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http断点续传简单实现(java)

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/* d]0:r]e  
**SiteFileFetch.java JvO1tA]ij  
*/ :SaZhY  
package NetFox; ):K%  
import java.io.*; !FgZI4?/Y=  
import java.net.*; 72;'8  
&GLDoLk6[  
MG=E 6:  
public class SiteFileFetch extends Thread { ,-6Oma -  
:|bL2T@>[  
%r|sb=(yT  
SiteInfoBean siteInfoBean = null; //文件信息Bean YYT;a$GTo  
long[] nStartPos; //开始位置 PaKa bPY  
long[] nEndPos; //结束位置 i%o%bib#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9Jwd*gevV  
long nFileLength; //文件长度 Z:{| ?4  
boolean bFirst = true; //是否第一次取文件 p4P=T@:  
boolean bStop = false; //停止标志 > 'R{,1# U  
File tmpFile; //文件下载的临时信息 7n5gXiI"  
DataOutputStream output; //输出到文件的输出流 "}3sL#|z  
PSJj$bt;<+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &@6xu{o  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ll KO(Q{"  
{ <N)!s&D  
siteInfoBean = bean;  vm! y2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); JRB6T_U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M@T{uo  
if(tmpFile.exists ()) v-#,@&Uwq  
{ )+L|<6JXA  
bFirst = false; ?-j/X6(\(  
read_nPos(); 3S3 a|_+%  
} %2:UsI  
else ^0zfQu+!  
{ e(s0mbJE  
nStartPos = new long[bean.getNSplitter()]; 6_%Cd`4Z  
nEndPos = new long[bean.getNSplitter()]; N[cIr{XBGN  
} +mrLMbBiD  
6 ) i-S<(  
K9@.l~n  
neU=1socJ  
} Y*BmBRN  
Jh.~]\u  
uUjjAGZ  
public void run() J'2 Yrn  
{ uqcG3Pi  
//获得文件长度 &MH8~LSb  
//分割文件 J?V$V >d  
//实例FileSplitterFetch byI" ?  
//启动FileSplitterFetch线程 %1 )c{7  
//等待子线程返回 L!:NL#M  
try{ :|(YlNUv  
if(bFirst) )Ra:s>  
{ 2{j$1EdI@-  
nFileLength = getFileSize(); L]MWdD  
if(nFileLength == -1) 0f5 ag&  
{ W/UA%We3+L  
System.err.println("File Length is not known!"); 0m3hL~0(a  
} $T K*w8@:  
else if(nFileLength == -2) z6w'XA1_+t  
{ bhD-;Y!6;  
System.err.println("File is not access!"); !Q"L)%)'A  
} -Y524   
else 6 ZRc|ZQ  
{ \~8W0q.4M  
for(int i=0;i<nStartPos.length;i++) dCo)en  
{ UnDCC_ud  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p l^;'|=M  
} :WRD<D_4  
for(int i=0;i<nEndPos.length-1;i++) uzxwJs'fz  
{ = 9Yf o,F  
nEndPos = nStartPos[i+1]; y CHOg  
} VKPEoy8H  
nEndPos[nEndPos.length-1] = nFileLength; wa,`BAKJ+F  
} *w;?&)8%  
} S }`f&  
79 4UY  
K1X-<5]{  
//启动子线程 Y-})/zFc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D zD5n  
for(int i=0;i<nStartPos.length;i++) ~0,v Q   
{ j)/Vtf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jvQ^Vh!mC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {*;8`+R&  
nStartPos,nEndPos,i); !%$[p'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bYLYJ`hH<R  
fileSplitterFetch.start(); x"Ll/E)\v]  
} N?m)u,6-l  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9X*Z\-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IiniaVuQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <%.%q  
nEndPos = " + nFileLength); te[uAJ1 N  
// fileSplitterFetch[nPos.length-1].start(); O^\:J 2I(  
cS Lj\'`b  
q5r7 KYH{  
//等待子线程结束 2W0nA t  
