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http断点续传简单实现(java)

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/* DLCkM*'  
**SiteFileFetch.java o-o'z'9  
*/ +S=Rn,  
package NetFox; vVE7fq3  
import java.io.*; UQ4% Xp  
import java.net.*; nJ" '  
oTT7M`P3h  
\w'*z&`W9  
public class SiteFileFetch extends Thread { ;*,f<  
not YeY7wR  
~,2/JDVJ5-  
SiteInfoBean siteInfoBean = null; //文件信息Bean i<(Xr  
long[] nStartPos; //开始位置 Dr6A ,3B  
long[] nEndPos; //结束位置 bBY^+c<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mq%<6/Y U  
long nFileLength; //文件长度 /x1MPP>fu  
boolean bFirst = true; //是否第一次取文件 ]%!u7z|\6  
boolean bStop = false; //停止标志 asC_$tsMe  
File tmpFile; //文件下载的临时信息 +CI1V>6^  
DataOutputStream output; //输出到文件的输出流 F-*2LMe  
'FYJMIs  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *s;|T?~i  
public SiteFileFetch(SiteInfoBean bean) throws IOException z.}[m,oTF  
{ vp.ZK[/`  
siteInfoBean = bean; ~.!c~fke  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )$,"u4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *& m#qEv  
if(tmpFile.exists ()) 2W$cFC  
{ TXZv2P9  
bFirst = false; K5"#~\D  
read_nPos(); )*:`':_a  
} Vi$-Bw$@  
else pBw0"ff  
{ S~Id5T:,  
nStartPos = new long[bean.getNSplitter()]; ~ Uo)0  
nEndPos = new long[bean.getNSplitter()]; ]Ta N{"  
} 72,rFYvpK  
EKp@9\XBC  
\.g\Zib )  
@UdfAyL  
} lqb/eN9(t  
sUYxT>R  
,<2DL p%%D  
public void run() 1J' 3g  
{ "al `$%(  
//获得文件长度 }E_#k]#*  
//分割文件 o`.R!wm:W  
//实例FileSplitterFetch `N5|Ho*C  
//启动FileSplitterFetch线程 K x~|jq  
//等待子线程返回 A7c/N=Cp^  
try{ $O^v]>h  
if(bFirst) ./$cMaDJ  
{ fJWC)E  
nFileLength = getFileSize(); C XHy.&Vt  
if(nFileLength == -1) *x) 8fAr  
{ HQ{JwW!m  
System.err.println("File Length is not known!"); ^S6u<,  
} PpsIhMq@  
else if(nFileLength == -2) xB !6_VlB  
{ wK}\_2?  
System.err.println("File is not access!"); C4NTh}6t T  
} tBct  
else rhL"i^  
{ lb:/EUd5  
for(int i=0;i<nStartPos.length;i++) RNQK  
{ M,5"b+mX[~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !'Q -yoHKD  
} ?,yj")+  
for(int i=0;i<nEndPos.length-1;i++) .Udj@{  
{ sm$ (Y.N  
nEndPos = nStartPos[i+1]; $fgf Y8  
} #);[mW{F  
nEndPos[nEndPos.length-1] = nFileLength; &[hLzlrg  
} vp(;W,ba:|  
} #b7$TV  
wR{'y)$  
=f(cH152T  
//启动子线程 V _c @b%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W14 Vm(`N  
for(int i=0;i<nStartPos.length;i++) ( 9]_ HW[  
{ &5 L<i3BX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cv/_ r#vN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), b}Zd)2G  
nStartPos,nEndPos,i); ".dZn6"mI  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :eZh'-c?  
fileSplitterFetch.start(); `CeJWL5{  
} *:O.97q@h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o!~Jzd.=h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9!><<7TS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V_Wwrhua  
nEndPos = " + nFileLength); # 6!5 2  
// fileSplitterFetch[nPos.length-1].start(); A_;8IlW  
F_bF  
apk4 j\i?5  
//等待子线程结束 ,<A$h3*  
//int count = 0; .6OgO{P:  
//是否结束while循环 !d&C>7nb  
boolean breakWhile = false; ^GBe)~MT  
nhN);R~o"1  
X";@T.ZGut  
while(!bStop) w}{5#   
{ 5Q=P4w!'  
