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http断点续传简单实现(java)

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/* h [nH<m  
**SiteFileFetch.java R<f#r03@|  
*/ ![^EsgEB*  
package NetFox; z 0~j  
import java.io.*; _9D|u<D  
import java.net.*; #|qm!aGs  
z^4KU\/JK  
FE/$(7rM  
public class SiteFileFetch extends Thread { zuUT S[  
F\>oxttS1  
oi7 3YOB  
SiteInfoBean siteInfoBean = null; //文件信息Bean K!3{M!B   
long[] nStartPos; //开始位置 ]e^R@w  
long[] nEndPos; //结束位置 : @'fpN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p/r~n'g$  
long nFileLength; //文件长度 - #3{{  
boolean bFirst = true; //是否第一次取文件 y L*LJ  
boolean bStop = false; //停止标志 \r)%R5_CQ  
File tmpFile; //文件下载的临时信息 4\p$4Hs}  
DataOutputStream output; //输出到文件的输出流 \% }raI;Y@  
vG Y!4@[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Y4QLs^IdB  
public SiteFileFetch(SiteInfoBean bean) throws IOException p3g4p  
{ Xo2^N2I  
siteInfoBean = bean; Mv|vRx^b  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); p1+7 <Y:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |y.zo cBj  
if(tmpFile.exists ()) |<sf:#YzY&  
{ K!GUv{fp  
bFirst = false; Z[Wlyb0  
read_nPos(); JW=uK$sO  
} Yt -W1vl  
else UM<@t%|>  
{ m7JPH7P@BM  
nStartPos = new long[bean.getNSplitter()]; 4[`[mE18.  
nEndPos = new long[bean.getNSplitter()]; {5>3;.  
} :]'q#$!  
t)LU\!  
0z/h+,  
g;8M<`qvf  
}  1Yud~[c  
Zp`~}LV{  
My. dD'C  
public void run() C1 W>/?XC  
{ .>P~uZiX!  
//获得文件长度 !~WZ_z  
//分割文件 *2`:VFEV  
//实例FileSplitterFetch h%' N hV  
//启动FileSplitterFetch线程 ?4,@, ae&  
//等待子线程返回 5? Wg%@  
try{ s}wO7Df=+  
if(bFirst) :AZp}  
{ $57\u/(  
nFileLength = getFileSize(); ) ]73S@P(=  
if(nFileLength == -1) iAK/d)bq  
{ ^]VcxKUJ  
System.err.println("File Length is not known!"); m$?.Yig?  
} B~?c3:6  
else if(nFileLength == -2) !}ilN 1>  
{ {gsW(T>)  
System.err.println("File is not access!"); 3!aEClRtq  
} |"Z-7@/k$i  
else D ZVXz|g  
{ o5P&JBX<  
for(int i=0;i<nStartPos.length;i++) %VWp&a8  
{ zO%w_7 w  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :<|Z.4}kJb  
} [UoqIU  
for(int i=0;i<nEndPos.length-1;i++) mH)OB?+lq  
{ GMBJjP&R]  
nEndPos = nStartPos[i+1]; /jR8|sb  
} }t\ 10nQ  
nEndPos[nEndPos.length-1] = nFileLength; ?~,JY  
} gwiR/(1  
} 8'KMxR  
iX{H,- C  
fWj@e"G  
//启动子线程 X@!X6j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G]-%AO{K  
for(int i=0;i<nStartPos.length;i++) 7%4.b7Q  
{ 45) D+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qwv '<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9\AS@SH{^T  
nStartPos,nEndPos,i); wlrIgn%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VG)="g[%)  
fileSplitterFetch.start(); uJY.5w  
} S 6GMUaR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #&V5H{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [t{](-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kbhX?; <`  
nEndPos = " + nFileLength); x6ahZ  
// fileSplitterFetch[nPos.length-1].start(); 9<l-NU9 _  
Zi/-~')E  
6 Uw;C84!  
//等待子线程结束 ^!}F%  
//int count = 0;  i S  
//是否结束while循环 _s*! t  
boolean breakWhile = false; ra]:$XJ5=a  
7/?DPwbx  
Y%g "Y  
while(!bStop) V9T 4 +  
{ N<liS3>  
write_nPos(); K_>/lirE?  
