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http断点续传简单实现(java)

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/* P'CDV3+  
**SiteFileFetch.java zF=E5TL-,4  
*/ 5Og=`T  
package NetFox; ^U@E rc#d  
import java.io.*; 0RGSv!w  
import java.net.*; NYN(2J  
]^@!ID$c  
yBxWBW*e  
public class SiteFileFetch extends Thread { nQ^ <h.  
73d7'Fw  
i_qR&X  
SiteInfoBean siteInfoBean = null; //文件信息Bean R4g% $}  
long[] nStartPos; //开始位置 srfM"Lb'  
long[] nEndPos; //结束位置 3eS *U`_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 hNJubTSE+)  
long nFileLength; //文件长度 TYh_uox6  
boolean bFirst = true; //是否第一次取文件  D^JuL6U  
boolean bStop = false; //停止标志 G8voqP  
File tmpFile; //文件下载的临时信息 3a]Omuu|=  
DataOutputStream output; //输出到文件的输出流 ZU-vZD>  
N|L Ey  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) lCMU{)  
public SiteFileFetch(SiteInfoBean bean) throws IOException  d365{  
{ s+yX82Y  
siteInfoBean = bean;  } h0 )  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O E56J-*}x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WAt| J2  
if(tmpFile.exists ()) [>tyx{T Ye  
{ u|a+ :r)*4  
bFirst = false; .V:H~  
read_nPos(); n9Xssl0  
} *w;=o}`  
else ?~>#(Q  
{ Vr=c06a2  
nStartPos = new long[bean.getNSplitter()]; j4G?=oDb  
nEndPos = new long[bean.getNSplitter()]; zS##YR  
} =9ISsI\Y6  
GGR hM1II  
WhHnF*I  
f}1R,N_fC  
} | D jgm7$*  
s!d"(K9E  
J0vCi}L  
public void run() ?!J{Mrdn  
{ s-He  
//获得文件长度 *[eh0$  
//分割文件 _DK%-,Spu  
//实例FileSplitterFetch mzl %h[9iI  
//启动FileSplitterFetch线程 do:3aP'S,  
//等待子线程返回 _bO4s#yI  
try{ T53|*~u  
if(bFirst) clZ jb  
{ K 9X0/  
nFileLength = getFileSize(); |hprk-R*OH  
if(nFileLength == -1) Gn*vVZ@`x  
{ t(|\3$z  
System.err.println("File Length is not known!"); ;{e;6Hq  
} xCOC5f5*@  
else if(nFileLength == -2) + W ? / A]  
{ >~kSe=Hsb4  
System.err.println("File is not access!"); uV:;q>XM'%  
}  ?vgHu  
else 0!c^pOq6  
{ `&"-|  
for(int i=0;i<nStartPos.length;i++) :Qg3B ';  
{ 52$7vYMto  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "]dNN{Wka  
} eJB !|  
for(int i=0;i<nEndPos.length-1;i++) [4qx+ypT  
{ ~ l'dpg  
nEndPos = nStartPos[i+1]; lkWID  
} (bIg6_U7\  
nEndPos[nEndPos.length-1] = nFileLength; 2sJj -3J  
} 94umk*ib  
} +@Oo)#V|.  
