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http断点续传简单实现(java)

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/* hPB^|#}  
**SiteFileFetch.java b,Vg3BS  
*/ #7}1W[y9}l  
package NetFox; ?' :v): J}  
import java.io.*; ^Voi 4;  
import java.net.*; H ]x-s  
}; ;Thfd  
q&RezHK l  
public class SiteFileFetch extends Thread { KtO|14R:  
-)p S\$GC  
_sGmkJi]  
SiteInfoBean siteInfoBean = null; //文件信息Bean RMvq\J}w!  
long[] nStartPos; //开始位置 L" GQ Q  
long[] nEndPos; //结束位置 _vV3A3|Ec,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =h Lw 1~  
long nFileLength; //文件长度 74p=uQ  
boolean bFirst = true; //是否第一次取文件 /)<x<7FKW  
boolean bStop = false; //停止标志 G)G 257K"~  
File tmpFile; //文件下载的临时信息 Ey#7L M)  
DataOutputStream output; //输出到文件的输出流 ^.|P&f~  
15X.gx  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) P< 5v\\  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3~o#1*->  
{ W Y]   
siteInfoBean = bean; p-Jp/*R5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h7"c_=w+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,|RN?1?U  
if(tmpFile.exists ()) L HW\A8  
{ 9{KL^O?g  
bFirst = false; * ",/7(  
read_nPos();  nLD1j  
} js..k*j  
else a7@':Rb n  
{ <9bfX 91  
nStartPos = new long[bean.getNSplitter()]; + ;LO|!  
nEndPos = new long[bean.getNSplitter()]; a-bj! Rs  
} x=M%QFe  
pv[Gg^  
*t%Z'IA  
U5RLM_a@M  
} dtT: ,&  
|W#(+m  
zo| '  
public void run() cTJi8f=g  
{ -Lhq.Q*a  
//获得文件长度 ,` 64t'g  
//分割文件 C==yl"w  
//实例FileSplitterFetch S6CI+W  
//启动FileSplitterFetch线程 /wI"oHZd  
//等待子线程返回 *671MJ 9  
try{ \_]X+o;  
if(bFirst) +6`+Q2qi  
{ J6I:UML  
nFileLength = getFileSize(); T!7B0_  
if(nFileLength == -1) 8g0VTY4$jP  
{ D){my_ /  
System.err.println("File Length is not known!"); IE|? &O  
} smUSR4VK  
else if(nFileLength == -2) 0,/I2!dF?  
{ Yu$QL@  
System.err.println("File is not access!"); OUk"aAo  
} w *M&@+3I  
else GoLK 95"]  
{ AP:Q]A6}  
for(int i=0;i<nStartPos.length;i++) ~].?8C.>*  
{ 3;RQ\{eM  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3_ly"\I\  
} ZZn$N-  
for(int i=0;i<nEndPos.length-1;i++) PU,%Y_xR  
{ Mbp7%^E"A  
nEndPos = nStartPos[i+1]; 6CCm1F{`  
} ]h?q1    
nEndPos[nEndPos.length-1] = nFileLength; 5-hnk' ~  
} /%mT2  
} e\em;GTy  
/9e?uC6  
byFO^pce  
//启动子线程 \xlG3nz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lSg[7lt  
for(int i=0;i<nStartPos.length;i++) _U_O0@xi  
{ _%[po%]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 31~nay15  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >%ovL8F  
