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http断点续传简单实现(java)

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/* 0drc^rj !  
**SiteFileFetch.java |'(IWU  
*/ SK2pOZN  
package NetFox; tjL#?j  
import java.io.*; a MD?^  
import java.net.*; 9$t@Gmn  
A#\X-8/  
'7%9Sqx  
public class SiteFileFetch extends Thread { ?q7Gs)B=^'  
-O6o^Dk  
8;bOw  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4K,&Q/Vdd7  
long[] nStartPos; //开始位置 SxyFFt  
long[] nEndPos; //结束位置 %|||M=akk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g-`NsqzD  
long nFileLength; //文件长度 Va:jMN  
boolean bFirst = true; //是否第一次取文件 J#^M   
boolean bStop = false; //停止标志 3KZ h?~B  
File tmpFile; //文件下载的临时信息 #7)6X:/O  
DataOutputStream output; //输出到文件的输出流 9EQ,|zf'  
riQ?'!a7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) HxAa,+k  
public SiteFileFetch(SiteInfoBean bean) throws IOException z(` kWF1<  
{ OTm"Iwzu@  
siteInfoBean = bean; Ds$;{wl#x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F U%b"gP^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 6 >2! kM7  
if(tmpFile.exists ()) D=+sD"<|  
{ 7X"cu6%\  
bFirst = false; d DTt_B  
read_nPos(); `8*$$JC  
} e<pojb1Q  
else 5 [*jfOz  
{ Ei!z? sxzx  
nStartPos = new long[bean.getNSplitter()]; uDUSR+E>  
nEndPos = new long[bean.getNSplitter()]; B$n\m854  
} dWEx55>,1  
Ro69woU  
-R]S)Odml  
"^%Il  
} p^3d1H3   
5^i ^?  
P^r8JhDJ  
public void run() q1j[eru  
{ 1,,:4 *)  
//获得文件长度 ~M=`f{-$K  
//分割文件 (nG  
//实例FileSplitterFetch Si(?+bda0c  
//启动FileSplitterFetch线程 ^|2qD: ;  
//等待子线程返回 W*#/@/5  
try{ jLU)S)  
if(bFirst) SX.v5plhc  
{ >U]. k8a)  
nFileLength = getFileSize(); qx NV~aK  
if(nFileLength == -1) /fEXAk  
{ G"(!5+DLy  
System.err.println("File Length is not known!"); ~5zhK:7c  
} 4H)a7 <,  
else if(nFileLength == -2) W\.(~-(So  
{ !cZIoz  
System.err.println("File is not access!"); N~_gT Jr~P  
} N[%IrN3  
else Ex{]<6UAu  
{ `K.yE0^i  
for(int i=0;i<nStartPos.length;i++) o>h>#!e  
{ G5Nub9_*X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); y+_U6rv[  
} 4ai3@f5  
for(int i=0;i<nEndPos.length-1;i++) G9TUU.T  
{  K!j2AP3  
nEndPos = nStartPos[i+1]; W&nVVV8s@  
} G}x^PJJt  
nEndPos[nEndPos.length-1] = nFileLength; 7Udr~ 0_)  
} g|Cnj  
} e~1??k.;=  
psBBiHB[L  
~EymD *  
//启动子线程 qp8;=Nfa  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +a{>jzR  
for(int i=0;i<nStartPos.length;i++) P^z)]K#sw  
{ d4U_Wu&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -#@;-2w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZzY6M"eUXD  
nStartPos,nEndPos,i); p}\!"&,^m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !!AutkEg>  
fileSplitterFetch.start(); (<t)5?@%  
} f#?R!pR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^"I!+Teb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o z QL2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )DW;Gc  
nEndPos = " + nFileLength); S!uyplYKF  
// fileSplitterFetch[nPos.length-1].start(); ]`x~v4JU  
l?d*g&  
