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http断点续传简单实现(java)

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/* ;>9pJ72r  
**SiteFileFetch.java eZi<C}z  
*/ GB3B4)cX4Y  
package NetFox; X;:xGZ-oY  
import java.io.*; Tt|6N*b'  
import java.net.*; }i:'f 2/  
N sL"p2w~  
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public class SiteFileFetch extends Thread { C 5 UDez  
:\_MA^<  
~*Qpv&y)  
SiteInfoBean siteInfoBean = null; //文件信息Bean bobkT|s^s  
long[] nStartPos; //开始位置 su;S)yZb  
long[] nEndPos; //结束位置 CaBS0' n  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Yur)_m  
long nFileLength; //文件长度 zP}v2  
boolean bFirst = true; //是否第一次取文件 iGLYM-  
boolean bStop = false; //停止标志 TP::y  
File tmpFile; //文件下载的临时信息 _ZBR<{  
DataOutputStream output; //输出到文件的输出流 FaE orQ  
wt S*w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) >r3< O=Z7  
public SiteFileFetch(SiteInfoBean bean) throws IOException GuvF   
{ z&,sm5Lb  
siteInfoBean = bean; FSs$ ] d;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ky$G$H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m?$G(E5  
if(tmpFile.exists ()) 4 GW[GT  
{ g}QTZT8  
bFirst = false; I>Fh*2  
read_nPos(); a&Du5(r;!  
} XF$]KA L0  
else z %E!tB2o  
{ C&N4<2b  
nStartPos = new long[bean.getNSplitter()]; s,H(m8#>  
nEndPos = new long[bean.getNSplitter()]; C)p<M H<  
} u#k ,G`  
AiK4t-  
iGVb.=)  
#-j! ;?  
} B-'BJ|*4I  
8k?L{hF|nW  
n@[</E(  
public void run() .BDRD~kB  
{ T JS1,3<  
//获得文件长度 kTc5KHJ7  
//分割文件 F{~r7y;0  
//实例FileSplitterFetch @]wem  
//启动FileSplitterFetch线程 ULmdt   
//等待子线程返回 {0WID D  
try{ 4Xk;Qd  
if(bFirst) M`pTT5r  
{ oHd0 <TO  
nFileLength = getFileSize(); +gCy@_2;  
if(nFileLength == -1) P Xn>x8z  
{ 1'm`SRX#e  
System.err.println("File Length is not known!"); {<4?o? 1 g  
} 6@;L$QYY-V  
else if(nFileLength == -2) _|wY[YJ[  
{ ikG9l&n  
System.err.println("File is not access!"); 4eL54).1O  
} 1"B9Z6jf  
else @ZR4%A"X4  
{ UH&1c8y}  
for(int i=0;i<nStartPos.length;i++) dQ`ZrWd_U  
{ !_H8Q}a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |SukiXJZF  
} f<4q]HCa  
for(int i=0;i<nEndPos.length-1;i++) )X!DCL:16  
{ | 4oM+n;Y  
nEndPos = nStartPos[i+1]; JX$NEq(  
} (g2r\hI  
nEndPos[nEndPos.length-1] = nFileLength; NF(IF.8G  
} XAxI?y[c  
} `m;"I  
S Y>,kwHO  
@TPgA(5NR  
//启动子线程 $0 S#d@v}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vJAAAS  
for(int i=0;i<nStartPos.length;i++) G[<[#$(  
{ Sb9=$0%\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f(s3TLM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K-k.=6mS  
nStartPos,nEndPos,i); ],}afa!A  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5QFXj)hR+4  
fileSplitterFetch.start(); h*%0@  
} D)ne *},  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6O@ ^`T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m#'rI=}!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Q1I_=fT  
nEndPos = " + nFileLength); *5_ 8\7d  
// fileSplitterFetch[nPos.length-1].start(); HZ<f(  
~muIi#4  
g6/N\[b%  
//等待子线程结束 vWi. []  
//int count = 0; Z0 IxYEp  
//是否结束while循环 8xpYQ<cax  
boolean breakWhile = false; NRuG?^/}d  
a.&#dxgW[  
$X=D9h  
while(!bStop) ctUF/[_w;  
{ g=g.GpFt  
write_nPos(); <AAZ8#^  
Utility.sleep(500); r~G]2*3  
breakWhile = true; h[ZN >T  
A;WwS?fyQ  
[T[9*6Kt  
for(int i=0;i<nStartPos.length;i++) 6:@t=C  
{  e(;`9T  
if(!fileSplitterFetch.bDownOver) CX ]\Q-y  
{  2H K  
breakWhile = false; kGuk -P  
break; R4~zL!7;  
} Wt)SdF=U/  
} ZH$sMh<xg  
if(breakWhile) 8}?Y;>s\  
break; )lDIzLp  
L^ #<HQ  
 kulQR>u  
//count++; Y:"v=EhB  
//if(count>4) ]D) 'I`  
// siteStop(); o&XMgY~  
} ss0'GfP  
VmOFX:j!,  
bDFCZH-:'O  
System.err.println("文件下载结束!"); A{8K#@!  
