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http断点续传简单实现(java)

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/* nXPl\|pXt  
**SiteFileFetch.java {q f gvu  
*/ @q:v?AO  
package NetFox; ?=,4{(/)  
import java.io.*; I.BsKB  
import java.net.*; {\z&`yD@  
|C}n]{*|  
|& OW_*l  
public class SiteFileFetch extends Thread { 5SPhdpIg@[  
=<Q_&_.60  
7Mq4$|qhD  
SiteInfoBean siteInfoBean = null; //文件信息Bean q)vdDdRe_  
long[] nStartPos; //开始位置 zmd,uhNc:  
long[] nEndPos; //结束位置 )a"rj5~-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .XDY1~w0  
long nFileLength; //文件长度 U$jw8I'.  
boolean bFirst = true; //是否第一次取文件 D#Qfa!=g  
boolean bStop = false; //停止标志 afrU>#+"  
File tmpFile; //文件下载的临时信息 Bu|U z0Y  
DataOutputStream output; //输出到文件的输出流 eD5:0;X2  
,p2BB"^_i  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #yz5CWu  
public SiteFileFetch(SiteInfoBean bean) throws IOException W <.h@Rz+  
{ ZI.;7G@|  
siteInfoBean = bean; ZS&>%G  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ETU.v*HT]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *FhD%><  
if(tmpFile.exists ()) 0kC}qru'  
{ `q =e<$  
bFirst = false; Z3jh-{0  
read_nPos(); GP=i6I6C  
} |m{Q_zAB  
else 8 Z|c!QIU  
{ 4#hDt^N~  
nStartPos = new long[bean.getNSplitter()]; _ nFsC  
nEndPos = new long[bean.getNSplitter()]; \i1>/`F  
} lS1-e0,h1  
$7M/rF;N5X  
~DY5`jV  
d'j8P  
} @;>i3?  
ybnq;0}$  
&"X6s%ZH|  
public void run() fzcPi9+  
{ r*$$82s  
//获得文件长度 xX;@ BS  
//分割文件 P(iZGOKUs=  
//实例FileSplitterFetch CbPCj.MH  
//启动FileSplitterFetch线程 0LI:R'P+P[  
//等待子线程返回 2K >tI9);  
try{ F:$Dz?F0v  
if(bFirst) 'zYKG5A  
{ "V/|RC  
nFileLength = getFileSize(); j5hM |\]  
if(nFileLength == -1) V[E7 mhqy  
{ 6 0C;J!D  
System.err.println("File Length is not known!"); :CH*~o  
} \1` L-lz  
else if(nFileLength == -2) e|Ip7`  
{ "F_o%!l  
System.err.println("File is not access!"); 6@0 wKV!D  
} 1X-KuGaD  
else aJh=4j~.  
{ x0t&hY>P!  
for(int i=0;i<nStartPos.length;i++) [s1Hd~$  
{ >| d^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +a'QHtg  
} D+$k  
for(int i=0;i<nEndPos.length-1;i++) TTNgnP  
{ -KzU''  
nEndPos = nStartPos[i+1]; /cmnX'z  
}  $^&SEz  
nEndPos[nEndPos.length-1] = nFileLength; q\ihye  
} !sF! (u7  
} <9za!.(zu  
OBF3)L]  
}h+_kRQ  
//启动子线程 TWv${m zE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2m`4B_g A  
for(int i=0;i<nStartPos.length;i++) :V)W?~Z7B  
{ i&cH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @(:ah  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _ F0qq j  
nStartPos,nEndPos,i); Dq T)%a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R'E8>ee; ^  
fileSplitterFetch.start(); Y~RZf /`  
} 7V/yU5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7e,<$PH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #xWC(*Ggp  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $Cu/!GA4.>  
nEndPos = " + nFileLength); *q5'~)W<  
// fileSplitterFetch[nPos.length-1].start(); ]mU,y$IQ  
0 O{Y Vk`  
!;Mh5*-  
//等待子线程结束 ETu7G5?  
