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http断点续传简单实现(java)

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/* bUJ5j kZ)  
**SiteFileFetch.java iPoh2  
*/ p{c+ +P5  
package NetFox; N!RkV\:X  
import java.io.*; U5_1-wV  
import java.net.*; eksYIQZ]  
&\[3m^L  
=XbOY[  
public class SiteFileFetch extends Thread { xweV8k/  
YI0ubB  
Rd#V,[d  
SiteInfoBean siteInfoBean = null; //文件信息Bean B}Lz#'5_  
long[] nStartPos; //开始位置 YhpNeP{A  
long[] nEndPos; //结束位置 gpt98:w:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2pu8')'P  
long nFileLength; //文件长度 g3*" ^C2=  
boolean bFirst = true; //是否第一次取文件  J^"  
boolean bStop = false; //停止标志 .~>Uh3S  
File tmpFile; //文件下载的临时信息 X"'c2gaa_  
DataOutputStream output; //输出到文件的输出流 T8*<  
O:K={#Xj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  B6| g2Tt  
public SiteFileFetch(SiteInfoBean bean) throws IOException X }UR\8g  
{ ^#:F8D  
siteInfoBean = bean; SY: gr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YS7R8|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?<7o\Xk#{  
if(tmpFile.exists ()) KB3zQJY  
{ 8Df(|>mK  
bFirst = false; TttD}`\.  
read_nPos(); i]sz*\P~  
} =[X..<bW9:  
else u>e4;f`F  
{ kaK0'l2%  
nStartPos = new long[bean.getNSplitter()]; *cNqgw#\qL  
nEndPos = new long[bean.getNSplitter()]; XnBpL6"T`  
} Ry5/O?Q L  
`F)Q=  
<X5'uve  
 3)5Gzn  
} 6L`{oSX!  
wTT_jyH)  
g`(' k5=  
public void run() o'9K8q\1  
{ aN\ps g  
//获得文件长度 P[|FK(l  
//分割文件 ^g[,}t:/d  
//实例FileSplitterFetch u2p5* gzZ  
//启动FileSplitterFetch线程 ~[E@P1  
//等待子线程返回 O^tH43C  
try{ "!\ON)l*  
if(bFirst) 86.LkwlqoH  
{ xUp[)B6?:  
nFileLength = getFileSize(); D'dE!CAUs  
if(nFileLength == -1) W6=j^nv  
{ QEUr+7[  
System.err.println("File Length is not known!"); oN0p$/La  
} z% ln}  
else if(nFileLength == -2) /~k)#44  
{ v&.`^ O3W  
System.err.println("File is not access!"); >O7ITy  
} ]{` 8C  
else In%K  
{ 8UA bTqB-  
for(int i=0;i<nStartPos.length;i++) ulcm  
{ 8(GH.)I+0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Mo4#UV  
} <4caG2~q  
for(int i=0;i<nEndPos.length-1;i++) m~upTQz  
{ 8|\0\Wd;vu  
nEndPos = nStartPos[i+1]; |sa{!tKJ  
} N S^(5g  
nEndPos[nEndPos.length-1] = nFileLength; iti~RV,  
} QH_0U`3  
} pI__<  
l?_h(Cq<  
i{['18Q$F3  
//启动子线程 OK=lp4X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z0XH`H|~  
for(int i=0;i<nStartPos.length;i++) pP1|/f5n`  
{ TB=KT j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T?p' R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gnAM}  
nStartPos,nEndPos,i); sn|q EH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m 6Xex.d  
fileSplitterFetch.start(); !^o(?1  
} bp'qrcFuiL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (WW*yv.J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  |7ga9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aY/msplC  
nEndPos = " + nFileLength); {i:5XL   
// fileSplitterFetch[nPos.length-1].start(); &}TfJ=gj  
Q}a, f75  
\ 2cI=Qf  
//等待子线程结束 RoL5uha,l  
//int count = 0; M"q]jeaM  
//是否结束while循环 Rnl 4  
boolean breakWhile = false; ^LA.Y)4C2%  
8{mQmG4  
h)O<bI8  
while(!bStop) 6SYQRK  
{ Iyo ey  
write_nPos(); @B<B#  
Utility.sleep(500); DXbzl +R  
breakWhile = true; eSV_.uvsb  
*b{C`[ =V  
q>$[<TsE&}  
for(int i=0;i<nStartPos.length;i++) bzz{ p1e  
{ ^8_`IT  
if(!fileSplitterFetch.bDownOver) Fx^e%":@ip  
{ uO4kCK<7C  
breakWhile = false; x~7_`=}rO  
break; >DHpD?Pm!  