} 0nD=|W\@{  
catch(Exception e){e.printStackTrace ();} qv0 DrL,3  
} 'Elj"Iiu  
`l gjw=  
)_c=mT  
//获得文件长度 EB29vHAt~  
public long getFileSize() dp[w?AMhM9  
{ B/sBYVU  
int nFileLength = -1; Id.Z[owC`Y  
try{ rxy{a  
URL url = new URL(siteInfoBean.getSSiteURL()); |:e|~sism  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H ?`)[#  
httpConnection.setRequestProperty("User-Agent","NetFox"); +F7<5YW&(  
3?*M{Y|  
l\=-+'Y  
int responseCode=httpConnection.getResponseCode(); NHFEr  
if(responseCode>=400) Bd[L6J)  
{ a:-)+sgHw  
processErrorCode(responseCode); pg?i F1  
return -2; //-2 represent access is error 7Js>!KR  
} e\A(#l@g  
2 %{YYT   
hM36QOdm  
String sHeader; `z?KL(rI  
=,AC%S_D~  
gaw4NZd)0  
for(int i=1;;i++) hLyTUt~\L  
{ FV^4   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =~\]3g  
//Utility.log(in.readLine()); Xb<DpBrk  
sHeader=httpConnection.getHeaderFieldKey(i); I NPYJ#%  
if(sHeader!=null) ^)hAVf~E  
{ }#ep}h  
if(sHeader.equals("Content-Length")) #j^('K|  
{ >9.5-5"   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wiq{wxe  
break; 4{*tn"y  
} |ilv|UV  
} XJ:>UNf5;  
else OBI+<2`Oc  
break; 0~Iu7mPY  
} up3?$hUc.  
} Gq0]m  
catch(IOException e){e.printStackTrace ();} @@%i( >4Z  
catch(Exception e){e.printStackTrace ();} jNe(w<',P  
wUK7um  
o9m  
Utility.log(nFileLength); bSrRsgKvT  
B=Zl&1  
lJ:M^.Em0  
return nFileLength; d`9W  
} jF38kj3O7  
c?!YFm  
/lS+J(I  
//保存下载信息(文件指针位置) kfqpI  
private void write_nPos() e~+(7_2  
{ f=:3!k,S  
try{ E7X!cm/2<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B]^>GH  
output.writeInt(nStartPos.length); >:F,-cx<  
for(int i=0;i<nStartPos.length;i++) VG<Hw{ c3r  
{ @cuD8<\i  
// output.writeLong(nPos); Ka]J^w;a  
output.writeLong(fileSplitterFetch.nStartPos); $5TepH0D  
output.writeLong(fileSplitterFetch.nEndPos); $=PWT-GIR  
} Qy=HrL]x  
output.close(); \Y!T>nWn)I  
} kgbobolA  
catch(IOException e){e.printStackTrace ();} Y{k>*: Ax_  
catch(Exception e){e.printStackTrace ();} HYjMNj0  
} b&lN%+%}  
*'9)H 0  
gEr4zae  
//读取保存的下载信息(文件指针位置) Si?$\H*:  
private void read_nPos() >aEL;V=}P  
{ x],8yR)R  
try{ [!1)mR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Fw_ (q!  
int nCount = input.readInt(); )p$\gwr=2  
nStartPos = new long[nCount]; M11"<3]D  
nEndPos = new long[nCount]; 4meidKw]  
for(int i=0;i<nStartPos.length;i++) u(pdP"  
{ \C]i|]tl  
nStartPos = input.readLong(); H+4=|mkQ  
nEndPos = input.readLong(); {8^Gs^c c  
} <u/a`E?  
input.close(); _4P;+Y  
} Q7,EY /  
catch(IOException e){e.printStackTrace ();} xn(+G$m  
catch(Exception e){e.printStackTrace ();} b!i`o%Vb  
} u.Mqj"o\  
c%|vUAq*  
cI*KRC U  
private void processErrorCode(int nErrorCode) )Vwj9WD  
{ UI!6aVL.  
System.err.println("Error Code : " + nErrorCode); _Ry_K3K  
} %&^Q(f  
R<f#r03@|  
rr|"r  
//停止文件下载 j~M#Ss-H8  
public void siteStop() OSp?okV  
{ 9pWi.J  
bStop = true; 6( >3P  
for(int i=0;i<nStartPos.length;i++) Dn~Z SrJ  
fileSplitterFetch.splitterStop();  f>.4-a?  