nStartPos,nEndPos,i); : r(dMU3%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZTibF'\5N  
fileSplitterFetch.start(); kO5lLqE  
} aeISb83Y|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GsmXcBzDw2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <.mH-Y5i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g)5mr:\  
nEndPos = " + nFileLength); CLTkyS)C  
// fileSplitterFetch[nPos.length-1].start(); oOLey!uZw  
rlaeqG  
ae2Q^yLA  
//等待子线程结束 &JXb) W  
//int count = 0; |his8\C+x  
//是否结束while循环 0,nz*UDk  
boolean breakWhile = false; XZ . T%g  
p#CjkL  
tYXE$ i  
while(!bStop) ESNI$[`  
{ *f3StX  
write_nPos(); ^DN:.qQ  
Utility.sleep(500); o K>(yC[  
breakWhile = true; jQ,Vs=*H  
x9,jXd  
{"+M%%`*#  
for(int i=0;i<nStartPos.length;i++) \"1>NJn&k)  
{ j)2I+[aoB  
if(!fileSplitterFetch.bDownOver) <)p.GAZ  
{ r=&,2meo  
breakWhile = false; 59O-"Sc[  
break; >v%js!`f  
} ?+))J~@t  
} kzjuW  
if(breakWhile) Jup)A`64  
break; +]s,VSL5`  
@uH!n~QV  
!uQT4< g  
//count++; Bz<hP*.O  
//if(count>4) ]bJz-6u#:  
// siteStop(); 6,A|9UX=`  
} \4L ur  
{YgU23;q  
{2h *NFp  
System.err.println("文件下载结束!"); R>* z8n  
} V6X )L>!xx  
catch(Exception e){e.printStackTrace ();} VD$5 Djq  
} ;NR|Hi]  
lcie6'<  
N#K)Z5J)b  
//获得文件长度 8u2k-_9  
public long getFileSize() GLn=*Dh#  
{ Zp> v  
int nFileLength = -1; 3uocAmY  
try{ x%l(0K  
URL url = new URL(siteInfoBean.getSSiteURL()); ? `p/jA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {+WBi(=W  
httpConnection.setRequestProperty("User-Agent","NetFox"); M bWby'  
b^VRpv  
J, -.5  
int responseCode=httpConnection.getResponseCode(); Hw o _;fV  
if(responseCode>=400) UZI:st   
{ sfyLG3$/  
processErrorCode(responseCode); 6sBt6?_T  
return -2; //-2 represent access is error >$JE!.p%o  
} Y"H`+UV  
|%C2 cx  
]SCHni_  
String sHeader; gz~oQ l)zJ  
J'}+0mln  
bzFac5n)Q  
for(int i=1;;i++) < D/K[mz-  
{ |9jK-F6   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J8emz8J  
//Utility.log(in.readLine()); LDr?'M!D  
sHeader=httpConnection.getHeaderFieldKey(i); $@L;j  
if(sHeader!=null) 0vqVE]C  
{ DyN[Yp|V  
if(sHeader.equals("Content-Length")) `;j1H<L  
{ Ddr.6`VJ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6Qkjr</  
break; tnJ7m8JmC  
} NV * 2  
} f)*?Ji|5F  
else <D.E .^Y  
break; \6|y~5Hw{r  
} Wq A) V,E  
} K=N&kda   
catch(IOException e){e.printStackTrace ();} 9<u&27.  
catch(Exception e){e.printStackTrace ();} m^QoB  
cb^IJA9}  
C ~h#pAh  
Utility.log(nFileLength); F_qApyU,7  
nLm'a_  
epsRv&LfC  
return nFileLength; nX (bVT4i  
} H1k)ya x4_  
P8YnKyI,.  
