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http断点续传简单实现(java)

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/* nl'J.dJe  
**SiteFileFetch.java df>kEvU5.^  
*/ WiNr866nB  
package NetFox; J[!x%8m  
import java.io.*; i6F:C &.  
import java.net.*; 1rv$?=Z  
,.oa,sku  
r'd:SaU+  
public class SiteFileFetch extends Thread { <,@H;|mZ  
&*aer5?`  
y Tw',N{  
SiteInfoBean siteInfoBean = null; //文件信息Bean w.D4dv_H  
long[] nStartPos; //开始位置 o9 i#N  
long[] nEndPos; //结束位置 Qb?y@>-[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AGEZ8(h  
long nFileLength; //文件长度 ByhOK}u;P4  
boolean bFirst = true; //是否第一次取文件 3|~(?4aE  
boolean bStop = false; //停止标志 V9zywM  
File tmpFile; //文件下载的临时信息 4ypRyO  
DataOutputStream output; //输出到文件的输出流 DhWWN>I  
D(qHf9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) P(pd0,%i;a  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]HyHz9QkL  
{ G}P)vfcH  
siteInfoBean = bean; MOP]\ypn  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $v:gBlj%"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); np-T&Pz2  
if(tmpFile.exists ()) K}PvrcO1  
{ rT flk  
bFirst = false; (F,(]71Z+  
read_nPos(); L2CW'Hd  
} Bw 3F7W~l  
else p;qRm} 0}  
{ gH i~nEH  
nStartPos = new long[bean.getNSplitter()]; m3xz=9Ve  
nEndPos = new long[bean.getNSplitter()]; D|TLTF"  
} wX)efLmyhY  
$/[Gys3"  
3`&VRF8  
V< i<0E  
} pxw{  
:3a&Pb*PL  
;23=p=/h  
public void run() *|];f#^9  
{ \|eJJC  
//获得文件长度 r7Nu>[r5  
//分割文件 j6tP)f^tD  
//实例FileSplitterFetch m\6SG' X  
//启动FileSplitterFetch线程 =$b-xsmeG  
//等待子线程返回 09  
try{ H\)gE>  
if(bFirst) _kn]#^ucCe  
{ +P [88!  
nFileLength = getFileSize(); u?q&K|  
if(nFileLength == -1) Zk]k1]u*5  
{ 3TU'*w &  
System.err.println("File Length is not known!"); 7o;x (9  
} >"cr-LB  
else if(nFileLength == -2) s.^c..e75C  
{ *nYB o\@g  
System.err.println("File is not access!"); K4j@j}zK9I  
} +jq 2pFQ  
else :v#k&Uh3y  
{ W *YW6  
for(int i=0;i<nStartPos.length;i++) j6n2dMRvSE  
{ #"Fg%36Zd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 99F>n[5  
} 4@DVc7\x$  
for(int i=0;i<nEndPos.length-1;i++) X$Q2m{dR  
{ B;eW/#`  
nEndPos = nStartPos[i+1]; x 8 f6,  
} RRx`}E9,  
nEndPos[nEndPos.length-1] = nFileLength; #mgA/q?A  
} KU+( YF$1  
} d@-wi%,^  
YO)')&  
LIr(mB"Y0  
//启动子线程 R]CZw;zS_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3hc#FmLr2b  
for(int i=0;i<nStartPos.length;i++) `6rrXU6|  
{ .r~'(g{qt  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TT|-aS0l(u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UUl*f!& o  
nStartPos,nEndPos,i); jEZ "  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &nQRa?3,   
fileSplitterFetch.start(); mYjf5  
} 5\VxXiy 0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %z1{Kus  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z8b _ _%Br  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +``>,O6  
nEndPos = " + nFileLength); q z=yMIy=  
// fileSplitterFetch[nPos.length-1].start(); b![t6-f^z  
 "\`>2  
"VV914*z  
//等待子线程结束 j,}4TDWa  