} IEi E6z]L(  
} Z*/*P4\  
if(breakWhile) amPC C  
break; Hk65c0  
6 (:^>@  
X >i`z  
//count++; ZBDEE+8e  
//if(count>4) (<u3<40[YN  
// siteStop(); vV2px  
} /xK5%cE>B  
O@.afk"{  
_}_lrg}U  
System.err.println("文件下载结束!"); &9Vm3X  
} P #_8$#G3  
catch(Exception e){e.printStackTrace ();} njz:7]>e  
} Tk9/1C{8  
M4;A4V=W  
z0@)@4z!  
//获得文件长度 In-W,   
public long getFileSize() 9fWr{fx  
{ /ae]v+  
int nFileLength = -1; D,aJ`PK~  
try{ Z;/"-.i  
URL url = new URL(siteInfoBean.getSSiteURL()); C:$12{I?*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QK+s}ny  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'O#,;n  
 eRlJ  
&"V%n  
int responseCode=httpConnection.getResponseCode(); &FQ]`g3_@  
if(responseCode>=400) ?K<m.+4b*y  
{ rUunf'w`e1  
processErrorCode(responseCode); l:!4^>SC  
return -2; //-2 represent access is error bL=32YS  
} yPKDn.1  
vt;<+"eps  
a'/yN{?p  
String sHeader; 69Y>iPRU  
dHU#Y,v  
'o2V}L'nG  
for(int i=1;;i++) YF{KSGq  
{ P7IxN)b7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4<`x*8` ,  
//Utility.log(in.readLine()); # ;,b4O7@  
sHeader=httpConnection.getHeaderFieldKey(i); _IAvFJI  
if(sHeader!=null) R/H ?/  
{ `r; .  
if(sHeader.equals("Content-Length")) m6qmZ2<  
{ +C~,q{u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8T5s6EmIOW  
break; {FR#je  
} >$gWeFu  
} dAOmqu, 6  
else bSW!2#~  
break; I,{9vew  
} TQx''$j\  
} E' p5  
catch(IOException e){e.printStackTrace ();} %@<}z|.4  
catch(Exception e){e.printStackTrace ();} 9R XT  
/rd6p{F  
05 ".;(  
Utility.log(nFileLength); (7nWv43  
7y",%WYSD  
Qtmsk:qm  
return nFileLength; MSPzOJQPy  
} 1=DUFl.  
>w:px$g4  
PI7M3\z  
//保存下载信息(文件指针位置) )J/,-p  
private void write_nPos() nq#k}Qx:  
{ r4}:t$  
try{ f-5vE9G3y7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .tB[8Y=J  
output.writeInt(nStartPos.length);  D7%`hU  
for(int i=0;i<nStartPos.length;i++) w.qpV]9>  
{ aHKv*-z-  
// output.writeLong(nPos); B\2<r5|QG  
output.writeLong(fileSplitterFetch.nStartPos); $'}:nwq6x  
output.writeLong(fileSplitterFetch.nEndPos); *iB_$7n`  
} V@jR8zv|_  
output.close(); Sqw.p#  
} 4|fI9.  