rN&fFI  
//保存下载信息(文件指针位置) }!iopu  
private void write_nPos() 6>WkisxG  
{ (2;Aqx5i  
try{ 5;XC!Gz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); c,r6+oX  
output.writeInt(nStartPos.length); >V^8<^?G  
for(int i=0;i<nStartPos.length;i++) <9]"p2  
{ k M /:n  
// output.writeLong(nPos); fz|*Plv  
output.writeLong(fileSplitterFetch.nStartPos); 5S4Nx>  
output.writeLong(fileSplitterFetch.nEndPos); ^VYR}1Mw  
} &E]) sJ0  
output.close(); fQ9af)d  
} Q,.dIPla  
catch(IOException e){e.printStackTrace ();} TIp\-  
catch(Exception e){e.printStackTrace ();} vu.ug$T  
} RhJ3>DL  
\;-Yz  
aUMiRm-   
//读取保存的下载信息(文件指针位置) Xn"#Zy_  
private void read_nPos() d[h=<?E5  
{ !*c%Dj  
try{ $D`Kz*/.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); '@24<T]  
int nCount = input.readInt(); W _[9  
nStartPos = new long[nCount]; mg*iW55g  
nEndPos = new long[nCount]; :30daKo  
for(int i=0;i<nStartPos.length;i++) d*TH$-F!p  
{ %;wD B2k*  
nStartPos = input.readLong(); %{ U (y#  
nEndPos = input.readLong(); hzAuj0-A  
} F~v0CBcAL  
input.close(); t,Tq3zB  
} AIP0PJI3  
catch(IOException e){e.printStackTrace ();} C,ldi"|  
catch(Exception e){e.printStackTrace ();} VnN(lJ  
} ;- i)}<  
}G(#jOYk  
ZXhNn<  
private void processErrorCode(int nErrorCode)  =glG |  
{ *[>{ 9V  
System.err.println("Error Code : " + nErrorCode); +v%+E{F$+  
} ([m4 dr  
6oWFjeZ0  
]@_|A, ]  
//停止文件下载 Z2;~{$&M+  
public void siteStop() P=_W{6  
{ N/C$8D34  
bStop = true; kJ* N`=  
for(int i=0;i<nStartPos.length;i++) )3F}IgD  
fileSplitterFetch.splitterStop(); h1'm[Y  
nF-l4=  
(;Bh7Ft  
} S!-t{Q+j^  
} 87pu\(,'  
//负责部分文件的抓取 4[Ko|  
**FileSplitterFetch.java {#=o4~u%;H  
*/ (R s;+S  
package NetFox; a'q&[08  
t%y i3  
s4Jy96<  
import java.io.*; 6d5q<C_3t  
import java.net.*; ^Ux.s Q  
zl, Vj%d  
ra ,.vJuT  
public class FileSplitterFetch extends Thread { B&(/,.  
eiA$) rzy  
B<|Vm.D  
String sURL; //File URL 2L.6!THG  
long nStartPos; //File Snippet Start Position ocS}4.a@  
long nEndPos; //File Snippet End Position Dl?:Mh  
int nThreadID; //Thread's ID 1n)YCSA  
boolean bDownOver = false; //Downing is over ?>R(;B|ER  
boolean bStop = false; //Stop identical )*}?EI4.  
FileAccessI fileAccessI = null; //File Access interface Dz$dJF1 8  
&?j\=%  
p`"Ic2xPJ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qus%?B{b}  
{ 1Si$Q  
this.sURL = sURL; P#:nXc$  
this.nStartPos = nStart; 9+Wf*:*EW  
this.nEndPos = nEnd; Tj2pEOu  
nThreadID = id; 5o^\jTEl^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z0 c|;  
} %4wHiCOg  
PmE 8O  
R<r,&X?m  
public void run() O^~nf%  
{ I 'ha=PeVn  
while(nStartPos < nEndPos && !bStop) S2 -J1 x2N  
{ TD/ 4lL~(x  
b. :2x4  
gP!k[E ,Q8  
try{ `Gg,oCQg  
URL url = new URL(sURL); a3[,3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]~pM;6Pu0  
httpConnection.setRequestProperty("User-Agent","NetFox"); %mS>v|  
String sProperty = "bytes="+nStartPos+"-"; Sq`Zuu9t  
httpConnection.setRequestProperty("RANGE",sProperty); K7,Sr1O `  
Utility.log(sProperty); OP``+z>  
GCrsf  
(Kw%fJT  
InputStream input = httpConnection.getInputStream(); +WCV"m  
//logResponseHead(httpConnection); =Nz;R2{@  
Xk:_aJ  
z|<?=c2P  
byte[] b = new byte[1024]; %y+v0.aWH+  
int nRead; Rf!$n7& \  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Tog'3k9Uw  
{ p3IhK>  
nStartPos += fileAccessI.write(b,0,nRead); IRsyy\[kp8  
//if(nThreadID == 1) dFk$rr>q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^HWa owy=  
} nKch:g  
^aqBL  
F ^)( 7}ph  
Utility.log("Thread " + nThreadID + " is over!"); Vo(bro4ZQi  
bDownOver = true; G4EuW *~  
//nPos = fileAccessI.write (b,0,nRead); i@ehD@.dH  
} LKM;T-  
catch(Exception e){e.printStackTrace ();} fHgvh&FU  
} \ Ju7.3.  
