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http断点续传简单实现(java)

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/* kjVJ!R\  
**SiteFileFetch.java z-X_O32  
*/ q|_t=YM@  
package NetFox; TEYn^/n~  
import java.io.*; |NoTwK  
import java.net.*; r#;GVJR6  
W{z{AxS  
t/`~(0F  
public class SiteFileFetch extends Thread { MrGq{,6C  
@;K-@*k3  
U81--'@y  
SiteInfoBean siteInfoBean = null; //文件信息Bean (yB)rBh>n  
long[] nStartPos; //开始位置 _I1:|y  
long[] nEndPos; //结束位置 (Sd8S`xO  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 i`hr'}x  
long nFileLength; //文件长度 |{en) {:  
boolean bFirst = true; //是否第一次取文件 4`M7 3k0  
boolean bStop = false; //停止标志 b)1v:X4Bv=  
File tmpFile; //文件下载的临时信息 Gi=s|vt  
DataOutputStream output; //输出到文件的输出流 yy*8Aw}  
d%wy@h  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 2uln)]  
public SiteFileFetch(SiteInfoBean bean) throws IOException &ap&dM0@%a  
{ QO&{Jx.^[  
siteInfoBean = bean; V ~%C me  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); & uMx*TTY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Vw>AD<Rl  
if(tmpFile.exists ()) >nqCUhS   
{ gFQ\zOlY8a  
bFirst = false; CNkI9>L=W`  
read_nPos(); KyQd6 1  
} b$W~w*O   
else _< LJQ  
{ yPXa  
nStartPos = new long[bean.getNSplitter()]; aB*'DDlx"r  
nEndPos = new long[bean.getNSplitter()]; w28&qNha  
} : FN-.1C  
Z&![W@m@0N  
 Ww&r  
`Hp=1a  
} GVK c4HGt  
$c0<I59&|  
p-o8Ctc?V  
public void run() L}M%z9K` h  
{ ]p-x ds#d  
//获得文件长度 + \jn$>E  
//分割文件 WZ6'"Cz`  
//实例FileSplitterFetch 5>!I6[{  
//启动FileSplitterFetch线程 ]*]#I?&'Hx  
//等待子线程返回 IDK~ (t  
try{ $No^\.mV  
if(bFirst) yE_T#FN  
{ VYw<8AEFY  
nFileLength = getFileSize(); Memb`3  
if(nFileLength == -1) "~:P-]`G  
{ TR&7AiqB  
System.err.println("File Length is not known!"); 9  M90X8  
} yW]>v>l:Eg  
else if(nFileLength == -2) W1 \dGskV  
{ .$U=ng j\t  
System.err.println("File is not access!"); h )% e  
} b`fWT:?=  
else Txa 2`2t7  
{ %zYTTPLZ  
for(int i=0;i<nStartPos.length;i++) DCSmEy`.  
{ q"-+`;^7(-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); kIJ=]wU|v  
} Fgw$;W  
for(int i=0;i<nEndPos.length-1;i++) #Fckev4  
{ jP31K{G?  
nEndPos = nStartPos[i+1]; l{8t;!2t  
} =l4F/?u]f@  
nEndPos[nEndPos.length-1] = nFileLength; S9E<)L  
} |[iEi  
} ZK`x(h{p)  
M!Ywjvw*)3  
:a*F>S!  