fXPD^}?Ux4  
a_UVb'z  
//启动子线程 k:Iz>3O3]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f*VBSg[`  
for(int i=0;i<nStartPos.length;i++) BTwLx-p9t  
{ m8q3Pp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7[wHNJ7)r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3%<Uq%pJ  
nStartPos,nEndPos,i); L,&R0gxi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H*DWDJxmV  
fileSplitterFetch.start(); :RsO $@0G  
} l@8UL</W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F j_r n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); H1(Zz n1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XCNfogl  
nEndPos = " + nFileLength); A Z7  
// fileSplitterFetch[nPos.length-1].start(); Nj2f?',;U  
o5(p&:1M  
8:%=@p>$  
//等待子线程结束 ?qeBgkL(B^  
//int count = 0; Md9b_&'  
//是否结束while循环 smpz/1U  
boolean breakWhile = false; :&#HrD[KT  
v(v Lk\K7  
*TpzX y  
while(!bStop) P< +5So0  
{ KWVEAHIn  
write_nPos(); un4q,Ac~0  
Utility.sleep(500); %rpJZ t  
breakWhile = true; F)we^'X  
D:9/;9V  
#Y3:~dmJ-  
for(int i=0;i<nStartPos.length;i++) ,"PKGd]^  
{ 47R4gs#W  
if(!fileSplitterFetch.bDownOver) x~Eg ax  
{ m@hmu}qz-  
breakWhile = false; WKf->W  
break; K|-?1)Um  
} pSQ)DqW  
} y9?~^pTx  
if(breakWhile) uaMf3HeYV  
break; B5>1T[T'-  
>^#OtFHuT)  
TO.71x|  
//count++; H+:SL $+<o  
//if(count>4) pu(a&0  
// siteStop(); 03ol!|X "9  
} -e"~UDq`  
yub|   
D|W^PR:@h  
System.err.println("文件下载结束!"); oT7=  
} SbNs#  
catch(Exception e){e.printStackTrace ();} 6&o9mc\I  
} ?UC3ES  
_pSCv:3T  
=&QC&CqEi  
//获得文件长度 ~Qzb<^9]  
public long getFileSize() W+[XNIg5   
{ Ca[H<nyj  
int nFileLength = -1; >E;-asD  
try{ 4Gl0h'!(  
URL url = new URL(siteInfoBean.getSSiteURL()); EG<YxNX,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j rX .e  
httpConnection.setRequestProperty("User-Agent","NetFox"); MP|J 0=H5  
(9_~R^='y  
cqzd9L6=  
int responseCode=httpConnection.getResponseCode(); `6KTQk'  
if(responseCode>=400) ;b=3iT-2"  
{ adG=L9 "n  
processErrorCode(responseCode); 0h~Iua5  
return -2; //-2 represent access is error yUb$EMo \  
} xjHOrr OQ  
8r^~`rL  
pyEi@L1p  
String sHeader; T:ye2yg  
/"A)}>a  
S/}6AX#F4  
for(int i=1;;i++) :DP%>H|  
{ B3V:?#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <qD/ #$   
//Utility.log(in.readLine()); J:  
sHeader=httpConnection.getHeaderFieldKey(i); ~]HeoQK  
if(sHeader!=null) 6iwIEb  
{ z4f\0uQ  
if(sHeader.equals("Content-Length")) x0^O?UR  
{ x!klnpGp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2c>eMfa  
break; 3.q%?S}*  
} 1eC1Cyw  
} uJz<:/rwZ-  
else O) ks  
break; 6"^Yn.  
} wB6 ILTu1  
} ViV"+b#gu  
catch(IOException e){e.printStackTrace ();} }."3&u't  
catch(Exception e){e.printStackTrace ();} fsU6o4  
G% wVQ|1  
7XKPC+)1ya  
Utility.log(nFileLength); Vv=/{31  
sY4sq5'!  
%T]NM3|U  
return nFileLength; IwC4fcZX6  
} 0be1aY;m&  
8spoDb.S  
2@``=0z  
//保存下载信息(文件指针位置) =M"H~;f]  
private void write_nPos() `UFRv   
{ tlw$/tMa  
try{ ]>R|4K_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yT Pi/=G  
output.writeInt(nStartPos.length); (are2!Oq  
for(int i=0;i<nStartPos.length;i++) !w['@x.  
{ +0U{CmH  
// output.writeLong(nPos);  zk8 o[4  
output.writeLong(fileSplitterFetch.nStartPos); rrK&XP&  
output.writeLong(fileSplitterFetch.nEndPos);  laX(?{_  
} >$=-0?.  
output.close(); ]3tg|? %B  
} ;SAurG$  
catch(IOException e){e.printStackTrace ();} uU v yZ  
catch(Exception e){e.printStackTrace ();} &fJ92v?%^S  
} ~F8M_  
`IQ01FuP  
-"qw5Y_oF?  