//int count = 0; o?G^=0T  
//是否结束while循环 +B*8$^,V)  
boolean breakWhile = false; MSEBv Z-  
wu*WA;FnA  
Kuh! b`9  
while(!bStop)  ]Ll <  
{ Q]*YIb~D  
write_nPos(); C,C=W]G  
Utility.sleep(500); DdI7%?hK  
breakWhile = true; !'14mN#A  
V/5hEoDt  
h6*=Fn7C  
for(int i=0;i<nStartPos.length;i++) T[$Sbz`  
{ `1%SXP1  
if(!fileSplitterFetch.bDownOver) v}6YbY Tq  
{ #Id.MLHxA_  
breakWhile = false; &`7~vA&c  
break; ':,6s  
} )k&pp^q\  
} ujcS>XN,1  
if(breakWhile) `92 D]^g  
break; ArkFC  
c%.f|/.k  
9X&Xs/B  
//count++; >/"XX,3  
//if(count>4) H*QN/{|RU  
// siteStop(); ~qNpPIrGr  
} =#XsY,r  
nf< <]iHf  
TJtW?c7  
System.err.println("文件下载结束!"); @S~'m;  
} }iy`Ko+B"b  
catch(Exception e){e.printStackTrace ();} zIbl[[M&  
} /,v:!*  
:,F^{  
Vvx(7p-GQ  
//获得文件长度 $"{V],:T |  
public long getFileSize() ADX}  
{ |Sg *j-.  
int nFileLength = -1; TGLkwXOkT  
try{ a@@!Eg A  
URL url = new URL(siteInfoBean.getSSiteURL()); vg5zsR0u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $52Te3n  
httpConnection.setRequestProperty("User-Agent","NetFox"); RCt)qh+  
@"9y\1u  
T4 SByX9  
int responseCode=httpConnection.getResponseCode(); "xdJ9Z-B  
if(responseCode>=400) xsRMF&8L  
{ 3w )S=4lB  
processErrorCode(responseCode); i:#R U^R  
return -2; //-2 represent access is error ilK8V4k<T)  
} :Puv8[1i  
"sFdrXJ  
Fc}wu W  
String sHeader; I#l9  
%9mCgHQ9  
Kw'Dzz%kN  
for(int i=1;;i++) "!)8bTW  
{ ,|I\{J #C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); We#*.nr{3Z  
//Utility.log(in.readLine()); v%3)wD  
sHeader=httpConnection.getHeaderFieldKey(i); ;lGa.RD[a  
if(sHeader!=null) d$rJW m5H  
{ KHr8\qLH  
if(sHeader.equals("Content-Length")) {(wV>Oc>Jw  
{ $!I$*R&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iy tSC  
break; MbnV5b:X  
} zi>f436-  
} 62EJ# q[  
else [ur/`   
break; mC~W/KReA  
} c%~'[W04\  
} {yyg=AMz  
catch(IOException e){e.printStackTrace ();} C>68$wd>  
catch(Exception e){e.printStackTrace ();} Op3 IL/  
|ry;'[*  
U7crbj;c)d  
Utility.log(nFileLength); any\}   
B_cn[?M  
W&06~dI1!  
return nFileLength; 8Z3+S)6  
} y8+?:=N.  
lRt8{GFy  
4)j<(5  
//保存下载信息(文件指针位置) ]^ O<WD  
private void write_nPos() ZuS+p0H"  
{ 2L<TqC{,-  
try{ ]VJcV.7`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4 d]  
output.writeInt(nStartPos.length); 6%S>~L66  
for(int i=0;i<nStartPos.length;i++) LO"HwN43h  
{ bf;IJ|v^  
// output.writeLong(nPos); A94VSUDA:  
output.writeLong(fileSplitterFetch.nStartPos); .h+<m7  
output.writeLong(fileSplitterFetch.nEndPos); YSrFHVq  
} ObM5vrEk|  
output.close(); }Pb!u9_  
} cjN4U [  
catch(IOException e){e.printStackTrace ();} D'nV &m  
catch(Exception e){e.printStackTrace ();} &I(|aZx?J  
} )%j)*Ymz;  
==FzkRA)  
X_!mZ\H7  
//读取保存的下载信息(文件指针位置) /@#)j( eY/  
private void read_nPos() ]}v`#-Px(  
{ rW\~sTH  
try{ !Rb7q{@>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iBUf1v  
int nCount = input.readInt(); T[Gz  
nStartPos = new long[nCount]; 6  09=o+  
nEndPos = new long[nCount]; }= <!j5:  
for(int i=0;i<nStartPos.length;i++) RTl7vzG  
{ NZlJ_[\$C  
nStartPos = input.readLong(); q',a7Tf:  
nEndPos = input.readLong(); 8%xtb6#7M  
} [2\`Wh:%P  
input.close(); )i!)Tv  
} SbI,9<  
catch(IOException e){e.printStackTrace ();} S?3{G@!  