write_nPos(); Pf F=m'  
Utility.sleep(500); ]x&u`$F  
breakWhile = true; z5bo_Eq  
s :`8ZBz~  
Cg616hyut  
for(int i=0;i<nStartPos.length;i++) 3 v")J*t  
{ }$\M{# C~  
if(!fileSplitterFetch.bDownOver) "z<azs  
{ Od?qz1  
breakWhile = false; -LM;}<  
break; hva2o`  
} <A9y9|>o  
} Jdy=_88MD  
if(breakWhile) %okzOKKX  
break; X{kpSA~  
KFZm`,+69  
QKE9R-K TE  
//count++; +-B^Z On  
//if(count>4) 6:% L![FX  
// siteStop(); JH7Ad (:  
} Ez{MU@Fk  
<[GYLN[0Q  
L>Mpi$L  
System.err.println("文件下载结束!"); C%~a`e|/Y  
} wZh:F !  
catch(Exception e){e.printStackTrace ();} Bb{!Yh].:A  
} >*$;  
GjB]KA^  
Kq.:G%  
//获得文件长度 -VZRujl  
public long getFileSize() .q][? mW3  
{ >\w&6 i~  
int nFileLength = -1; 8_K6 0eXz  
try{ +wW@'X  
URL url = new URL(siteInfoBean.getSSiteURL()); U}$DhA"r"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4'p=p#o  
httpConnection.setRequestProperty("User-Agent","NetFox"); )f dE6  
VGqa)ri"  
irk*~k ?  
int responseCode=httpConnection.getResponseCode(); p*5\+WO>!(  
if(responseCode>=400) C[WCg9Av  
{ _j>;ipTb+  
processErrorCode(responseCode); +}Av-47`h  
return -2; //-2 represent access is error aiCn"j  
} 1 qi@uYDug  
pb0E@C/R  
]xd^%q*  
String sHeader; -A-tuyIsh"  
79=45'8  
Z2"? &pKV  
for(int i=1;;i++) hO[3Z ^X  
{ 6x=YQwn~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a,7 &"  
//Utility.log(in.readLine()); dd|W@Xp -  
sHeader=httpConnection.getHeaderFieldKey(i); Iak0 [6Ey  
if(sHeader!=null) x7T +>  
{ 8e0."o.6  
if(sHeader.equals("Content-Length")) s/Xb^XjS1  
{ htP|3B  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1nPZ<^A&@  
break; w{ `|N$  
} ^nVl (^{  
} {0!#>["<  
else 3 ?&h^UX  
break; fE,9zUo  
} *5,c Rz  
} CVXytS?@x  
catch(IOException e){e.printStackTrace ();} #=}$OFg  
catch(Exception e){e.printStackTrace ();} R.s|j=  
`P@- %T  
]IJv-(  
Utility.log(nFileLength); c<+;4z  
%f8Qa"j  
@U -$dw'4  
return nFileLength;  8RwX=  
} t5 a7DD  
BKU'`5`  
~YCuO0t  
//保存下载信息(文件指针位置) fRTo.u  
private void write_nPos() Mp\<cE  
{ 6aOp[-Le  
try{ ) gR=<oa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1px\K8  
output.writeInt(nStartPos.length); nws"RcP+Z  
for(int i=0;i<nStartPos.length;i++) FbACTeB  
{ A<YsfDa_d  
// output.writeLong(nPos); j;K#]  
output.writeLong(fileSplitterFetch.nStartPos); O7aLlZdg~  
output.writeLong(fileSplitterFetch.nEndPos); u1K\@jlw  
} NE|[o0On  
output.close(); 0=v{RQ;W4  
} *Dr5O9Y  
catch(IOException e){e.printStackTrace ();} )y7_qxwbV  
catch(Exception e){e.printStackTrace ();} em2_pq9q  
} t^E hE  
d`Q7"}uZ  
6Gn4asoA  
//读取保存的下载信息(文件指针位置) > 7`&0?  