//读取保存的下载信息(文件指针位置) 7;dTQ.%n  
private void read_nPos() y9d[-j ;w  
{ mA|&K8H  
try{ y:Xs/RS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L/1zG/@  
int nCount = input.readInt(); l2uh"!  
nStartPos = new long[nCount]; (vm &&a@  
nEndPos = new long[nCount]; fMe "r*SU  
for(int i=0;i<nStartPos.length;i++) ugexkdgM  
{ Xg:w;#r,  
nStartPos = input.readLong(); *<k8H5z8]  
nEndPos = input.readLong(); ;K<e]RI;?  
} F&US-ce:M  
input.close(); fUQuEh5_  
} q[4{Xh  
catch(IOException e){e.printStackTrace ();} \F]X!#&+  
catch(Exception e){e.printStackTrace ();} )(~s-x^\z@  
} o JC-?  
OgJd^  
su]CaHU  
private void processErrorCode(int nErrorCode) lqFDX d  
{ ;cQhs7m(9  
System.err.println("Error Code : " + nErrorCode); NpV# zzE  
} (Fq|hgOA>M  
s(*L V2fa  
:5!>h8p;  
//停止文件下载 Jlw<% }r  
public void siteStop() 9{{QdN8  
{ 2N_8ahc  
bStop = true; =}N&c4I[j  
for(int i=0;i<nStartPos.length;i++) G t 4| ]  
fileSplitterFetch.splitterStop(); K#bdb  
$ o rN>M42  
}gL:"C"~  
} (.Hiee43  
} bJc<FL<E  
//负责部分文件的抓取  L><# I  
**FileSplitterFetch.java WP,Ll\K)7  
*/ rU?sUm,ch  
package NetFox; / fBi9=}+  
q{v:T}Q|A  
D=}UKd  
import java.io.*; %H=d_Nm{  
import java.net.*; C?@vBM}  
n_;qB7,,  
N3?hyR<T  
public class FileSplitterFetch extends Thread { SN!TE,=I  
s*`_Ka57]~  
>ZMB}pt`  
String sURL; //File URL A4RA5N/}  
long nStartPos; //File Snippet Start Position XWH{+c"  
long nEndPos; //File Snippet End Position Il(p!l<Xz#  
int nThreadID; //Thread's ID om%L>zfB  
boolean bDownOver = false; //Downing is over );T0n  
boolean bStop = false; //Stop identical C^ngdba\  
FileAccessI fileAccessI = null; //File Access interface y]|Hrx  
""cnZZ5)  
-dXlGOD+C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ? b;_T,S[  
{ (_S`9Z8=  
this.sURL = sURL; x] [/9e  
this.nStartPos = nStart; u6o:~=WwM  
this.nEndPos = nEnd; RlH|G  
nThreadID = id; *?|LE C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \]Nlka  
} VC%{qal;q  
~R7F[R  
SMHQo/c r  
public void run() MD(?Wh  
{ [JAHPy=+w  
while(nStartPos < nEndPos && !bStop) >TSPEvWc  
{ eF]`?AeWQ  
P{ YUW~  
Vfkm{*t)  
try{ hV5Aw;7C  
URL url = new URL(sURL); O <;Au|>*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); kTQ.7mo/\'  
httpConnection.setRequestProperty("User-Agent","NetFox"); USgZ%xk2  
String sProperty = "bytes="+nStartPos+"-"; ^0A}iJL  
httpConnection.setRequestProperty("RANGE",sProperty); 9Q{-4yF9k  
Utility.log(sProperty); yV=Ku  
p=F!)TnJN  
yo\R[i(  
InputStream input = httpConnection.getInputStream(); 7!%/vO0m  
//logResponseHead(httpConnection); E'3=qTbiD  
*v1M^grKd  
2aQR#lcv  
byte[] b = new byte[1024]; B|%(0j8  
int nRead; j8k5B"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >b2j j+8  
{ Jg3OM Ut  
nStartPos += fileAccessI.write(b,0,nRead); FT.6^)-  
//if(nThreadID == 1) }DH3_M!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }^|g|xl!  
} uTsxSkHb/  
s"u6po.'  
