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http断点续传简单实现(java)

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/* G8Du~h!!U  
**SiteFileFetch.java NVRLrJWpp  
*/ XVU2T5s}  
package NetFox; z?35=%~w   
import java.io.*; (y^vqMz  
import java.net.*; Z(Jt~a3o  
n?V+dC=F}  
-lv)tHs<  
public class SiteFileFetch extends Thread { K$d$m <  
1@$Ko5  
fDSv?crv  
SiteInfoBean siteInfoBean = null; //文件信息Bean P9 Z}H(?C  
long[] nStartPos; //开始位置 )2M>3C6>f  
long[] nEndPos; //结束位置 ~y7jCcd`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 = 9 T$Gr  
long nFileLength; //文件长度 64 5z#_}C$  
boolean bFirst = true; //是否第一次取文件 iTaWup  
boolean bStop = false; //停止标志 J[&b`A@.o  
File tmpFile; //文件下载的临时信息 3 h<,  
DataOutputStream output; //输出到文件的输出流 ]kboG%Dl?9  
RD.V'`n"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) jVq(?Gc  
public SiteFileFetch(SiteInfoBean bean) throws IOException l} qE 46EL  
{ PdvqDa8  
siteInfoBean = bean; 4f<$4d^md  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q%f|~Kl-hd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <m'ow  
if(tmpFile.exists ()) Ps<d('=  
{ B/n[m@O  
bFirst = false; V dn&c  
read_nPos(); p'om-  
} +zs4a96[  
else x,'!eCKN  
{ z<5m fAm  
nStartPos = new long[bean.getNSplitter()]; =Qn ;_+Ct  
nEndPos = new long[bean.getNSplitter()]; * oybD=%4  
} Qa.u Mq  
jq!tT%o*B  
4 uQT5  
K^R,Iu/M  
} @$z<i `4  
e>AE8T  
^4o;$u4R  
public void run() R=KQ  
{ PsZ >P|e1  
//获得文件长度 |n] d34E  
//分割文件 'g{9@PkGn  
//实例FileSplitterFetch S<J}[I7V  
//启动FileSplitterFetch线程 y\x+  
//等待子线程返回 Mec5h}^  
try{ [n/hkXa$\  
if(bFirst) .c$316  
{ }-@`9(o`)  
nFileLength = getFileSize(); iya"ky~H  
if(nFileLength == -1) *<!oHEwkN  
{ Y &K;l_  
System.err.println("File Length is not known!"); B2O}1.  
} h*<P$t  
else if(nFileLength == -2) wKsT7c'  
{ ki)#d' }  
System.err.println("File is not access!"); [VWUqlNt>  
} Rx+p.  
else YtWJX kB  
{ x|5k<CiA  
for(int i=0;i<nStartPos.length;i++) /Js7`r=Rx  
{ CH<E,Z C1T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b?'yAXk  
} -xP!"  
for(int i=0;i<nEndPos.length-1;i++) 4f;HQ-Iv  
{ RZCq{|L  
nEndPos = nStartPos[i+1]; Q6r7.pk"SU  
} pn^ d]rou?  
nEndPos[nEndPos.length-1] = nFileLength; G2FXrkU  
} ]H1I,`=@  
} LA)[ip4  
tq|hPd<C  
@i*|s~15  
//启动子线程 7!N2-6GV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lMbAs.!  
