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http断点续传简单实现(java)

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/* 8z\v|-%Z  
**SiteFileFetch.java kGbtZ} W  
*/ 8nn%wps  
package NetFox; B;f\H,/59  
import java.io.*; lt 74`9,f  
import java.net.*; R zG7Xr=t  
\[</|]'[  
LJ7Qwh_",  
public class SiteFileFetch extends Thread { QR4!r@*=  
Z6@W)QX  
Y] Q=kI  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~RdJP'YF-  
long[] nStartPos; //开始位置 R:49Gn:F  
long[] nEndPos; //结束位置 `uL^!-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [|{2&830  
long nFileLength; //文件长度 $kPC"!X\  
boolean bFirst = true; //是否第一次取文件 n^Co  
boolean bStop = false; //停止标志 YCJcDab  
File tmpFile; //文件下载的临时信息 #gjhs"$~  
DataOutputStream output; //输出到文件的输出流 nff X  
Jv*[@ -.k  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) C>\0 "}iD  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,S.<qmf  
{ @2H"8KX  
siteInfoBean = bean; WDznhMo  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K/)*P4C-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fZM)>  
if(tmpFile.exists ()) -"m4 A0  
{ ]&l.-0jt  
bFirst = false; ')]K&  
read_nPos(); ?LE\pk R  
} jhs('n,  
else ~loJYq'y  
{ ce3w0UeV  
nStartPos = new long[bean.getNSplitter()]; p6=L}L  
nEndPos = new long[bean.getNSplitter()]; _ U/[n\oC  
} Skm$:`u;  
.Z[Bz7  
#Av6BGM|,  
WO=X*O ne  
} $nX4!X  
RZwjc<T  
6$42 -a%b  
public void run() Dw\)!,,i7U  
{ |g o jb  
//获得文件长度 a;},y|'E  
//分割文件 y^utMH  
//实例FileSplitterFetch Z' cQ< f  
//启动FileSplitterFetch线程 /`d|W$vN  
//等待子线程返回 R4xoc;b  
try{ ;=.i+  
if(bFirst) ?|Q[QP  
{ hN(sz  
nFileLength = getFileSize(); vkFfHzR$  
if(nFileLength == -1) [=Qv?am  
{ SkGh@\  
System.err.println("File Length is not known!"); `gI`Cq4  
} ?`& l Y  
else if(nFileLength == -2) g[Tl#X7F  
{ %O9kq  
System.err.println("File is not access!"); V1aWVLltj  
} \tL 9`RKpg  
else j/I^\Ms  
{ ' KX'{Gy  
for(int i=0;i<nStartPos.length;i++) :g1C,M~  
{ RPb/U8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); gY)NPi}!`  
} f T7Z6$  
for(int i=0;i<nEndPos.length-1;i++) /^#8z(@B  
{ #2N']VP  
nEndPos = nStartPos[i+1]; iw`,\V&  
} -!X,M DO  
nEndPos[nEndPos.length-1] = nFileLength; <IiX_*  
}  C~C}b  
} `5VEGSP]  
mkJC *45  
>U.)?>G/dt  
//启动子线程 +9 Uo<6}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <r[5 S5y  
for(int i=0;i<nStartPos.length;i++) nEtG(^N  
{ wUnz D)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f:/[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I-@A{vvPK  
nStartPos,nEndPos,i); UIhU[f]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3['aK|qk.  
