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http断点续传简单实现(java)

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/* vWH>k+9&X  
**SiteFileFetch.java ([-=NT}Aq  
*/ =7Vl{>*1N  
package NetFox; HJR<d&l;p  
import java.io.*; H| U/tU-  
import java.net.*; e}[we:  
jPNfLwVkl:  
jSYg\ Z5!  
public class SiteFileFetch extends Thread { Z D%_PgiT  
_%vqBr*  
Rl4zTAI  
SiteInfoBean siteInfoBean = null; //文件信息Bean -0 da"AB  
long[] nStartPos; //开始位置 oB R(7U ~0  
long[] nEndPos; //结束位置  MK"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Zw][c7%  
long nFileLength; //文件长度 x,gE$dNzy  
boolean bFirst = true; //是否第一次取文件 u^zitW!X$  
boolean bStop = false; //停止标志 4E\ntufo  
File tmpFile; //文件下载的临时信息 V55J[s*6!  
DataOutputStream output; //输出到文件的输出流 =awO63j>  
@:9fS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) t} i97;  
public SiteFileFetch(SiteInfoBean bean) throws IOException m8j-lNu  
{ m2CWQ[u  
siteInfoBean = bean; chmJ|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j& iL5J;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); i:M*L< +  
if(tmpFile.exists ()) P`dHR;Y0  
{ Jav2A6a  
bFirst = false; RIEv*2_O  
read_nPos(); 1bZiPG{  
} |cGeL[  
else #S%Y; ilq  
{ vj&5`  
nStartPos = new long[bean.getNSplitter()]; .*~u  
nEndPos = new long[bean.getNSplitter()]; /cC6qhkp%  
} YOV4)P"  
E97+GJ3  
C!{AnWf  
NS4'IR=;E!  
} r`R~{;oT  
2HGD{;6>v{  
p;=kH{uu  
public void run() N@*wi"Q  
{ PT#eXS9_  
//获得文件长度 $l,Zd6<1q  
//分割文件 CQzjCRS d  
//实例FileSplitterFetch Wt9iL  
//启动FileSplitterFetch线程 (:-Jl"&R@  
//等待子线程返回 #C1A5JE&  
try{ V.Ba''E7  
if(bFirst) 04guud }  
{ EKeh>3;?  
nFileLength = getFileSize(); `X<`j6zaG  
if(nFileLength == -1) [s{r$!Gl  
{ Y3$PQwn .P  
System.err.println("File Length is not known!"); 25a#eDbqi  
} PIEW\i  
else if(nFileLength == -2) rW~?0  
{ sh(kRrdY3  
System.err.println("File is not access!"); *rn]/w8ZW  
} 3> \fP#oQ  
else C8qTz".5$  
{ 0L0Jc,(F+  
for(int i=0;i<nStartPos.length;i++) 3Wb2p'V7$?  
{ +*_fN ]M  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )'!ml  
} ]bN&5.|  
for(int i=0;i<nEndPos.length-1;i++) ,t%CK!8  
{ ?S@R~y0K  
nEndPos = nStartPos[i+1]; }-{b$6]  
} `[@^m5?b-  
nEndPos[nEndPos.length-1] = nFileLength; 2rO)qjiH  
} M*O(+EM  
} &cu] vw  
*hZ~i{c,7  
;Lsjh#  
//启动子线程 GL 5^_`n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i9;27tT~<  
for(int i=0;i<nStartPos.length;i++) }*.:Hv"  
{ 4aN+}TkH@G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), eyf4M;goz}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /~Zc}o,J  
nStartPos,nEndPos,i); ~)wwX:;B_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wrQydI  
fileSplitterFetch.start(); R2N^'  
} 13.{Y)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bk7^%O>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &gWMl`3^*!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @TA8^ND  
nEndPos = " + nFileLength); JN&MyA"  
// fileSplitterFetch[nPos.length-1].start(); m)@Q_{=6M  
Mr=}B6`  
K5!";V  
//等待子线程结束 3s?v(1 {)  
//int count = 0; t&R!5^R  
//是否结束while循环 C|4 U78f{  
boolean breakWhile = false; &@4.;u  
NWJcFj_  
p*pn@z  
while(!bStop)  Iys6R?~  
{ HZDk <aU/!  
