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http断点续传简单实现(java)

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/* '6nA F  
**SiteFileFetch.java %vn"{3y>rF  
*/ T#T*Zw"+  
package NetFox; j1Y~_  
import java.io.*; 4B8 oO  
import java.net.*; R"/GQ`^AqA  
59 T 8r  
{Y(zd[  
public class SiteFileFetch extends Thread { yM6pd U]i  
Z\bmW%av  
K(e$esLs-  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1SQ3-WU s  
long[] nStartPos; //开始位置 Ljm[?*H#  
long[] nEndPos; //结束位置 D%[mWc@1I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r(>@qGN  
long nFileLength; //文件长度 k>Is:P  
boolean bFirst = true; //是否第一次取文件 VD;01"#'  
boolean bStop = false; //停止标志 `f,/`''R  
File tmpFile; //文件下载的临时信息 *nT<m\C6  
DataOutputStream output; //输出到文件的输出流 t5^{D>S1  
;>%r9pz ~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) rK 8lBy:<  
public SiteFileFetch(SiteInfoBean bean) throws IOException XW 2b|%T  
{ RN1y^`  
siteInfoBean = bean; ].avItg  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <)C#_w)-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j7Yu>cr  
if(tmpFile.exists ()) @Myo'{3vF  
{ YH}'s>xZz  
bFirst = false; nUaJzPl  
read_nPos(); '&P%C" 5  
} )rIwqUgp6\  
else j.[.1G*("  
{ zF`0J  
nStartPos = new long[bean.getNSplitter()]; &Q/W~)~  
nEndPos = new long[bean.getNSplitter()]; F>Ah0U0  
} c`)\Pb/O  
etQCzYIhn  
;HfmzY(  
'?{OZXg  
} EgEa1l!NSQ  
dM.f]-g  
IV~>I-rd  
public void run() ~f2z]JLr:  
{ SBu"3ym  
//获得文件长度 RXMISt3+{y  
//分割文件 djl*H  
//实例FileSplitterFetch YR\faVk  
//启动FileSplitterFetch线程 ?6!JCQJ<  
//等待子线程返回 o+iiST JEe  
try{ G{~J|{t\yz  
if(bFirst) tn\yI!a  
{ '`[&}R  
nFileLength = getFileSize(); fC d&D  
if(nFileLength == -1) n t;m+by  
{ Rxt^v+ ,$  
System.err.println("File Length is not known!"); -a}Dp~j  
} ]"As1"  
else if(nFileLength == -2) y%$AhRk*U  
{ 6?gW-1mY  
System.err.println("File is not access!"); AEI>\Y  
} [T4J{y64Y  
else T9|m7  
{ ];$L &5^  
for(int i=0;i<nStartPos.length;i++) >0y'Rgfe  
{ f1RWP@iar  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {GT*ZU*  
} & bm 1Fz  
for(int i=0;i<nEndPos.length-1;i++) "m$##X\  
{ IZ-1c1   
nEndPos = nStartPos[i+1]; w>&aEv/f  
} PCee<W_%YE  
nEndPos[nEndPos.length-1] = nFileLength; / y40(l?  
} \[i1JG  
}  `,*3[  
9 RgVK{F  
6dr%;Wp  
//启动子线程 PcMD])Z{G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0cH`;!MZ  
for(int i=0;i<nStartPos.length;i++) |-67 \p]  
{ <]t%8GB2V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :as$4|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wo{gG?B  
nStartPos,nEndPos,i); qbN =4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \fLMr\LL&  
fileSplitterFetch.start(); \A#41  
} Q~]uC2Mw  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F`W?II?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :K,i\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T@B/xAq5!  
nEndPos = " + nFileLength); /N10  
// fileSplitterFetch[nPos.length-1].start(); k/_ 59@)  
dh iuI|?@  
E?f-wQF  
//等待子线程结束 ;%9|k U  
//int count = 0; 9!\B6=r y4  
//是否结束while循环 DH!~ BB;  
boolean breakWhile = false; N7zft  
?pmHFlx  
[ -K&R  
while(!bStop) B)g[3gQ  
{ N0Lw}@p  
write_nPos(); !dnH 7 "  
Utility.sleep(500); `:KY\  
breakWhile = true; Ykw*&opz  
>Eto( y"q  
K#d`Hyx  
for(int i=0;i<nStartPos.length;i++) ;(Or`u]Dr  
{ 9ULQrq$?  