xK f+.6 wz  
//等待子线程结束 gw-l]@;1  
//int count = 0; mi+I)b=  
//是否结束while循环 sSxra!tv4  
boolean breakWhile = false; b@k3y9 &  
wcO_;1_ H  
6N ^FJCs  
while(!bStop) &7cy9Z~m  
{ z]pH'c39  
write_nPos(); MC3{LVNK  
Utility.sleep(500); q QQ~ [JL  
breakWhile = true; >A6lX)  
tO#y4<  
#Uo 9BM  
for(int i=0;i<nStartPos.length;i++) <?!#QA  
{ 3:r;(IaX  
if(!fileSplitterFetch.bDownOver) dCBJV  
{ D<:9pLD(  
breakWhile = false; >:.Bn8-  
break; 3s+D x$Ud  
} Z+4J4Ka^!(  
} 1*s Lj#  
if(breakWhile) @d)6LA9Ec  
break; q;U[f6JjE  
aV1(DZ83  
&WIPz\  
//count++; !GO4cbdQ  
//if(count>4) N?aU<-Tn  
// siteStop(); #qzozQ4  
} giv cq'L  
3 ;&N3:,X  
p AD@oPC  
System.err.println("文件下载结束!"); hP #>`)aNY  
} y3l sAe#  
catch(Exception e){e.printStackTrace ();} 6D>o(b2  
} ~<aCn-h0  
a`}HFHm\2,  
:)&_  
//获得文件长度 FXIQS'  
public long getFileSize() ^ `!6Yax?  
{ L(iWFy1& T  
int nFileLength = -1; hTF]-& hZ  
try{ W n|w~{d{  
URL url = new URL(siteInfoBean.getSSiteURL()); v vFX\j3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h4]yIM `8d  
httpConnection.setRequestProperty("User-Agent","NetFox"); nlKWZYv  
N( Cfv3{  
3S Dw-k  
int responseCode=httpConnection.getResponseCode(); ]kr OPM/  
if(responseCode>=400) =6ojkTk  
{ zg|]Ic  
processErrorCode(responseCode); 1 #_R`(C{  
return -2; //-2 represent access is error 0-7xcF@s  
} #P1k5!u  
3ILEc:<0J  
ZT!DTb B  
String sHeader; l =#uy  
A@GyKx%x$  
`6'fX[j5  
for(int i=1;;i++) ^;M!u8[  
{ e4t'3So  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b}Jcj  
//Utility.log(in.readLine()); r@ ]{`qA  
sHeader=httpConnection.getHeaderFieldKey(i); A+AqlM+$i  
if(sHeader!=null) 94A re<  
{ U:p<pTnMR  
if(sHeader.equals("Content-Length")) (2 X`imJ  
{ tONxV`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v]BN.SHE_  
break; `uY77co6  
} (c_E*>c)  
} 26j ; RV  
else Y2}\~I0  
break; Go8 m  
} :\>@yCD  
} f$R]m2  
catch(IOException e){e.printStackTrace ();} \ 7jK6;R<  
catch(Exception e){e.printStackTrace ();} N,L$+wm  
C/!kMMh>vV  
? 3Td>x  
Utility.log(nFileLength); so1% MV  
.,I^)8c  
Bf.@B0\  
return nFileLength; Ft'?43J  
} Y'wQ(6ok  
yi PMJ  
THC34u]  
//保存下载信息(文件指针位置) ;BsyN[bF  
private void write_nPos() }Til $TT%H  
{ x^&D8&4^  
try{ ry0P\wY}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !IF#L0z  
output.writeInt(nStartPos.length); \G:\36l  
for(int i=0;i<nStartPos.length;i++) _DS_AW}D  
{ mGb,oj7l  
// output.writeLong(nPos); e2~&I`ct  
output.writeLong(fileSplitterFetch.nStartPos); @-)jU!  
output.writeLong(fileSplitterFetch.nEndPos); l!5fuB8  
} B E!HM{-  
output.close(); edD19A  
} bkTk:-L5:  
catch(IOException e){e.printStackTrace ();} [jU.58*  
catch(Exception e){e.printStackTrace ();} ]hRCB=G  
} qXcHf6  
J sde+G,N  
-pvF~P?8U  
//读取保存的下载信息(文件指针位置) llN#4D9s  
private void read_nPos() [f 4Nq \i  
{ 7S|nn|\Kp  
try{ ' GcN9D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6B'd]Fe  
int nCount = input.readInt();  [,JUC<  
nStartPos = new long[nCount]; VXX7Y? !  
