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http断点续传简单实现(java)

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/* du_4eB  
**SiteFileFetch.java /&^W#U$4  
*/ uOd& XW  
package NetFox; K\u_Ji]k  
import java.io.*; y t5H oy  
import java.net.*; -DjJ",h( $  
,6{iT,~@8  
JeCg|@  
public class SiteFileFetch extends Thread { ]Y`Ib0$  
]JXKZV8$0  
[M%._u,  
SiteInfoBean siteInfoBean = null; //文件信息Bean dg_Gs>?2  
long[] nStartPos; //开始位置 ac8P\2{"  
long[] nEndPos; //结束位置 A6 !F@Ic[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 A&"%os  
long nFileLength; //文件长度 ^x m$EY*Y,  
boolean bFirst = true; //是否第一次取文件 YlF%UPp  
boolean bStop = false; //停止标志 H,y4`p 0  
File tmpFile; //文件下载的临时信息 -oP'4QVb  
DataOutputStream output; //输出到文件的输出流 q%i-`S]}qL  
=5x&8i  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Lja7   
public SiteFileFetch(SiteInfoBean bean) throws IOException %JyXbv3m,  
{ {<=#*qx[Y!  
siteInfoBean = bean; />44]A<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ,|h)bg7.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2VGg 6%  
if(tmpFile.exists ()) U*)m' ,  
{ oD.r `]k  
bFirst = false; `$TRleSi  
read_nPos(); )Xtn k  
} 3\:y8|  
else 'hqBo|  
{ &JP-O60  
nStartPos = new long[bean.getNSplitter()]; 5Qh?>n>*  
nEndPos = new long[bean.getNSplitter()]; }`\/f  
} bB}5U@G|  
`5~3G2T  
rsXq- Pq*  
\tN-(=T  
} XYr J/!*.  
<RNJ>>0  
eq4C+&O&  
public void run() Wwujh2g"0|  
{ >znRyQ~bM  
//获得文件长度 -E4XIn  
//分割文件 Sa1 l=^  
//实例FileSplitterFetch 7msAhz  
//启动FileSplitterFetch线程 $F'>yop2b  
//等待子线程返回 DA&?e~L&H  
try{ Np+&t}  
if(bFirst) RQB 4s^t  
{ 36.N>G,  
nFileLength = getFileSize(); "vZ!vt#'Y  
if(nFileLength == -1) Qnd5X`jF#  
{ RsJ6OFcWV  
System.err.println("File Length is not known!"); 'T<iHV&  
} }Gyqq6Aeb  
else if(nFileLength == -2) VVP:w%yW  
{ 5L,}e<S$  
System.err.println("File is not access!"); sarq`%zrk  
} ',^+bgs5  
else Uyx!E4pl(  
{ ~@.%m"<.  
for(int i=0;i<nStartPos.length;i++) 3&&9_`r&_  
{ j hbonuV_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )lk&z8;.=  
} 0 &_UH}10  
for(int i=0;i<nEndPos.length-1;i++) Vv1|51B  
{ ?L&|Uw+  
nEndPos = nStartPos[i+1]; M-V&X&?j  
} z7GTaX$d  
nEndPos[nEndPos.length-1] = nFileLength; 9d[5{" 2j  
} D,qu-k[jMI  
} v[e:qi&fG  
RPd}Wf  
Z[__"^}  
//启动子线程 u VyGk~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2owEw*5jl/  
for(int i=0;i<nStartPos.length;i++) o]:3H8  
{ Ig]iT  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kVK/9dy-F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OCZaQ33  
nStartPos,nEndPos,i); s, k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LJk%#yV|_  
fileSplitterFetch.start(); &F STpBu  
} ;2'q_Btk4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Urr#N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X3'H `/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l7#yZ*<v  
nEndPos = " + nFileLength); 6`vC1PK^  
// fileSplitterFetch[nPos.length-1].start(); M" ^PW,k  
EnOU?D  
ib{-A&  
//等待子线程结束 N_:qRpp6i  
//int count = 0; _=CZR7:O  
//是否结束while循环 EBz}|GY;  
boolean breakWhile = false; [(1c<b2r  
9z)5Mdf1j  
w?kJ+lmOQy  
while(!bStop) U!U$x74D5  
{ sBrI}[oyx  
write_nPos(); {ZY+L;eg1  
Utility.sleep(500); P) 3mX.(}  
breakWhile = true; U- )i+}Ng  
J{^RkGF  
E4 m`  
for(int i=0;i<nStartPos.length;i++) ,|&9M^  
{ A\8}|r(>9E  
if(!fileSplitterFetch.bDownOver) K2%w0ohC  
{ ,^#yo6-  
breakWhile = false; KM^ufF2[  
break; #9K-7je;j  
} ME'|saP  
} _6 ay-u  
if(breakWhile) RV@*c4KvO+  
break; 6G=j6gK%P  
M1KqY:9E  
-D6exTxh"  
//count++; vWGwVH/K  
//if(count>4) 4:gRr   
// siteStop(); }.s~T#v  
} M|:UwqV>  
Yw#2uh  
tHzZ@72B7  
System.err.println("文件下载结束!"); Qxj JN^Q  
} M(/r%-D  
catch(Exception e){e.printStackTrace ();} g<~Cpd  
} bV,}Pp+/"!  
