSplitterFetch 4%k_c79>  
//启动FileSplitterFetch线程 "2bCq]I0  
//等待子线程返回 ,Z I"+v  
try{ "GofQ5,|  
if(bFirst) 8~|PZ,oZ  
{ re/l5v,|3  
nFileLength = getFileSize(); Z`b{r;`m8  
if(nFileLength == -1) ^T|~L<A3  
{ W7"ks(  
System.err.println("File Length is not known!"); oFV >b  
} )/9/p17:xu  
else if(nFileLength == -2) X;0DQnAI8j  
{ I(Yyg,1Z  
System.err.println("File is not access!"); bmO[9 )G  
} RtR]9^:~  
else )y:~T\g  
{ VscEdtkd  
for(int i=0;i<nStartPos.length;i++) uIvE~<  
{ U{o0Posg  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Hd)4_ uBt  
} dLm~]V3  
for(int i=0;i<nEndPos.length-1;i++) U.G**v  
{ ;[@< ,  
nEndPos = nStartPos[i+1]; Ui 7S8c#tH  
} u1&pJLK0[  
nEndPos[nEndPos.length-1] = nFileLength; Ij}RlYQz  
} LdAfY0  
} "tbKKh66  
b#^UP  
; ,]T|> M  
//启动子线程 j xr~cp?4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fNx3\<~V=  
for(int i=0;i<nStartPos.length;i++) X] &Q^  
{ m>'sM1s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fgP_NYfOj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tq^H)  
nStartPos,nEndPos,i); T?c:z?j_9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >_]j{}~\k  
fileSplitterFetch.start(); }CA oB::&  
} Uok?FEN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l M5Xw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =?3D:k7z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t3b%f`D  
nEndPos = " + nFileLength); N$H0o+9-Y  
// fileSplitterFetch[nPos.length-1].start(); AjK'P<:/  
g#1_`gK  
Jn. WbS  
//等待子线程结束 g~Zel}h#  
//int count = 0; ,\f!e#d  
//是否结束while循环 `Q*L!/K+  
boolean breakWhile = false; 0t1WvW  
{ CkxUec  
<w.W[ak  
while(!bStop) V 3-5:z  
{ b$+.}&M  
write_nPos(); 0Q=4{*:?  
Utility.sleep(500); A5zT^!`[  
breakWhile = true; 'tp1|n/1  
vO"Sy{)Z>  
O s@ d&wm  
for(int i=0;i<nStartPos.length;i++) Bls\)$  
{ %9xz[Ng  
if(!fileSplitterFetch.bDownOver) 41WnKz9c  
{ B`} ?rp  
breakWhile = false; .S17O}  
break; n97A'"'wz  
} wz5xJ:Tj  
} keEyE;O}u  
if(breakWhile) 70l"[Y  
break; &CFHH"OsT  
/v E>*x  
w9h\J#f  
//count++; i!<,8e=  
//if(count>4) auqM>yx  
// siteStop(); ao<@a{G  
} BM#cosV7%h  
"8aw=3A  
iNgHx[*?  
System.err.println("文件下载结束!"); XS]=sfN  
} M& GA:`  
catch(Exception e){e.printStackTrace ();} cTFyF)  
} rE-Xv. |  
CEE`nn  
;Id%{1  
//获得文件长度 6)kF!/J  
public long getFileSize() b/ h,qv  
{ oBQr6-nZ  
int nFileLength = -1; P7(+{d{  
try{ JGp~A#H&  
URL url = new URL(siteInfoBean.getSSiteURL()); &+=A;Y)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EUU9JnQhBJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); C+$dm)M/q  
iK1<4)  
1K&z64Q5J  
int responseCode=httpConnection.getResponseCode(); [J0L7p*6  
if(responseCode>=400) Y!v `0z  
{ G:$wdT(u  
processErrorCode(responseCode); Iu^# +n  
return -2; //-2 represent access is error k`6T% [D]  
} Zg%U4m:  
l~wx8 ,?G  
P}y}IR{6  
String sHeader; ^_r8R__S:  
eXWiTi@  
_) 2fXG!  