for(int i=0;i<nStartPos.length;i++) %Ijj=wW  
{ \0gM o&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #KiRfx4G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }3L@J8:D"  
nStartPos,nEndPos,i); A\.GV1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^) s2$A:L  
fileSplitterFetch.start(); L{`JRu  
} E)fglYWs2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {qa Aq%'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @#-q^}3  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <(-hx+^  
nEndPos = " + nFileLength); /n8B,-Z5s5  
// fileSplitterFetch[nPos.length-1].start(); w/K_B:s  
HC}YY2  
:]1 TGfS  
//等待子线程结束 ziCHjqT  
//int count = 0; ,YMp<C  
//是否结束while循环 aT$9;  
boolean breakWhile = false; _zwUE  
'uxX5k/D@t  
) v,:N.@Q  
while(!bStop) Ck|8qUz-  
{ L;f!.FX#  
write_nPos(); 5kz)5,KjM  
Utility.sleep(500); ,c)uX#1  
breakWhile = true; 2]ape !(  
>cCR2j,r  
VH1d$  
for(int i=0;i<nStartPos.length;i++) =>! Y{: y(  
{ ]]wA[c~G  
if(!fileSplitterFetch.bDownOver) }B.H|*uO  
{ 7?%k7f  
breakWhile = false; v*[.a#1^  
break; oGRhnP'PF+  
} M )2`+/4  
} G-.^O,%  
if(breakWhile) #"5 Dk#@  
break; a qc?pqM  
$+I;oHWI  
^~A>8CQOU  
//count++; n;T7=1_"  
//if(count>4) UZpIcj cL  
// siteStop(); <N9[?g)  
} %&Q$dzgb_  
aWY gR  
_&b4aW9<  
System.err.println("文件下载结束!"); 4sT88lG4n  
} Z7?~S2{c  
catch(Exception e){e.printStackTrace ();} '`uwJ&@  
} wL:flH@  
:65~[$2  
 W0]gLw9*  
//获得文件长度 5qP:/*+  
public long getFileSize() ZXuv CI  
{ %GS(:]{n  
int nFileLength = -1; XUlS\CH@{  
try{ Uh):b%bS;J  
URL url = new URL(siteInfoBean.getSSiteURL()); fk x \=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a,WICv0E  
httpConnection.setRequestProperty("User-Agent","NetFox"); L');!/:  
KW^7H  
y;o^- O  
int responseCode=httpConnection.getResponseCode(); BjzPz  
if(responseCode>=400) .ODR]7{  
{ q*7VqB  
processErrorCode(responseCode); vsl]92xI  
return -2; //-2 represent access is error x" L20}  
} :FTMmW,>'  
e F3,2DD C  
{ >)#HD  
String sHeader; _<OSqE  
vG"=h%  
uD @#  
for(int i=1;;i++) z\%Ls   
{ `.Qi?* ^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9uA>N  
//Utility.log(in.readLine()); VQS~\:1  
sHeader=httpConnection.getHeaderFieldKey(i); ~15N7=wCM  
if(sHeader!=null) z3;*Em8Ir  
{ # a8B/-  
if(sHeader.equals("Content-Length"))  VN\W]jT  
{ @-!}BUs?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); suzZdkMA  
break; DuHu\>f<S  
} %YC_Se7  
} 1BpiV-]=  
else [CXrSST")E  
break; ?3.b{Cq{-  
} /VN f{p  
} ]33>m|?@  
catch(IOException e){e.printStackTrace ();} ^>hWy D  
catch(Exception e){e.printStackTrace ();} lUvpszH=  
)j0TeE1R  
TO?R({yx*  
Utility.log(nFileLength); 7OJ'){R$  
Gf<'WQ[  
ikv Wh<=>H  
return nFileLength; r 0iK  
} l)&X$3?tz  
esMX-.8Cx  
ap+JQ@b  
//保存下载信息(文件指针位置) s pp f  
private void write_nPos() ~2QR{; XQ  
{ }%_ b$  
try{ \}"$ ?d'f  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~U@;gLoD  
output.writeInt(nStartPos.length); n4R(.N00  
for(int i=0;i<nStartPos.length;i++) io-![^{  
{ LH8 fBhw  
// output.writeLong(nPos); J2xw) +  
output.writeLong(fileSplitterFetch.nStartPos); ~ijVmWNk  
output.writeLong(fileSplitterFetch.nEndPos); B=^)Ub5'  
} ov_j4 j>6P  
output.close(); [8=vv7wS  
} ?-dX`n  
catch(IOException e){e.printStackTrace ();} 6&!PmKFO.  