[ j'L *j  
Utility.log("Thread " + nThreadID + " is over!"); y$,K^f  
bDownOver = true; =MQpYX  
//nPos = fileAccessI.write (b,0,nRead); )xJCH9h  
} SU,S1C_q8  
catch(Exception e){e.printStackTrace ();} Z>=IP-,>  
} 1'.SHY|  
} +Sz%2 Q  
t8vR9]n  
L=`QF'Im  
//打印回应的头信息 *nb `DR  
public void logResponseHead(HttpURLConnection con) <2b&AF{En  
{ f uzz3#  
for(int i=1;;i++) )`,||sQ  
{ f3,qDbQyJ  
String header=con.getHeaderFieldKey(i); MA}~bfB  
if(header!=null) m |K"I3W$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -Ky<P<@ezm  
Utility.log(header+" : "+con.getHeaderField(header)); | .w'Z7(s  
else _+c' z  
break; )OjTn"  
} i.QS(gM  
} N=Q<mj;,  
9f UD68Nob  
QaAA@l  
public void splitterStop() ;/ wl.'GA  
{ g.L~Z1-  
bStop = true; ^\<nOzU?  
} \X3Q,\H @  
JONfNb+  
X#;n Gq)5  
} h%4aL38  
\!O3]k,r  
UA>3,|gV1  
/* n $Nw/Vm  
**FileAccess.java KGM9 b  
*//文件访问(定位,写) gMXs&`7P  
package NetFox; _*&I[%I5  
import java.io.*; j-~x==c-;  
}j+Af["W?  
g`7C1&U*T  
public class FileAccessI implements Serializable{ 9Hu;CKs  
^pB}eh.@U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w\V1pu^6@  
RandomAccessFile oSavedFile; ^$FNu~|K  
long nPos; J&P{7a  
Bb[WtT}=  
RB\ Hl  
public FileAccessI() throws IOException ]izrr  
{ bEQy5AX  
this("",0); %rFR:w`{  
} PL/g@a^tY  
z6IOVQ*r  
X| !VjUH  
public FileAccessI(String sName,long nPos) throws IOException M&QzsVH  
{ ?xa70Pb{;  
oSavedFile = new RandomAccessFile(sName,"rw"); eeVDU$*e=  
this.nPos = nPos; /"+CH\) E  
oSavedFile.seek(nPos); MQc<AfW3/  
} N_:H kI6  
bA_/ 6r)u  
%IA1Y>`  
public synchronized int write(byte[] b,int nStart,int nLen) }4uHT.)  
{ MV{\:l}y  
int n = -1; [ Xa,|  
try{ %fT%,( w}t  
oSavedFile.write(b,nStart,nLen); -R]Iu\  
n = nLen; vU,V[1^a  
} &6feR#~A  
catch(IOException e) bUzo>fm_  
{ ,59G6o  
e.printStackTrace (); '2S/FOb  
} [X9T$7q#  
DX2_} |$!  
SD/=e3  
return n; #ORZk6e  
} IdS=lN$  
'iM#iA8  
"L0Q"t:  
} (U{,D1?  
Z5j\ M  
[S~/lm  
/* $+k|\+iJ  
**SiteInfoBean.java CL|d>  
*/ "[QQ(]={  
package NetFox; u Gmv`R_  
c$.Zg=  
N&uRL_X .  
public class SiteInfoBean { 3 <A?  
`K7UWtp  
4 -CGe  
private String sSiteURL; //Site's URL SeV`RUO  
private String sFilePath; //Saved File's Path 8aqH;|fG}  
private String sFileName; //Saved File's Name K/YXLR +  
private int nSplitter; //Count of Splited Downloading File +C}s"qrb@  
|EGC1x]j=  
rNK<p3=7)  
public SiteInfoBean() }PXtwp13&u  
{//nSplitter的缺省值为5 bA-/"'Vp9  
//default value of nSplitter is 5 KqL+R$??"(  
this("","","",5); S.zY0  
} @tX8M[.eA  
@+6cKP  
.rw a=IW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o5E5s9n  
{ GI<3L K\  
sSiteURL= sURL; 0{OafL8&l  
sFilePath = sPath; %p(X*mVX  
sFileName = sName; ~eyZH8&  
this.nSplitter = nSpiltter; ,/ YTW@N  
N79?s)l:K  
3Q#Tut  
} Ez/>3:;  
d4m@u$^1B  
#AR$'TE#  
public String getSSiteURL() DO 0  
{ R0#'t+7^  
return sSiteURL; dw-o71(1d  
} k|^YYi= xF  
h:AB`E1  
-l~+cI\2  
public void setSSiteURL(String value) NI:3hfs  
{ eJ0Xfw%y%T  
sSiteURL = value; G+1i~&uV  
} ]i/Bq!d l  
M+VAol}1  
:'4 ",  
public String getSFilePath() ;lQ>>[*  
{ !{?<(6;t  
return sFilePath; +,_%9v?3  
}  K,o&gY  
o3X0c6uU  
NdmwQJ7e"  
public void setSFilePath(String value) uqM=/T^A  
{ {pXqw'"1.  