if(!fileSplitterFetch.bDownOver) S!CC }3zw  
{ AM\'RHL  
breakWhile = false; cd_yzpL@}J  
break; :J@ gmY:C  
} xwq (N_  
} L|7R9+ZG  
if(breakWhile) c ( C%Hld  
break; C`9+6T  
I-*S&SiXjI  
B hGu!Y6f  
//count++; 5r|,CQ7o  
//if(count>4) OX!tsARC@  
// siteStop(); ~rKrpb]ow  
} L|xbR#v  
0RLg:SV  
YnAm{YyI  
System.err.println("文件下载结束!"); $k%2J9O  
} 7(8;t o6(  
catch(Exception e){e.printStackTrace ();} <{cQM$ #  
} _C?hHWSf"  
9~XA q^e  
hx%v+/  
//获得文件长度 Rtl"Ub@HV  
public long getFileSize() WX?IYQ+  
{ J=I:CD%  
int nFileLength = -1; PiIpnoM  
try{ Vn}0}Jz  
URL url = new URL(siteInfoBean.getSSiteURL()); K7:)nv E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WPMSm<[  
httpConnection.setRequestProperty("User-Agent","NetFox"); )9`qG:b'  
KL57# gV  
,T$U'&;  
int responseCode=httpConnection.getResponseCode(); +gtbcF@rx  
if(responseCode>=400) mSF(q78?  
{ E A1?)|}n  
processErrorCode(responseCode); WiR(;m<g  
return -2; //-2 represent access is error d#4**BM  
} )23H1  
l'.VKh\C  
"(~^w=d:$  
String sHeader; <uw9DU7G  
x2\qXN/R  
f+,qNvBY/  
for(int i=1;;i++) [!#L6&:a8  
{ w-MCZwCr)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X51:  
//Utility.log(in.readLine()); Fj3a.'  
sHeader=httpConnection.getHeaderFieldKey(i); 0gr/<v  
if(sHeader!=null) xy[3u?,&s!  
{ | rtD.,m   
if(sHeader.equals("Content-Length")) Yu^4VXp~M%  
{ ~Otoqu|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m nX2a  
break; 7WS p($  
} {qJ1ko)$  
} G@X% +$I  
else BG]#o| KW  
break; 9 -a0:bP  
} '$(^W@M#6  
} E]n&=\  
catch(IOException e){e.printStackTrace ();} H3=qe I  
catch(Exception e){e.printStackTrace ();} s)D;a-F  
!``,gExH  
u^I|T.w<r6  
Utility.log(nFileLength); LYK"(C  
{]@= ijjf  
YZ8>OwQz2  
return nFileLength; [<yaXQxl  
} vw/J8'  
uh  > ; 8  
q{LF>Wi  
//保存下载信息(文件指针位置) G}raA%  
private void write_nPos() Z0", !6nS  
{ L^?qOylu  
try{ +lcbi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~P **O~  
output.writeInt(nStartPos.length); :{l_FY436  
for(int i=0;i<nStartPos.length;i++) #r\4sVg  
{ yq\K)g*=  
// output.writeLong(nPos); A]oV"`f  
output.writeLong(fileSplitterFetch.nStartPos); "JV_2K_i  
output.writeLong(fileSplitterFetch.nEndPos); hD!7Cl Q  
} wc4{)qDE  
output.close(); By4<2u38u  
} '-XXo=>0MV  
catch(IOException e){e.printStackTrace ();} 2eY_%Y0  
catch(Exception e){e.printStackTrace ();} bwMm#f  
} w;amZgD>  
~HsJUro  
N5 6g+,w%)  
//读取保存的下载信息(文件指针位置) `d`T*_  
private void read_nPos() :OT0yA=U  
{ Y]2A&0  
try{ K Z91-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n 0L^e  
int nCount = input.readInt(); S|N_o   
nStartPos = new long[nCount]; =X:Y,?  