catch(Exception e){e.printStackTrace ();} <?riU\-]y  
} = 's(|  
F.=2u"[*&  
G?;e-OhV  
//读取保存的下载信息(文件指针位置) f-`)^5E  
private void read_nPos() yEhTNBa*h{  
{ :<bB?N(  
try{ #0P$M!%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4O)1uF;  
int nCount = input.readInt(); v{ 0=  
nStartPos = new long[nCount]; 0dGAP  
nEndPos = new long[nCount]; e'~J,(fB  
for(int i=0;i<nStartPos.length;i++) P'Ux%Q+B>  
{ UJ CYs`y  
nStartPos = input.readLong(); (2^gVz=j  
nEndPos = input.readLong(); 2[O&NdP\Zk  
} ~l]ve,W[  
input.close(); {pnS  Q  
} , P70J b  
catch(IOException e){e.printStackTrace ();} jw^<IMAG\8  
catch(Exception e){e.printStackTrace ();} hp5|@  
} 2Q/4bJpd  
mUdOX7$c>  
QSszn`e  
private void processErrorCode(int nErrorCode) pgQV/6  
{ 4GY[7^  
System.err.println("Error Code : " + nErrorCode); ]pNvxXbeW  
} 1+jAz`nA:T  
 ]<cK";  
w1OI4C)~  
//停止文件下载 O$&mFL[`  
public void siteStop() ,}EC F>  
{ CsoiyY -2  
bStop = true; i*Sqda $  
for(int i=0;i<nStartPos.length;i++) FtfKe"qw  
fileSplitterFetch.splitterStop(); -xEXN[\S  
%t" CX5 n  
UQC=g  
} Vr^n1sgE}r  
} kT"Kyd  
//负责部分文件的抓取 +'I+o5*  
**FileSplitterFetch.java B&[M7i  
*/ W;'!gpa  
package NetFox; VcSVu  
2\jPv`Ia  
LWz&YF#T-  
import java.io.*; YkniiB[/  
import java.net.*; w35J.zn  
]+XYEv  
Z{ X|6.  
public class FileSplitterFetch extends Thread { ?fUlgQ }N  
r^3acXl  
-EkWs/'h  
String sURL; //File URL G MX?  
long nStartPos; //File Snippet Start Position $c:ynjL|P-  
long nEndPos; //File Snippet End Position Vzdh8)Mu\  
int nThreadID; //Thread's ID W&& ;:Fr  
boolean bDownOver = false; //Downing is over vd 0ljA  
boolean bStop = false; //Stop identical HkUWehVm  
FileAccessI fileAccessI = null; //File Access interface pgI^4h  
q_g+Jf P-D  
)4gJd? 8R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6@{(;~r  
{ VEqS;~[  
this.sURL = sURL; }L+L"l&  
this.nStartPos = nStart; %,6#2X nX%  
this.nEndPos = nEnd; Sa?ksD2IaB  
nThreadID = id; TDFkxB>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #LL?IRH9^  
} zF8dKFE~  
:Q $K<)[  
q Gw -tPD<  
public void run() g X ]-\  
{ njScz"L~  
while(nStartPos < nEndPos && !bStop) +eyc`J  
{ s:/8[(A  
4'`{H@]tb  
 \N!AXD  
try{ U(Nu%  
URL url = new URL(sURL); % NA9{<I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fPn>v)lN{  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5NS[dQG5  
String sProperty = "bytes="+nStartPos+"-"; %r%Mlj:#  
httpConnection.setRequestProperty("RANGE",sProperty); KxYwJ  
Utility.log(sProperty); Rs-]N1V  
 86 W9rR  
F)&@P-9+  
InputStream input = httpConnection.getInputStream(); aY'C%^h]  
//logResponseHead(httpConnection); x(etb<!jd  
#{?PbBE}  
P9^-6;'Y  
byte[] b = new byte[1024]; >/kc dWl  
int nRead; uxtWybv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q[vJqkgT  
{ wRcAX%n&  
nStartPos += fileAccessI.write(b,0,nRead); Kw efs;<E?  