`WH[DQ  
F\>oxttS1  
} oi7 3YOB  
} K!3{M!B   
//负责部分文件的抓取 Y)$52m5rM  
**FileSplitterFetch.java blJIto '  
*/ MV%Xhfk  
package NetFox; )-=2w-ZX  
mJ)tHv"7  
"XCU'_k=  
import java.io.*; }qer   
import java.net.*; rmOQ{2}  
C&=x3Cz  
BjM+0[HC  
public class FileSplitterFetch extends Thread { xTW3UY  
+'-rTi\  
bfFmTI$,  
String sURL; //File URL 31WZJm^  
long nStartPos; //File Snippet Start Position $Axng J c  
long nEndPos; //File Snippet End Position {tPnj_|n<  
int nThreadID; //Thread's ID m"n.Dz/S  
boolean bDownOver = false; //Downing is over \CcmePTN#x  
boolean bStop = false; //Stop identical (nGkZ}p  
FileAccessI fileAccessI = null; //File Access interface F[5S(7M 7  
)))2f skZ  
#nKRTb+{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g^1r0.Sp{8  
{ j5kA^MTG  
this.sURL = sURL; ^w>&?A'!  
this.nStartPos = nStart; Ig<}dM.Z[  
this.nEndPos = nEnd; '<TD6jBs  
nThreadID = id; 9oEpPL5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |Eb&}m:E$  
} xJ-*%'(KZ  
~%`EeJwT  
|VK:2p^ u  
public void run() VSh!4z1  
{ `%|u!  
while(nStartPos < nEndPos && !bStop) *xPB<v2N:P  
{ ugno]5Ni  
Qh^R Ax  
/mc*Hc 8R8  
try{ dgXg kB'  
URL url = new URL(sURL); ] GNh)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I-,>DLG  
httpConnection.setRequestProperty("User-Agent","NetFox"); pDGT@qJ  
String sProperty = "bytes="+nStartPos+"-"; Rfht\{N 7  
httpConnection.setRequestProperty("RANGE",sProperty); <KtBv Ip]  
Utility.log(sProperty); 5:c;RRn  
+kM\ D~D1  
`4LJ;KC(  
InputStream input = httpConnection.getInputStream(); ;d4 y{  
//logResponseHead(httpConnection); 6z Ay)~  
Jz0K}^Dj[  
N r<9u$d9=  
byte[] b = new byte[1024]; TFO74^  
int nRead; i-b1d'?Rb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) CJp-Y}fGEA  
{ I:F <vE  
nStartPos += fileAccessI.write(b,0,nRead); /u=aX  
//if(nThreadID == 1) >5.zk1&H  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `$at9  
} )S2iIi;Bq  
mf}\s]_c  
>PIPp7C  
Utility.log("Thread " + nThreadID + " is over!"); 8 }-7{  
bDownOver = true; ABcBEv3  
//nPos = fileAccessI.write (b,0,nRead); w,Q)@]_  
} k {a)gFH O  
catch(Exception e){e.printStackTrace ();} k d+l k:  
} fWj@e"G  
} X@!X6j  
hfg O  
,ijW(95{k  
//打印回应的头信息 )A"jVQjI%w  
public void logResponseHead(HttpURLConnection con) PK+ x6]x  
{ &U&Zo@ot"x  
for(int i=1;;i++) (xL :;  
{ *Rq`*D>:U}  
String header=con.getHeaderFieldKey(i); 3T1P$E" m  
if(header!=null) +C_*Vs@4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2SciB*5  
Utility.log(header+" : "+con.getHeaderField(header)); KY g3U  
else ~T02._E  
break; +`| mJa  
} Ir27ZP  
} _dr*`yXi  
9`BEi(z  
Z(HZB  
public void splitterStop() Y%g "Y  
{ b/nOdFO@  
bStop = true; /'4Q{8.a  
} Ff<)4`J  
c;wA  
)|RZa|`-G  
} J)*8|E9P  
4)^vMG&  
=/Wu'gG)  
/* #h N.=~  
**FileAccess.java (@q3^)I4  
*//文件访问(定位,写) JpK[&/Ct  
package NetFox; SKR;wu  
import java.io.*; q 5p e~  
hJ[UB  
*S4aF*Qk  
public class FileAccessI implements Serializable{ \XS]N_}8>  
sJ~P:g  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qlUzr.^-  
RandomAccessFile oSavedFile; dE [Ol   
long nPos; Ea]T>4  
F7T E|LZ  
QKccrAo  