//int count = 0; [FB&4>V/  
//是否结束while循环 !\aV 0,  
boolean breakWhile = false; rwoF}}  
q1UBKhpnH  
--Oprl  
while(!bStop) c+1vqbqHG  
{ LlU' _}>  
write_nPos(); '#H&:Htm;L  
Utility.sleep(500); {b(rm,%  
breakWhile = true; ?LM:RADCm  
h>dxBN  
]yo_wGiwY  
for(int i=0;i<nStartPos.length;i++) fb /qoZ  
{ aJI>FTdK  
if(!fileSplitterFetch.bDownOver) l x7Kw%  
{ h:f;mn?x  
breakWhile = false; FnY$)o;   
break; ?3[tJreVj  
} pXssh  
} {&uT3*V1  
if(breakWhile) 9 >%+bA(  
break; \ZqK\=  
}gCG&7C  
U%L -NMe  
//count++; vsH3{:&;"P  
//if(count>4) [4Y[?)7  
// siteStop(); n9DbiL1{  
} ~+<<bzY  
g+.0c=G(  
T\jAk+$Jo  
System.err.println("文件下载结束!"); mIRAS"Q!m  
} C}9Kx }q  
catch(Exception e){e.printStackTrace ();} .U<F6I:<md  
} C]/&vh7ta  
6zuze0ud  
k'x #t(  
//获得文件长度 D 0  
public long getFileSize() HQl~Dh0DJ  
{ I:nI6gF  
int nFileLength = -1; WI6(#8^p  
try{ >ZX|4U[$P  
URL url = new URL(siteInfoBean.getSSiteURL()); jSB'>m]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1ADv?+j)A/  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^L ]B5,} -  
N^lAG"Jao[  
wajZqC2yg  
int responseCode=httpConnection.getResponseCode(); 4x(F&0  
if(responseCode>=400) bhn5Lz$z  
{ o,J^ e_  
processErrorCode(responseCode); {(%~i37  
return -2; //-2 represent access is error !\ZcOk2  
} ( :iPm<  
J=@xAVBc  
|f<9miNu  
String sHeader; V7BsEw  
B7|c`7x(  
S4)A6z$  
for(int i=1;;i++) kAeNQRjR  
{ KYf;_C,$  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fL2^\dB;  
//Utility.log(in.readLine()); !f`5B( @  
sHeader=httpConnection.getHeaderFieldKey(i); [$;,Ua-mt  
if(sHeader!=null) W=3? x  
{ V;k#})_-  
if(sHeader.equals("Content-Length")) l**3%cTb  
{ P0)AU i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0TmZ*?3!4  
break; hD*(AJ  
} &5d\~{;  
} /w0w* n H  
else {gw [%[ZM  
break; pD[pTMG@$  
} QhsVIta  
} } YRO'Q{  
catch(IOException e){e.printStackTrace ();} hox< vr4  
catch(Exception e){e.printStackTrace ();} j-QGOuvW  
lM$t!2pRB  
>%l:Dw\A:  
Utility.log(nFileLength); 9ZhDZ~)p,  
gX_SKy  
]hL:33  
return nFileLength; a}dw9wU!:  
} js -2"I  
[<Q4U{F  
?;_O 9  
//保存下载信息(文件指针位置) >C*4_J7  
private void write_nPos() nSHNis  
{ lA]N04 d  
try{ _CL{IY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m d_g}N(C  
output.writeInt(nStartPos.length); me:iQ.g  
for(int i=0;i<nStartPos.length;i++) \+9;!VWhl  
{ JL``iA  
// output.writeLong(nPos); c@9##DPn  
output.writeLong(fileSplitterFetch.nStartPos); Ok,HD7  
output.writeLong(fileSplitterFetch.nEndPos); n>S2}y  
} bM^7g  
output.close(); >x*)GPDa  
} FllX za)  
catch(IOException e){e.printStackTrace ();} `6}Yqh))  
catch(Exception e){e.printStackTrace ();} 5#2jq<D  
} >MPa38  
*{4 ETr7  
bJPJ.+G7  
//读取保存的下载信息(文件指针位置) 6#vI;d[^  
private void read_nPos() ` jyKCm.$#  
{ &//2eL  
try{ ;t!9]1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >8(jW  
int nCount = input.readInt(); 'B,KFA<  
nStartPos = new long[nCount]; {"t5\U6cKM  
nEndPos = new long[nCount]; \ FXp*FbQ  
for(int i=0;i<nStartPos.length;i++) ~?d>fR:X  
{ ;Yv14{T!  
