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http断点续传简单实现(java)

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/* nJlrBf_Kj  
**SiteFileFetch.java 8I3"68c_a  
*/ q@H?ohIH  
package NetFox; 7$k[cL1  
import java.io.*; B<x)^[<v  
import java.net.*; 8NWvi%g  
O:WFh;c  
XX#YiG4|J  
public class SiteFileFetch extends Thread { zaf%%  
x<4-Q6'{S  
Y&'Bl$`  
SiteInfoBean siteInfoBean = null; //文件信息Bean s9?klJg  
long[] nStartPos; //开始位置 ANZD7v6a  
long[] nEndPos; //结束位置 QD-#sU]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ojni+}>_  
long nFileLength; //文件长度 H[BY(a@c  
boolean bFirst = true; //是否第一次取文件 ;"Q{dOvp  
boolean bStop = false; //停止标志 " P c"{w  
File tmpFile; //文件下载的临时信息 |]w0ytL>(2  
DataOutputStream output; //输出到文件的输出流 x!"S`AM  
:Em[> XA  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) "WV]| TS"]  
public SiteFileFetch(SiteInfoBean bean) throws IOException HeCQF=R  
{ sFqZ@t}~  
siteInfoBean = bean; 9X/c%:)\=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h/W@R_Y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); :)_Ap{9J  
if(tmpFile.exists ()) m_wBRan  
{ F 0 q#.   
bFirst = false; sluR @[l  
read_nPos(); Pfj{TT.#L  
} f$[6]7P  
else I4.^I/c(  
{ /~Zxx}<;  
nStartPos = new long[bean.getNSplitter()]; -$yNJ5F`  
nEndPos = new long[bean.getNSplitter()]; 96x0'IsaG  
} nSdta'6  
pHSq,XP-  
481J=8H  
R] L|&{   
} </(bwc~2  
#0V$KC*>  
$)t ]av  
public void run() l( /yaZ`  
{ `],'fT|,S  
//获得文件长度 &>y[5#qOl  
//分割文件 r*'a-2A u  
//实例FileSplitterFetch hY X H9:  
//启动FileSplitterFetch线程 aVcQ  
//等待子线程返回 \W Kly  
try{ Y).5(t7zaR  
if(bFirst) !c,=%4Pb  
{ s_xWvx8?4.  
nFileLength = getFileSize(); 5RD\XgyN]  
if(nFileLength == -1) .cJWYMC  
{ MdM^!sk&`  
System.err.println("File Length is not known!"); )D?\ru H  
} / V}>v  
else if(nFileLength == -2) *Y(v!x \L  
{ uH 1%diL^  
System.err.println("File is not access!"); f Glvx~  
} Gu?O yL  
else %GG:F^X#  
{ frV *+  
for(int i=0;i<nStartPos.length;i++) r6k0=6i  
{ ocOzQ13@Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }+";W)R  
} /cM<  
for(int i=0;i<nEndPos.length-1;i++) S?_/Po|  
{ *[K\_F?^h  
nEndPos = nStartPos[i+1]; /3`#ldb%}  
} FrXFm+8 F  
nEndPos[nEndPos.length-1] = nFileLength; ;T6{J[ h  
} U"\$k&  
} )pELCk  
6apK]PT  
`D)ay  
//启动子线程 -ZwQL="t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ')ZxWYT O^  
for(int i=0;i<nStartPos.length;i++) v|r\kr k  
{ rS1mBrqD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T*YbmI]4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c 4Q{  
nStartPos,nEndPos,i); <5rs~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XwWp4`Fd  
fileSplitterFetch.start(); n-iy;L^b  
} bV|(V>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oj\av~cI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ti6\~SY  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v[4A_WjT  
nEndPos = " + nFileLength); $ qOV#,@  
// fileSplitterFetch[nPos.length-1].start(); IoUQ~JviA  
6b& <5,=d:  
wXdtY  
//等待子线程结束 Hjl{M>z  
//int count = 0; qIEe7;DO  
//是否结束while循环 xe ng`!  