//if(nThreadID == 1) \Xm,OE_v"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &]e'KdXF  
} s2'yY(u/  
TUV&vz{  
,SynnE68  
Utility.log("Thread " + nThreadID + " is over!"); Szq/hv=Q  
bDownOver = true; < Z{HX[y  
//nPos = fileAccessI.write (b,0,nRead); L;VoJf  
} Cjqklb/  
catch(Exception e){e.printStackTrace ();} iop2L51eJ  
} C([phT;  
} Vr6@> @SC  
S1p;nK  
*.sVr7=j  
//打印回应的头信息 v0-cd  
public void logResponseHead(HttpURLConnection con) 42e|LUZg  
{ S M0~fAtE  
for(int i=1;;i++) tZ=E')!\  
{ C${Vg{g7a  
String header=con.getHeaderFieldKey(i); {QcLu"?c  
if(header!=null) gVq;m>\|F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4L ;% h  
Utility.log(header+" : "+con.getHeaderField(header)); WHsgjvh"  
else  tBq nf v  
break; pm*xb]8y  
} k9:{9wW  
} y.e^hRKb  
o<<xY<  
1rv)&tKs  
public void splitterStop() ])|d"[ur=  
{ %_+2@\  
bStop = true; M9V q -U18  
} rR9|6l 3  
mef<=5t  
[5zx17'  
} Izhee%c  
,sA[)wP{  
G;v8$)Zj  
/* #33fGmd[  
**FileAccess.java r"``QmM  
*//文件访问(定位,写) %X4xv_o`f  
package NetFox; WF1px%  
import java.io.*; 8P^I TL z%  
c(:f\Wc3Z  
U*( izD  
public class FileAccessI implements Serializable{ &u /Nf&A  
[s"O mAy4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4{hps.$?~  
RandomAccessFile oSavedFile; X%Z{K-  
long nPos; @y='^DQ*  
9:ze{ c $  
LQtj~c>X-|  
public FileAccessI() throws IOException |zQ4u  
{ P;P%n  
this("",0); g .onTFwN  
} lJu;O/  
J?RabYd ~  
eoai(&o0$  
public FileAccessI(String sName,long nPos) throws IOException W=#:.Xj[  
{ !n* +(lZ  
oSavedFile = new RandomAccessFile(sName,"rw"); 9Wnn'T@Tl  
this.nPos = nPos; +?u~APjNN  
oSavedFile.seek(nPos); q#vQv 5  
} ]bj&bk#  
.q `Hjmg<  
Xe<sJ. &Wf  
public synchronized int write(byte[] b,int nStart,int nLen) ]$Yvj!K*Q  
{ Fs{x(_LOr  
int n = -1; q;<h[b?  
try{ ~aMlr6;  
oSavedFile.write(b,nStart,nLen); ^cczJOxB  
n = nLen; \ ^ZlG.  
} P%{^i]  
catch(IOException e) 1QLbf*zeIW  
{ |+iws8xK?  
e.printStackTrace (); txiP!+3OWB  
} 5&v~i\Q  
LXbP 2  
^Wc@oa`  
return n; 0Uo\wyd  
} FrTi+& <  
AWP"b?^G|  
]|MEx{BG-  
} .Xce9C0SW  
( M7pT  
1#.>a$>  
/* Z @^9PQG$  
**SiteInfoBean.java J3n-`k8  
*/ Tav*+  
package NetFox; ?YZ- P{rTS  
``ou/Z  
JBJhG<J  
public class SiteInfoBean {  _59huC.  