fileSplitterFetch.start(); ]Q?`|a+i  
} V$D+Joj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^h q?E2-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g;N)K3\2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a4zq`n|3U  
nEndPos = " + nFileLength); Zd2B4~V  
// fileSplitterFetch[nPos.length-1].start(); D..dGh.MY  
iL^bf*  
f-w-K)y$ht  
//等待子线程结束 ^jY'Hj.Bs  
//int count = 0; i_ha^mq3  
//是否结束while循环 6qCRM*V  
boolean breakWhile = false; 3^ct;gz  
T d7f  
5PaOa8=2f  
while(!bStop) Z *9Qeu-N:  
{ \Lp|S:u  
write_nPos(); pZpAb+  
Utility.sleep(500); d&!;uzOx  
breakWhile = true; o09)esy  
{FIr|R&  
#84<aM  
for(int i=0;i<nStartPos.length;i++) TLBIM  
{ L7~9u|7a#  
if(!fileSplitterFetch.bDownOver) 17-D\ +}  
{ hJkP_( +J\  
breakWhile = false; byT@O:fL  
break; .3yoDab  
}  b7]MpL  
} nnv&~C  
if(breakWhile) OKXELP  
break; =jz*|e|V  
T#HW{3  
PWch9p0U  
//count++; :A~6Gk92A  
//if(count>4) x] e &G!|  
// siteStop(); TSgfIE|  
} )D_\~n/5  
s{"}!y=]  
B+8lp4V9%  
System.err.println("文件下载结束!"); 'Gr}<B$A3  
} 6~:eO(pK l  
catch(Exception e){e.printStackTrace ();} dX720/R  
} JO|%Vpco  
m %=] j<A  
4#dS.UfI  
//获得文件长度  ZQY]c  
public long getFileSize()  T:~c{S4&  
{ %%7~<=rk  
int nFileLength = -1; | Ns-l (l  
try{ ^ UB*Q  
URL url = new URL(siteInfoBean.getSSiteURL()); Rxl )[\A*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); u3[A~V|0=  
httpConnection.setRequestProperty("User-Agent","NetFox"); h$[tEmD%  
W/*2I3a  
u,<#z0R|;$  
int responseCode=httpConnection.getResponseCode(); /cn=8%!N  
if(responseCode>=400) =nQ"ye  
{ >)g`;iO  
processErrorCode(responseCode); >T*/[{L8;  
return -2; //-2 represent access is error .~#<>  
} oqzx}?0  
VgfA&?4[  
:1Jg;G  
String sHeader; d-%!.,F#W  
R"Q=U}?$  
BMlnzi  
for(int i=1;;i++) 3QL I|VpO  
{ R~40,$e{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -phwzR\(t  
//Utility.log(in.readLine()); b!W!Vvf^x  
sHeader=httpConnection.getHeaderFieldKey(i); HX1RA 5O  
if(sHeader!=null) `<I+(8]Uz  
{ &A=>x  
if(sHeader.equals("Content-Length")) S{cy|QD  
{ x!CCSM;q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %E q} H  
break; g~FA:R  
} &WW|! 6  
} <^j,jX  
else H]@M00C  
break; 8BnI0l=\  
} _tE`W96J  
} n(-1vN  
catch(IOException e){e.printStackTrace ();} N}0-L$@SL  
catch(Exception e){e.printStackTrace ();} D[) Z$+D4f  
2/.E uf   
f?O?2g  
Utility.log(nFileLength); UR')) 1n  
jOs&E^">&B  
DyiyH%SSD  
return nFileLength; c8qsp n  
} cPcp@Dp  
?3ldHWa  
o#V}l^uU=  
//保存下载信息(文件指针位置) Bob K>db  
private void write_nPos() @y,pf Wh`  
{ 3DH} YAUU  
try{ 7MXi_V;p<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZTV|rzE   
output.writeInt(nStartPos.length); }?zy*yL  
for(int i=0;i<nStartPos.length;i++) a6AD`| U8  
{ -LAYj:4  
// output.writeLong(nPos); XW]'by  
output.writeLong(fileSplitterFetch.nStartPos); Vf S&V*un  
output.writeLong(fileSplitterFetch.nEndPos); @ i $jyc  
} @1_M's;  
output.close(); HyKvDJ 3_  
} pWY $aI  
catch(IOException e){e.printStackTrace ();} ,Y|WSKY*  
catch(Exception e){e.printStackTrace ();} wO6 D\#  
} }Gmwm|`*  
sTx23RJ9  
L+s3@ C;b  
//读取保存的下载信息(文件指针位置) BeAkG_uG  
private void read_nPos() 5>{S^i~!  