private void read_nPos() Gt/4F-Gn  
{ # k5#j4!b  
try{ lu UYo  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :6;e\UE  
int nCount = input.readInt(); |sgXh9%x<  
nStartPos = new long[nCount]; 5nCu~<uJ  
nEndPos = new long[nCount]; ``?6=mO  
for(int i=0;i<nStartPos.length;i++) 6-,m}Ce\  
{ PI5j"u UO  
nStartPos = input.readLong(); wz -)1!  
nEndPos = input.readLong(); TF+ l5fv  
} TA}UY7v  
input.close(); EEf ]u7  
} R_D c)  
catch(IOException e){e.printStackTrace ();} iz}sM>^  
catch(Exception e){e.printStackTrace ();} Qu{c B^Ga*  
} (*l2('e#@  
~tm0QrJn/  
`{FwTZ=6{  
private void processErrorCode(int nErrorCode) INMP"1  
{ +lO'wa7|3  
System.err.println("Error Code : " + nErrorCode); igDyp0t  
} A~-#@Z  
qg,Nb  
zXc}W*ymj  
//停止文件下载 xQt 3[(Z  
public void siteStop() a}.Y!O&  
{ :\V,k~asl  
bStop = true; E1>/R  
for(int i=0;i<nStartPos.length;i++) m[2'd  
fileSplitterFetch.splitterStop(); S-E++f9D~  
6 o[/F3`  
,&a`d}g&G  
} oJaAM|7uv  
} V"d=.Hb>  
//负责部分文件的抓取 zJ& b|L  
**FileSplitterFetch.java WO%h"'iJ  
*/ DacJ,in_I{  
package NetFox; )@:l^$x  
jv}=&d  
w;`m- 9<Y  
import java.io.*; VfSGCe  
import java.net.*; "zV']A>4H  
?9U:g(v  
@Y' I,e  
public class FileSplitterFetch extends Thread { /B HepD}  
Di??Q_$ak  
/! ^P)yU,  
String sURL; //File URL ~mILA->F  
long nStartPos; //File Snippet Start Position _C+DBA  
long nEndPos; //File Snippet End Position MguL$W&l  
int nThreadID; //Thread's ID aMCO"66b  
boolean bDownOver = false; //Downing is over 8l xY]UT  
boolean bStop = false; //Stop identical T+TF-] J  
FileAccessI fileAccessI = null; //File Access interface ! sYf<  
#w~0uCzQ@  
B7 "Fp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S=R 3"~p  
{ lpEDPvD_Vm  
this.sURL = sURL; {Jx7_T&  
this.nStartPos = nStart; 8&a_A:h  
this.nEndPos = nEnd; ,hE/II`-d'  
nThreadID = id; %RFYm  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ch,|1}bi  
} R+. Nn  
}V^e7d  
-Z?Ck!00  
public void run() |>s v8/!  
{ ?6:cNdN  
while(nStartPos < nEndPos && !bStop) Fd !iQ  
{ ],?pe  
IrO +5w  
M]ap:  
try{ 9.Ap~Ay.  