g=QDu7Ux  
 c|M6 <}  
private String sSiteURL; //Site's URL -amBB7g  
private String sFilePath; //Saved File's Path Zrvz;p@~  
private String sFileName; //Saved File's Name a#>Yh;FA  
private int nSplitter; //Count of Splited Downloading File MC<PM6w  
_(h&7P9  
T(t+ iv  
public SiteInfoBean() A<1hOSCz\  
{//nSplitter的缺省值为5 n}'=yItVL1  
//default value of nSplitter is 5 c17_2 @N  
this("","","",5); _tBTE%sO  
} S<4c r  
 /% M/  
@^T1XX  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _~piZmkG$  
{ 5\e9@1Rc  
sSiteURL= sURL; "tB;^jhRs  
sFilePath = sPath;  OU8Lldt  
sFileName = sName; Wzw7tLY._  
this.nSplitter = nSpiltter; ,QcF|~n  
=K6($|'=  
XzIl`eH  
} j#+!\ft5  
Fxm$9(Y  
1UE6 4Kl:S  
public String getSSiteURL() dYL"h.x  
{ (+B5|_xQu  
return sSiteURL; =>M^02"  
} r7b1-  
5*1D$mxD"  
+R|z{M)*  
public void setSSiteURL(String value) ; mZW{j  
{ !4^C #{$  
sSiteURL = value; m^b Nuo  
} VzY8rI  
K?BOvDW"`  
',:*f8Jk  
public String getSFilePath() `[W[H(AjQ  
{ h"_MA_]~  
return sFilePath; 1(|'WyD  
} 8$0rR55  
\3pc"^W  
/7}It$|nhy  
public void setSFilePath(String value) [[;e)SoA  
{ 6f\Lf?vF  
sFilePath = value; U-R6xxPZ  
} `QyO`y=?[Y  
{&\jW!&n  
=5kY6%E7c  
public String getSFileName() Mz~M3$$9n  
{ Of4^?` ^  
return sFileName; "x3lQ  
} )XYv}U   
fSs4ZXC  
p$PKa.Y3  
public void setSFileName(String value) X)7x<?DAy  
{ 0l-Ef 1  
sFileName = value; {\c(ls{  
} J2 'Nd'  
WJ4li@T7V  
`/EGyN6X  
public int getNSplitter() A^)?Wt%*  
{ 0V'nK V"|  
return nSplitter; Mf&{7%  
} kPF9Z "l  
]%?YZn<{  
G>1eFBh }  
public void setNSplitter(int nCount) F W/W%^  
{ t.`@{R$hoA  
nSplitter = nCount; `bZ/haU}A  
} kw"SwdP5  
} >g+?Oebgw  
Y#u}tE d  
%<an9WMF  
/* }j*KcB_  
**Utility.java r=X}%~_8X  
*/ qoj$]   
package NetFox; S"OR%  
rdJ d#S  
1n:8s'\  
public class Utility { ?<(m 5Al7  
[^U#Qj)hL  
d5D$&5Ec  
public Utility() n&-qaoNl  
{ ?34 e-  
iVy7elT;R  
V`bi&1?6\  
} 5A sP5  
,!7 H]4Qx  
//线程睡眠 `"&d a#N]  
public static void sleep(int nSecond) h $L/<3oP6  
{ ;uw Ryd  
try{ ]cGA~d  
Thread.sleep(nSecond); A7%:05  
} t4-pM1]1_  
catch(Exception e) XVv K2(  
{ k;w- E  
e.printStackTrace (); .)<(Oj|4  
} rz@=pR :  
} -lhLA`6_R  
WC.t_"@  
//日志 kX>f^U{j  
public static void log(String sMsg) Y0_),OaY  
{ )FpZPdN+h  
System.err.println(sMsg); q.2ykL  
} 3>R#zJf  
%=/)  
~Uxsn@nLr  
public static void log(int sMsg) uoXAQ6k  
{ L7V G`h;  
System.err.println(sMsg); \>7^f 3m  
} {|1Y:&M?   
} .8y3O]  
F@<CsgKB-  
ad:&$  
/* 49w=XJ  
**TestMethod.java Ee3hG2d`  
*/ op6CA"w  
package NetFox; 1. rj'  
L (khAmm  
l PK +$f$  
public class TestMethod { ,=|ZB4HA  
+ j W1V}h  
,B0_MDA +  
public TestMethod() iv>SsW'p_  
{ ///xx/weblogic60b2_win.exe il \$@Bn  
try{ \'CDRr"uw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2EfF=Fm>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Oh'Y0_oB>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); AKRTBjG"  
fileFetch.start(); e(I =^#u6  
} hrhb!0  
catch(Exception e){e.printStackTrace ();} Xt#4/>dlR  
&9"-`-[e:  
}b0; 0j  
} <_XWWT%  
8`fjF/  
4qYUoCR&  
public static void main(String[] args) I;Bjfv5  
{ UGuxV+Nwf  
new TestMethod(); x >^Si/t  
} QCX8IIHG  
} cdG |m[  
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