{ G:'hT=8  
try{ L4bx [  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SJ(<u2J]  
int nCount = input.readInt(); 0[(TrIpXl  
nStartPos = new long[nCount]; @edx]H1~^  
nEndPos = new long[nCount]; EqW/Wxv7b  
for(int i=0;i<nStartPos.length;i++) xY] Y  
{ `acX1YWh5  
nStartPos = input.readLong(); B(+J?0Dj  
nEndPos = input.readLong(); ~\;s}Fv.  
} pY75S5h:  
input.close(); cB,O"-  
} |Tn+Aq7  
catch(IOException e){e.printStackTrace ();} /DxaKZ ;b  
catch(Exception e){e.printStackTrace ();} _ISIq3A?  
} .UJp#/EHs  
QahM)Gb  
QrmiQ]d*p  
private void processErrorCode(int nErrorCode) AUZ^XiK  
{ @3T)J,f  
System.err.println("Error Code : " + nErrorCode); vwA d6Tm  
} tGq0f"}'J  
CKoRq|QG_  
9 b?Nlk8d  
//停止文件下载 9fLxp$`(T  
public void siteStop() Qq,w6ekr  
{ [nL{n bli  
bStop = true; ~!bA<q  
for(int i=0;i<nStartPos.length;i++) s/' ]* n  
fileSplitterFetch.splitterStop(); rd#O ]   
3<c_`BWu  
M$@Donx  
} =t,}I\_^c  
} zh{:zT)(1  
//负责部分文件的抓取 xA?(n!{P  
**FileSplitterFetch.java ZT;8Wvo  
*/ 2h:*lV^  
package NetFox; mpcO-%a  
aJAQ G  
1?!z<<  
import java.io.*; v'fX'/  
import java.net.*; MlbQLtw  
)I/K-zj  
@nPXu2c?u7  
public class FileSplitterFetch extends Thread { B<et&r;  
$0(~ID  
I=vGS  
String sURL; //File URL 71)DLGL  
long nStartPos; //File Snippet Start Position g`NJ `  
long nEndPos; //File Snippet End Position Q^p> hda  
int nThreadID; //Thread's ID i'6>_,\(  
boolean bDownOver = false; //Downing is over }VetaO2*  
boolean bStop = false; //Stop identical [pAW':  
FileAccessI fileAccessI = null; //File Access interface |ORro r}  
5:" zs  
vv 7T/C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dE ,NG)MH  
{ b~5Q|3P9  
this.sURL = sURL; ke~S[bL%-  
this.nStartPos = nStart; Oo-%;l`&  
this.nEndPos = nEnd; &@&0n)VTd  
nThreadID = id; TmH'_t.*T~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7BNu.5*y  
} =~|:93]k  
C VyYV &U,  
*F_ dP  
public void run() 3M@!?=| U  
{ y?r:`n  
while(nStartPos < nEndPos && !bStop) ug?])nO.C  
{ \os iY ^  
mW+QJ`3  
(hb\1 wZ  
try{ FxK2 1  
URL url = new URL(sURL); m h5ozv$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6`V2-zv$  
httpConnection.setRequestProperty("User-Agent","NetFox"); M~o\K'  
String sProperty = "bytes="+nStartPos+"-"; +^@;J?O  
httpConnection.setRequestProperty("RANGE",sProperty); OS.oknzZZ  
Utility.log(sProperty); 3lW7auH4Y{  
&OXnZT3P  
(*XSr Q  
InputStream input = httpConnection.getInputStream(); S1`;2mAf*  
//logResponseHead(httpConnection); Wwf],Ya  
{&qB!axj  
9^AfT>b~f  
byte[] b = new byte[1024]; vz^w %67&  
int nRead; v})-:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 83|7#L  
{ CSBk  
nStartPos += fileAccessI.write(b,0,nRead); doj$chy  
//if(nThreadID == 1) 5PCMxjon  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;O Td<  
} O! t> @%)  
kCuIEv@  
.=u8`,sO  
Utility.log("Thread " + nThreadID + " is over!"); ivi,/~L  
bDownOver = true; o`EL)K{  
//nPos = fileAccessI.write (b,0,nRead); "j]85  
} iW\Q>~0#_  
catch(Exception e){e.printStackTrace ();} FFvF4]|L  
} ]-7$wVQ<  
} /Ayo78Pi  
XXe?@w2{  
Hyj<Fqr!.  