URL url = new URL(sURL); Kx]> fHK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A +!sD5d  
httpConnection.setRequestProperty("User-Agent","NetFox"); w#{l 4{X|  
String sProperty = "bytes="+nStartPos+"-"; }GRMZh_8  
httpConnection.setRequestProperty("RANGE",sProperty); h;n\*[fDc  
Utility.log(sProperty); jyjQzt >\  
^('cbl  
?Leyz  
InputStream input = httpConnection.getInputStream(); ?Y!U*& 7  
//logResponseHead(httpConnection); U?6yke  
^uBwj }6  
!1-&Y'+  
byte[] b = new byte[1024]; V [4n'LcE  
int nRead; DNho%Xk  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9}n,@@  
{ h3t$>vs2F"  
nStartPos += fileAccessI.write(b,0,nRead);  [`bZ5*&  
//if(nThreadID == 1) *SGlqR['\e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D{svR-~T  
} eYDgEM  
00,9azs  
5&|5 a} 8  
Utility.log("Thread " + nThreadID + " is over!"); pDhY%w#  
bDownOver = true; lu3.KOD/  
//nPos = fileAccessI.write (b,0,nRead); V* Qe5j9  
} $F1_^A[  
catch(Exception e){e.printStackTrace ();} 3B"7VBK{  
} As}eUm)B5c  
} u[mY!(>nQ  
Gy^FrF   
g =x"cs/[  
//打印回应的头信息 %LcH>sV  
public void logResponseHead(HttpURLConnection con) d q pgf@  
{ =jG?v'X  
for(int i=1;;i++) G:hU{S7  
{ a],h<wGEx  
String header=con.getHeaderFieldKey(i); d"!yD/RD  
if(header!=null) l qXc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ge~,[If+  
Utility.log(header+" : "+con.getHeaderField(header)); |Pf(J;'[  
else D@5s8xv  
break; M4H"].Zm  
} i?W]*V~ply  
} .S6ji~;r  
CjmV+%b4  
8qmknJC  
public void splitterStop() (7 ijt  
{ mLULd}g/o  
bStop = true; <hMtE/05B  
} 1 Xa+%n9  
wVQdUtmk  
xi.IRAZX  
} a G@nErdW  
W7W3DBKtSm  
5R"2Wd  
/* +0U#.|?  
**FileAccess.java z[Z2H5[  
*//文件访问(定位,写) # hZQ>zcF  
package NetFox; 4D GY6PS  
import java.io.*; Y@ObwKcG  
Kc-4W6?$  
1h{>[ 'L  
public class FileAccessI implements Serializable{ \"J?@  
(`F|nG=X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EM=xd~H  
RandomAccessFile oSavedFile; UIz:=DJ  
long nPos; >6k}HrS1V  
[Ek42%  
hRRkFz/0&  
public FileAccessI() throws IOException *3P3M}3~\  
{ HIsB|  
this("",0); @kz!{g]Sn  
} \w3%[+c  
0K/G&c?;=  
RP(a,D|  
public FileAccessI(String sName,long nPos) throws IOException KS?mw`Nr  
{ Y>G*'[U  
oSavedFile = new RandomAccessFile(sName,"rw"); / =-6:L  
this.nPos = nPos; V0s,f .a  
oSavedFile.seek(nPos); 8s~\iuk  
} Q%I#{+OT  
hR!}u}ECd  
\hrrPPD1z  
public synchronized int write(byte[] b,int nStart,int nLen) %N>\:8 5?  
{ { v,{x1  
int n = -1; })KJ60B  
try{ nW~$ (Qnd  
oSavedFile.write(b,nStart,nLen); di--:h/  
n = nLen; ,TEuM|  
} @W#fui<<}Y  
catch(IOException e) LSSW.Oz2L  
{ %V31B\]Nz7  
e.printStackTrace (); r?>Vx -  
}  gm(De9u  
'YBi5_  
|PI)A`  
return n; =l_rAj~I|  
} Zd8drT'@#  
-% >8.#~G  
c%ZeX%p  
} E(% XVr0W  
AfUZO^<  
qQL.c+%L  
/* 5dqQws-,?1  
**SiteInfoBean.java 8^8>qSD1  
*/ A%h~Z a  
package NetFox; ]7v81G5E  
Wgav>7!9  
ax4*xxU  
public class SiteInfoBean { O+p]3u  
MF&3e#mdB  
>_-!zjO8u  
private String sSiteURL; //Site's URL ``+c`F?5  
private String sFilePath; //Saved File's Path cES;bwQ  
private String sFileName; //Saved File's Name $p jf#P8U  