catch(IOException e){e.printStackTrace ();} Rv=(D^F,  
catch(Exception e){e.printStackTrace ();} [guJd";  
} ~4th;#'  
#UH|,>W6  
Q!Rknj 2  
//读取保存的下载信息(文件指针位置) v&}mbt-  
private void read_nPos() 9N>Dp N  
{ [((P ,v*  
try{ [`P+{ R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &Y"u*)bm  
int nCount = input.readInt(); XW6>;:4k  
nStartPos = new long[nCount]; D_,}lsrb  
nEndPos = new long[nCount]; -#v1b>ScY  
for(int i=0;i<nStartPos.length;i++) `gq@LP"o  
{ 3_(fisvx  
nStartPos = input.readLong(); qw[)$icP  
nEndPos = input.readLong(); [Q,E( s  
} uX@RdkC  
input.close(); #$(F&>pj  
} ^{8r(1,  
catch(IOException e){e.printStackTrace ();} _yT Gv-  
catch(Exception e){e.printStackTrace ();} ' }rUbJo  
} b_*Y5"(*  
 +Io^U  
*a xOen  
private void processErrorCode(int nErrorCode) >\hu1C|W  
{ //VgPl  
System.err.println("Error Code : " + nErrorCode); +*[lp@zU{  
} lmb5Z-xB  
qp>O#tj[  
ev>gh0  
//停止文件下载 1R)4[oYN\<  
public void siteStop() sW 7R&t!G  
{ G S-@drZp_  
bStop = true; 79<{cexP  
for(int i=0;i<nStartPos.length;i++) L.bR\fE   
fileSplitterFetch.splitterStop(); oDul ?%  
xg)cA C\=  
)sG`sET]`f  
} ppIMaP  
} I9Af\ k|^  
//负责部分文件的抓取 O3#4B!J$E  
**FileSplitterFetch.java [ aj F  
*/ +_uT1PsBY  
package NetFox; djV^A  
A?8f 6  
_wp6rb:8!  
import java.io.*; %^xY7!{  
import java.net.*; F*hOa|7/  
ZRO   
7Zp'}Om<I  
public class FileSplitterFetch extends Thread { \I; lgz2  
92+LY]jS  
Cul^b_UmP#  
String sURL; //File URL ZLe@O~f;%  
long nStartPos; //File Snippet Start Position wwVK15t  
long nEndPos; //File Snippet End Position ',nGH|K.  
int nThreadID; //Thread's ID #/t^?$8\\  
boolean bDownOver = false; //Downing is over Pq`]^^=be'  
boolean bStop = false; //Stop identical s=Pwkte  
FileAccessI fileAccessI = null; //File Access interface $-Q,@Bztq  
dK,j|  
0EfM~u  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p=jD "lq  
{ wI\v5&X-B  
this.sURL = sURL; bb[.Kvq5  
this.nStartPos = nStart; E$m3Gg)s>N  
this.nEndPos = nEnd; DLe?@R5  
nThreadID = id; jx a?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cP63q|[[  
} j?4k{?x  
aH'Sz'|E  
E[HXbj"  
public void run() :9q=o|T6D  
{ #4_'%~-e  
while(nStartPos < nEndPos && !bStop) Ua]shSjyI  
{ T(K~be  
j K?GB  
Z8+{ -  
try{ `s(T (l  
URL url = new URL(sURL); ZWaHG_ U)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %qL0=ad  
httpConnection.setRequestProperty("User-Agent","NetFox"); .]g>.  
String sProperty = "bytes="+nStartPos+"-"; qQ[&FjTO`  
httpConnection.setRequestProperty("RANGE",sProperty); (1gfb*L  
Utility.log(sProperty); O]RP?'vO  
vttmSdY  
x9R_KLN:;  
InputStream input = httpConnection.getInputStream(); F,EcqM'f  
//logResponseHead(httpConnection); B!H4 6w~  
54s+4R FL  
sG*1?  