Utility.sleep(500); y@A6$[%(E|  
breakWhile = true; ^X &)'H  
B'p5M.6d#:  
b66R}=P l  
for(int i=0;i<nStartPos.length;i++) < eQ[kM  
{ 5mavcle{4r  
if(!fileSplitterFetch.bDownOver) nhewDDu  
{ Hd 0Xx}3&  
breakWhile = false; 3D[=b%2\  
break; O: JPJ"!  
} (B:uc_+  
} {2:d` fqD  
if(breakWhile) (;UP%H>  
break; +i=p5d5  
C8.W5P[U  
e!Br>^8l  
//count++; JT)k  
//if(count>4) x> \Bxa8  
// siteStop(); rz.IoQo  
} 3]^'  
<Oa9oM},d  
$)*xC!@6X  
System.err.println("文件下载结束!"); TKOP;[1h  
} <tuS,.  
catch(Exception e){e.printStackTrace ();} Dx3%K S  
} c&*l"  
hk} t:<  
5 `=KyHi:b  
//获得文件长度 t77'fm  
public long getFileSize() Ea]T>4  
{ v459},!P  
int nFileLength = -1; Q]#Z9H  
try{ + |C=ZU  
URL url = new URL(siteInfoBean.getSSiteURL()); ^f|<R8`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -~O/NX  
httpConnection.setRequestProperty("User-Agent","NetFox"); V#J"c8n  
RZh}:  
X+iK<F$  
int responseCode=httpConnection.getResponseCode(); &@6 GI<  
if(responseCode>=400) g$w6kz_[  
{ A(+:S"|@  
processErrorCode(responseCode); Hf%_}Du /`  
return -2; //-2 represent access is error e+@xs n3  
} QNArZ6UQ  
,|pp67  
t$ZkdF  
String sHeader; J3=BE2L  
J=*K"8Qr  
)GJP_*Ab  
for(int i=1;;i++) v[&'k\  
{ ,I`_F,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^|?1_r  
//Utility.log(in.readLine()); ?3jdg]&  
sHeader=httpConnection.getHeaderFieldKey(i); HO5d%85  
if(sHeader!=null) G),db%,X2  
{ Yy h=G  
if(sHeader.equals("Content-Length")) Hku=pr3Gn  
{ 4RQ5(YTTuR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /{X_ .fv<v  
break; ]:et~pfW  
} k1fRj_@WPT  
} w>vH8f  
else KlU qoJ;"  
break; d#\W hRE  
} "2;N2=~7  
} C9jbv/c  
catch(IOException e){e.printStackTrace ();} 0H[LS  
catch(Exception e){e.printStackTrace ();} T~J? AKx  
*Jt8  
?9e]   
Utility.log(nFileLength); }bMWTT  
J+Bdz6lt  
IN^_BKQt  
return nFileLength; V@Wcb$mgk  
} #DUh(:E'`  
|C D}<r(N  
nwf7M#3d  
//保存下载信息(文件指针位置) 4#:\?HAu!  
private void write_nPos() ~NNv>5 t5  
{ (WE,dY+.  
try{ wiE]z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yd>}wHt  
output.writeInt(nStartPos.length); ?/d!R]3  
for(int i=0;i<nStartPos.length;i++) wL2XNdo}<  
{ l!IGc:  
// output.writeLong(nPos); ``9 GY  
output.writeLong(fileSplitterFetch.nStartPos); ^,V[nfQR  
output.writeLong(fileSplitterFetch.nEndPos); Q4wc-s4RN  
} q# vlBL  
output.close(); ,%hj cGX11  
} };sMU6e  
catch(IOException e){e.printStackTrace ();} <*Y'lV  
catch(Exception e){e.printStackTrace ();} GBbhar},g  
} 5@P-g  
]0/p 7N14  
]MAT2$"le  
//读取保存的下载信息(文件指针位置) I KcKRw/O$  
private void read_nPos() ;fGx;D  
{  (M`|'o!  