//打印回应的头信息 *w/})Y3^  
public void logResponseHead(HttpURLConnection con) SZ*Nr=X  
{ VD).UdUn  
for(int i=1;;i++) !-OPzfHrI  
{ $vQ#ah/k  
String header=con.getHeaderFieldKey(i); ;n"Nv }<C  
if(header!=null) "'8^OZR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q^_*&},V  
Utility.log(header+" : "+con.getHeaderField(header)); N-~Uu6zr  
else B>!OW2q0D  
break; P*\h)F/3}t  
} "PI]k  
} |;[%ZE"  
6')pM&`t  
:hA=(iz  
public void splitterStop() x KZLXQ'e-  
{ IL\2?(&Z  
bStop = true; ap7ZT7KW  
} 9|}u"jJB%E  
x_yQoae  
Km=dId7]  
} c[h{C!d1  
Q`Z=}^  
!MNnau%O  
/* lebwGW,!  
**FileAccess.java P m Zb!|  
*//文件访问(定位,写) n& j@7R  
package NetFox; eMDO;q  
import java.io.*; |IL/F]I  
I1 Jo8s  
C(Bh<c0@  
public class FileAccessI implements Serializable{ .*3.47O  
f7mN,_Lt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vfn _Nq;  
RandomAccessFile oSavedFile; )e1&[0  
long nPos; tcm?qro)  
,'KS:`m!  
k /hD2tBLu  
public FileAccessI() throws IOException q3CcXYY  
{ 'DDlX3W-  
this("",0); KTQy pv  
} WaaF;| ,(  
fH#*r|~  
{Y\W&Edw%  
public FileAccessI(String sName,long nPos) throws IOException - s}  
{ l[_ y|W5  
oSavedFile = new RandomAccessFile(sName,"rw"); K ]  
this.nPos = nPos; 3t*e|Ih&j5  
oSavedFile.seek(nPos); a (mgz&*  
} 2!7)7wlj0  
Zs$Qo->F  
qir/Sa' [  
public synchronized int write(byte[] b,int nStart,int nLen) V\!6K  
{ ;$\?o  
int n = -1; }u>F}mUa  
try{ %YH+=b:uW  
oSavedFile.write(b,nStart,nLen); )37.H^7  
n = nLen;  wh A  
} f4h|Nn%;  
catch(IOException e) Tx+Bkfj  
{ -$; h+9BO  
e.printStackTrace (); 3Y L  
} qId-v =L  
QO-R>  
LhfI"fc  
return n; 6r x%>\UkS  
} s%{8$> 8V.  
`ZC{<eVJ}=  
ib3 u:  
} w6PKr^  
w[WyT`6h!  