nEndPos = new long[nCount]; DvhJkdLB>  
for(int i=0;i<nStartPos.length;i++) }f45>@uMW  
{ 8iQ8s;@S&>  
nStartPos = input.readLong(); jOV,q%)^,:  
nEndPos = input.readLong(); G&,F-|`  
} "k&QS@l  
input.close();  xY v@  
} YBF|0A{[Y  
catch(IOException e){e.printStackTrace ();} 4Qwv:4La  
catch(Exception e){e.printStackTrace ();} A0JlQE&U  
} EbXWCD  
t*KgCk1  
G*`Y~SJp  
private void processErrorCode(int nErrorCode) -y]e`\+[  
{ u4hC/!  
System.err.println("Error Code : " + nErrorCode); ;d5d$Np@m&  
} uf q9+}  
Q6%dM'fR  
s 1~&PH^  
//停止文件下载 F)XO5CBK  
public void siteStop() re[v}cB  
{ },#@q_E  
bStop = true; l<X8Ooan#{  
for(int i=0;i<nStartPos.length;i++) =zBc@VTp  
fileSplitterFetch.splitterStop(); c{4Y?SSx  
J7a_a>Y  
,0k3Qi%  
} 4@0y$Dv\  
} x:dI:G  
//负责部分文件的抓取 n3x< L:)  
**FileSplitterFetch.java BeFCt;  
*/ -aSj-  
package NetFox; n06T6oc  
P~xP@? I%  
ZE393FnE  
import java.io.*; ,Kl6vw8Htg  
import java.net.*; ~!//|q^ J]  
A-S!Z2m\  
 a>6@1liT  
public class FileSplitterFetch extends Thread { #z$g1\v  
Cg#@JuwHa  
T'8d|$X  
String sURL; //File URL 85gdmla@9  
long nStartPos; //File Snippet Start Position ';,Rq9-'  
long nEndPos; //File Snippet End Position MbbKo-7F$  
int nThreadID; //Thread's ID ` b$u w  
boolean bDownOver = false; //Downing is over h_*!cuH  
boolean bStop = false; //Stop identical }LYK:?_/  
FileAccessI fileAccessI = null; //File Access interface I)s~kA.e  
KdN+$fe*g  
v2K6y|6,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0vYHx V  
{ MeCHn2zwB  
this.sURL = sURL; 3+~m9:9  
this.nStartPos = nStart; L>@:Xo@  
this.nEndPos = nEnd; Fx!NRY_  
nThreadID = id; g._`"c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @3g$H[}  
} 9lU"m_ QT4  
&GKtD)  
V =9  
public void run() K."%PdC  
{  iup "P  
while(nStartPos < nEndPos && !bStop) CQ;.}=j ,  
{ |g)/6jG<-  
;nx? 4f+6h  
DWXxB  
try{ @a~GHG[x  
URL url = new URL(sURL); QtSJ9;eP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZkA05wPZ#  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0cF +4,5  
String sProperty = "bytes="+nStartPos+"-"; .+#<~Jv  
httpConnection.setRequestProperty("RANGE",sProperty); (Vz\02,K  
Utility.log(sProperty); Thc"QIk&4  
!TwH;#U w  
,Y+J.8.H   
InputStream input = httpConnection.getInputStream(); E!rgR5Bd  
//logResponseHead(httpConnection); JbR;E`8  
XSBh+)0Ww  
-h%!#g  
byte[] b = new byte[1024]; z\g6E/%%  
int nRead; yb4Jsk5%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LFwRTY,G  
{ $_5a1Lq1  
nStartPos += fileAccessI.write(b,0,nRead); ]:g;S,{  
//if(nThreadID == 1) 09_5niaz[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S W; %2  
} L!qXt(`  
 "o{o9.w  
VC T~"T2R  
Utility.log("Thread " + nThreadID + " is over!"); .e Jt]K  
bDownOver = true; kklM"Av  
//nPos = fileAccessI.write (b,0,nRead); =}pPr]Cc  
} :i};]pR   
catch(Exception e){e.printStackTrace ();} d&G#3}kOb%  
} P \k5%  
} n`TXm g  
\+3P<?hD#  
0x1#^dII  
//打印回应的头信息 Tm) (?y  
public void logResponseHead(HttpURLConnection con) $C^tZFq  
{ aePLP  
for(int i=1;;i++) iVdY\+N!<  
{ 3;-P(G@  
String header=con.getHeaderFieldKey(i); K3I|d;Y~X!  