try{  Oh`2tc-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (X}@^]lpa  
int nCount = input.readInt(); T~s}Nx#  
nStartPos = new long[nCount]; yVS\Q,:J9  
nEndPos = new long[nCount]; FT/amCRyT  
for(int i=0;i<nStartPos.length;i++) HC7JMj  
{ cOku1 g8  
nStartPos = input.readLong(); zj%cQkZ  
nEndPos = input.readLong(); \+Y!ILOI  
} GDPo`# ~  
input.close(); HFS+QwHW  
} jvs[ /  
catch(IOException e){e.printStackTrace ();} rAXX}"l6s  
catch(Exception e){e.printStackTrace ();} #D)x}#V\  
} }.{}A(^YR  
9;KJr[FQV  
j|K.i/  
private void processErrorCode(int nErrorCode) &U &%ka<*  
{ iZ; TYcT  
System.err.println("Error Code : " + nErrorCode); np6HUH  
} ~L4eZ  
D;js.ZF  
Y\?j0X;  
//停止文件下载 0ar=cuDm  
public void siteStop() |F!F{d^p  
{ ^l!L)iw  
bStop = true; CV^c",b_  
for(int i=0;i<nStartPos.length;i++) `="v>qN2\  
fileSplitterFetch.splitterStop(); AS;.sjgk  
G|9B )`S  
z{?4*Bq  
} J_xG}d  
} T:!MBWYe|  
//负责部分文件的抓取 2k1aX~?  
**FileSplitterFetch.java QnKC#   
*/ K/Y Agg  
package NetFox; BUC,M:J+H  
tWD|qg_  
V(mn yI  
import java.io.*; xb$yu.c  
import java.net.*; $']VQ4tZ  
kh?. K#  
(0jr;jv  
public class FileSplitterFetch extends Thread { fp&Got!pB  
L11L23:  
.JAcPyK^  
String sURL; //File URL /f3m)pT  
long nStartPos; //File Snippet Start Position s AE9<(g&@  
long nEndPos; //File Snippet End Position vA-PR&  
int nThreadID; //Thread's ID n Ga1a  
boolean bDownOver = false; //Downing is over 8wIK:   
boolean bStop = false; //Stop identical crn k|o  
FileAccessI fileAccessI = null; //File Access interface ybvI?#  
]T^ is>  
oR %agvc^^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a %K}j\M  
{ |:2c$zq  
this.sURL = sURL; +ld;k/  
this.nStartPos = nStart; KQ)T(mIqp  
this.nEndPos = nEnd; N@1p]\  
nThreadID = id; j Z'&0x"U  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 - L~Uu^o  
} 0HbJKix!  
<abKiXA"  
a [C&e,)}  
public void run() "!q?P" @C  
{ bK=c@GXS  
while(nStartPos < nEndPos && !bStop) Y';>O`  
{ !_^g8^>2(  
Y4To@TrN#\  
Z"tQp Jg  
try{ qrDcL>Hrn  
URL url = new URL(sURL); /`+7_=-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *K)0UKBr  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4e9E' "8%  
String sProperty = "bytes="+nStartPos+"-"; 8:{ q8xZ=k  
httpConnection.setRequestProperty("RANGE",sProperty); tWk{1IL  
Utility.log(sProperty); zM59UQU;  
.#!mDlY;  
,- HIFbXx@  
InputStream input = httpConnection.getInputStream(); 9X]f[^  
//logResponseHead(httpConnection); V/bH^@,sA  
IJPgFZ7  
[ud|dwP"  
byte[] b = new byte[1024]; .,mPdVof  
int nRead; ']?=[`#NL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8"M<{72U]  
{ p\S8oHWe  
nStartPos += fileAccessI.write(b,0,nRead); `C'}e  