} C:vVFU|4  
' $"RQ=  
3oApazH*  
//打印回应的头信息 5?>ES*  
public void logResponseHead(HttpURLConnection con) K#x|/b'5d  
{ % 3<7HY]~  
for(int i=1;;i++) m :2A[H+  
{ cJ'OqV F  
String header=con.getHeaderFieldKey(i); I(qFIV+H R  
if(header!=null) R-Gg= l5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ugs9>`fF&  
Utility.log(header+" : "+con.getHeaderField(header)); mv#*%St5  
else +-Z `v  
break; d*LW32B@  
} =F46v{la  
} ` c"  
Ed1y%mR>  
6P0 2=  
public void splitterStop() FlT5R*m  
{ wB"`lY   
bStop = true; bg^ <e}{<H  
} !d1a9los  
5Rae?* XH  
!9_'_8  
} `r&]Ydu:  
h*\u0yD)  
>LW}N!IBy  
/* L fZF  
**FileAccess.java C40o_1g  
*//文件访问(定位,写) ]&X}C{v)G  
package NetFox; ">vi=Tr  
import java.io.*; ur[^/lxx0  
FzG>iC}  
-[[( Zx  
public class FileAccessI implements Serializable{ M<P8u`)>4H  
!i\ gCLg2_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y;k iU  
RandomAccessFile oSavedFile; xcH&B %;f  
long nPos; I5ZM U  
mB"1QtD  
6!wk5#  
public FileAccessI() throws IOException 664D5f#EJ  
{ w YQEm  
this("",0); $CZ'[`+  
} ?@;#|^k9  
%Rk DR  
ygQe'S{!S\  
public FileAccessI(String sName,long nPos) throws IOException `UT UrM  
{ 5<YL^m{/L  
oSavedFile = new RandomAccessFile(sName,"rw"); n/S+0uT  
this.nPos = nPos; "<LWz&e^^  
oSavedFile.seek(nPos); gyuBmY  
} /@I`V?Q!a  
JX{_,2*$  
"uFwsjz&B  
public synchronized int write(byte[] b,int nStart,int nLen) ',/2J0_  
{ lSc=c-iOv  
int n = -1; iUk#hLLC  
try{ tHK>w%|\R  
oSavedFile.write(b,nStart,nLen); zjOOEvi  
n = nLen; B<0Kl.V  
} Y=5P=wE  
catch(IOException e) [v\m)5  
{ h J0U-m  
e.printStackTrace (); ?wFL\C  
} "lSh 4X  
` 46z D ?  
T"<)B^8f  
return n; 'b y+hXk  
} @0d"^  
dCe LW  
3#Bb4\_v  
} 8:> V'j  
eze%RjO}  
gd*2*o$g(  
/* eTuKu(0 E  
**SiteInfoBean.java fP\q?X@]E  
*/ ,Vw>3|C  
package NetFox; w ?*eBLJ(G  
ZvMU3])u  
N$x&k$w R  
public class SiteInfoBean { EC 1|$Co  
)Yv=:+f  
?^W1WEBm  
private String sSiteURL; //Site's URL &{UqGD#1&  
private String sFilePath; //Saved File's Path B(ktIy  
private String sFileName; //Saved File's Name *UJ4\  
private int nSplitter; //Count of Splited Downloading File tRZ4\Bu  
G]4Ca5;Z!N  
Qd{8.lB~LQ  
public SiteInfoBean() b $J S|  
{//nSplitter的缺省值为5 ]Yw$A  
//default value of nSplitter is 5 gdA2u;q  
this("","","",5); x~vNUyEN)  
} ],k~t5+  
O9ps?{g  
JO+tY[q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }ML2-k  
{ E6Z kO/  
sSiteURL= sURL; =$fz</S=J  
sFilePath = sPath;  ]%FAJ\  
sFileName = sName; gXJBb+P   
this.nSplitter = nSpiltter; N+@ Ff3M  
owQ,op #  