//int count = 0; hbYstK;]Z  
//是否结束while循环 /$%&fo\[  
boolean breakWhile = false; `.;U)}Tn  
KK 7}q<&i  
7[=G;2<  
while(!bStop) 8qkQ*uJP  
{ dm/3{\ 4  
write_nPos(); 7W}%ralkg  
Utility.sleep(500); "yH?df24  
breakWhile = true; !r.-7hR$  
274j7Y'  
9+y&&;p  
for(int i=0;i<nStartPos.length;i++) ~ ?nn(Q-  
{ dlvU=^G#G  
if(!fileSplitterFetch.bDownOver) r3x;lICx-  
{ ]+`K\G ^X  
breakWhile = false; d s`YVXKH  
break; FrMXf,}  
} \\EX'L  
} 9Avj\G  
if(breakWhile) &wU"6E  
break; ,62~u'hR5  
e,#w* |  
;S^"Y:7)  
//count++; \ o2oQ3  
//if(count>4) [<i3l'V/[  
// siteStop(); 5 `TMqrk  
} M>=@Z*u/+  
~I N g9|  
:kcqf,7  
System.err.println("文件下载结束!"); &(<>} r  
} <`-sS]=d}  
catch(Exception e){e.printStackTrace ();} l'<&H#A;'  
} PO5,lcBD<  
\roJf&O }  
pGU .+[|(  
//获得文件长度 W0x9^'=s\  
public long getFileSize() v8)wu=u  
{ \ P6 !  
int nFileLength = -1; 7>im2"zm  
try{ , l!>+@  
URL url = new URL(siteInfoBean.getSSiteURL()); An>ai N]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9Znc|<  
httpConnection.setRequestProperty("User-Agent","NetFox"); b`%u}^B {  
< - sr&  
\6GNKeN  
int responseCode=httpConnection.getResponseCode(); V %[t'uh  
if(responseCode>=400) {_W8Qm`.  
{ U}HSL5v  
processErrorCode(responseCode); /Q9Cvj)"  
return -2; //-2 represent access is error q8ZxeMqx%  
} _=x*yDPG}  
851BOkRal4  
q/w5Dx|:  
String sHeader; tHaHBx1P  
bkR~>F]FAu  
0-OKbw5%=b  
for(int i=1;;i++) QpzdlB44l  
{ <gX({FA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <9H3d7%  
//Utility.log(in.readLine()); Q7pCF,;  
sHeader=httpConnection.getHeaderFieldKey(i); vD2(M1Q  
if(sHeader!=null) :?EZ\WM7  
{ Lm!]m\LRZD  
if(sHeader.equals("Content-Length")) C!547(l[  
{ 29 !QE>Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &!;o[joG  
break; c{`!$Z'k<  
} ((AK7hb  
} PC"=B[OlJ  
else 4D 5Wse  
break; D$KP>G  
} | J'k 9W"  
} q%bFR[p<*  
catch(IOException e){e.printStackTrace ();} (Of`VT3ZOA  
catch(Exception e){e.printStackTrace ();} *eD[[HbKX  
l %zbx"%x  
s`Z.H5V>\  
Utility.log(nFileLength); G$_)X%Vb I  
{8":c n j  
QgH{J8 0  
return nFileLength; ekfa"X_  
} 5KbPpKpd  
i \Yd_  
Q7`)&^ Hx  
//保存下载信息(文件指针位置) @) MG&X  
private void write_nPos() jB9~'>JY  
{ S_*Gv O  
try{ rpEIDhHv  
output = new DataOutputStream(new FileOutputStream(tmpFile)); F@z%y'5 Z*  
output.writeInt(nStartPos.length); [ZG>FJDl8  
for(int i=0;i<nStartPos.length;i++) |0p@'X1  
{ RwK6u-u#9  
// output.writeLong(nPos); b&,Z mDJh  
output.writeLong(fileSplitterFetch.nStartPos); .|DrXJ \c  
output.writeLong(fileSplitterFetch.nEndPos); 5m@'( ] j  
} qoT&N,/  
output.close(); TqS s*as5  
} 5s%e9x|kP  
catch(IOException e){e.printStackTrace ();} cJ?,\@uuP  
catch(Exception e){e.printStackTrace ();} FW2x  
} 1foG*   
:SwA) (1  
|ggtb\W  
//读取保存的下载信息(文件指针位置) /J"fbBXwY  
private void read_nPos() !:xE X~  
{ 7uUq+dp  
try{ AW_YlS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i,;a( Sy4  
int nCount = input.readInt(); SG~HzQ\%  
nStartPos = new long[nCount]; TXd6o=  
nEndPos = new long[nCount]; D'moy*E  