//启动子线程 { 4B7a6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B*^8kc:)L  
for(int i=0;i<nStartPos.length;i++) *qKf!&  
{ q@d6P~[-gj  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fiQ/ &]|5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kPYQcOK8  
nStartPos,nEndPos,i); <ahcE1h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6#Bg99c  
fileSplitterFetch.start(); 7 aN}l QM  
} ar:qCq$\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wl{wY,u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QuBaG<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kYu"`_n}  
nEndPos = " + nFileLength); E@8&#<  
// fileSplitterFetch[nPos.length-1].start(); Mo&Po9  
WZf}1.Mh*  
| (: PX  
//等待子线程结束 V]|P>>`v9p  
//int count = 0; .xg, j{%(  
//是否结束while循环 J72 YZrc  
boolean breakWhile = false; AUwIF/>F(]  
iYz!:TxP  
F17nWvF  
while(!bStop) ZZU"Q7`^  
{ +\~Mx>Cn  
write_nPos(); K2ry@haN  
Utility.sleep(500); oT[8Iu  
breakWhile = true; r8vF I6J  
r&D&xsbQ  
pu5-=QN  
for(int i=0;i<nStartPos.length;i++) "hXB_73)V  
{ -\~D6OA  
if(!fileSplitterFetch.bDownOver) zP#%ya :I  
{ ;T?4=15c  
breakWhile = false; pYaq1_<+  
break; Xw<Nnvz6  
} X5wYfN  
} AE&IN.-  
if(breakWhile) jl~?I*Gr  
break; /]"2;e-s+  
VH5Vg We  
 B!+`km5  
//count++; yXL]uh#b  
//if(count>4) PV/S zfvIq  
// siteStop(); e$y VV#  
} {;XO'  
Z}4 `y"By  
:s`\jJ  
System.err.println("文件下载结束!"); ( mKuFz7  
} 'hl4cHk14  
catch(Exception e){e.printStackTrace ();} 1VC:o]$  
} uQlQ%n%  
q(I`g;MF  
JJ$q*  
//获得文件长度 CN, oH4IU  
public long getFileSize() ?O<D&CvB  
{ GV T[)jS  
int nFileLength = -1; {@w!kl~8  
try{ E/_I$<,_y  
URL url = new URL(siteInfoBean.getSSiteURL()); P85@G 2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wc#E:GJcK  
httpConnection.setRequestProperty("User-Agent","NetFox"); xf]_@T;  
O#962\  
Au-h#YV  
int responseCode=httpConnection.getResponseCode(); >2w^dI2  
if(responseCode>=400) eAD uk!Iq  
{ >=Pn\" j  
processErrorCode(responseCode); z<c%Xl\$%  
return -2; //-2 represent access is error -@EAL:kY  
} 08TeGUjJ  
l mRd l>  
^<VJ8jk<  
String sHeader; 8A ;)5!  
 nW*D  
nF!6  
for(int i=1;;i++) b,Vg3BS  
{ H${5pY_M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z>si%Npm\  
//Utility.log(in.readLine()); ;mAlF>6]\  
sHeader=httpConnection.getHeaderFieldKey(i); %P2l@}?a  
if(sHeader!=null) :|tWKA  
{ C6T?D5  
if(sHeader.equals("Content-Length")) (L3Etan4RE  
{ rV0X*[]J>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DZ7<-SFU  
break; 2`;&Uwt  
} e: aa  
} Qmg2lP.)  
else +-*Ww5Zti  
break; GWvw<`4  
} 4,]z  
} ;qN;oSK  
catch(IOException e){e.printStackTrace ();} (rfR:[JkC2  
catch(Exception e){e.printStackTrace ();} 15X.gx  
W:gpcR]>  
# zbAA<f  
Utility.log(nFileLength); dz>2/'  
$,)PO Z  
Sr#\5UDS  
return nFileLength; ~Bi>T15e  
} o<8('j   
{)?:d6"  
]~K&b96(  
//保存下载信息(文件指针位置) js..k*j  
private void write_nPos() bQlvb  
{ ("r\3Mvs  
try{ :2zga=)g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); o^ zrF  
output.writeInt(nStartPos.length); X;&Iu{&=  
for(int i=0;i<nStartPos.length;i++) }nUq=@ej  
{ yCvP-?2  
// output.writeLong(nPos); QHDR* tB:{  
output.writeLong(fileSplitterFetch.nStartPos); [2$mo;E?  