boolean breakWhile = false; zGKDH=Yy ;  
lFvRXV^+f  
022nn-~  
while(!bStop) mY[s2t  
{ g+shz{3zvz  
write_nPos(); pe(31%(h  
Utility.sleep(500); %g1{nGah  
breakWhile = true; " p]bsJG  
`R:p-"'b  
oJ|8~:)  
for(int i=0;i<nStartPos.length;i++) (Ic{C5'  
{ %tx~CD  
if(!fileSplitterFetch.bDownOver) ?M2#fD]e  
{ !&4<"wQ  
breakWhile = false; "XQj ~L  
break; }<?1\k  
} O7r<6(q(  
} 9[.vtk\iyH  
if(breakWhile) a3}#lY):  
break; GMc{g  
|.kYomJ   
Hj&mwn]  
//count++; pPr/r& r  
//if(count>4) !YUMAp/  
// siteStop(); #XSs.i{  
} cH$zDm1  
/>1Ndj  
(S ~|hk^  
System.err.println("文件下载结束!"); 43_;Z| T  
} j TVh`d< N  
catch(Exception e){e.printStackTrace ();} We7~tkl(  
} m$glRs @  
l+# l\q%l  
UuDT=_1Sh  
//获得文件长度  B _;W!  
public long getFileSize() B I9~% dm  
{ 77y_?di^I  
int nFileLength = -1; SCbN(OBN!  
try{ z=ItKoM*<  
URL url = new URL(siteInfoBean.getSSiteURL()); MF+J3)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~lB im$o  
httpConnection.setRequestProperty("User-Agent","NetFox"); j9)WInYc:  
3@u<Sa  
GE+ %V7  
int responseCode=httpConnection.getResponseCode(); tnx)_f  
if(responseCode>=400) n<Vq@=9AE  
{ "YIrqk  
processErrorCode(responseCode); Y6LoPJ  
return -2; //-2 represent access is error ?~G D^F  
} X6_m&~}15  
UdBP2lGd  
\9[_*  
String sHeader; hVvPI1[2  
Z<7FF}i  
j@OGl&'^-  
for(int i=1;;i++) \5g7_3,3W  
{ %;5AF8#c  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OyTEd5\3  
//Utility.log(in.readLine()); lZyxJDZ A  
sHeader=httpConnection.getHeaderFieldKey(i); t- Rp_2t  
if(sHeader!=null) ?Bg<74  
{ ` oBlv  
if(sHeader.equals("Content-Length")) REd"}zDI  
{ ?QzA;8H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z#8O)GK  
break; Y yI4T/0s_  
} b"`Vn,  
} :mwNkT2et  
else 4]\ f}  
break; T<!&6,N A  
} [c6I/U=-  
} yc|j]?  
catch(IOException e){e.printStackTrace ();} eUiJl6^x  
catch(Exception e){e.printStackTrace ();} )ZkQWiP-  
[" '0vQ  
M,0@@:  
Utility.log(nFileLength); $@8$_g|Wz  
Ift @/A  
YXD6GJWo  
return nFileLength; 3$YgGum  
} ^QX3p,Y  
WM8 Ce0E  
W'2a1E  
//保存下载信息(文件指针位置) $6p_`LD0  
private void write_nPos() n0o'ns  
{ \k6Ho?PL  
try{ +.i?UHNB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J{98x zb  
output.writeInt(nStartPos.length); !1MSuvWP  
for(int i=0;i<nStartPos.length;i++) :5/P{Co (  
{ k!/"J ;  
// output.writeLong(nPos); zbL!q_wO  
output.writeLong(fileSplitterFetch.nStartPos); r[P5 ufy2]  
output.writeLong(fileSplitterFetch.nEndPos); G]q1_q4P1?  