for(int i=0;i<nStartPos.length;i++) rkh%[o 9"/  
{ .`u8(S+  
nStartPos = input.readLong(); F&CvqPI  
nEndPos = input.readLong(); ZJFF4($qN  
} >^W6'Q$P<  
input.close(); F;/^5T3wI  
} fGH)Fgo`  
catch(IOException e){e.printStackTrace ();} #u"@q< )  
catch(Exception e){e.printStackTrace ();} s7jNRY V  
} fhdqes])  
rT-.'aQ2t  
%#EzZD  
private void processErrorCode(int nErrorCode) LH`$<p2''r  
{ a_\7Ho$^  
System.err.println("Error Code : " + nErrorCode); 2!9W:I7  
} s LDEa  
$zhvI*0  
ut]&3f''  
//停止文件下载 iBWEZw)  
public void siteStop() ME)='~E  
{ $t6t 6<M)  
bStop = true; SY.koW  
for(int i=0;i<nStartPos.length;i++) g@t..xJ,  
fileSplitterFetch.splitterStop(); B4zuWCE@  
5KTFf6Uq  
?|`n&HrP  
} PxWH)4  
} gDw(_KC  
//负责部分文件的抓取 &_@M 6[-  
**FileSplitterFetch.java 7^@ 1cA=S  
*/ 2=<,#7zlJ  
package NetFox; ())_4 <  
!Dc;R+Ir0!  
I"8Z'<|/\q  
import java.io.*; qv2J0'd'.  
import java.net.*; VWYNq^<AT  
e<8KZ  
iB~dO @  
public class FileSplitterFetch extends Thread { S<*1b 6%D  
+?QHSIQo  
sVnq|[ /  
String sURL; //File URL W<O/LHKHdn  
long nStartPos; //File Snippet Start Position <Vh5`-J  
long nEndPos; //File Snippet End Position pvWj)4e  
int nThreadID; //Thread's ID t"~X6o|R  
boolean bDownOver = false; //Downing is over 1 K^-tms  
boolean bStop = false; //Stop identical {65Y Tt%  
FileAccessI fileAccessI = null; //File Access interface 5,O:"3>c  
ZOppec1D  
eH*i_g'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gC%$)4-:  
{ cdI"=B+C\  
this.sURL = sURL; c>r~pY~$  
this.nStartPos = nStart; b; vVlIG  
this.nEndPos = nEnd; 2>J;P C[;  
nThreadID = id; JHg;2xm"<K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1x sJz^%V  
} i$:yq.DW  
P;X0L{u0H  
6%o@!|=I  
public void run() tp ky  
{ E=bZ4 /  
while(nStartPos < nEndPos && !bStop) ={p<|8`"  
{ xvWP^Qkb  
,WoB)V.{(  
*uxKI:rB:  
try{ }`2+`w%uZ  
URL url = new URL(sURL); az}zoFl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R(}!gv}s  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;d}n89DXj  
String sProperty = "bytes="+nStartPos+"-"; %X\Rfn0J"  
httpConnection.setRequestProperty("RANGE",sProperty); w8KxEV=  
Utility.log(sProperty); ;?-{Uk  
`$JOFLa  
D-m%eP.  
InputStream input = httpConnection.getInputStream(); ePSD#kY5  
//logResponseHead(httpConnection); |\C.il7  
,W]}mqV%.'  
:4\_upRE  
byte[] b = new byte[1024]; h7xgLe@  
int nRead; h-m0Ro?6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,oEAWNbgQ  
{ b$*G&d5  
nStartPos += fileAccessI.write(b,0,nRead); Jcp=<z*0  
//if(nThreadID == 1) d(5j#?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p-z!i+  
} (f* r  
AO7X-,  
7 lq$PsC  
Utility.log("Thread " + nThreadID + " is over!"); L<Z2  
bDownOver = true; ?Qpi(Czbpq  
//nPos = fileAccessI.write (b,0,nRead); S!iDPl~  
} # ?u bvSdU  
catch(Exception e){e.printStackTrace ();} ?]}=4  
} D{+D.4\  
} 1P BnGQYM  
F=UW[zy/[  
pC&i!la{o}  
//打印回应的头信息 09iD| $~  
public void logResponseHead(HttpURLConnection con) [eDRghK  
{ g)<[-Q1  
for(int i=1;;i++) /pGx !  