nStartPos = input.readLong(); >uHb ^  
nEndPos = input.readLong(); {!r#f(?uT  
} _ ~[M+IO   
input.close(); 1fRP1  
} )(]Envb?A0  
catch(IOException e){e.printStackTrace ();} `,P >mp)uU  
catch(Exception e){e.printStackTrace ();} N8QH*FX/F1  
} TaWaHf  
d#8e~  
.:N:pWe  
private void processErrorCode(int nErrorCode) FB_NkXR  
{ dXK-&Po'  
System.err.println("Error Code : " + nErrorCode); ^7^2D2[  
} j76%UG\Ga  
K[]K53Nk  
v^TkDf(Oz  
//停止文件下载 e[8UH=`|  
public void siteStop() 1yS&~ y?a  
{ V)h y0_  
bStop = true; ~ aA;<#  
for(int i=0;i<nStartPos.length;i++) t#~XLCE  
fileSplitterFetch.splitterStop(); _*n)mlLln  
7@3sUA_Go  
B!uxs  
} ^cn@?k((A  
} #a'r_K=ch)  
//负责部分文件的抓取 sG1BNb_  
**FileSplitterFetch.java ST% T =_q  
*/ s??czM2O  
package NetFox; yV2e5/i  
wASX\D }  
GFt1  
import java.io.*; gyFr"9';c  
import java.net.*; \Z'/+}^h  
shzG Eb  
uJ 8x  
public class FileSplitterFetch extends Thread { #j.FJFGX  
#R<G,"N5  
b5S7{"<V  
String sURL; //File URL mLaCkn  
long nStartPos; //File Snippet Start Position  P63 (^R  
long nEndPos; //File Snippet End Position %qi%$  
int nThreadID; //Thread's ID '$6PTa  
boolean bDownOver = false; //Downing is over S(tEw Xy  
boolean bStop = false; //Stop identical R"{l[9j4>  
FileAccessI fileAccessI = null; //File Access interface `I#`:hj  
lRH0)5`  
aaT5u14%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,5. <oDH  
{ |*fNH(8&H  
this.sURL = sURL; ,Z5Fea  
this.nStartPos = nStart; cd&B?\I  
this.nEndPos = nEnd;  Fs)  
nThreadID = id; qRl/Sl#F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4m\([EO  
} {$|/|*  
I=5dYq4 l  
i*68-n  
public void run() PkO!'X  
{ ])UwC-l  
while(nStartPos < nEndPos && !bStop) I*( 1.%:m  
{ H`gb}?9R  
 J `x}{K  
3Y(9\}E@`  
try{ ofK='G .  