for(int i=1;;i++) l=[<gPE  
{ =9GL;z:R+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .0S.7w3dZo  
//Utility.log(in.readLine()); b40zYH`'{  
sHeader=httpConnection.getHeaderFieldKey(i); 5@bLD P  
if(sHeader!=null) KD*,u{v;  
{ !9DqW&8  
if(sHeader.equals("Content-Length")) ' D+h_*H  
{ d>eVR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CeoK@y=o  
break; "d>{hP  
} r}MXXn,f  
} ` ZXX[&C  
else gX5I`mm  
break; dU\,>3tG  
} V6?ku6k  
} $%"i|KTsv:  
catch(IOException e){e.printStackTrace ();} 1 e1$x@\\  
catch(Exception e){e.printStackTrace ();} IL?3>$,  
v{^_3 ]  
wP- pFc  
Utility.log(nFileLength); f@T/^|`mh  
ZFNM>C^  
2j` x^  
return nFileLength; ]fI v{[A_  
} MbC7`Sp&i  
#.UooFk+Y  
(EGsw o  
//保存下载信息(文件指针位置) v-J*PB.0p  
private void write_nPos() ;(fDR8  
{ Q5b?- P  
try{ h.ojj$f,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *fso6j#%  
output.writeInt(nStartPos.length); RxY ;'NY  
for(int i=0;i<nStartPos.length;i++) -mOSB(#bo  
{ A9ia[2[  
// output.writeLong(nPos); wGD".CS0  
output.writeLong(fileSplitterFetch.nStartPos); x'@0]f.  
output.writeLong(fileSplitterFetch.nEndPos); tbF>"?FY/  
} Nt9M$?\P  
output.close(); A1zM$ wDU  
} *x2+sgSf_0  
catch(IOException e){e.printStackTrace ();} |X k'd@<  
catch(Exception e){e.printStackTrace ();} _>%P};G{>  
} 2i*-ET  
mBSa*s)  
W# E`h  
//读取保存的下载信息(文件指针位置) *P_(hG&c  
private void read_nPos() 4=td}%  
{ CTQF+Oe8O  
try{ [URo#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hC?:XVt  
int nCount = input.readInt(); $As;Tvw.  
nStartPos = new long[nCount]; @ |v4B[/  
nEndPos = new long[nCount]; <61T)7  
for(int i=0;i<nStartPos.length;i++) Vrz x;V%  
{ eTem RNz  
nStartPos = input.readLong(); n~l9`4wJY  
nEndPos = input.readLong(); q%%8oaEI  
} NypM+y  
input.close(); @&t ';"AE  
} hJ\IE?+  
catch(IOException e){e.printStackTrace ();} 1r;]==  
catch(Exception e){e.printStackTrace ();} qZACX.Hw  
} =<R")D]4z  
R)MWO5  
%^ f! = *  
private void processErrorCode(int nErrorCode) xDv$z.=Y  
{ i"Hec9Ri  
System.err.println("Error Code : " + nErrorCode); Md(AqaA  
} AM  cHR=/  
>UvLeS2h:y  
t+7h(?8L  
//停止文件下载 @^]wT_r  
public void siteStop() 9J h"1i>x2  
{ jh0``{  
bStop = true; l{ja2brX  
for(int i=0;i<nStartPos.length;i++) JpqZVu"7  
fileSplitterFetch.splitterStop(); _jg&}HM  
u :AKp<'  
xDU>y  
} lx$]f)%~  
} ivDmPHj{  
//负责部分文件的抓取 8+Sa$R  
**FileSplitterFetch.java {q f gvu  
*/ f#mBMdj  
package NetFox; /8(c^  
~XGBE  
I[,tf!  
import java.io.*; dCv@l7hE  
import java.net.*; &HBqweI  
i3#To}g5V  
idW=  
public class FileSplitterFetch extends Thread { b5K6F:D22  
I,;@\  
P"d7Af  
String sURL; //File URL Y|JC+ Ee  
long nStartPos; //File Snippet Start Position $BHbnsaQ  
long nEndPos; //File Snippet End Position 5p!X}u ]  
int nThreadID; //Thread's ID ^'>kZ^w0  
boolean bDownOver = false; //Downing is over 4g<F."  
boolean bStop = false; //Stop identical h!.#r*vV  
FileAccessI fileAccessI = null; //File Access interface u"eO&Vc  
zj:= 9$  
!lQGoXQ'4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException D+edTAQ8  
{ YuufgPE*H  
this.sURL = sURL; i4;`dCT|A  
this.nStartPos = nStart; ${I$@qq83  
this.nEndPos = nEnd; x?s5vxAKf  
nThreadID = id; xuBXOr4"P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5@l[!Jl0k  
} XRoMD6qf;  
GZJIIP#  
l{q$[/J~)  
public void run() Z9P rw/8P  
{ K5l#dl_T  
while(nStartPos < nEndPos && !bStop) [O~' \ Q  
{ s}"5uDfn1F  
:lf;C T6$  
OSP#FjH  
try{ ~DY5`jV  
URL url = new URL(sURL); d'j8P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @;>i3?  