9k{PBAP  
/ X1 x  
//获得文件长度 _a1x\,R|DB  
public long getFileSize() )"pF R4  
{ uu`G 2[t  
int nFileLength = -1; S~|T4q(  
try{ 72'5%*1  
URL url = new URL(siteInfoBean.getSSiteURL()); pR~U`r5z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8<Hf" M  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5LOo8xN  
,c NLkoN  
KZ/=IP=  
int responseCode=httpConnection.getResponseCode(); e=.]F*:J  
if(responseCode>=400) ght$9>'n  
{ T?X_c"{8M  
processErrorCode(responseCode); <>Hj ;q5p  
return -2; //-2 represent access is error (DI>5.x"  
} 6'FdGS  
qT+%;(  
X 7rMeu  
String sHeader; uC cYPvm  
SJHr_bawd  
L*:jXmUM_~  
for(int i=1;;i++) aTt 12Sc  
{ '*3h!lW1.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kBffF@{  
//Utility.log(in.readLine()); j:VbrR  
sHeader=httpConnection.getHeaderFieldKey(i); b9l;a+]d  
if(sHeader!=null) OLE[UXD-E  
{ fZoHf\B]{  
if(sHeader.equals("Content-Length")) jbAx;Xt'=M  
{ OynXkH]0T+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <[-nF"Q  
break; pS:4CNI{  
} o,)?!{k}  
} ;5)P6S.D  
else ]?(-[  
break; B8}Nvz /  
} ajEjZ6  
} @<elq'2  
catch(IOException e){e.printStackTrace ();} Fx2bwut.K  
catch(Exception e){e.printStackTrace ();} yPal<c  
3qf Ym}d  
r[*Vqcz  
Utility.log(nFileLength); va0{>Dc+  
jEZMUqGY!  
Rd#WMo2Xd  
return nFileLength; Eq j_m|@  
} rogT~G}q  
Rx}$0c0  
o6uJyCO  
//保存下载信息(文件指针位置) ~GZY5HF  
private void write_nPos() ):[7E(F=  
{ >7QvK3S4%  
try{ =Lf,?"S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); XzEc2)0'v  
output.writeInt(nStartPos.length); s*-n^o-  
for(int i=0;i<nStartPos.length;i++) TIQkW,  
{ I+tb[*X+  
// output.writeLong(nPos); NeE t  
output.writeLong(fileSplitterFetch.nStartPos); q-}Fvel u  
output.writeLong(fileSplitterFetch.nEndPos); lIW }EM  
} bAx-"Lu  
output.close(); SMpH._VFeE  
} zo4qG+>o  
catch(IOException e){e.printStackTrace ();} & tg&5_  
catch(Exception e){e.printStackTrace ();} FG.em  
} F9,DrB,B{  
,Y/ g2 4R  
!:q/Ye3.  