catch(Exception e){e.printStackTrace ();} k6Tpaf^  
} !m(6/*PAl  
q6G([h7  
2PeI+!7s  
private void processErrorCode(int nErrorCode) h,p&/oU4U  
{ 2!6Kzq  
System.err.println("Error Code : " + nErrorCode); b6/:reH{  
} I(7gmCV  
shn-Es*  
L0_=R;.<  
//停止文件下载 dJ&s/Z/>E  
public void siteStop() >y8Z{ALQ5  
{ 3o^V$N.  
bStop = true; 57MoO  
for(int i=0;i<nStartPos.length;i++) \U-5&,fP  
fileSplitterFetch.splitterStop(); 7I44BC*R~  
E Fv+[  
eqf~5/Z  
} /gdo~  
} $OhL 95}7  
//负责部分文件的抓取 eD(a +El}  
**FileSplitterFetch.java T]zjJwa  
*/ g1{wxBFE  
package NetFox; 9E#(iP  
oaXD^ H\  
+es6c')  
import java.io.*; %4-pw|':  
import java.net.*; hBqu,A  
U&/S  
>S3 >b  
public class FileSplitterFetch extends Thread { <A&R%5Vs  
*oWzH_  
=N0cz%  
String sURL; //File URL =~S   
long nStartPos; //File Snippet Start Position o{Ep/O`  
long nEndPos; //File Snippet End Position uJ y@  
int nThreadID; //Thread's ID vVf!XZF  
boolean bDownOver = false; //Downing is over )/pPY  
boolean bStop = false; //Stop identical 5(|ud)v  
FileAccessI fileAccessI = null; //File Access interface HWU{521  
ZT8j9zs  
Oxvw`a#  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A&7jE:Ew  
{ `&6]P:_qp  
this.sURL = sURL; puyL(ohem  
this.nStartPos = nStart; j w462h  
this.nEndPos = nEnd; >k#aB.6  
nThreadID = id; {2Ibd i  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;5l|-&{@*  
} [eN{Ft0x  
,5?MRqCM  
W!^=)Qs  
public void run() w#$k$T)  
{ J|q_&MX/  
while(nStartPos < nEndPos && !bStop) mNY z7N  
{ _L72Ae(_  
xd.C&Dx5  
?(=B=a[  
try{ $ g^;*>yr  
URL url = new URL(sURL); )5v .9N 6v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cA\W|A)  
httpConnection.setRequestProperty("User-Agent","NetFox"); K!~ ](_W!  