if(header!=null) wR@"]WkR=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &ZR}Z7E*=  
Utility.log(header+" : "+con.getHeaderField(header)); {37v.4d;  
else +$SJ@IH[<  
break; L0QF(:F5  
} > 3SZD  
} +BaZl<ZP1s  
,e93I6  
$kD ;*v=  
public void splitterStop() l2|[  
{ :d{-"RAG"  
bStop = true; a?K3/0G  
} Ro:DAxi @L  
xa&5o`>1G  
lHI ;fR  
} '2=$pw  
BK/_hNz  
zMI_8lNz  
/* 9o<5Z=  
**FileAccess.java /$Ca }>  
*//文件访问(定位,写) e]Q bC "  
package NetFox; ?y`we6~\1  
import java.io.*; S?BI)shmg  
KP*cb6vA  
Wm#F~<$  
public class FileAccessI implements Serializable{ 8H7=vk+  
1Ht&;V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QoBM2Q YO  
RandomAccessFile oSavedFile; (_.0g}2  
long nPos; >"?jW@|g  
mYRsM s  
kh5VuXpe  
public FileAccessI() throws IOException )/mBq#ZS  
{ j.:I{!R#  
this("",0); -qNun3  
} fnZ?YzLI  
2Q81#i'Cm  
F!*tE&Se+  
public FileAccessI(String sName,long nPos) throws IOException -RKqbfmi=  
{ b2vCr F;  
oSavedFile = new RandomAccessFile(sName,"rw"); Y k @/+PE  
this.nPos = nPos; .tQeOZW'  
oSavedFile.seek(nPos); `-)Hot)  
} `~;`q  
jBLLx{  
zNRR('B?  
public synchronized int write(byte[] b,int nStart,int nLen) HpGI\s  
{ Zv|TvlyT"  
int n = -1; Uw5AHq).  
try{ =6H  
oSavedFile.write(b,nStart,nLen); 'fS&WVR?  
n = nLen; i8Xz'Sw07  
} FhJtiw@  
catch(IOException e) bg/a5$t  
{ |SSe n#PYp  
e.printStackTrace (); !E.CpfaC  
} t;/s^-}  
kPvR ,  
{[:]}m(c  
return n; ~/m=Q<cV  
} ?Jy /]j5fI  
W\1V`\gF  
4qvE2W}&  
} +.pri  
j[Z<|Da  
[$e\?c  
/* 4Gor*{  
**SiteInfoBean.java )Rc  
*/ MfG8=H2#|  
package NetFox; PW QRy  
MiN|u  
C.N#y`g  
public class SiteInfoBean { o8c5~fG1  
F\Q X=n  
M"!{Dx~  
private String sSiteURL; //Site's URL  P0<)E  
private String sFilePath; //Saved File's Path >hv8zHOO:  
private String sFileName; //Saved File's Name vlVHoF;&  
private int nSplitter; //Count of Splited Downloading File .8]buM5_G  
FXG,D J:  
6^NL>|?  