{ 1aUu:#c  
String header=con.getHeaderFieldKey(i); K$$%j"s  
if(header!=null) S;{[];  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); m .En!~t  
Utility.log(header+" : "+con.getHeaderField(header)); C+C1(b;1  
else 0.wN&:I8t  
break; :yOJL [x  
} pQm-Hr78j  
} v1NFz>Hx  
BK.RYSN  
(<|1/^~=  
public void splitterStop() q}&+{dN\1  
{ You~ 6d6Om  
bStop = true; L[:M[,?=`  
} .4=A:9  
d%1 Vby  
N VDvd6  
} oTpoh]|[  
J=#9eW  
^$8WV&5q>  
/* tkHUX!Ow;  
**FileAccess.java 52*KRq o  
*//文件访问(定位,写) r"lh\C|  
package NetFox; &{x`K4N  
import java.io.*; _<)HFg6  
7{[i)  
tkdyR1-  
public class FileAccessI implements Serializable{ uF T5Z  
EmV ZqW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9lX+?m~ ~  
RandomAccessFile oSavedFile; (=s%>lW|  
long nPos; %S%0/  
u z:@  
)Mw 3ZE92  
public FileAccessI() throws IOException 7$:Jea  
{ MV?sr[V-oP  
this("",0); +AOpB L'  
} t`x_@pr  
y)`q% J&  
PO0/C q)  
public FileAccessI(String sName,long nPos) throws IOException d 4;   
{ 42 rIIJ1A  
oSavedFile = new RandomAccessFile(sName,"rw"); S ^@# %>  
this.nPos = nPos; `6G:<wX  
oSavedFile.seek(nPos); u$1^=  
} 5S #6{Y =  
\Xg`@JrTM  
;;zd/n2b  
public synchronized int write(byte[] b,int nStart,int nLen) '/F~vSQsR  
{ o@|kq1m8  
int n = -1; [i]%PVGW  
try{ ]Ai!G7s8P  
oSavedFile.write(b,nStart,nLen); )B Xl|V,  
n = nLen; 5R#:ALwX:  
} No w2ad&  
catch(IOException e) I]N!cEr;@-  
{ '\LU 8VC  
e.printStackTrace (); C2K<CDVw  
} 3;EBKGg|  
? )"v~vs  
n,|YJ,v[  
return n; /_/Z/D!  
} z-h7v5i"  
yc@ :*Z  
bKPjxN?!9  
} #r80FVwiD  
G4,BcCPQ  
.J9\Fr@  
/* 8"x\kSMb  
**SiteInfoBean.java h,2?+}Fn  
*/ 9h^TOZK)  
package NetFox; g);.".@"  
$s5D/60nO  
<D(|}5qR  
public class SiteInfoBean { ~fly6j|u  
ltmD=-]G_  
q62U+o9G  
private String sSiteURL; //Site's URL d>1#|  
private String sFilePath; //Saved File's Path 7e<\11uI]a  
private String sFileName; //Saved File's Name v7D3aWoe  
private int nSplitter; //Count of Splited Downloading File KKJa?e`C  
qnU$Pd  
vXc gl  
public SiteInfoBean() 4ak} "Z  
{//nSplitter的缺省值为5 3_c4+u"6  
//default value of nSplitter is 5 [[8h*[:  
this("","","",5); HlX2:\\  
} ]"\XTL0  
VDPq3`$+v{  
Wi!$bL`l  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (:J U  
{ G)y'exk  
sSiteURL= sURL; 4 !M6 RL8{  
sFilePath = sPath; F}_Zh9/$(  
sFileName = sName; ${, !Ll7)  
this.nSplitter = nSpiltter; m:5bb 3  
L"V~M F  
wHhIa3_v  
} DBzF\-  
ZZF\;  
azp XE  
public String getSSiteURL() Hbz,3{o5  
{ BjbpRQ,  
return sSiteURL; '3ZYoA%  
} >U') ICD~  
H6-{(: *<  
#h7 $b@  
public void setSSiteURL(String value) 'd|E>8fejG  
{ <=!|U0YV  
sSiteURL = value; #Xd#Nc j  
} ou'|e"tI  
4 {3< `  
-*&C "%e  
public String getSFilePath() N!=Q]\ZD  
{ 5[>N[}Ck>  
return sFilePath; dZjh@yGP.  