//if(nThreadID == 1) e1P7 .n}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7a<_BJXx  
} B||c(ue  
(6k>FSpg  
\_ -DyD#3  
Utility.log("Thread " + nThreadID + " is over!"); F]5\YYXO  
bDownOver = true; re uYTH  
//nPos = fileAccessI.write (b,0,nRead); D[~}uZ4\  
} ;$;rD0i|  
catch(Exception e){e.printStackTrace ();} tpU D0Z)  
} ou6j*eSN  
} [g|Hj)(  
v@_in(dk  
@^CG[:|  
//打印回应的头信息 {!=2<-Aq  
public void logResponseHead(HttpURLConnection con) ;3 UvkN  
{ 3;y_mg  
for(int i=1;;i++) E@pFTvo  
{ F= i!d,S  
String header=con.getHeaderFieldKey(i); NI\H \#bJ  
if(header!=null) xF8 :^'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /=ylQn3 *  
Utility.log(header+" : "+con.getHeaderField(header)); (C`@a/q  
else RVP18ub.S  
break; 1+^n!$  
} $L&BT 0  
} AbZ:(+@cP  
%6]\^  
4oJ$dN  
public void splitterStop() +/q0Y`v  
{ yW> RRE;  
bStop = true; J3&Sj{ o  
} QUp?i  
@?/\c:cp  
DV,DB\P$  
} Jvj=I82  
{^wdJZ~QLK  
rfTe  
/* XnY"oDg^>  
**FileAccess.java J wFned#T  
*//文件访问(定位,写) o?dR\cxj  
package NetFox; la702)N{  
import java.io.*; PP-kz;|  
xt))]aH  
D3.VXuKn6  
public class FileAccessI implements Serializable{ 8.2`~'V  
g)cY\`&W8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s##Ay{  
RandomAccessFile oSavedFile; ]ymC3LV]  
long nPos; .K7C-Xn=  
6Ahr_{  
7TdQRB  
public FileAccessI() throws IOException 0||F`24  
{ Ilef+V^qr  
this("",0); p`p?li  
} k<O y%+C  
%M6 c0d[9-  
C8MWIX}  
public FileAccessI(String sName,long nPos) throws IOException jGiw96,Y  
{ 4:`[qE3  
oSavedFile = new RandomAccessFile(sName,"rw"); raHVkE{<  
this.nPos = nPos; 2Oi'E  
oSavedFile.seek(nPos); /.v_N%*-v  
} >)y$mc6  
YkI9d&ib+  
DZP*x  
public synchronized int write(byte[] b,int nStart,int nLen) 97]4 :Zv  
{ Y?t2,cm   
int n = -1; `EVg'?pl  
try{ H9E(\)@  
oSavedFile.write(b,nStart,nLen); R8uj3!3^  
n = nLen; `WlH*p)z9  
} *|poxT G  
catch(IOException e) InN{^uN  
{ cD8Ea(  
e.printStackTrace (); @T/qd>T o  
} P57GqT  
m9Il\PoTq  
-p^'XL*Z  
return n; P'F~\**5  
} g8v[)o(qd  
P4[]qbfd,  
@it/$>R^)  
} yU!GS-  
{\Ys@FF  
@E(P9zQ/zy  
/* V" }*"P-%  
**SiteInfoBean.java 6lZGcRO  
*/ _'lmCj8L  
package NetFox; p2^)2v  
j%u8=  
$^IjFdD  
public class SiteInfoBean { ,P~QS  
!U[:5@s06  
Pv[ykrm/  
private String sSiteURL; //Site's URL 2_.CX(kI  
private String sFilePath; //Saved File's Path L?Tu)<Mn  
private String sFileName; //Saved File's Name kz_M;h>  
private int nSplitter; //Count of Splited Downloading File kkL(;H:%  
F~'sT}A*  
B6uRJcD4  
public SiteInfoBean() !^-OfqIHfV  
{//nSplitter的缺省值为5 ]f5c\\)  
//default value of nSplitter is 5 &~}@u[=ux  
this("","","",5); vgN@~Xa  
} fOLnK y#  
W W35&mI)k  
F#KF6)P  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [brkx3h  