write_nPos(); { r6]MS#l1  
Utility.sleep(500); O1?B{F/ e  
breakWhile = true; 1 [fo'M  
_x\-!&[p  
+R "AA_A?  
for(int i=0;i<nStartPos.length;i++) *CeQY M  
{ ;Ze"<U  
if(!fileSplitterFetch.bDownOver) 5jn$7iE`  
{ ,VKQRmd  
breakWhile = false; 0W~.WkD  
break; :%/\1$3P  
} 0rku4T  
} .Lojzx  
if(breakWhile) 20rN,@2<  
break; n> MD\ZS  
N@cMM1  
bbd0ocva  
//count++; Lzh9DYU6  
//if(count>4) @+?+6sS  
// siteStop(); AA))KBXq  
} >vQ6V'F  
_&W0e}4  
kU #:I9PO  
System.err.println("文件下载结束!"); f\h%; X  
} ,dHP`j ?  
catch(Exception e){e.printStackTrace ();} z@!^ow)`J  
} Y*Y&)k6 t  
tCWJSi`IJ  
cwu$TP A>  
//获得文件长度 <9@&oN+T  
public long getFileSize() X$BXT  
{ `Uz s+k-]  
int nFileLength = -1; sL)Rg(rkx  
try{ ?N4A9W9  
URL url = new URL(siteInfoBean.getSSiteURL()); ]ddHA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  LsQs:O  
httpConnection.setRequestProperty("User-Agent","NetFox"); $!a?i@  
>W8bWQ^fK  
{V[Ha~b%*  
int responseCode=httpConnection.getResponseCode(); ;US83%*  
if(responseCode>=400) dKU5;  
{ %z1{Kus  
processErrorCode(responseCode); z8b _ _%Br  
return -2; //-2 represent access is error +``>,O6  
} d2ohW|  
&c20x+  
ZR1+ O 8  
String sHeader; LPq2+:JpS  
DXKyRkn6e  
Ip>^O/}$1  
for(int i=1;;i++) h=hoV5d@  
{ DeA@0HOxh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }g}6qCv7  
//Utility.log(in.readLine()); 3nwz<P  
sHeader=httpConnection.getHeaderFieldKey(i); !loO%3_)  
if(sHeader!=null) ]a)IMIh;  
{ lNHNL a>W  
if(sHeader.equals("Content-Length")) yHl@_rN sC  
{ M6\7FP6G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @|^jq  
break; Z%Vr+)!4  
} DX|uHbGg  
} pw!@Q?R  
else {n\6BTs  
break; 'w}p[(  
} bpGzTU  
} HP;|'b  
catch(IOException e){e.printStackTrace ();} Wt(Kd5k0'2  
catch(Exception e){e.printStackTrace ();} ?;Un#6b  
=Qyqfy*@D?  
6mwvI4)  
Utility.log(nFileLength); # 2d,U\_  
PDhWFF  
,`<]>;s  
return nFileLength; Bgf=\7;5  
} mLJDxh'B  
$>;a 'f~  
$;y1Q iel  
//保存下载信息(文件指针位置) Cgo9rC~]  
private void write_nPos() gTnS[  
{ oK)[p!D?0{  
try{ B0v|{C   
output = new DataOutputStream(new FileOutputStream(tmpFile)); fO #?k<p  
output.writeInt(nStartPos.length); ,pn ) >  
for(int i=0;i<nStartPos.length;i++) 9MT3T?IS  
{ 3#9uEDdE  
// output.writeLong(nPos); RXM}hqeG  
output.writeLong(fileSplitterFetch.nStartPos); am2a#4`  
output.writeLong(fileSplitterFetch.nEndPos); A$Wx#r7)  
} 0E yAMu  
output.close(); 691G15  
} =9(tsB gTX  
catch(IOException e){e.printStackTrace ();} X\kjAMuW/*  
catch(Exception e){e.printStackTrace ();} NK~PcdGl  
} {b2 aL7  
_1P`]+K\D$  
)'`CC>Q  
//读取保存的下载信息(文件指针位置) |!oXvXU  
private void read_nPos() lO[E[c G  
{ q4) Ey  
try{ GJvp{U}y9I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n_J5zQJ  
int nCount = input.readInt(); Jns/v6  
nStartPos = new long[nCount]; <z',]hy  
nEndPos = new long[nCount]; +ZX .1[O  
for(int i=0;i<nStartPos.length;i++) Y3<b~!f  
{ X CzXS.  