httpConnection.setRequestProperty("User-Agent","NetFox"); OS|uZ<"Rq3  
String sProperty = "bytes="+nStartPos+"-"; &XG k  
httpConnection.setRequestProperty("RANGE",sProperty); kkWqP20q  
Utility.log(sProperty); w&&uk[Gh/a  
*;^!FBT  
QY14N{]T\p  
InputStream input = httpConnection.getInputStream(); }{FKs!(4  
//logResponseHead(httpConnection); P$l-p'U-  
Ce&nMgd~  
o=/Cje  
byte[] b = new byte[1024]; R}~p1=D  
int nRead; 9J>b6   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (EZ34,k'S  
{ ?naPti1GX  
nStartPos += fileAccessI.write(b,0,nRead); p#-ov-znp  
//if(nThreadID == 1) lIR0jgP@z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Hgu:*iYA  
} H<tk/\C  
<eWGvIEP[  
$xx5+A%,  
Utility.log("Thread " + nThreadID + " is over!"); /rMxl(wD'  
bDownOver = true; |GmV1hN  
//nPos = fileAccessI.write (b,0,nRead); #bRr|`  
} ;VQFz&Q$u  
catch(Exception e){e.printStackTrace ();} 9{OH%bF  
} Eu%19s; u  
} oL?[9aww  
t:A,pT3  
00DWXGt20o  
//打印回应的头信息 $#Mew:J  
public void logResponseHead(HttpURLConnection con) 1-z*'Ghys  
{ xL.T}f~y2>  
for(int i=1;;i++) {sn:Lj0  
{ 'Na \9b(  
String header=con.getHeaderFieldKey(i); -I, _{3.S  
if(header!=null) 44s K2  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  ]J= S\  
Utility.log(header+" : "+con.getHeaderField(header)); >;E[XG^  
else !83x,*O  
break; q;I`&JK  
} B@ab[dm280  
} iEDZ\\,  
{?a9>g-BW  
R'E8>ee; ^  
public void splitterStop() Y~RZf /`  
{ 7V/yU5  
bStop = true; 7e,<$PH  
} +{%@kX<V_  
+ n1jP<[<N  
^iaeY jI  
} vBUl6EmWu  
OtopA)  
?nm:e.S+?  
/* !U02>X   
**FileAccess.java >M` swEj  
*//文件访问(定位,写) Kd_WN;l  
package NetFox; )G(6=l*  
import java.io.*; ^V^In-[!y:  
#=WDJ T:  
K#"@nVWJ.m  
public class FileAccessI implements Serializable{ <`dF~   
qZ!1>`B  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \!UNa le  
RandomAccessFile oSavedFile; S"|sD|xOb  
long nPos; M/U$x /3K  
_ Ko0  
0F'75  
public FileAccessI() throws IOException CK e  
{ ]{9oB-;,  
this("",0); ?KxI|os  
} .js4)$W^  
-;$+`<%  
W7N Hr5RC  
public FileAccessI(String sName,long nPos) throws IOException 7YRDQjg  
{ =q|fe%#  
oSavedFile = new RandomAccessFile(sName,"rw"); uTJi }4cw  
this.nPos = nPos; D#%J||  
oSavedFile.seek(nPos); ?o0#h  
} dRZor gar  
XEqg%f  
S(A0),  
public synchronized int write(byte[] b,int nStart,int nLen) d9/E^)TT  
{  w'=#7$N  
int n = -1; *D1fSu!  
try{ z(< E %  
oSavedFile.write(b,nStart,nLen); X7kJWX  
n = nLen; ;>=hQC{f>  
} Q:+Y-&||"  
catch(IOException e) K*J8(/WkD  
{ a@@!Eg A  
e.printStackTrace (); vg5zsR0u  
} 8Gb=aF1  
hoC}@8_  
.Jdw:  
return n; ?Di, '  
} ?xf59mY7  
yZ&By?.0  
yZ:|wxVY  
} cFLu+4.jsG  
F *; +-e  
+ZXGT  
/* Rn{q/h  
**SiteInfoBean.java 2h&pm   
*/ ;J\{r$q  
package NetFox; BN4dr9T  
)<.S 3  
pb%#`2"  
public class SiteInfoBean { 3Gn2@`GC  
9BANCW"  
HkvCQH  
private String sSiteURL; //Site's URL c7\bA7.  