String sProperty = "bytes="+nStartPos+"-"; <>oW f  
httpConnection.setRequestProperty("RANGE",sProperty); iau&k `b`  
Utility.log(sProperty); R}Y=!qjYE=  
:F\f}G3  
E;Hjw0M'k  
InputStream input = httpConnection.getInputStream(); {cI<4><  
//logResponseHead(httpConnection); J)-> 7h =  
A~>=l=  
y_&XF>k91  
byte[] b = new byte[1024]; X9j+$X \j  
int nRead; =R"tnjR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N-|Jj?c  
{ bW|y -GM  
nStartPos += fileAccessI.write(b,0,nRead); O5?Eb  
//if(nThreadID == 1) yB1>83!q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u2Obb`p S  
} ?rDwYG(u]@  
a40BisrD~6  
xL"% 2nf  
Utility.log("Thread " + nThreadID + " is over!"); F)w83[5_d  
bDownOver = true; 8IH gsW";  
//nPos = fileAccessI.write (b,0,nRead); I2T2'_I  
} k#&SWp=  
catch(Exception e){e.printStackTrace ();} .#J3UZ  
} co80M;4  
} : \OvVS/  
~dLZ[6Z  
nSiNSLv  
//打印回应的头信息 H%N+V r3O,  
public void logResponseHead(HttpURLConnection con) xTZ5q*Hqx  
{ uSJP"Lw  
for(int i=1;;i++) pAuwSn#i  
{ 5XHkRcESZ  
String header=con.getHeaderFieldKey(i); {LDb*'5Cy  
if(header!=null) k]iS3+nD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~=ktFuEa  
Utility.log(header+" : "+con.getHeaderField(header)); bYc qscW  
else HWBom8u0  
break; 5aNDW'z`f  
} lg+g:o  
} Sq,ty{j2%  
Qg!*=<b  
zY+Et.lg]^  
public void splitterStop() 3(&F.&C$$  
{ EYG E#C; d  
bStop = true; #^ #i]{g  
} Zto E= 7K  
du,-]fF  
y9hZ2iT  
} w#,v n8  
R-fjxM*  
f4_G[?9,  
/* '=.Uz3D'0  
**FileAccess.java JUFO.m^w  
*//文件访问(定位,写) Q8oo5vqQ#C  
package NetFox; |plo65  
import java.io.*; *Mc\7D  
:t^})%  
C>dJ:.K%H  
public class FileAccessI implements Serializable{ iGk{8Da<  
{B.]w9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q?4uH;h:^G  
RandomAccessFile oSavedFile; A5ID I<a  
long nPos; Uc0'XPo3I  
MlE~ gCD  
h';v'"DoW`  
public FileAccessI() throws IOException e&4u^'+K  
{ CD[=z)<z{  
this("",0); G\ZRNb  
} :q<%wLs  
m4>o E|\  
h_yR$H&tX  
public FileAccessI(String sName,long nPos) throws IOException &X,)+ b=  
{ %iC63)(M  
oSavedFile = new RandomAccessFile(sName,"rw"); y03a\K5[KQ  
this.nPos = nPos; O Zm[i H  
oSavedFile.seek(nPos); MToQ8qKs  
} .G~5F- 8'  
'LLx$y.Ei[  
#%"TU,[+  
public synchronized int write(byte[] b,int nStart,int nLen) UO<claV  
{ R7c)C8/~  
int n = -1; *AR<DXE L  
try{ Ki6.'#%7  
oSavedFile.write(b,nStart,nLen); NV4W2thYo  
n = nLen; >%dAqYi $  
} i bs "Iv34  
catch(IOException e) }zxh:"#K  
{ O>5u5n  
e.printStackTrace (); NOp=/  
} 6G$tYfX  
xH#a|iT?(  
RyWOiQk;  
return n; Yj/nzTVJ[  
} !DL53DQ#  
nY-9 1q?Y  
'OW"*b  
} p!QneeA`&X  
 m+{: ^  
U2lC !j%K  
/* @M^Qh Hs  
**SiteInfoBean.java PVc|y.  
*/ YPDsE&,J)  
package NetFox; 7d8qs%nA  
T)tHN#6I  
pbxcsA\  
public class SiteInfoBean { Lj-&TO}OZ  
aq/Y}s?  
@<yc .>  
private String sSiteURL; //Site's URL :wmf{c  
private String sFilePath; //Saved File's Path 6ilC#yyp  
private String sFileName; //Saved File's Name ]J=)pD rk  
private int nSplitter; //Count of Splited Downloading File /1#Q=T  
xWe1F2nY  
vP)~j1  
public SiteInfoBean() E(kb!Rz  
{//nSplitter的缺省值为5 p<fgUVR  
//default value of nSplitter is 5 wK`ieHmp  
this("","","",5); xYVjUb(,X  
} D4]B>  
4U;XqUY /  
Q <-%jBP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 64rk^Um  
{ $RNUr \9A  
sSiteURL= sURL; a{Hb7&  
sFilePath = sPath; IetGg{h.  
sFileName = sName; VD&3%G!  