//读取保存的下载信息(文件指针位置) t%E!o0+8Z  
private void read_nPos() sTn<#l6  
{ hHV";bk  
try{ ,[P{HrHx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hpO`]  
int nCount = input.readInt(); [PNT\ElT  
nStartPos = new long[nCount]; ?#}N1k\S  
nEndPos = new long[nCount]; =A83W/4  
for(int i=0;i<nStartPos.length;i++) pHLB= r  
{ BRgXr  
nStartPos = input.readLong(); JvVWG'Z"  
nEndPos = input.readLong(); cj$[E]B3V*  
} UG+d-&~Ll  
input.close(); 5kCUaPu  
} 1;Ou7T9w  
catch(IOException e){e.printStackTrace ();} wea-zN  
catch(Exception e){e.printStackTrace ();} b4[bL2J$h1  
} H9YW  
Nn!+,;ut  
W*Zkc:{eB  
private void processErrorCode(int nErrorCode) DH\0z[  
{  : y%d  
System.err.println("Error Code : " + nErrorCode); g/CSG IIT  
} 1_PoqD!q  
&,{fw@#)_  
M l Jo`d  
//停止文件下载 _`&m\Qe>  
public void siteStop() `d5%.N  
{ 1Q<^8N)pf  
bStop = true; )u[emv$  
for(int i=0;i<nStartPos.length;i++) A kC1z73<  
fileSplitterFetch.splitterStop(); $4h5rC g0  
ywGd>@  
J}v}~Cv  
} }dgfqq  
} 4T|b Cs?e  
//负责部分文件的抓取 kmP]SO?tx  
**FileSplitterFetch.java >=:&D)m"  
*/ "s0)rqf<  
package NetFox; VVac:  
WW4vn|0v  
v%+:/m1  
import java.io.*; Br1&8L-|%  
import java.net.*; % 5M/s'O?i  
kMi/>gpQ  
e2s]{obf  
public class FileSplitterFetch extends Thread { HK,cJah q  
}wr{W:j  
g{OwuAC_  
String sURL; //File URL RJ  8+h  
long nStartPos; //File Snippet Start Position dCi?SIN  
long nEndPos; //File Snippet End Position $'BSH4~|.  
int nThreadID; //Thread's ID Pg,b-W?n*  
boolean bDownOver = false; //Downing is over + jc!5i .  
boolean bStop = false; //Stop identical Q=;U@k@>  
FileAccessI fileAccessI = null; //File Access interface &"f";  
n}F&1Z  
JTO~9>$ B  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException de.&`lPRf  
{ Dz>^IMsY  
this.sURL = sURL; )h"<\%LU  
this.nStartPos = nStart; 8!O5quEc  
this.nEndPos = nEnd; Ta ?_5  
nThreadID = id; }vxw*8d?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~zCEpU|@N  
} -JMdE_h  
{XR6>]  
*H"B _3<n  
public void run() -]/I73!b  
{ #lmB AL~3  
while(nStartPos < nEndPos && !bStop) t<#mP@Mz=N  
{ UQ)W%Y;[0  
Aw$x;3y  
zi|+HM  
try{ F U_jGwD  
URL url = new URL(sURL); `q}I"iS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zMbN;tu  
httpConnection.setRequestProperty("User-Agent","NetFox"); @L<*9sLWh  
String sProperty = "bytes="+nStartPos+"-"; 7Ri46Tkt  
httpConnection.setRequestProperty("RANGE",sProperty); Xe6w|  
Utility.log(sProperty); ~ {E'@MU  
wvO|UP H\  
R;s?$;I  
InputStream input = httpConnection.getInputStream(); l~c@^!  