output.writeLong(fileSplitterFetch.nEndPos); v6 C$Y+5~  
} D>fg  
output.close(); 5(=5GkE)>  
} XU y[l  
catch(IOException e){e.printStackTrace ();} [o"<DP6w  
catch(Exception e){e.printStackTrace ();} D 0 O^=v|  
} 1PB"1.wnd  
J6I:UML  
yiw4<]{IX  
//读取保存的下载信息(文件指针位置) U EjP`  
private void read_nPos() 48IrC_0j  
{ @tvz9N  
try{ XkPE%m_5D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $*Kr4vh  
int nCount = input.readInt(); 6Hp+?mmh  
nStartPos = new long[nCount]; uCr :+"C  
nEndPos = new long[nCount]; (Z0_e&=*  
for(int i=0;i<nStartPos.length;i++) Rb!y(&>v  
{ xG(xG%J  
nStartPos = input.readLong(); J%u,qF}h  
nEndPos = input.readLong(); ZZn$N-  
} uOO\!Hqq  
input.close(); apOa E7|  
} 3=Q:{  
catch(IOException e){e.printStackTrace ();} "<"m}rE?Q  
catch(Exception e){e.printStackTrace ();} g<N;31:c\  
} xg}Q~,:  
Q5^ #:uZ  
.ht-*  
private void processErrorCode(int nErrorCode) :sQ>oNnz  
{ iF9d?9TWl  
System.err.println("Error Code : " + nErrorCode); 31~nay15  
} )q66^% ;S  
$nb.[si\  
D4b-Y[/"  
//停止文件下载 RA!q)/ +  
public void siteStop() MkL)  
{ t/}NX[q  
bStop = true; \BuyJskE  
for(int i=0;i<nStartPos.length;i++) hrm<!uKn  
fileSplitterFetch.splitterStop(); =W &Mt  
o@BV&|  
Q~tXT_  
} Zwm/c]6`  
} H %c6I  
//负责部分文件的抓取 _1NK9dp:  
**FileSplitterFetch.java [}YUi>NGA  
*/ -OSj<m<  
package NetFox; (Vr%4Z8  
4EHrd;|   
FJDE48Vi  
import java.io.*; F#>00b{Q  
import java.net.*; zGFD71=#  
MoE&)~0u&  
W&=OtN U!  
public class FileSplitterFetch extends Thread { R0}1:1}$Sn  
*68 TTBq(  
~N/r;omVc  
String sURL; //File URL Km;}xke6  
long nStartPos; //File Snippet Start Position i1|>JM[V  
long nEndPos; //File Snippet End Position :{#O   
int nThreadID; //Thread's ID S~i9~jA  
boolean bDownOver = false; //Downing is over [Q0V5P~Q'  
boolean bStop = false; //Stop identical {u/1ph-  
FileAccessI fileAccessI = null; //File Access interface P&uSh?[ ^  
Rh ^(91d  
0eNdKE  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException V2ih/mh   
{ bAPMD  
this.sURL = sURL; ?id) 2V0s  
this.nStartPos = nStart; TIKkS*$  
this.nEndPos = nEnd; uhh7Ft#H  
nThreadID = id; Xj 1Oxm 42  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _6nAxm&x`%  
} $Lr& V~  
y)fMVD"(  
`*3A7y  
public void run() ==OUd6e}  
{ &t^*0/~  
while(nStartPos < nEndPos && !bStop) Cgx:6TRS  
{ V 9Qt;]mQ  
dS ojq6M  
8YFG*HSa  
try{ ~t)cbF(UO  
URL url = new URL(sURL); s/tLY/U/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C< c6Ub  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vr EGR$  
String sProperty = "bytes="+nStartPos+"-"; (oG YnN,2  
httpConnection.setRequestProperty("RANGE",sProperty); Byc;r-Q5V  
Utility.log(sProperty); ]p`y  
1.du#w  
|9jK-F6   
InputStream input = httpConnection.getInputStream(); 7|5kak>=  
//logResponseHead(httpConnection); %J M$]  
-D~K9u]U_  
I=kqkuW  
byte[] b = new byte[1024]; g8Ex$,\,  
int nRead; !T,<p    
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |dgiW"tUm  
{ g{V(WyT@  
nStartPos += fileAccessI.write(b,0,nRead); 4Hz3 KKu  
//if(nThreadID == 1) .o/|]d`%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )/jDt dI  
} K=N&kda   
rRRh-%.RU  
IU8zidn&  
Utility.log("Thread " + nThreadID + " is over!"); $5i\D rs  
bDownOver = true; ,/?J!W@m  
//nPos = fileAccessI.write (b,0,nRead); &V?+Y2  
} N|yA]dg[  
catch(Exception e){e.printStackTrace ();} KNeVSZT  
} D`p2aeI  
} ArtY;.cg%  
mW"e  
jA1S|gV  
//打印回应的头信息 SSI> +A  
public void logResponseHead(HttpURLConnection con) 5;XC!Gz  
{ ?ES{t4"  
for(int i=1;;i++) eQ'E`S_d  
{ k{f1q>gd  
String header=con.getHeaderFieldKey(i); fz|*Plv  
if(header!=null) "o- -MBq4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +PYV-@q  
Utility.log(header+" : "+con.getHeaderField(header)); zu}uW,XH-  
else < dE7+w  
break; 1O Ft}>1  
} MEI&]qI  
} s>DFAu!  