private String sFilePath; //Saved File's Path !U`T;\,v5  
private String sFileName; //Saved File's Name p)ZlQ.d#Y  
private int nSplitter; //Count of Splited Downloading File ?l,i(I  
+bm2vIh$  
f.jAJ; N>  
public SiteInfoBean() 6o;lTOes  
{//nSplitter的缺省值为5 ]CC= \ <  
//default value of nSplitter is 5 ;_j\E(^%  
this("","","",5); .WL507*"Ce  
} w & RpQcV  
mQ%kGqs  
9+QLcb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NtTLvO6  
{ =mqV&FgRo  
sSiteURL= sURL; l O, 2  
sFilePath = sPath; j<deTK;.  
sFileName = sName; b&~uK"O'7d  
this.nSplitter = nSpiltter; #Mbt%m  
!^axO  
#bu`W!p}  
} mKpUEJ<a  
k5-mK{RZ  
-I=}SZ  
public String getSSiteURL() qUtVqS  
{ XQ(`8Jl&^  
return sSiteURL; rvE!Q=y~  
} >^J!Z~;L)  
lYw A5|+  
'%RMpyK~  
public void setSSiteURL(String value) 1rPeh{SZ  
{ c<&+[{|  
sSiteURL = value; 4kXx(FE  
} .h+<m7  
YSrFHVq  
ObM5vrEk|  
public String getSFilePath() }Pb!u9_  
{ WgPL4D9=  
return sFilePath; 5RLK]=  
} 5 (H; x74  
==FzkRA)  
VDnAQ[T@d  
public void setSFilePath(String value) E#ys-t 42  
{ Z<,gSut'Y  
sFilePath = value; Kv#daAU  
} aRG[F*BY  
P`bR;2o  
?tA- `\E  
public String getSFileName() G~esSL^G/  
{ J"83S*2(j  
return sFileName; 0_]aF8j  
} 0)2lBfHQ&  
wG{o bsL.!  
V GvOwd)E  
public void setSFileName(String value) G,"$Erx  
{ 4|+ |L_  
sFileName = value; qw, >~  
} _^'k_ a  
;%k%AXw  
t#pY2!/T3  
public int getNSplitter() Gc 8  
{ .`h+fqa  
return nSplitter; O3BU.X1'%  
} t o?"{  
hXr vb[6  
pP/o2  
public void setNSplitter(int nCount) #ASu SQ  
{ lmc-ofEv  
nSplitter = nCount; 8v6rS-iHP  
} `UJW:qqW  
} v'@LuF'e8  
^#t<ILUa  
SQ1&n;M}f  
/* cEQa 6  
**Utility.java [cW  
*/ v Cmh3TQ  
package NetFox; mE7Jv)@  
aEM#V  
&GZR-/  
public class Utility { O~Fk0}-  
:YI>AaYWDO  
9(PFd%  
public Utility() k m|wB4  
{ $7bmUQ|  
CKR9APkv  
P<(mH=K  
} QA9vH'  
z"vgwOP su  
//线程睡眠  nm~  
public static void sleep(int nSecond) J~Ph)|AiS  
{ >WEg8'#O  
try{ nagto^5X  
Thread.sleep(nSecond); vVf!XZF  
} )/pPY  
catch(Exception e) Z"^@B2v  
{ enr mjA&3  
e.printStackTrace (); mT9\%5d3  
} A&7jE:Ew  
} puyL(ohem  
j w462h  
//日志 >k#aB.6  
public static void log(String sMsg) {2Ibd i  
{ ;5l|-&{@*  
System.err.println(sMsg); [eN{Ft0x  
} 6qDD_:F  
NNdS:(  
Yt'o#"R)  
public static void log(int sMsg) ~S6N'$^  
{ iTvCkb48m  
System.err.println(sMsg); =w8 YZs8w  
} Lgfr"{C  
} srkOa d  
ou-;k }  
/W>"G1)  
/* 7L6M#B[)e5  
**TestMethod.java <>oW f  
*/ iau&k `b`  
package NetFox; ]]ZBG<#  
5~F0'tb|}  
!R@4tSu  
public class TestMethod { f*~fslY,o  
pp`U]Q5"gX  
G<eJ0S  
public TestMethod() a+i+#*8wm  
{ ///xx/weblogic60b2_win.exe gD\}CxtG  
try{ DIAP2LR ?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ATHz~a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 463dLEd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }{y$$X<:  
fileFetch.start(); BSf"'0I&  
} u\wd<<I']  
catch(Exception e){e.printStackTrace ();} qh 3f  
xL"% 2nf  
F)w83[5_d  
} dp70sA!JF  
}+J@;:  
g < o;\\  
public static void main(String[] args) VLN3x.BY  
{ n}?G!ySg  
new TestMethod(); 7A6sSfPUy  
} }b(e  
} J5T#}!f  
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