nEndPos = new long[nCount]; E*K;H8}s  
for(int i=0;i<nStartPos.length;i++) 0~/_|?]`7  
{ 7[XRd9a5(  
nStartPos = input.readLong(); -C]5>& W  
nEndPos = input.readLong(); >KhOz[Zg  
} nmKp[-5  
input.close(); [hv~o~q  
} GGs}i1m  
catch(IOException e){e.printStackTrace ();} f r6 fj  
catch(Exception e){e.printStackTrace ();} {hrX'2:ClT  
} Ai3*QX  
I,vJbvvl!  
lX4 x*  
private void processErrorCode(int nErrorCode) ~=l;=7 T  
{ ENs&RZ;  
System.err.println("Error Code : " + nErrorCode); B[?Ng}<g`  
} A$0fKko  
qu{&xjTH8  
g1"kTh  
//停止文件下载 Dp-z[]})1  
public void siteStop() ]Q)OL  
{ DsCcK3 k  
bStop = true; BUXpC xQ  
for(int i=0;i<nStartPos.length;i++) 'zuIBOH`j3  
fileSplitterFetch.splitterStop(); 1\2no{Vh  
>U27];}y  
fJ!R6D  
} fuf"Ae  
} `Eo.v#<  
//负责部分文件的抓取 J}K$(;:  
**FileSplitterFetch.java n9ej7oj  
*/ ,R* ]>'  
package NetFox; p6!x=cW  
sS'm!7*(3  
T}v4*O.,  
import java.io.*; cU!vsdR3  
import java.net.*; [5Mr@f4I  
~U&AI1t+J  
[?N~s:}  
public class FileSplitterFetch extends Thread { ope^~+c~\  
~dTrf>R8M  
z_4J)?3  
String sURL; //File URL v;D~Pa  
long nStartPos; //File Snippet Start Position Y O}<Ytx  
long nEndPos; //File Snippet End Position M&9+6e'-F  
int nThreadID; //Thread's ID LBDjIpR6  
boolean bDownOver = false; //Downing is over HvJs1)Wo&  
boolean bStop = false; //Stop identical _ *Pf  
FileAccessI fileAccessI = null; //File Access interface +Q"4Migbe@  
VQOezQs\  
n<R?ffy  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "'?>fe\qG  
{ {8bSB.?R  
this.sURL = sURL; ^>v+( z5R  
this.nStartPos = nStart; f\L0 xJ  
this.nEndPos = nEnd; B>P{A7Q  
nThreadID = id; )R1<N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^RIl  
} w@w(-F!%l  
8P&:_T!  
|z^^.d~a0  
public void run() ZyFjFHe+  
{ ?)d~cJ  
while(nStartPos < nEndPos && !bStop) e^1Twz3z  
{ gT6jYQ  
O k=hT|}Y  
)oPBa  
try{ bq0zxg%  
URL url = new URL(sURL); )irEM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'YSHi\z ](  
httpConnection.setRequestProperty("User-Agent","NetFox"); z9Rp`z&`E  
String sProperty = "bytes="+nStartPos+"-"; U9MxI%tb  
httpConnection.setRequestProperty("RANGE",sProperty); oE]QF.n#  
Utility.log(sProperty); AFE~ v\Gz  
G2: agqL/  
4ID5q~  
InputStream input = httpConnection.getInputStream(); +A?U{q  
//logResponseHead(httpConnection); <=C!VVk4f  
)MTOU47U  
#Ki[$bS~6  
byte[] b = new byte[1024]; &\*(Q*2N  
int nRead; d5:c^`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j*r{2f4Rt  
{ /hyN;.hpOO  
nStartPos += fileAccessI.write(b,0,nRead); *VxgARIL  
//if(nThreadID == 1) i?^L/b`H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /aZ`[m2  
} I^$fMdT  
smo~7;  
bY~pc\V:`w  
Utility.log("Thread " + nThreadID + " is over!"); PALc;"]O  
bDownOver = true; :,6\"y-  
//nPos = fileAccessI.write (b,0,nRead); aO4?m+  
} draN0v f  
catch(Exception e){e.printStackTrace ();} w NdisI  
} PB\x3pV!}  
} u.xnOcOH!  