C/!P&`<6  
i|h{<X7[  
public void splitterStop() Jj ]<SWh  
{ '{,JuX"n  
bStop = true; dU-:#QV6  
} W _[9  
KYTXf+oh  
"I=Lbh-`  
} ):Fg {7b]n  
%{ U (y#  
:LuA6  
/* CM~x1f*v  
**FileAccess.java =&g:dX|q8  
*//文件访问(定位,写) ~e|E5[-i  
package NetFox; *=md!^x`  
import java.io.*; rE "FN~9P  
fm#7}Y  
`_&vvJPn@!  
public class FileAccessI implements Serializable{ 6oWFjeZ0  
tv-SX=T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \`8$bpW[nS  
RandomAccessFile oSavedFile; D{7sfkcJ  
long nPos; Bz{"K  
mb'{@  
U7LCd+Z 5X  
public FileAccessI() throws IOException M3eSj`c3  
{ 9n5uO[D  
this("",0); \]F Pv7!  
} 'QpDx&~QP  
auB+g'l  
:MYLap&L&  
public FileAccessI(String sName,long nPos) throws IOException g6gwNC:aF  
{ KsTE)@ F:  
oSavedFile = new RandomAccessFile(sName,"rw"); f. h3:_r  
this.nPos = nPos; "MPS&OK  
oSavedFile.seek(nPos); %f\j)qw  
} 4<EC50@.  
6R2F,b(_  
F.Bij8\  
public synchronized int write(byte[] b,int nStart,int nLen) h1Y^+A_  
{ eiA$) rzy  
int n = -1; N+]HJ`K  
try{ Zirp_[KZ%  
oSavedFile.write(b,nStart,nLen); uxX 3wY;M  
n = nLen; iDCQqj`  
} 1n)YCSA  
catch(IOException e) 1k%HGQM{  
{ J6 A3Hrg  
e.printStackTrace (); A)#Fyde  
} jlyuu  
oB<!U%BN  
F)aF.'$-/  
return n; -LFk7a  
} )|]*"yf:E  
Q{ g{  
kK&AK2  
} ND3|wQ`M0  
bdBLfWe  
Nah\4-75&  
/* }?CKE<#%  
**SiteInfoBean.java y?iW^>|?L=  
*/ =QwT)KRB%  
package NetFox; =+VDb5= TV  
wF-H{C'  
U]M5&R=?  
public class SiteInfoBean { eV9,G8  
HSACaTVK  
bhKe"#m|S  
private String sSiteURL; //Site's URL =+4om*  
private String sFilePath; //Saved File's Path y=}o|/5"  
private String sFileName; //Saved File's Name GCrsf  
private int nSplitter; //Count of Splited Downloading File E,/nK  
- ^>7\]  
F~GIfJU  
public SiteInfoBean() BWkTQd<t  
{//nSplitter的缺省值为5 TOx@Y$_9Q8  
//default value of nSplitter is 5 `nd$6i^#W  
this("","","",5); mW3 IR3 b  
} Ibv`/8xh  
ZQsVSz( 1  
g]?QV2bX6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $L72%T  
{ ]_m(q`_  
sSiteURL= sURL; G#.q%Up  
sFilePath = sPath; W#L/|K!S  
sFileName = sName; `cFNO:  
this.nSplitter = nSpiltter; G4EuW *~  
b}ODc]3  
SM.KM_%K  
} xE6hE'rh.O  
=BO>Bi&&  
>%c>R'~h  
public String getSSiteURL() B*}:YV  
{ V+$fh2t  
return sSiteURL; >UXNR`?  