sFilePath = value; P#|}]oG%  
} Ck:+F+7_v  
_7;D0l  
3Ct:AJeg  
public String getSFileName() 6 u1|pX8  
{ 4iv&!hAc;  
return sFileName; zGwM# -  
} oh7tE$"c  
iOtf7.@  
}Oq P`B  
public void setSFileName(String value) n= q7*<l  
{ d/[kky}  
sFileName = value; :rU,7`sE/  
} 6@VgLa,  
-br): }f  
C{>dE:*K^  
public int getNSplitter() fizL_`uMqb  
{ iEx4va-j  
return nSplitter; 25;(`Td 5  
} 2Z-QVwa*U  
3*E] :l_  
&W}6Xg(  
public void setNSplitter(int nCount) mgTzwE_\  
{ MnP+L'|  
nSplitter = nCount; B2Kh~Xd  
} %R<xe.X  
} 8<{i=V*x4  
\ cdns;  
T0@$6&b%\z  
/* *mkVk7]c  
**Utility.java WFTwFm6  
*/ NpxgF<G  
package NetFox; 9TZ6c  
eVzZfB-=4}  
r%9=75HA  
public class Utility { Wjli(sT#-  
$|N\(}R  
?ph>:M  
public Utility() MvTp%d.  
{ x@@bC=iY$  
6$K@s  
3:>hHQi  
} M}$Td_g  
K,,'{j2#f  
//线程睡眠 qFI19`?8E  
public static void sleep(int nSecond) &YBZuq2?  
{ kz G W/  
try{ xkQT#K=i  
Thread.sleep(nSecond); ~sdM~9@ '  
} iZ4"@G:,  
catch(Exception e) wlEK"kKU  
{ DUwms"I,%  
e.printStackTrace (); (o^?i2)g  
} !gcea?I  
} .vie#,la  
pwRCfR)"X  
//日志 JL [!8NyU  
public static void log(String sMsg) Y8h 96  
{ y[zjs^-vCv  
System.err.println(sMsg); qC B{dp/  
} XRTiC #6  
C#B|^A_  
i7e_~K  
public static void log(int sMsg) oPVt qQ  
{ s{*bFA Z1F  
System.err.println(sMsg); i0Rj;E=:]  
} S%e)br}  
} P26"z))~d  
}D-jTZlC  
,YJn=9pTl  
/* u'^kpr`y  
**TestMethod.java +.gj/uy*  
*/ =2YXh,i  
package NetFox; HBZ6Pj  
x<7?  
;#^ o5ht  
public class TestMethod { yq1 G6hw  
+|TXKhm{  
v3G$9 (NE;  
public TestMethod() UY .-Qt  
{ ///xx/weblogic60b2_win.exe p=\Q7<Z6d,  
try{ qt6@]Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k9;t3-P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QP<.~^ao  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zN=s]b=/  
fileFetch.start(); yMC6 Gvp  
} c|K:oi,z  
catch(Exception e){e.printStackTrace ();} 2%*\XPt)  
2XEE/]^  
li{!Jp5]1b  
} C{+JrHV%h  
TF80WMt  
YI`BA`BQ8  
public static void main(String[] args) BO8?{~i  
{ [7NO !^  
new TestMethod(); QKhGEW~G  
} /,~g"y.;,  
} h lSav?V_  
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