sp/l-a  
/* e13{G @  
**SiteInfoBean.java /^F_~.u{  
*/ sy ]k  
package NetFox; P$ a `8~w  
H(JgqbFB*  
tfSY(cXg'T  
public class SiteInfoBean { R.Plfm06Ue  
iq25|{1$  
7jj.maK  
private String sSiteURL; //Site's URL }k`-n32)|  
private String sFilePath; //Saved File's Path n%SR5+N"  
private String sFileName; //Saved File's Name fku\O<1  
private int nSplitter; //Count of Splited Downloading File wc&`/'<p  
'V*ixK8R0  
p}b:(QN~m  
public SiteInfoBean() O!,WH?r  
{//nSplitter的缺省值为5 \o&\r)FX  
//default value of nSplitter is 5 SRUg2)d  
this("","","",5); ?)Psf/  
} k^JV37;bl  
_7)>/YK?}4  
S\,~6]^T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^AI5SjOUx  
{ B8f BX!u/  
sSiteURL= sURL; ^ B>BA  
sFilePath = sPath; :RxWHh3O  
sFileName = sName; YqJ `eLu  
this.nSplitter = nSpiltter; h()Ok9]  
pG|+\k/B  
v$P<:M M  
} EJ%Kr$51K  
kF1Tg KSd  
ZFJ qI  
public String getSSiteURL() L"_l(<g  
{ 3pV^Oe^9  
return sSiteURL; o\#C#NiT  
} jMpV c E#  
>dr34=(  
']x`d  
public void setSSiteURL(String value) VssD  
{ bzl-|+!yB  
sSiteURL = value; {mkD{2)KQ  
} <$V!y dO  
"%mu~&Ga  
w~3~:w$  
public String getSFilePath() e hgUp =  
{ bXx2]E227  
return sFilePath; ,4OH9 -Q1  
} /qKO9M5A  
oZ /z{`  
:c_>(~  
public void setSFilePath(String value) A#&,S4Wi|  
{ )6t=Bel  
sFilePath = value; " iz'x-wy  
} 4U;Zs3  
6AA "JX  
;%wY fq~P  
public String getSFileName() ~8j4IO(  
{ .!B>pp(9  
return sFileName; Y*KP1=Md  
} ~vL`[JiK  
/'ukeK+'  
I?z*.yA*  
public void setSFileName(String value) a%IJ8t+mn  
{ W`d\A3v  
sFileName = value; IHrG!owf  
} Gy3t   
;ATn&  
HgY>M`U  
public int getNSplitter() @ uF$m/g  
{ ZDhl$m [m  
return nSplitter; 4(hHp6}b  
} _'.YC<;  
egd%,`  
`yvH0B -  
public void setNSplitter(int nCount) 0o>l+c  
{ zDD1EycH  
nSplitter = nCount; @j{n V@|  
} in[yrqFb7t  
} mjI $z3  
fPj*qi  
NmH:/xU?^  
/* xV}ybRKV  
**Utility.java [3~mil3rO  
*/ -!s?d5k")  
package NetFox; ^]_5oFRIj  
$.g)%#h:  
kvoEnwBe_  
public class Utility { PAcbC| y  
p?#%G`dm  
Z4ZR]eD  
public Utility() -IP3I  
{ $YPQi.  
8K;wX%_,  
D$vP&7pOr4  
} 8A,="YIt  
7k==?,LG3  
//线程睡眠 .zMM!l3  
public static void sleep(int nSecond) ;'fn{j6C  
{ mKh <M)Bz  
try{ nWzGb2Y  
Thread.sleep(nSecond); M,WC+")Z=  
} |Ox !tvyr  
catch(Exception e) R c.8j,]  
{ =I6u*$9<  
e.printStackTrace (); E{#Y=  
} a=%QckR*  
} L74Sx0nk=  
g 218%i  
//日志 $At,D.mGkb  
public static void log(String sMsg) |TE\]  
{ rf:C B&u  
System.err.println(sMsg); noLb  
} ~p'DPg4  
KJ]ejb$  
h=`1sfz  
public static void log(int sMsg) I8]q~Q<-P  
{ y9@DlK  
System.err.println(sMsg); HbUadPr  
} ,VTX7vaH  
} 1r-#QuV#  
N:yyDeGyW  
(8?5REz  
/* (qky&}H  
**TestMethod.java FhyA_U%/nF  
*/ MY$-D+#/`  
package NetFox; GSh~j-C'  
G"'[dL)N>  
b#2$Pd:(  
public class TestMethod { ?xgrr7  
cYaf QyU  
)b_ GKA `  
public TestMethod() u3XQ<N{Gj  
{ ///xx/weblogic60b2_win.exe ^^m3 11=  
try{ G;CB%qXI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a!?&8$^<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;&9A Yh.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C*f3PB=H_  
fileFetch.start(); w&E*{{otJ  
} ?V>\9?zb  
catch(Exception e){e.printStackTrace ();} a!!>}e>Cj*  
=yZiBJ  
U $ bLt  
} UJX=lh.o  
YhzDi>hob  
1D pRm(  
public static void main(String[] args) t;~H6  
{ ?[ts<Ltp  
new TestMethod(); &d8z`amP  
} @A-^~LoP.  
} NIQX?|;b{  
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