} W/dl`UDY  
output.close(); XqD/~_z;  
} }*+?1kv  
catch(IOException e){e.printStackTrace ();} 'BE &lW  
catch(Exception e){e.printStackTrace ();} {Vz.| a[T  
} .r~!d|  
.]_Ye.}  
z6B(}(D  
//读取保存的下载信息(文件指针位置) jR/YG ru  
private void read_nPos() v634{:'e  
{ B1]5%B  
try{ [<~1.L^I  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W}6(;tI  
int nCount = input.readInt(); _sU|<1  
nStartPos = new long[nCount]; l V[d`%(  
nEndPos = new long[nCount]; {3RY4HVT?  
for(int i=0;i<nStartPos.length;i++) `N 0Mm7  
{ AF5$U8jf  
nStartPos = input.readLong(); !f~ =p  
nEndPos = input.readLong(); ]fH U/%  
} 9Vp|a&Ana  
input.close(); uus}NZ:*l  
} E|u#W3-:  
catch(IOException e){e.printStackTrace ();} 1i;-mYGaMn  
catch(Exception e){e.printStackTrace ();} ;lqtw]4v  
} ,Y~{RgG  
np|3 os  
r3a$n$Qw  
private void processErrorCode(int nErrorCode) imcq H  
{ hQ!slO  
System.err.println("Error Code : " + nErrorCode); kz]vXJ  
} z@E-pYV  
pDr%uL  
%U]_1"d,<\  
//停止文件下载 ]d#Lfgo  
public void siteStop() 3`@alhD'  
{ Vl;GQe  
bStop = true; w9D<^(_}/  
for(int i=0;i<nStartPos.length;i++) w*.q t<rH)  
fileSplitterFetch.splitterStop(); Yk',a$.S  
]"SH pq  
2ye^mJ17  
} w3lR8R]  
} 5IeF |#g  
//负责部分文件的抓取 2mS3gk  
**FileSplitterFetch.java e %VJ:Dj  
*/  <b7 4L  
package NetFox; et|P5%G  
A|sTnhp~  
i_OoR"J%  
import java.io.*; fm2,Mx6  
import java.net.*; 5>.)7D%  
[uxhdR`T  
wT?.Mte  
public class FileSplitterFetch extends Thread { ODn6%fp%  
rK%<2i  
ajIgL<x  
String sURL; //File URL 5Z{h!}Y  
long nStartPos; //File Snippet Start Position %AbA(F  
long nEndPos; //File Snippet End Position J{$+\  
int nThreadID; //Thread's ID +RexQE  
boolean bDownOver = false; //Downing is over x2B~1edf  
boolean bStop = false; //Stop identical Sbub|  
FileAccessI fileAccessI = null; //File Access interface #W#GI"K  
;Ab`b1B  
*ayn<Vlh`^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mQt';|X@  
{ %1ofu,%  
this.sURL = sURL; 6x KbK1W  
this.nStartPos = nStart; }>vf(9sF`  
this.nEndPos = nEnd; wD>tR SW  
nThreadID = id; SX)giQLU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c)8V^7=Q  
} &0*l=!:G^  
3ThCY`  
7 }`c:u~j  
public void run() qJQE|VM&  
{ |B&KT  
while(nStartPos < nEndPos && !bStop) G5W6P7-<X  
{ UeB8|z  
Z&W|O>QTl  
ZbTU1Y/'   
try{ *z4n2"<l  
URL url = new URL(sURL); qM F'&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '$u3i #. \  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1Sox@Ko  
String sProperty = "bytes="+nStartPos+"-"; E@\e37e  
httpConnection.setRequestProperty("RANGE",sProperty); X%"P0P  
Utility.log(sProperty); uG2(NwOL  
o)'u%m  
$ wGDk  
InputStream input = httpConnection.getInputStream(); y'?|#%D  
//logResponseHead(httpConnection); /G$8j$  
J<x?bIetj  
U,"lOG'  
byte[] b = new byte[1024]; i:`ur  
int nRead; ? lC. Pq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) XQ.czj  
{ $Gb] K{e  
nStartPos += fileAccessI.write(b,0,nRead); _+0l+a*D  
//if(nThreadID == 1) @AUx%:}0Y:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )c=R)=N  
} xZjl_ b J  
7|3Qcn7P)@  
jR7 , b5  
Utility.log("Thread " + nThreadID + " is over!"); <N"t[N70;  
bDownOver = true; p D!IB`cA4  
//nPos = fileAccessI.write (b,0,nRead); IdTeue  
} 4kGA`XhS*  
catch(Exception e){e.printStackTrace ();} n k]tq3.[  
} v0!>":  
} >B$ZKE  
F\ !;}z  
\Ku=a{Ne  
//打印回应的头信息 9_'xq.uP  
public void logResponseHead(HttpURLConnection con) @`2<^-r\  
{ 'U]= T<  
for(int i=1;;i++) Q&:% U  
{ y XZZ)i_  
String header=con.getHeaderFieldKey(i); E",s]  
if(header!=null) 5)4*J.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *leQd^47  
Utility.log(header+" : "+con.getHeaderField(header)); 3/8o)9f.  