public SiteInfoBean() Qy7pM8~h  
{//nSplitter的缺省值为5 $i;m9_16  
//default value of nSplitter is 5 TW~%1G_v  
this("","","",5); /H~]5JZ3-E  
} 8z)J rO}  
S(#v<C,hd  
]Il}ymkIZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8/"R&yAh  
{ WbJ  
sSiteURL= sURL; JJ4w]Dd4  
sFilePath = sPath; .Ge`)_e  
sFileName = sName; <pIel   
this.nSplitter = nSpiltter; 2OZ<t@\OY  
L#MgoBXr  
9+"ISXS  
} `;)op3A'  
E++3GagdiD  
8;y\Ln?B  
public String getSSiteURL() 4L<;z'   
{ S5/p3;O\c  
return sSiteURL; K_GqM9  
} FM,o&0HSd  
'4)4*3z,  
,Q,3^v-  
public void setSSiteURL(String value) e !N%   
{ Y,M 2 D  
sSiteURL = value; b NR@d'U  
} 2Kz407|'  
.1F41UyL  
WCyjp  
public String getSFilePath() KMP[Ledr  
{ lXip%6c7  
return sFilePath; yi:1cLq2  
} 1k!$#1d<  
=;{8)m  
iLk"lcX  
public void setSFilePath(String value) %@^9(xTE  
{ &UIS17cT  
sFilePath = value; Rja>N)MzBf  
} iD) P6"  
NszqI  
H,Yrk(O-  
public String getSFileName() KvmXRf*z  
{ 9E2OCLWrE  
return sFileName; >2ny/AK|  
} Gdv{SCV  
I<!,_$:  
R_gON*9  
public void setSFileName(String value) Lm7fz9F%  
{ ~}g) N  
sFileName = value; ?P"j5  
} e$N1m:1*  
I>:.fHvUC  
,~>u<Wc!S  
public int getNSplitter() Bxk2P<d  
{ N4w&g-  
return nSplitter; Dpkc9~z  
} g-<[* nF  
5@EX,$h  
wpa^]l  
public void setNSplitter(int nCount) b|u,[jEB  
{ x }i'2   
nSplitter = nCount; 7'RU\0QG  
} (|sqN8SbA  
} MrhJk  
Hh'o:j(^  
# 66vkf*  
/* j1K?QH=e#{  
**Utility.java >=YQxm}GJ  
*/ b X4]/4%  
package NetFox; dF'oZQz  
iCdq-r/r!6  
Z4{~  
public class Utility { :tp{(MF  
Y|L]#  
85ND 3F6q4  
public Utility() ,8+Jt@L  
{ Ae'N1V  
=|qYaXjT$  
$O,IXA  
} 7%yP5c B  
r-ljT<f%J[  
//线程睡眠 VE*& t>I  
public static void sleep(int nSecond) ^K[[:7Aem  
{ 4_w{~  
try{ |V mQ  
Thread.sleep(nSecond); w C-x'  
} T^H`$;\  
catch(Exception e) *wV`7\@  
{ L87=*_!B;  
e.printStackTrace (); %i@Jw  
} .1h1J  
} m-R`(  
{%QWv%|  
//日志 ty b-VO  
public static void log(String sMsg) -bp7X{&  
{ ;xjw'%n,  
System.err.println(sMsg); T9]:, z  
} :.?%e{7  
e`;U9Z  
s3oQ( wC %  
public static void log(int sMsg) Df0m  
{ v}&J*}_XZ  
System.err.println(sMsg); y-vQ4G5F|  
} }bYk#6KX  
} 5Cl;h^R|m  
c'Zs2s7$  
WxS$yUu  
/* N>',[4pJ|  
**TestMethod.java  6adXE  
*/ rM)-$dZ  
package NetFox; 2IFEl-IB[  
=R0#WMf$@  
dPyZzMes=  
public class TestMethod { #i| AE`  
5 DvD  
Cm[^+.=I  
public TestMethod()  ui1h M  
{ ///xx/weblogic60b2_win.exe l5l#LsaQb  
try{ <9aa@c57  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q|kkdK|N/Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); );*#s~R  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Rx.dM_S  
fileFetch.start(); |gM@}!DL  
} ]VHO'z\m  
catch(Exception e){e.printStackTrace ();} .{66q#.  
n]snD1?KX  
8? &!@3n  
} h}f l:J1C  
h0Ilxa   
PVX23y;  
public static void main(String[] args) jHBP:c  
{ .?;"iv+  
new TestMethod(); mE3M$2}  
} xQ@gh ( (  
} DT>Giic  
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