URL url = new URL(sURL); hLo>R'@uN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T]uKH29.%  
httpConnection.setRequestProperty("User-Agent","NetFox"); `-u7 I  
String sProperty = "bytes="+nStartPos+"-"; :*cHA  
httpConnection.setRequestProperty("RANGE",sProperty); ThiN9! Y  
Utility.log(sProperty);  Oq}ip  
Ck@M<(x  
^9=4iXd  
InputStream input = httpConnection.getInputStream(); om>VQ3  
//logResponseHead(httpConnection); Ko+al{2  
Q0WY$w1 <  
x G^f  
byte[] b = new byte[1024]; zQ<88E&&Xs  
int nRead; :P,2K5]y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }PmTR4F!}  
{ o X@nP?\  
nStartPos += fileAccessI.write(b,0,nRead); N3Z@cp  
//if(nThreadID == 1) yf?W^{^|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qCQu^S' iD  
} I{EIHD<  
?b"Vj+1:x  
m/{Y]D{2  
Utility.log("Thread " + nThreadID + " is over!"); ,ex]$fQ'  
bDownOver = true; 1J&#&\,f&  
//nPos = fileAccessI.write (b,0,nRead); BCBUb  
} #fN/LO  
catch(Exception e){e.printStackTrace ();} L^)qe^%3  
}  C/  
} zhjJ>d%w  
zWtj|%ts  
9cz)f\  
//打印回应的头信息 zuMO1s  
public void logResponseHead(HttpURLConnection con) @.1Qs`pt  
{ E[ 0Sst x  
for(int i=1;;i++) _jo$)x+'x  
{ oSmjs  
String header=con.getHeaderFieldKey(i); Yw1Y-M  
if(header!=null) @7-D7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); WAv@F[  
Utility.log(header+" : "+con.getHeaderField(header)); ?Nu#]u-  
else NZfd_? 3  
break; yi|:}K$  
} s&0*'^'O[S  
} j3LNnZY  
0R*}QXph  
NN11}E6  
public void splitterStop() :v#8O~  
{ ey*,StT5a  
bStop = true; 77tZp @>hn  
} ]`K[W&  
j C9<hLt  
%]!?{U\*k  
} ExQ--!AC=  
w~]} acP  
F=: c5z  
/* Txu>/1N,  
**FileAccess.java `BpCRKTG  
*//文件访问(定位,写) RW)k_#%=  
package NetFox; &*jixqzvn  
import java.io.*; HwM /}-t  
c[Yq5Bu{y  
}-dF+m:  
public class FileAccessI implements Serializable{ v|>BDN@,6  
tpE3|5dZF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =uS8>.Qj  
RandomAccessFile oSavedFile; TtZrttCE6  
long nPos; Rn8#0%/Q  
^>eFm8`N  
Nl=+.d6 Qo  
public FileAccessI() throws IOException +yvBSpY  
{ yG4MUf6  
this("",0); F; 0Dp  
} #|q;t   
X!m;uJZp  
oR7 7`  
public FileAccessI(String sName,long nPos) throws IOException u$\Tg3du2  
{ ~O8] 3+U  
oSavedFile = new RandomAccessFile(sName,"rw"); >H8^0n)?  
this.nPos = nPos; |]I#CdO  
oSavedFile.seek(nPos); _4O[[~  
} ,I=O"z>9  
6mX:=Q  
8XgVY9]Qm  
public synchronized int write(byte[] b,int nStart,int nLen)  eMztjN  
{ /1U,+g^O>  
int n = -1; aQC 7V!v  
try{ E|\3f(aF  
oSavedFile.write(b,nStart,nLen); K:C+/O  
n = nLen; Kgps_tY%  
} D=<t;+|  
catch(IOException e) - f+CyhR"*  
{ k#BU7Exij  
e.printStackTrace (); uLF\K+cz  
} 3$;J0{&[i  
N c9<X  
Ogn,1nm%  
return n; oK%K+h  
} #xDDh`  
^BQ>vI'.4  
zv>ZrFl*  
} Z5 w`-#  
nvw NjN  
L>eQ*311  
/* I):m6y@  
**SiteInfoBean.java Z(#XFXd  
*/ 34HFrMi  
package NetFox; X}kVBT1w+x  
s#M? tyhj  
'Wd3`4V$  
public class SiteInfoBean { ikeJDKSG  
@?(nwj~ s`  
+ ?[ ACZF  
private String sSiteURL; //Site's URL QJb7U5:B+  
private String sFilePath; //Saved File's Path @DRfNJ}  
private String sFileName; //Saved File's Name \3,$YlG  
private int nSplitter; //Count of Splited Downloading File %jYQ  
8.6no  
9N`+ O  
public SiteInfoBean() yN%3w0v  
{//nSplitter的缺省值为5 }mkA Hmu4  
//default value of nSplitter is 5 q=(M!9cE  
this("","","",5); t"jIfU>'a/  
} o%y+Y;|?J  
bL6L-S  
ufHuI*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6yV5Yjs  
{ =P@M&Yy'  
sSiteURL= sURL; ;))[P_$zB  
sFilePath = sPath; :T8u?@ .  
sFileName = sName; hlY S=cgY=  
this.nSplitter = nSpiltter; Ih9ORp7  
rcD.P?"  