this.nSplitter = nSpiltter; ?[1qC=[Z<  
15T[J%7f  
9AddF*B  
} J}_Dpb[L  
,3- -ERf  
,!%R5*?=D  
public String getSSiteURL() 8Y~=\(5>  
{ Cm<j*Cnl  
return sSiteURL; S}Y|s]6  
} {r2|fgi  
zpr@!76  
C9Z\G 3  
public void setSSiteURL(String value) %x8`fm  
{ <eFAI}=s  
sSiteURL = value; J[Yg]6  
} CC(*zrOd-  
S{(p<%)[  
q(tG bhQ  
public String getSFilePath() P(gVF |J?  
{ ?(ls<&s{w  
return sFilePath; 8u5 'g1M  
} ,\9mAt1O  
u}LX,B-n(  
m5em<P!G  
public void setSFilePath(String value) dGD^op,6g  
{ DEQE7.]3q  
sFilePath = value; CL'Xip')T  
} x gT~b9  
hn\Q6f+  
K _+;"G  
public String getSFileName() oSA*~N:  
{ b801O F  
return sFileName; LUDJPIk  
} |~b R.IA  
DMcxa.Sd!  
Ag4Ga?&8ec  
public void setSFileName(String value) -6~y$c&c  
{ 1.95 ^8  
sFileName = value; eBC%2TF  
} ZecvjbnVY  
,WB_C\.#XN  
Z-h7  
public int getNSplitter() +5t bK  
{ 7Cd_zZ  
return nSplitter; X:``{!~geo  
} u|OzW}xb7j  
G>w?9:V}  
^2C /!Y<  
public void setNSplitter(int nCount) :EmQ_?(^  
{ KW|\)83$  
nSplitter = nCount; 2Jo~m_  
} ig2 +XR#%  
} ImV]}M~_  
ey\m)6A$  
E R]sDV  
/* BF@5&>E  
**Utility.java {s8U7rmML  
*/ << ;HY}s  
package NetFox; (e8G (  
]Q4PbW  
WfDX"rA  
public class Utility { M,t*nG  
C3\E.u ?  
"7yNKO;W  
public Utility() &`yOIX-H_  
{ Gh2Q$w:  
@ <OO  
5Z9~ &U  
} Z<ajET`)  
<wt$Gglk  
//线程睡眠 'cAc{\)  
public static void sleep(int nSecond) .;HIEj zq  
{ J}(6>iuQY?  
try{ ;;?vgrz  
Thread.sleep(nSecond); ```d:f  
} 1X::0;3  
catch(Exception e) 7k] RO  
{ l 70,Jo?78  
e.printStackTrace (); jWXR__>.  
} %0yS98']g  
}  k6O. H  
I%9bPQ  
//日志 3T|Y}  
public static void log(String sMsg) Ts(t:^  
{ j1puB  
System.err.println(sMsg); -Aa]aDAz68  
} WDE e$k4.  
!.3R~0b  
% Cu.u)/+  
public static void log(int sMsg) WGh. ;-  
{ wy{\/?~c  
System.err.println(sMsg); (A29Z H  
} -!J2x 8Ri  
} W}XYmF*_?  
`l>93A  
gwSN>oj &  
/* /Fv/oY  
**TestMethod.java 0%s3Mp6H  
*/ L`UG=7r q  
package NetFox; Q PFeBl  
<t{?7_ 8  
s) Cpi  
public class TestMethod { JBR[; zM  
!TP6=ks  
ohrw\<xsu  
public TestMethod() g4:VR:o  
{ ///xx/weblogic60b2_win.exe %5JW< 9  
try{  9<|m4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a`H\-G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); FUaI2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +7Yu^&  
fileFetch.start(); hCzjC|EO~  
} #(%t*"IY;  
catch(Exception e){e.printStackTrace ();} )n7|?@5U  
|l|_dn  
[J0*+C9P*  
} ^ <qrM  
CQdBf3q  
tTotPPZf}  
public static void main(String[] args) YP[LQ>  
{ 'nRp}s1^[  
new TestMethod(); NJ ZXs_%>$  
} n6b3E *  
} 6*ZU}xT  
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