}  ,zrShliU  
%Z6\W; (n  
Zl`sY5{1  
public void setSFilePath(String value) N`i`[ f  
{ %c,CfhEV%&  
sFilePath = value; 55|.MXzq  
} 7!E7XP6,~>  
E 5bo60z  
Z~Z+Yt;,9a  
public String getSFileName() `_H^k !^  
{ v_ W03\  
return sFileName; t%>x}b"2T  
} AZjj71UE  
I~I$/j]e`  
]%/a'[  
public void setSFileName(String value) ]$96#}7N  
{ nXF|AeAco  
sFileName = value; z6J fu:_N!  
} b'~IFNt*^  
i3\6*$Ug  
9k>=y n  
public int getNSplitter()  |{@_J  
{ @IwVR  
return nSplitter; QG=&{-I~[3  
} SB`"%6  
U?Icyn3q0  
HFd>UdT%  
public void setNSplitter(int nCount) vxC,8Z  
{ auT$-Ki8  
nSplitter = nCount; i#y3QCNqf^  
} 6J%+pt[tu  
} j{a3AEmps  
iVGc\6+'  
*Ad7GG1/u  
/* yS:1F PA$_  
**Utility.java 2Md'<.  
*/ IKV:J9  
package NetFox; ZIrJ"*QO=  
A?sU[b6_  
W e*)RXm%  
public class Utility { n/]$k4h  
Yl6\}_h`  
~_Mz05J-\_  
public Utility() :-kXZe  
{ ]w=6.LzO*  
juuV3et  
iy_\1jB0  
} zx{O/v KG  
r'ydjy  
//线程睡眠 5=.EngG  
public static void sleep(int nSecond) q#~]Hp=W5  
{ 35[8XD  
try{ XK5qE"  
Thread.sleep(nSecond); = A !;`G  
} /RmHG H!  
catch(Exception e) _}B:SM  
{ R?Or=W)i  
e.printStackTrace (); ~:%rg H  
} K9y!ZoB  
} nC5  
NK@G0p~O  
//日志 &`'gO 9  
public static void log(String sMsg) 7E9h!<5v  
{ .1F^=C.w  
System.err.println(sMsg); H19CVc\B  
} k98}Jx7J)"  
L){rv)?="  
_8'FI_E3  
public static void log(int sMsg) k&1~yW  
{ '.wyfSH@  
System.err.println(sMsg); y[l19eU  
} RZ[r XV5  
} )ccd fSe  
1Bz'$u;  
FT* o;&_QS  
/* jbqhNsTNK  
**TestMethod.java ^Q?I8,4}  
*/ GBZx@B[TY  
package NetFox; =R^V[zTn_  
?_F,HhQ  
0F<O \  
public class TestMethod { w^&TG3m1~  
^E7>!Lbvx  
?)cNe:KY  
public TestMethod() $[Fh|%\  
{ ///xx/weblogic60b2_win.exe ntSPHK|'  
try{ F=hfbCF5x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uj-q@IKe  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -hP@L ++D  
SiteFileFetch fileFetch = new SiteFileFetch(bean); khb Gyg%  
fileFetch.start(); %L./U$  
} ?~a M<rcZ  
catch(Exception e){e.printStackTrace ();} jz$)*Kdi*  
-< 7KW0CA  
OZ q/'*  
} WbS2w @8  
8<t?o'9I  
<&o `T4  
public static void main(String[] args) .O'gD.|^N  
{ <)]B$~(a  
new TestMethod(); m//(1hWv7  
} `oh'rm3'8  
} 1Ly?XNS  
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