s?L  
*u;Iw{.{  
//打印回应的头信息 1#+S+g@#  
public void logResponseHead(HttpURLConnection con) p H2Sbs:Tk  
{ ]Er$*7f  
for(int i=1;;i++) ;>7De8v@@  
{ 0YDR1dO(*  
String header=con.getHeaderFieldKey(i); nZYBE030  
if(header!=null) ^^D0^k!R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7WZ+T"O{I  
Utility.log(header+" : "+con.getHeaderField(header)); k@W1-D?  
else hM@>q&q_  
break; A6(/;+n  
} ., 6-u  
} P\k# >}}  
c\AfaK^KF  
;u)I\3`*!  
public void splitterStop() 1yu4emye4  
{ [`7ThHX  
bStop = true; wz%Nb Ly-  
} *gWwALGo5  
$-sHWYZ  
@E|}Y  
} ?gGHj-HYJ  
:"/d|i`T  
G" "ZI$`  
/* 9'bwWBf7  
**FileAccess.java R8'RA%O9J  
*//文件访问(定位,写) Ds:'Lb  
package NetFox; rFL;'Cj@  
import java.io.*; P/_['7  
j&qub_j"xX  
/9fR'EO{x  
public class FileAccessI implements Serializable{ O :Tj"@h  
Xc&9Glf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Qzw;i8n{  
RandomAccessFile oSavedFile; /mzlH  
long nPos; P~X2^bw  
EXqE~afm2  
}0Ed ]  
public FileAccessI() throws IOException CzrC%xy  
{ b d!Y\OD  
this("",0); t"oeQ*d%  
} I-l_TpM)  
X=&KayD  
hp|YE'uYT  
public FileAccessI(String sName,long nPos) throws IOException U&qZ"  
{ /cP"h!P}~~  
oSavedFile = new RandomAccessFile(sName,"rw"); ?%[jR=w  
this.nPos = nPos; IW] rb/H  
oSavedFile.seek(nPos); ysY*k`5  
} T]~ xj4  
pTLCWbF?  
6.yu-xm  
public synchronized int write(byte[] b,int nStart,int nLen) x7 ,5  
{ tc_3sC7jN  
int n = -1; 7 HYwLG:\~  
try{ @f3E`8  
oSavedFile.write(b,nStart,nLen); %d9uTm;  
n = nLen; { 2f-8Z&>  
}  rjnrju+  
catch(IOException e) e$Pj.>-<=  
{ mQ"-,mMI  
e.printStackTrace (); pOoEI+t  
}  _6vW F  
dG?*y  
]3Sp W{=^(  
return n; |M;7>'YNC*  
} =[7Av>  
8zW2zkv2|#  
=41?^1\  
} =Nr-iae#  
g *+>H1}  
[v!f<zSQK  
/* _7_Y={4=`  
**SiteInfoBean.java 19%i mf  
*/ \1M4Dl5!  
package NetFox;  _;\_l  
M/`lM$98:  
ysnx3(+|  
public class SiteInfoBean { ('+d.F[109  
vKAN@HSYr  
 K_}K@'  
private String sSiteURL; //Site's URL >Y@H4LF;1x  
private String sFilePath; //Saved File's Path M x" \5i  
private String sFileName; //Saved File's Name Q^^niVz  
private int nSplitter; //Count of Splited Downloading File tw)mepwB  
^E>3|du]O  
~WF\  
public SiteInfoBean() 5~DJWi,  
{//nSplitter的缺省值为5 Xne1gms  
//default value of nSplitter is 5 dft!lBN  
this("","","",5); 4 s9LB  
} t\O16O7S  
4Ftu  
N!tX<u~2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R[+<^s}p/  
{ SOaoo^,O  
sSiteURL= sURL; <qt|d&  
sFilePath = sPath; +R75v)  
sFileName = sName; gf\oC> N  
this.nSplitter = nSpiltter; +R:(_:7  
1s;S aq+  
&=mtc%mL  
} 6j|{`Zd)G  
)%fH(ns(  
(S Yln>o  
public String getSSiteURL() gbD KE{  
{ 2y1Sne=<Kb  
return sSiteURL; HTTC TR  
} % |L=l{g  
`){.+S(5C  
:\_ 5oVb  
public void setSSiteURL(String value) Qn2&nD%zi  
{ buHJB*?9  
sSiteURL = value; $3kH~3{]  
} 7F~X,Dk_  
9} .z;prz  
es0hm2HT3  
public String getSFilePath() sV*H`N')S  
{ wVtwx0|1  
return sFilePath; ChQx a  
} Lu%b9Jk  
G=bCNn<  
[()koU#w.  