else DUf=\p6`f  
break; m`C(y$8fU  
} V x1C4  
} j &)Xi^^  
:P`sK&b_  
RC Fb&,51  
public void splitterStop() GL&ri!,  
{ f9H;e(D9]  
bStop = true; "m +Eu|{  
} /b,+YyWi%  
XNwY\y  
iRo UM.%  
} [7B:{sH  
1\q(xka{  
c38RE,4U  
/* (8o~ XL  
**FileAccess.java B1m@  
*//文件访问(定位,写) \~:Kp Kq  
package NetFox; 3:jKuOX  
import java.io.*; A<^IG+Q,B7  
o:#l r{  
9F)v=  
public class FileAccessI implements Serializable{ W >eJGZ<  
b_-ESs]g  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +<6L>ZAL  
RandomAccessFile oSavedFile; STu!v5XY}-  
long nPos; g[Ah> 5  
;[WW,,!Y  
%@q52ZQ  
public FileAccessI() throws IOException tu6oa[s  
{ RL |.y~  
this("",0); 9Q- /Yh  
} o%h"gbvMY!  
N( E\  
;RZ@t6^  
public FileAccessI(String sName,long nPos) throws IOException W3* BdpTw  
{ @B5@3zYs  
oSavedFile = new RandomAccessFile(sName,"rw"); [P8Y  
this.nPos = nPos; +Y(cs&V*  
oSavedFile.seek(nPos); t3u"2B7oG  
} bO1J#bcZ  
raY5 nc{  
S$\l M<M  
public synchronized int write(byte[] b,int nStart,int nLen) 0trVmWQ8  
{ w=d#y )1  
int n = -1; 8lI#D)}  
try{ mk_cub@  
oSavedFile.write(b,nStart,nLen); 7{f&L '  
n = nLen; +o(t5O[G  
} R'qB-v.  
catch(IOException e) _z\oDd`'  
{ 84)$ CA+NX  
e.printStackTrace (); 3v;o`Em&  
} ??12 J#  
~\4l*$3(^  
)v;>6(  
return n; ('Wo#3b$  
} )u]J`.OA  
4;Z`u.1  
ZH/^``[.  
} \k0%7i[nZ/  
f7{E(,  
OGg9e  
/* Htl6Mr*{  
**SiteInfoBean.java ^DXERt&3  
*/ }$#e&&)n  
package NetFox; +mhYr]Z  
=$Sf]L  
(f5!36mz  
public class SiteInfoBean { J|_&3@r  
^M6v;8EU  
[ik D4p=  
private String sSiteURL; //Site's URL iN+Dmq5  
private String sFilePath; //Saved File's Path LP_d}ve  
private String sFileName; //Saved File's Name W+BM|'%}|  
private int nSplitter; //Count of Splited Downloading File N}nU\e6 Y  
f'F:U^  
H`]nY`HYg  
public SiteInfoBean() yw"FI!M  
{//nSplitter的缺省值为5 cy*Td7)/  
//default value of nSplitter is 5 fF[n?:VV  
this("","","",5); |TF,Aj   
} \D?6_ ,O  
f}^}d"&F  
3!Zd]1$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P~redX=t@  
{ GV6!`@<  
sSiteURL= sURL; l*uNi47|  
sFilePath = sPath; qd~)Ya1  
sFileName = sName; \.myLkm  
this.nSplitter = nSpiltter; 3ag*dBbs  
MHVqRYz  
78#je=MDg  
} #6fp "  
H&E c *MT  
8U0y86q>)E  
public String getSSiteURL() "p.MJxH  
{ #<0%_Ca  
return sSiteURL; tvP_LNMF  
}  ;4 R1  
|@]J*Kh  
DF%\ 1C>  
public void setSSiteURL(String value) * gr{{c  
{ kLR4?tX!  