nStartPos = input.readLong(); +|9f%f6vp  
nEndPos = input.readLong(); $5x]%1 R  
} 5\&]J7(  
input.close(); };^}2Xo+  
} ]'tJ S]  
catch(IOException e){e.printStackTrace ();} 4b=Gg  
catch(Exception e){e.printStackTrace ();} \KCWYi]  
} L $SMfx  
T!(sZf  
TywK\hH  
private void processErrorCode(int nErrorCode) .D!WO  
{ w]}f6VlEl  
System.err.println("Error Code : " + nErrorCode); ^( DL+r,  
} J B(<.E 2  
5~QT g  
1) 'Iu`k/  
//停止文件下载 [EER4@_  
public void siteStop() 7/ t:YBR  
{ xdqK.Z%  
bStop = true; 7C?E z%a@  
for(int i=0;i<nStartPos.length;i++) Tv1]v.  
fileSplitterFetch.splitterStop(); ;5N41_hG  
^;4YZwW5w  
12-EDg/1  
} }Bi@?Sb  
} B>,A(X&  
//负责部分文件的抓取 \qB6TiB/  
**FileSplitterFetch.java ~@@ Z|w  
*/ W6i3Psjsw  
package NetFox; qW3x{L$c  
}1Z6e[K?  
i\  "{#  
import java.io.*; :Pf>Z? /d  
import java.net.*; WI{; #A  
:xtT)w  
@<a|  
public class FileSplitterFetch extends Thread { M|H 2kvl  
 pr/'J!{^  
K'V 2FTJI  
String sURL; //File URL cl_T F[n?  
long nStartPos; //File Snippet Start Position a MsJO*;>  
long nEndPos; //File Snippet End Position 3Soy3Xp  
int nThreadID; //Thread's ID ,WGc7NN`  
boolean bDownOver = false; //Downing is over %0zS  
boolean bStop = false; //Stop identical 'gCZ'edM  
FileAccessI fileAccessI = null; //File Access interface ~5T$8^K  
']h IfOD"r  
lCHo+>\Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?aFZOc4   
{ 5aG5BA[N  
this.sURL = sURL; (2tH"I  
this.nStartPos = nStart; LZa% x  
this.nEndPos = nEnd; xj7vI&u.  
nThreadID = id; n$xszuNJ`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MOeoU1Hn  
} ZJvo9!DL|  
hX3@f;[B2  
Q vJZkGX  
public void run() =|"= l1  
{ 2LC w*eT{)  
while(nStartPos < nEndPos && !bStop) q~M2:SN@X  
{ OT@yPG  
_@K YF)  
7f* RM  
try{ r>O|L%xpv  
URL url = new URL(sURL); \OY}GRKt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :X Lp  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2lo:a{}j  
String sProperty = "bytes="+nStartPos+"-"; |EEi&GOR(y  
httpConnection.setRequestProperty("RANGE",sProperty); QXY}STs  
Utility.log(sProperty); x) 5LT}p  
kV+ R5R  
MyFCJJ/  
InputStream input = httpConnection.getInputStream(); _ Mn6L=  
//logResponseHead(httpConnection); wPgDy  
Si R\a!,C  
mr qaM2,(I  
byte[] b = new byte[1024]; g>T  
int nRead; ai9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s [T{c.F  
{ /B[}I}X  
nStartPos += fileAccessI.write(b,0,nRead); U!Mf]3  
//if(nThreadID == 1) `S$sQ&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t\%%d)d9  