byte[] b = new byte[1024]; 5$0@f`sj  
int nRead; |=2E?&%?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MHmaut#  
{ vs;T}' O  
nStartPos += fileAccessI.write(b,0,nRead); |H 0+.f;  
//if(nThreadID == 1) Fp..Sjh 6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q:@$$}FjL  
} !q;EC`i#  
%YLdie6c  
J4!Om&\@  
Utility.log("Thread " + nThreadID + " is over!"); iZ2|/hnw  
bDownOver = true; &S9Sl  
//nPos = fileAccessI.write (b,0,nRead); =FQ]eb*  
} ,2S w6u  
catch(Exception e){e.printStackTrace ();} >Du5B&41  
} C4e3Itc9X  
} $EHAHNL?Lx  
d-nqV5  
W*i PseXq  
//打印回应的头信息 x0B|CO  
public void logResponseHead(HttpURLConnection con) ;o }pRC  
{ @SeE,<  
for(int i=1;;i++) j4Ppn  
{ 6O8'T`F[  
String header=con.getHeaderFieldKey(i); A$.woE@  
if(header!=null) [xq"[*Evv  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /H&:  
Utility.log(header+" : "+con.getHeaderField(header)); )MqF~[k<-  
else B]~#+rMK  
break; `G> 6  
} cN_e0;*Ua  
} \xJTsdd  
/Ps}IW  
pfsRV]  
public void splitterStop() fl>*>)6pm  
{ @/i{By^C  
bStop = true; cLR02  
} 3OTq  
FC+K2Yf1=0  
~Q%C>  
} (cJb/|?3  
GY 4?}T^s  
MB;< F  
/* m~ :W$x1+  
**FileAccess.java ZOvMA]Rf  
*//文件访问(定位,写) F M:ax{  
package NetFox; 94Mh/A9k  
import java.io.*; _UKH1qUd4  
QWG?^T fi  
f@Mm{3&.  
public class FileAccessI implements Serializable{ i2`i5&*  
"mr;|$Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i3g;B?54  
RandomAccessFile oSavedFile; 9NLO{kN  
long nPos; {FyGh */  
nsk`nck  
Tx"}]AyB6  
public FileAccessI() throws IOException <Okk;rj2  
{ +Z[(s!  
this("",0); /~*U'.V  
} aY7kl  
P [-2^1P"  
5\/h3 i"I  
public FileAccessI(String sName,long nPos) throws IOException rSDS9Vf(  
{ c-8Pc ]+g  
oSavedFile = new RandomAccessFile(sName,"rw"); !m(5N4:vV  
this.nPos = nPos; z 17  
oSavedFile.seek(nPos); TZL)jf hj  
} e!wBNcG2  
Q?rb(u(  
x"0*U9f  
public synchronized int write(byte[] b,int nStart,int nLen) wQiRj.  
{ Z[:fqvXQ  
int n = -1; s8iJl+Jm  
try{  L>Bf}^  
oSavedFile.write(b,nStart,nLen); r2H_)Oi  
n = nLen; ~$ } `R=  
} :{<( )gfk  
catch(IOException e) W _(  
{ -~T?xs0_  
e.printStackTrace (); _ q`$W9M+k  
} Av[L,4A  
Rg~ ~[6G>  
*l:5FT p  
return n; %m r  
} sxcpWSGA^  
oZ;u>MeZ  
?z>ZsD  
} 1!<k-vt  
7Wub@Mp  
6( TG/J  
/* <*u[<  
**SiteInfoBean.java &scHyt  
*/ Qk?;nF  
package NetFox; #7K&x.w$  
!Tuc#yFw  
gf2<dEff  
public class SiteInfoBean { ZVu&q{s,  
.nX+!EXeS  
PEZ~og:w  
private String sSiteURL; //Site's URL [|<2BQX  
private String sFilePath; //Saved File's Path RGy4p)z*+  
private String sFileName; //Saved File's Name Ftu~nh}  
private int nSplitter; //Count of Splited Downloading File g,/gApa  
|KFRC)g  
>en,MT|  
public SiteInfoBean() fnV^&`BB  
{//nSplitter的缺省值为5 xe5|pBT  
//default value of nSplitter is 5 !X721lNP  
this("","","",5); .z7%74p  
} j<w";I&Diz  
Xi3:Ok6FZ  
Ht#5;c2/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xFcJyjo^z  
{ i_8q!CL@{  
sSiteURL= sURL; A9^t$Ii  
sFilePath = sPath; bQc-ryC+.  