sSiteURL = value; m46Q%hwV  
} sI/Hcm  
\ lP c,8)  
"@W0Lk[  
public String getSFilePath() yU\&\fD>j  
{ D#x D-c  
return sFilePath; go m< V?$  
} Dk&cIZ43  
);@Dr!H  
E:4`x_~qQ  
public void setSFilePath(String value) uTA /E9OY  
{ F)j-D(c4  
sFilePath = value; QOlm#S  
} " ^ydoRZ  
H!4!1J.=xw  
;TF(opW:  
public String getSFileName() Bt[`p\p@  
{ z!)_'A  
return sFileName; SW UHHl  
} wg^#S  
&fdH HN  
m;WUp{'  
public void setSFileName(String value)  "@Bc eD  
{ -2o4v#d  
sFileName = value; VxLq,$B76  
} (WR&Vt4Rh  
;i^p6b j  
T.<er iv  
public int getNSplitter() 49nZWv48"_  
{ gZ%B9i:  
return nSplitter; ~KD x  
} W tnZF]1:u  
.UakO,"z  
rhMsZ={M  
public void setNSplitter(int nCount) IQMk:  
{ A@j;H|  
nSplitter = nCount; Um)0jT  
} '$ ~.x|  
} l2+qP{_4  
2JYp.CJv  
+G"=1sxJ  
/* Y]{<IF:  
**Utility.java p H5IBIf'  
*/ Zd1+ZH  
package NetFox; $/}*HWVZ  
v$K`C;  
? 1?^>M  
public class Utility { W*QD'  
e7t).s)b{  
oylY1~~}0K  
public Utility() VW<s_  
{ <P3r+ 1|R  
e,={!P"f  
bESmKe(  
} -TU7GCb=  
C (vi ns  
//线程睡眠 >T%Jlj3ZG  
public static void sleep(int nSecond) 8Z4d<DIJ  
{ $^.LZ1Jd  
try{ 3%/]y=rA  
Thread.sleep(nSecond); Vl{CD>$,  
} $yIcut7  
catch(Exception e) <^U B@'lCm  
{ 9U>ID{  
e.printStackTrace (); jj0@ez{3  
} :4}?%3&;  
} 4;M  
5@tpJ8E8$  
//日志 }Jk.c~P)  
public static void log(String sMsg) 7ks09Cy  
{ Ms<^_\iPN  
System.err.println(sMsg); GxLoNVr  
} (ivV[  
8 2&JYx  
V5i_\A  
public static void log(int sMsg) ^TyusfOz  
{ fPiq  
System.err.println(sMsg); _{8f^@I"+  
} sRE$*^i  
} Un]`Gd]:  
]cc4+}L~  
|b;}' *  
/* Q nDymVF  
**TestMethod.java q =b.!AZy  
*/ Oo`P +S#  
package NetFox; n]}+ :  
UIvTC S  
n4 KiC!*i0  
public class TestMethod { -WB? hmx  
/&$'v:VB  
U)zd~ug?m  
public TestMethod() Yi{[llru  
{ ///xx/weblogic60b2_win.exe $G"PZ7  
try{ .bB_f7TH.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); aP!a?xq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A]Zp1XEG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r[eZV"  
fileFetch.start(); k*-_CO-h  
} D=mU!rjr1  
catch(Exception e){e.printStackTrace ();} Lbq"( b  
_0)#-L>xKF  
X9/V;!  
} C(3yJzg>y  
i`gsT[JQRX  
P~#!-9?  
public static void main(String[] args) ?#qA>:2,  
{ V3$!`T}g4  
new TestMethod(); G`R Ed-Z[  
} W:3u$LTf*f  
} b5_A*-s$M  
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