} . pP7"E4]  
,cD1{T\  
L;lk.~V4T  
Utility.log("Thread " + nThreadID + " is over!"); 32^#RlSu8  
bDownOver = true; @,e8t BL  
//nPos = fileAccessI.write (b,0,nRead); #9,=Owup  
} \4QH/e  
catch(Exception e){e.printStackTrace ();} B\0t&dai|'  
} Eu4 &-i  
} zi.mq&,]R  
z7k$0&  
P5P< "  
//打印回应的头信息 2LZS|fB9o  
public void logResponseHead(HttpURLConnection con) Qt~B#R. V  
{ (Vap7.6;_  
for(int i=1;;i++) Z'ao[CG  
{ aaT5u14%  
String header=con.getHeaderFieldKey(i); ,5. <oDH  
if(header!=null) |*fNH(8&H  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t)'dF*L  
Utility.log(header+" : "+con.getHeaderField(header)); .pW o>`"  
else nALnB1  
break; 7UDq/:}Fo  
} L#!$hq9{_  
} ~j]dct7  
rKT)!o'  
?Q?598MC  
public void splitterStop() #Qsk}Gv  
{ X  Ny Y$  
bStop = true; ZRP y~wy>  
} j.B>v\b_3  
f~R[&q +  
A _i zSzC1  
} bBG/gQ  
N6q5`Ry  
{#9,j]<  
/* qy&\Xgn;GA  
**FileAccess.java J'Gm7h{   
*//文件访问(定位,写) gi1j/j7  
package NetFox; xU:4Y0y8  
import java.io.*; `0z/BCNB  
B.RRdK+:  
:~er h}~ps  
public class FileAccessI implements Serializable{ 8,y{q9O  
m_$JWv\|\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K( z[ }  
RandomAccessFile oSavedFile; MH FaSl  
long nPos; 3sb 5E]P  
vzcz<i )  
ydup)[n  
public FileAccessI() throws IOException {lMqcK  
{ j-6v2MH  
this("",0); 82s 5VQ6  
} pl?kS8#U?  
k,lqT>C  
l#ZyB|  
public FileAccessI(String sName,long nPos) throws IOException 4&]%e6,jH  
{ 1J&#&\,f&  
oSavedFile = new RandomAccessFile(sName,"rw"); BCBUb  
this.nPos = nPos; #fN/LO  
oSavedFile.seek(nPos); L^)qe^%3  
}  C/  
*_#&"(P  
g&kH'fR8  
public synchronized int write(byte[] b,int nStart,int nLen) O{nC^`X  
{ g}YToOs  
int n = -1; B*2{M  
try{ zsQF,7/}B  
oSavedFile.write(b,nStart,nLen); PqI![KxZW  
n = nLen; %z2oDAjX  
} RQ|?Ce",  
catch(IOException e) nNu[c[V  
{ Pj._/$R[/  
e.printStackTrace (); W8VO)3nmD  
} KX=/B=3~  
H>Ks6V)RL4  
80HEAv,O  
return n; \6i 9q=  
} jceHK l  
L\YZT| K(  
%UBPoq  
} O"8P#Ed  
wR(ttwxK3  
A(NEWO  
/* wa2~C [  
**SiteInfoBean.java Hva{A #  
*/ a}w&dE$!-  
package NetFox; pJn>oGeJ&  
@BXaA0F4  
Kn. iyR  
public class SiteInfoBean { Lg b  
1 0V+OIC  
FbuKZp+  
private String sSiteURL; //Site's URL c[Yq5Bu{y  
private String sFilePath; //Saved File's Path ]a=l^Pc(xN  
private String sFileName; //Saved File's Name PB@-U.Z  
private int nSplitter; //Count of Splited Downloading File $6Z[|9W^A  
ah>Dqb*  
9T/<x-FD  
public SiteInfoBean() sI$:V7/!  