3 h d30o  
} ?5J#  
^9:`D@Z+  
.<F46?HS  
public String getSSiteURL() bXOKC  
{ O ~6%Iz`  
return sSiteURL; UaF~[toX  
} OtmDZ.t;`  
 d]`6N  
|w}j!}u  
public void setSSiteURL(String value) CV.|~K0O  
{ ws+'*7  
sSiteURL = value; 2&>t,;v@  
} d#a/J.Z$A  
N=KtW?C  
7I XWv-  
public String getSFilePath() zMFTkDY  
{ jDpA>{O[  
return sFilePath; H3<tsK=:  
} uR5+")r@S  
R ~kO5jpW  
( .cA'f?h  
public void setSFilePath(String value) :J]'c}  
{ jRU: un4  
sFilePath = value; w\o6G7  
} $t):r@L  
AX8~w(sv  
p%>sc  
public String getSFileName() fq6Obh=A#  
{ 6r<a  
return sFileName; 5 ix*wu`,  
} U 5J _Y  
<v|"eq}  
eV|N@  
public void setSFileName(String value) k773h`;  
{ 'NhQBk  
sFileName = value; I"88O4\@  
} FT- .gi0  
ey DV911  
=# Sw.N  
public int getNSplitter() z_ $c_J  
{ UJI2L-;Ul  
return nSplitter; E{u6<B*  
} LUMbRrD-  
O D}RnKL  
q>2bkcGY#  
public void setNSplitter(int nCount) uGMzU&+  
{ \dtiv&x  
nSplitter = nCount; u]IbTJ'  
} \N*([{X  
} wc;n= %  
3 }fOb  
.d1ff] ;  
/* (4+P7Z,Nc  
**Utility.java ,I jZQ53q~  
*/ $9,&BW_*  
package NetFox; M,]|L ch  
10FiA;  
]$@a.#}  
public class Utility { =b%}x >>  
6eV#x%z@v'  
2 |je{  
public Utility() AEyvljv  
{ XDemdMy$  
8F}drK9>F  
YZg#H) w%  
} |sZqqgZ-  
~5N}P>4 *  
//线程睡眠 l{k_;i!D  
public static void sleep(int nSecond) Y$=jAN  
{ D<SC `  
try{ =u<:'\_  
Thread.sleep(nSecond); p~$cwbQ!  
} DzAZv/h76  
catch(Exception e) 4@ PA+(kvS  
{ yH/A9L,Z  
e.printStackTrace (); yajdRU  
} RxP H[7oZ  
} -'&/7e6>y  
%j7b0pb  
//日志 <Y]LY_(  
public static void log(String sMsg) 3z8i0  
{ X94a  
System.err.println(sMsg); C-&ymJC|  
} w' 7sh5  
<`}P  
/WuYg OI  
public static void log(int sMsg) ~non_pJ  
{  &9y Zfp  
System.err.println(sMsg); I!sT=w8V  
} _'=,c"  
} C96/   
IO%kXF.[  
jeC=s~  
/* 0fsVbC  
**TestMethod.java @5>#<LV=E#  
*/ #<*Vc6pC  
package NetFox; 39X~<\&'  
FdU]!GO- X  
s2<!Zb4  
public class TestMethod { GK@OdurAR  
MEDh  
'cD?0ou`o  
public TestMethod() I|@+O#  
{ ///xx/weblogic60b2_win.exe s3>a  
try{ da$FY7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }3(!kW  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); aO'#!k*R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $L/`nd  
fileFetch.start(); s0SzO,Vi  
} ]VI^ hhf  
catch(Exception e){e.printStackTrace ();} jI-a+LnEm  
^m>4<~/  
98[uRywI  
} Itl8#LpLM  
Ca2r<|uA  
<:S qMf  
public static void main(String[] args) |L2>|4  
{ -&Rv=q>  
new TestMethod(); DH(<{ #u  
} qmrT d G  
} ].d2CJ'  
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