eA;j/&qH  
} iPR!JX _  
zzDNWPzsA  
e)fJd*P  
public String getSSiteURL() A?%XO %  
{ TW;|G'}$  
return sSiteURL; *rujdQf  
} $_%2D3-;D  
'US8"83  
)of5229  
public void setSSiteURL(String value) eHfG;NsV /  
{ *RUd!]bh  
sSiteURL = value; VuYWb)@  
} ^H@!)+ =  
oi%5t)VsS  
0%(4G83gw  
public String getSFilePath() 81%qM7v9H  
{ WHdqO8  
return sFilePath; j};pv2  
} >vNk kxWyQ  
8VBkIYgb  
v)v{QNQp^  
public void setSFilePath(String value) a!SR"3 k  
{ KBUAdpU8  
sFilePath = value; 83p$!8]u  
} 0e7O#-  
 h;:Se  
g(z#h$@S  
public String getSFileName() ^"6D0!'N  
{ 7k[`]:*o  
return sFileName; =]2RC1#}e  
} MfZ}xu  
8 H$@Xts  
N'Z_6A*-  
public void setSFileName(String value) umHs" d  
{ <7sF<KD  
sFileName = value; |{}d5Z"5;}  
} ?$`1%Y9  
KqG$zC^N  
` i^`Q  
public int getNSplitter() c=jTs+h'  
{ *n$m;yI  
return nSplitter; z!Pdivx  
} }hObtAS  
(pRy1DH~  
Rzn0-cG  
public void setNSplitter(int nCount) F?+Uar|-a  
{ |tolgdj  
nSplitter = nCount; J T0,Z  
} !@]h@MC$7  
} JVIcNK)  
Nsy9 h}+A  
^0 ,&R\e+  
/* G+ \~rl  
**Utility.java .-1{,o/&Q  
*/ 5D02%U2N)G  
package NetFox; .ON$vn7  
KzFs#rhpn  
V }r_   
public class Utility { UU:QK{{E  
0I ND9h. %  
Z:o' +oh  
public Utility() v'2OHb#  
{ Kw5+4R(5  
bju,p"J1-E  
+XaO?F[c  
} ]a Ma*fF  
~]t2?SqNm  
//线程睡眠 yI)RG OV  
public static void sleep(int nSecond) (/rIodHJO  
{ 3 v,ae7$U&  
try{ F" #3s=  
Thread.sleep(nSecond); ju2X*  
} L^ jC& dF  
catch(Exception e) YQ[&h  
{ SJ|.% gn  
e.printStackTrace (); 5IF~]5s  
} BX)cV  
} W~@GK  
 M$-(4 0  
//日志 yKk,);  
public static void log(String sMsg) G4`sRaT.  
{ p=P0$P+KM  
System.err.println(sMsg); iRr& 'k  
} M6>\R$  
/-<m(72wF  
n*8RYm)?  
public static void log(int sMsg) 1_E3DXe  
{ :92a34  
System.err.println(sMsg); J;]@?(  
} NB6h/0*v  
} #L*@~M^]  
%cjGeS6}  
KL_}:O68  
/* /n3&e  
**TestMethod.java V/[,1W[B  
*/ B[m{2XzGH  
package NetFox; )^' B:ic  
moM&2rgdrQ  
e^fKatI1  
public class TestMethod { $A!h=]  
v(nQd6;T  
(R 2P< Zr  
public TestMethod() R"kE5 :  
{ ///xx/weblogic60b2_win.exe Chi<)P$^  
try{ 1Qe!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~X(xa  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N)I T?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PHL@1K{)  
fileFetch.start(); CzsY=DBH=  
} Dp |FyP_w  
catch(Exception e){e.printStackTrace ();} Q1&dB{L  
B+H9c~3$  
rls#g w  
} qA\kx#v]P  
'!L1z45  
ob5nk ^y  
public static void main(String[] args) I!0 +RP(  
{ G78j$ ^/0  
new TestMethod(); %_=R&m'n`  
} U=#ylQ   
} Z1lF[d,f;  
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