{ G}q<{<+$  
sSiteURL= sURL; `xGT_0&ck  
sFilePath = sPath; \eT/%$  
sFileName = sName; 3wo'jOb  
this.nSplitter = nSpiltter; nAvs~J  
Cg7)S[zl  
c~37 +^B:  
} B/rzh? b  
N:7.:Yw  
3jS7 uU  
public String getSSiteURL() &rcdr+'  
{ s4N,^_j  
return sSiteURL; xlk5Gob*  
} ;8uHRcdQ  
A`g.[7  
-FaaFw:Z;A  
public void setSSiteURL(String value) :k\} I k  
{ <oQ6ZX  
sSiteURL = value; IBDVFA  
} lj Y  
"5 y<G:$+~  
~Z7)x7 z  
public String getSFilePath() T"IW Jpc  
{ PH[4y:^DN  
return sFilePath; 0+rW;-_(  
} ^SgN(-QH  
y%JF8R;n  
m+p4Mc%u  
public void setSFilePath(String value) ~RAzFLt6x  
{ $Q=$?>4U  
sFilePath = value; x~%\y  
} 0:jsV|5B8  
=I7[L{+~Y  
L-j/R1fTvl  
public String getSFileName() y>4p~  
{ 7WXiG0  
return sFileName; pTN%;`) {  
} xS-w\vbLV  
b#e]1Q  
@PKAz&0  
public void setSFileName(String value) \6U 2-m'  
{ 1T:)Zv'  
sFileName = value; DhHtz.6  
} N-Qu/,~+  
x4@MO|C  
Cy]"  
public int getNSplitter() a$A2IkD  
{ xJ$Rs/9C  
return nSplitter; haN"/C^  
} B5 D3_ iX]  
9#Z zE/  
:J<Owh@  
public void setNSplitter(int nCount) 8 qn{  
{ g~eJ YS,  
nSplitter = nCount; e#K rgUG  
} L(W%~UGN V  
} K6ciqwUO  
\MF3CK@/  
]Qh[%GD  
/* $3lt{ %  
**Utility.java t$tsWAmiA[  
*/ ' l|41wxk  
package NetFox; dvC0 <*V  
ex{)mE4Cd  
Fka1]|j9  
public class Utility { k>7gy?Y!K<  
g9M')8a n  
 b$PT_!d  
public Utility() C3]\$  
{ }klE0<W|5\  
| pF5`dX  
v`@5enr  
} ?.]o_L_K  
i-|/2I9%  
//线程睡眠 ,xm;JXJ  
public static void sleep(int nSecond) )-MA!\=<  
{ zuK/(qZ  
try{ z]'|nX  
Thread.sleep(nSecond); -$'~;O3s  
} 3csm`JVK  
catch(Exception e) M-{b  
{ vd2uD2%con  
e.printStackTrace (); Q@PJ)fwN  
} oH!$eAU?  
} `i"$*4#<  
Z|V"8jE  
//日志 MA~|y_V  
public static void log(String sMsg) H(  
{ =1%zI%  
System.err.println(sMsg); iK$Vd+Lgc  
} f6keWqv<GW  
 JsZAP  
%@M00~-  
public static void log(int sMsg) AGw1Pl8]K  
{ |Ba4 G`  
System.err.println(sMsg); 3?a0 +]  
} @m*&c*r  
} |#Yu.c*  
tI/mE[W  
x.jYip  
/* Ukk-(gjX  
**TestMethod.java UchALR^5  
*/ i{Y=!r5r  
package NetFox; K,`).YK  
IKNFYe[9e  
Jnh;;<  
public class TestMethod { =;~%L  
z ^gDbXS  
W}#QKZ)MB  
public TestMethod() G%V=idU*"  
{ ///xx/weblogic60b2_win.exe EuR!yD  
try{ 1puEP *P  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;oN{I@}k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U89]?^|bb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :F!dTD$  
fileFetch.start(); EM>c%BH<N  
} eONeWY9  
catch(Exception e){e.printStackTrace ();} .y/NudD  
SX1Fyy6 w  
T! &[  
} rahHJp.Ws  
.{'Uvn  
[[Jv)?jm  
public static void main(String[] args) o$[a4I  
{ .ruz l(6  
new TestMethod(); rw}5nv  
} qv ;1$  
} ')1}#V/I  
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