public void setSFilePath(String value) 5 SQ 8}Or3  
{ [mueZQyI?0  
sFilePath = value; YuwI&)l  
} |;{6& S  
7 _[L o4_  
-$Ih@2"6  
public String getSFileName() ~)M~EX&pK  
{ %\:Wi#w>  
return sFileName; dqcL]e  
} @>7%qS  
`">=  
V0Hj8}l;M  
public void setSFileName(String value) %B?=q@!QWn  
{ iH'p>s5L  
sFileName = value; hgE71H\s  
} akTk(  
1k^oS$UT  
?Q;=v~-Q  
public int getNSplitter() 2st3  
{ #B w0,\  
return nSplitter; IdN41  
} U #0Cx-E  
0PCGDLk8  
\z)%$#I  
public void setNSplitter(int nCount) JK] PRDyD  
{ %@Jsal'  
nSplitter = nCount; MnHNjsO#  
} ue>D 7\8  
} /g.U&oI]D  
.fs3>@T"#  
7uk[Oy<_  
/* UC$ppTCc?  
**Utility.java yWf`rF{  
*/ zKK9r~ M  
package NetFox; HK% 7g  
l%=;  
MpOc  
public class Utility { V]?R>qhgu  
l}P=/#</T  
u$`a7Lp,n  
public Utility() 9j Gu}V o  
{ -F3-{E  
EiaW1Cs  
wdoR%b{M  
} qxJ\ye+'*  
.X;K%J2  
//线程睡眠 "uf%iJ:%  
public static void sleep(int nSecond) *=xr-!MEk  
{  _','9|  
try{ c1gQ cqF  
Thread.sleep(nSecond); hCo|HB  
} FC4wwzb  
catch(Exception e) f,Ghb~y  
{ !TcJ)0   
e.printStackTrace (); bN=P*hdf  
} [PbOfxxgA  
} $Z>'Jp  
7PF%76TO  
//日志 YHl;flv  
public static void log(String sMsg) [KQ6Ta.  
{ f<6lf7qzC  
System.err.println(sMsg); L4l!96]a  
} 8JUwf  
NZz8j^  
,wPr"U+7  
public static void log(int sMsg) W(/h Vt  
{ k|f4Cf,  
System.err.println(sMsg); CTA 3*Gn  
} |gY^)9ei  
} ] }X  
,"0 :3+(8;  
P1f[% 1  
/* 7IM@i>p%  
**TestMethod.java K~ EmD9  
*/ pmYHUj #  
package NetFox; r,2g^ K)6  
|sZHUf_  
eJ81-!)  
public class TestMethod { j*m%*_kO  
9(<@O%YU  
Yu`~U,m  
public TestMethod() r:TH]hs12+  
{ ///xx/weblogic60b2_win.exe wwcBsJ1{  
try{ ^LzF@{ G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _h1mF<\ X^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7Fsay+a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @9|hMo  
fileFetch.start(); PeEj&4k  
} U,1-A=Og{o  
catch(Exception e){e.printStackTrace ();} ={Qi0Pvt  
| VDV<g5h  
IO:G1;[/2L  
} Y\'}a+:@Ph  
Wh{tZ~c  
%e} Saf  
public static void main(String[] args) bi;1s'Y<D  
{ g< .qUBPKX  
new TestMethod(); Rbv;?'O$L  
}  "-V"=t'  
} o#1 $q`Z  
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