//logResponseHead(httpConnection); sGy eb5c  
bLlKe50  
G_;)a]v8)  
byte[] b = new byte[1024]; 2`7==?  
int nRead; GPkmf%FJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2D75:@JL}|  
{ xHL( !P F  
nStartPos += fileAccessI.write(b,0,nRead); 7!@-*/|!S9  
//if(nThreadID == 1) EYtL_hNp}I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cii_U=   
} -~s!73pDY  
Isvx7$Vu+  
6h|q'.Y  
Utility.log("Thread " + nThreadID + " is over!"); z.7cy@N6  
bDownOver = true; f[<m<I  
//nPos = fileAccessI.write (b,0,nRead); B:5Rr}eY+  
} K-bD<X  
catch(Exception e){e.printStackTrace ();} *W.C7=  
} <;vbsksZeH  
} f,h J~  
h].<t&  
"$#xK|t  
//打印回应的头信息 ;YA(|h<  
public void logResponseHead(HttpURLConnection con) |SoCRjuCPM  
{ }YB*]<]  
for(int i=1;;i++) :o|\"3  
{ \w/yF4,3<w  
String header=con.getHeaderFieldKey(i); `IP/d  
if(header!=null) +ln9c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^V?<K.F  
Utility.log(header+" : "+con.getHeaderField(header)); S|SV$_ (  
else [$qyF|/K`n  
break; v25R_""~  
} 4" Cb/y3  
} "S8uoSF`>  
vMA]j>>  
wN@oYFoL  
public void splitterStop() 2/vMoVT,  
{ -=%@L&y1  
bStop = true; QqFR\6  
} (\\eo  
r[2ILe  
}Ga\wV  
} gRCdY8GH  
6g|*`x{  
d ^^bke$~  
/* GGNvu )"  
**FileAccess.java BzkooJ  
*//文件访问(定位,写)  3L< wQ(  
package NetFox; 7op`s5i  
import java.io.*; &+cEV6vb+  
iIMd!Q.)@  
2;z b\d  
public class FileAccessI implements Serializable{ _2h S";K  
SG6kud\b  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 H<VTa? n  
RandomAccessFile oSavedFile; _y),J'W^3u  
long nPos; tz5e"+Tz  
W=j[V Oq  
Cbg!:Cws  
public FileAccessI() throws IOException FKIw!m ~  
{ f-bVKHt  
this("",0); h}*/Ge]aM  
} kO,zZF&  
V}J)\VZ2#  
w1hPc!I  
public FileAccessI(String sName,long nPos) throws IOException kw#;w=\>R{  
{ D>HOn^   
oSavedFile = new RandomAccessFile(sName,"rw"); y+X2Pl  
this.nPos = nPos; M.x=<:upp  
oSavedFile.seek(nPos); gnFr}L&j  
} C9~52+S  
",^Mxm{  
kqM045W7  
public synchronized int write(byte[] b,int nStart,int nLen) I%r{]-Obr-  
{ JG" R\2  
int n = -1; ey2S#%DF]  
try{ $CY~5A`l9  
oSavedFile.write(b,nStart,nLen); @aAW*D~-J  
n = nLen; 8VeQ-#7M/  
} isQ[ Gc!8  
catch(IOException e) !B\R''J5  
{ Rtb7|  
e.printStackTrace (); ?\vh9  
} %6t2ohO"  
\ Pj  
!zkZQ2{Wn  
return n; zfc'=ODX  
} SW*"\X;  
: ]sUpO  
$K]m{  
} Z1 Bp+a3  
6A>dhU  
!D@ZYK;  
/* |_] Q$q[[%  
**SiteInfoBean.java 8kU! 8^mH  
*/ C"!gZ8*\!9  
package NetFox; o9JMH.G  
v*;-yG&  
ex::m&  
public class SiteInfoBean { ]b\yg2  
+_; l|uhT;  
8.XoVW#  
private String sSiteURL; //Site's URL X.Rb-@  
private String sFilePath; //Saved File's Path /JHc!D  
private String sFileName; //Saved File's Name J&M o%"[)  
private int nSplitter; //Count of Splited Downloading File 7[> 6i  
b\3Oyp>  
?98("T|y;  
public SiteInfoBean() :[O 8  
{//nSplitter的缺省值为5 ()5[x.xK@  
//default value of nSplitter is 5 X;i~ <Tq  
this("","","",5); EH256f(&  
} gu0j.XS^  
iH/6M  
d{SG Cr 9d  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Jth[DUH8H  
{ %/|9@er  
sSiteURL= sURL; ;5zz<;Zy  
sFilePath = sPath; x c/}#>ED  
sFileName = sName; E7.2T^o;M  
this.nSplitter = nSpiltter; P>s[tM  
t"= E^r  
2nSSF x r  
} >33=<~#n  
|$vX<. S  
{[+mpKq  
public String getSSiteURL() vhpNpgz  
{ Kla'lCZ  
return sSiteURL; $6mX  
} cki81bOT  
\HKxh:F'  
YL]Z<%aKt  
public void setSSiteURL(String value) |G?htZF  
{ Y8m1M-#w  
sSiteURL = value; .#rJ+.2  
} `(YxI  
umiBj)r  
E%r k[wI  
public String getSFilePath() CDP U\ZG  
{ { OXFN;2  
return sFilePath; ,q}ML TS i  
} H@q?v+2  
U*22h` S  
ujlY! -GM  
public void setSFilePath(String value) g/P+ZXJ  
{ -(  
sFilePath = value; bYEy<7)x  
} iV&6nh(  
x4E7X_  
ldiD2 Q  
public String getSFileName() Fs9I7~L3  
{ "uaMk}[ <!  