} *$Z?Owl7  
H6M G5f_  
5>fAO =u!Q  
public void setSSiteURL(String value) 0>ce~KU  
{ %vRCs]  
sSiteURL = value; ugs9>`fF&  
} mv#*%St5  
4V'HPD>=V  
O-n JuZJgX  
public String getSFilePath() ,b t j6hg  
{ ,3Aiz|v-  
return sFilePath; ?:i,%]zxC  
} ka*#O"}L8  
5jsZJpk$  
xk s M e  
public void setSFilePath(String value) sV]I]DR  
{ /1b7f'  
sFilePath = value; R#W=*cN  
} I M G^L  
U.N?cKv  
v4, Dt  
public String getSFileName() +.QJZo_  
{ L.:8qY  
return sFileName; EKEJ9Y+47H  
} ]l, ,en5V  
^p3W}D  
P[tYu:  
public void setSFileName(String value) QSOG(}w  
{ =X7_!vSv  
sFileName = value; ^ U~QQ  
} bbT$$b-  
E@4/<;eKK  
\;JZt[  
public int getNSplitter() \jx3Fs:Q  
{ ?@;#|^k9  
return nSplitter; KtHkLYOCG  
} Gr#WD=I-}  
L2OR<3*|Av  
Rx?ze(  
public void setNSplitter(int nCount) ;*0?C'h=  
{ PlCj<b1D:  
nSplitter = nCount; &^l(RBp]0  
} V)P8w#,  
} <>)N$$Rx&  
7mE9Zo1  
[v`kqL~  
/* mv^X{T  
**Utility.java O&,8X-Ix  
*/ _<=h#lH  
package NetFox; [2E(3`-u  
'xEK0~awD  
%Aqf=R_^  
public class Utility { +wxsAGy_j  
7Gy:T47T\@  
wE}Wh5  
public Utility() _ ,/~P)  
{ kP ]Up&'  
'ztOl`I5V  
SV>tw`2  
}  LgNIb  
?uq`|1`  
//线程睡眠 ~(^P(  
public static void sleep(int nSecond) 7y'uZAF  
{ e?]5q ez  
try{ t@qf/1  
Thread.sleep(nSecond); kXSX<b<%  
} UY< PiP  
catch(Exception e) SndR:{  
{ t WI-  
e.printStackTrace (); H$h#n~W~  
} U g"W6`  
} Y$=jAN  
32YbBGDN!f  
//日志 JXB)'d0  
public static void log(String sMsg) puC91  
{ p~$cwbQ!  
System.err.println(sMsg); &jP1Q3  
} 5'} V`?S  
'#'noB;,  
L'= \|r  
public static void log(int sMsg) [8iY0m_Qe  
{ BX >L7n  
System.err.println(sMsg); M R#*/Iw~  
} npdljLN  
} G *CPj^O  
mJSfn"b}K  
Hb)FeGsd).  
/* Q\$3l'W  
**TestMethod.java SI}s  
*/ xlI =)ak{  
package NetFox; :7v'[b  
jxog8 E  
_'=,c"  
public class TestMethod { !jj`Ht)  
Xh9QfT,  
/I%z7f91O  
public TestMethod() * ,hhX psa  
{ ///xx/weblogic60b2_win.exe HlGSt$woX  
try{ -o ).<&#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XiW1X6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5J5?cs-!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); PYkhY;*  
fileFetch.start(); +9_Y0<C  
} Lljn\5!r<  
catch(Exception e){e.printStackTrace ();} y9:4n1fg  
+?_!8N8  
}p)K6!J0  
} 8 x{Owj:Q  
vSgT36ZF  
o<G 9t6~  
public static void main(String[] args) qN!oN*  
{ ^m>4<~/  
new TestMethod(); /fI}QY1  
} &LLU@|  
} nS+Rbhs  
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