sFileName = sName; yZFm<_9>  
this.nSplitter = nSpiltter; [U[saR\  
dX|(n.}  
\5.36Se  
} 3D>syf  
apQ` l^  
7A@GN A  
public String getSSiteURL() ]&%_Fpx  
{ C8i6ESmU  
return sSiteURL; 1B+uv0lA  
} q]+'{Ci@  
Ru8k2d$B  
nE+OBdl  
public void setSSiteURL(String value) tM3eB= .*  
{ Stqlp<xy  
sSiteURL = value; "i/ l'  
} Oi# F  
xu[6h?u(h8  
=jZ}@L/+  
public String getSFilePath() )Cl!,m)~  
{ NU>={9!  
return sFilePath; u'}SaX]0  
} _ S%3?Q  
`?)ivy>\:  
kd^CZ;O  
public void setSFilePath(String value) IfF@$eO  
{  wc# #'u  
sFilePath = value; `!{m#BBT}  
} K~Lh'6  
R5=2EwrGP  
A?I/[zkc  
public String getSFileName() ,YzrqVY  
{ )`5k fj  
return sFileName; w yi n  
} _(=[d  
w_o|k&~,  
M_@%*y\o  
public void setSFileName(String value) --*Jv"/0  
{ t,|`#6Ft  
sFileName = value; _kR);\V.8  
} ]A)`I  
kGbtZ} W  
d%tF~|#A%  
public int getNSplitter() K^0cL%dB  
{ c zTr_>  
return nSplitter; wWV`k  
} oGz-lO{lt  
()L[l@m  
[:Kl0m7  
public void setNSplitter(int nCount) Q; DN*  
{ (dZu&  
nSplitter = nCount; % \OG#36  
} }c/p+Wo  
} Uz(Sv:G  
wxw3t@%mNm  
hxcRFqX"  
/* 9 -7.4!]I  
**Utility.java ~RdJP'YF-  
*/ -olD!zKS  
package NetFox; a(>oQG8F  
-90qG"@  
I75>$"$<  
public class Utility { *N5cC#5`=  
!Yuu~|  
7q_B`$ata  
public Utility() @&!`.Y oy  
{ Th&-n%r9K  
8%-+@ \=  
3q7Z?1'o  
} CjW`cHd  
LU$aCw5 B;  
//线程睡眠 v5J% p4  
public static void sleep(int nSecond) Jo%5NXts4  
{ ]:Y@pZ  
try{ (.6~t<DRv  
Thread.sleep(nSecond); a "*DJ&  
} 8}9B*m  
catch(Exception e) &fH;A X.  
{ tNsiokOm  
e.printStackTrace (); 'F3cvpc`  
} D vG9(Eh  
} C:Tjue{G2  
)*!"6d)^  
//日志 J=QuZwt  
public static void log(String sMsg) 2M`]nAk2a  
{ $$my,:nH  
System.err.println(sMsg); <_X`D4g]XO  
} !V|%n(O"  
v X=zqV  
6:Eu[PE~w  
public static void log(int sMsg) 34k}7k~n  
{ g5THkxp  
System.err.println(sMsg); cBxBIC  
} /]pBcb|<  
} .Pz( 0Y  
x\/N09  
px`o.%`'  
/* 9ure:Dko(Y  
**TestMethod.java j,@N0~D5  
*/ []opPQ 1  
package NetFox; k [6%+  
i-6,r[<  
P<&-8QA  
public class TestMethod { i7@qfe$fR  
cL/ 6p0S  
hEG-,   
public TestMethod() ?9jl8r>  
{ ///xx/weblogic60b2_win.exe `$V7AqX(  
try{ V4c$V]7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); cRt[{ HE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )"Ef* /+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); kJ^)7_3  
fileFetch.start(); mM*jdm(!  
} EP!zcp2' C  
catch(Exception e){e.printStackTrace ();} cM9z b6m  
W*D]?hXU;  
0MV^-M   
} 3I|&}+Z6  
4}mp~AXy;z  
CHeU`!:  
public static void main(String[] args) /$]#L%   
{ a(|YLN  
new TestMethod(); U%E6"Hg  
} Dm=d   
} SkGh@\  
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