{//nSplitter的缺省值为5 bje' Oolc  
//default value of nSplitter is 5 z30=ay1  
this("","","",5); /CbkqNV  
} .C6gl]6y@  
<9 T [yg  
X!m;uJZp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) oR7 7`  
{ u$\Tg3du2  
sSiteURL= sURL; ~O8] 3+U  
sFilePath = sPath; y^ 3,X_0  
sFileName = sName; R4yJ.f  
this.nSplitter = nSpiltter; -^0KE/  
=qan%=0"h  
Of!|,2`(  
} 7;~ 2e  
oUCVd}wH  
:%pw`b, =V  
public String getSSiteURL() [&fWF~D-p<  
{ =g1D;  
return sSiteURL; 1/!nV  
} Qve`k<Cj"  
K:C+/O  
b\H/-7<  
public void setSSiteURL(String value) /oBK&r[(  
{ H_v/}DEG  
sSiteURL = value; gr[D!D >  
} i;gw= Be  
-g~iE]x6Y  
2~+'vi  
public String getSFilePath() MuN [U17FB  
{ +h9`I/R  
return sFilePath; MV7}  
} S".owe$\  
YstXNN4  
bl6':m+  
public void setSFilePath(String value) CR P7U  
{ [@jp9D H  
sFilePath = value; @b4b{d5[  
} zR_9D}  
^o,y5 ,  
m21QN9(i%  
public String getSFileName() l[:^TfB  
{ VNr!|bp5  
return sFileName; 4c~*hMr y  
} 1V#B]x:  
rAtai}Lx  
w}fqs/)w  
public void setSFileName(String value) "~B~{ _<j  
{ ^Jc$BMaVg  
sFileName = value; &?&'"c{;m  
} MA l{66  
3ZLr"O1l)  
DX7Ou%P,mg  
public int getNSplitter() 8s\8`2=  
{ x A@|I#  
return nSplitter; =lw4 H_  
} 9_I[o.q   
o<9yaQ;  
_gis+f/8h  
public void setNSplitter(int nCount) 2&3eAJC  
{ yOn H&Jj  
nSplitter = nCount; 3^uL`ETm@  
} ;2+ FgOj  
} 9CgXc5  
r! cNc  
vy>];!Cu  
/* +y tT)S  
**Utility.java 3uB=L 7.  
*/ ^d5gz0d  
package NetFox; vY8WqG]  
^' edE5  
T9&,v<f  
public class Utility { zzDNWPzsA  
e)fJd*P  
A?%XO %  
public Utility() TW;|G'}$  
{ `Pz!SJ|  
5p N08+  
Off: ~  
} E1mI Xd;.  
BZnp #}f  
//线程睡眠 N> uZt2  
public static void sleep(int nSecond) b7F3]W<`&  
{ U)IsTk~}O  
try{ 7zz(#  
Thread.sleep(nSecond); mH7CgI  
} (@N~ j&  
catch(Exception e) f z/?=  
{ MZ >0K  
e.printStackTrace (); g~i''lng  
} ?(|TP^  
} $Sc08ro  
`Lb _J  
//日志 `&"H* Ie  
public static void log(String sMsg) *;V2_fWJ@  
{ K{`2jK#  
System.err.println(sMsg); S]#=ES'^/  
} Cz$H k;3\6  
jSOa   
q_%w l5\F  
public static void log(int sMsg) Y'+F0IZ+  
{ 8xeun~e"vS  
System.err.println(sMsg); *R9mgv[  
} X7imUy'.  
} tOlzOBzR  
9phD5b~j  
9>} (]T  
/* !Ed<xG/  
**TestMethod.java *cb D&R\  
*/ (<AM+|  
package NetFox; { 8|Z}?I  
 5Fl  
H8=vQy  
public class TestMethod { /(WX!EEsB  
}AeE|RNc  
Npg5Z%+y  
public TestMethod() 0N} wD-  
{ ///xx/weblogic60b2_win.exe ho SU`X  
try{ }y -AoG  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8m1 3M5r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l yLK$B?/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); s K$Sar  
fileFetch.start(); D3ZT''  
} gw}7%U`T9  
catch(Exception e){e.printStackTrace ();} zN 729wK  
{) '" k6w  
^0 ,&R\e+  
} )oz-<zW  
sL[(cX?;2  
j_YZ(: =  
public static void main(String[] args) 5D02%U2N)G  
{ G3^n_]Jb  
new TestMethod(); 2=UTH% 1D  
} j)lM:vXR  
} xVwi }jtG|  
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