private int nSplitter; //Count of Splited Downloading File TH<fbd  
d[) _sa  
qC\]"Z`m  
public SiteInfoBean() r@olC7&  
{//nSplitter的缺省值为5 6`_!?u7  
//default value of nSplitter is 5 u\M4`p!g=  
this("","","",5); kNRyOUy  
} 'G<}U343=8  
>~h>#{&  
L^3~gM"!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;0;3BH A  
{ `<S/?I8  
sSiteURL= sURL; ZEL/Ndk  
sFilePath = sPath; SrdE>fNbs  
sFileName = sName; j\!~9  
this.nSplitter = nSpiltter; U&,r4>V@h>  
M`)s>jp@w  
m &9)'o  
} \P*PjG?R  
P)Z/JHB  
Uc\|X;nkRk  
public String getSSiteURL() '&N: S-  
{ 2_Pz^L  
return sSiteURL; ^a086n  
} B"7$!Co  
^Vl^,@  
`x2fp6  
public void setSSiteURL(String value) qnabwF  
{ 's=Q.s  
sSiteURL = value; =ZCH1J5"  
} RcY6V_Qx  
se~ *<5  
:|?~B%-p[  
public String getSFilePath() 5OPS&:  
{ ?+bTPl;%'  
return sFilePath; Tf9&,!>V  
} JCM)N8~i  
UN,<6D3\b  
5JQd)[Im  
public void setSFilePath(String value) %T3j8fC{s  
{ hCU)W1q#  
sFilePath = value; p#ZMABlE,P  
} K.:6YXVs<  
;[?J5X,  
\7|s$ XQ\  
public String getSFileName() 7'-)/Pk  
{ Iu)L3_+  
return sFileName; 9c"0~7v  
} cFRSd }p=  
~+nS)4 (  
 <'g0il  
public void setSFileName(String value) V->.|[J  
{ o%vIkXw  
sFileName = value; N5:D8oWWXR  
} nvU+XCx  
Q'FX:[@x-S  
o@qN#Mg?>}  
public int getNSplitter() F@>w&A ~K  
{ =_#ye}E  
return nSplitter; h-z%C6  
} +}Qv6s#  
E`oSi ez)  
ZkJY.H-F  
public void setNSplitter(int nCount) &>d:ewM\  
{ $=\oJ-(!@S  
nSplitter = nCount; @qg0u#k5  
} ~0VwF  
} I>N-95  
*D,v>(  
[,\'V0  
/* E&RoaY0  
**Utility.java [VfL v.8w  
*/ *T.={>HE8  
package NetFox; RM?_15m  
rnzsfr-|(2  
,gAr|x7_  
public class Utility { jK ?  
[+ %p!T  
a(Gk~vD;"  
public Utility() ]=$-B  
{ J,dG4.ht  
}M"-5K}  
>i><s>=I`  
} "wc`fg"3  
[15hci+-  
//线程睡眠 &*V0(  
public static void sleep(int nSecond) Sa?~t3*H  
{ rwi2kk#@P  
try{ '^P*F9  
Thread.sleep(nSecond); R7\{w(`K  
} :ofE8]  
catch(Exception e) kMwIuy  
{ y1@"H/nYJ  
e.printStackTrace (); ~Mg8C9B?%3  
} EvGUj$  
} 'W<a54T?z  
1CF7  
//日志 44/ 0}v]  
public static void log(String sMsg) @&am!+z  
{ [T$$od[.  
System.err.println(sMsg); L!G9O]WB  
} ^>P@5gcoE(  
3rXL0&3w%  
2vk8+LA(6  
public static void log(int sMsg)  d'**wh,  
{ h0y\,iWXb  
System.err.println(sMsg); S`'uUvAA  
} Ggxrj'r  
} %8z+R m,Ot  
37ri b  
8V53+]c$Y  
/* skmDsZzw  
**TestMethod.java P /f ~  
*/ h!JjN$  
package NetFox; E| 8s2t  
I'6 ed`|  
\nWzn4f  
public class TestMethod { hj#+8=  
#!<+:y'S?  
]0/~6f  
public TestMethod() +Qb2LR  
{ ///xx/weblogic60b2_win.exe ]UpHD.Of[t  
try{ 4n.i<K8K[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .{Eg(1At  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }E)8soQR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ' /@!"IXz  
fileFetch.start(); *YE IG#`  
} %]P@G^Bv  
catch(Exception e){e.printStackTrace ();} h} b^o*  
Jn^Wzn[q  
ND99 g  
} Z{R=h7P  
Do{*cSd  
tM?I()Y&P  
public static void main(String[] args) FdK R{dX}  
{ wTJMq`sY_  
new TestMethod(); 9g^./k\8%  
} N#xM_Mpt  
} w4&v( m  
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