return sFileName; lfqiyYFm  
} t m7^yn:  
f"%{%M$K  
W3MU1gl6k{  
public void setSFileName(String value) wE?'Cl  
{ KwPOO{4]g  
sFileName = value; B"!l2  
} a-=8xs'  
^pQCNKLBY  
y#U+c*LB  
public int getNSplitter() G LIi6  
{ aqj@Cjk4Z  
return nSplitter; gk"$,\DI  
} c_vqL$Dl  
cc~O&?)i  
n=y[CKS  
public void setNSplitter(int nCount)  %-c*C$  
{ hw= Ft4L  
nSplitter = nCount; "|qqUKJZ  
} orWbU UC  
} ;[M}MFc/`  
9f&C  
>pp5;h8!  
/* "nw;NIp!  
**Utility.java b[o"7^H  
*/ 6YGubH7%_  
package NetFox; 6]W=nAD  
BYVY)<v/  
KG|n  
public class Utility { LR".pH13  
nV-mPyfL8  
^,/RO5  
public Utility() .k%[4:Fe  
{ ?~hHGf\^b6  
Qo;zHZ'  
VJickXA  
} {<R2UI5m5  
8,? h~prc  
//线程睡眠 {q `jDDM  
public static void sleep(int nSecond) B9NWW6S  
{ 19E 8'@  
try{ tt0f-:#  
Thread.sleep(nSecond); @zU6t|mhz  
} .J)I | '  
catch(Exception e) 6W]9$n\"?  
{ ABD)}n=%c  
e.printStackTrace (); e?JW   
} 1~Oe=`{&  
}  SL#0kc0x  
hc>HQrd  
//日志 <{V(.=11  
public static void log(String sMsg) Mxyb5h  
{ glM$R&/  
System.err.println(sMsg); '>cKH$nVC}  
} ]:Ns f|C0  
NQ(1   
@mw5~+  
public static void log(int sMsg) k <=//r  
{ 4dO~C  
System.err.println(sMsg); eYN5;bx)W  
} |wiqGzAr{  
} $$ Oey)*  
aMWmLpv4'  
"alyfyBu'M  
/* x4;"!Kq\  
**TestMethod.java ?[g=F <r  
*/ "Zl5<  
package NetFox; 5ni~Q 9b  
T 6)bD&  
b{L/4bu  
public class TestMethod { r:f[mk"-"A  
S- pV_Ff  
nbm&wa[  
public TestMethod() 1FlX'[vh  
{ ///xx/weblogic60b2_win.exe U+:m4a  
try{ _+K_5IO4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }1Gv)l7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Cd,jDPrw  
SiteFileFetch fileFetch = new SiteFileFetch(bean); eJxw) zd7  
fileFetch.start(); qf!p 9@4F[  
} YH vLGc%  
catch(Exception e){e.printStackTrace ();} w<Wf?aG  
YG3J$_?y0  
'gC_)rK*  
} /fZe WU0W  
jcuB  
/{+y2.{j  
public static void main(String[] args) mRL"nC  
{ "D63I|O)  
new TestMethod(); +jS|2d  
} Sdt`i  
} X-6de>=   
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