public FileAccessI() throws IOException -k{ Jp/-D  
{ RZh}:  
this("",0); a#y{pT2 b  
} XG&K32_fs  
;SY.WfVA7  
S+ebO/$>  
public FileAccessI(String sName,long nPos) throws IOException GV8)Kor%  
{ _|<BF  
oSavedFile = new RandomAccessFile(sName,"rw"); "IwM:v  
this.nPos = nPos; ,I`_F,  
oSavedFile.seek(nPos); |>2: eH  
} y|sma;D  
_- %d9@x  
Qq3fZ=  
public synchronized int write(byte[] b,int nStart,int nLen) UX_I6_&  
{ M<(u A'  
int n = -1; T~J? AKx  
try{ 5pJ*1pfeo  
oSavedFile.write(b,nStart,nLen); hYb9`0G"2  
n = nLen; u+2Lm*M  
} ^>m^\MuZ  
catch(IOException e) _M5Xk?e=  
{ U3F3((EYJ  
e.printStackTrace (); GuO`jz F  
} yd>}wHt  
7Fl-(Nv`  
9=$ !gC)  
return n; bk3Unreh  
} )N7n,_#T>  
l~1AT%  
KzVTkDn,  
} /6U 4S>'(  
};sMU6e  
:3? |VE F  
/* ~E*d G  
**SiteInfoBean.java z+3 9ee  
*/ R2LK.bTVn  
package NetFox; Y&~M7TYb  
s'L?;:)dyB  
{oWsh)[x2  
public class SiteInfoBean { sX:lE^)-z  
Y {c5  
<xn;bp[  
private String sSiteURL; //Site's URL de YyaV  
private String sFilePath; //Saved File's Path aws"3O% uW  
private String sFileName; //Saved File's Name 8R xc&`_X  
private int nSplitter; //Count of Splited Downloading File #J$qa Ul  
M!{'ED  
>5Lexj  
public SiteInfoBean() n )K6i7]xk  
{//nSplitter的缺省值为5 \!H{Ks{#R.  
//default value of nSplitter is 5 B*@6xS[IL  
this("","","",5); Dg2uE8k  
} 7>-yaL{  
%j{.0 H  
:'*DMW~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EXpSh}  
{ 1r 571B*O  
sSiteURL= sURL; cwynd=^nC  
sFilePath = sPath; %EI<@Ps8c  
sFileName = sName; DU{bonR`  
this.nSplitter = nSpiltter; @ yxt($G  
CBHc A'L  
2P5_zND  
} _e'Y3:  
{4rQ7J4Ux  
7ZFJexN]  
public String getSSiteURL() o4)hxs  
{ TnE+[.Qu  
return sSiteURL; /F~X,lm*~  
} +R[4\ hC0Y  
J_xG}d  
T:!MBWYe|  
public void setSSiteURL(String value) 5 09Q0 [k  
{ z[&s5"  
sSiteURL = value; ]k+m=OR{/  
} _;e\:7<m  
@]'S eiNp  
g%\L&}Jd  
public String getSFilePath() qm(1:iK,0  
{ 1^{`lK~2  
return sFilePath; ._<ii2K'  
} JSW&rn  
=n0*{~r  
-(;LQDG |  
public void setSFilePath(String value) /EFq#+6  
{ @@} `hii  
sFilePath = value; zvf3b!}  
} [7W(NeMk  
77We;a  
O&$0&dhc  
public String getSFileName() Iql5T#K+  
{ =! m JG  
return sFileName; P5URvEnz:  
}  Q_4Zb  
OE"<!oIs  
((MLM3zJ  
public void setSFileName(String value) PXEKV0y  
{ V5 MO}  
sFileName = value; B\_[R'Pf&  
} Y60"M4j  
JTUNb'#RZ  
~_PYNY`"  
public int getNSplitter() r!K|E95oj9  
{ K $-;;pUl  
return nSplitter; y1C/v:;  
} lbkL yp2  
#T% zfcUj  
gdi`x|0  
public void setNSplitter(int nCount) xzk}[3P{  
{ z="L4  
nSplitter = nCount; $D_HZ"ytu  
} JR1 *|u  
} H/jm f5  
l{%a&/  
Y';>O`  
/* !_^g8^>2(  
**Utility.java Y4To@TrN#\  
*/ IZ~.{UQ  
package NetFox; <lo`q<q  
GqUSVQ  
)%mAZk-*;^  
public class Utility { 3{3/: 7  
3k{ @.V ?]  
r/AHJU3&eY  
public Utility() v2J0u:#,  
{ D/s?i[lb  
MsjnRX:c3u  
#&siHHs \  
} zilaP)5x6  
4}-#mBV]/  
//线程睡眠 wj%wp[KA$  
public static void sleep(int nSecond) j=j+Nf$  
{ 9#@Zz4Ww  
try{ IVteF*8hU  
Thread.sleep(nSecond); ,F: =(21  
} (~#G'Hd  
catch(Exception e) }1m_o@{3P  
{ KXe ka  
e.printStackTrace (); O5-;I,)H  
} 3*WS"bt  
} p@tp]u`7  
re uYTH  
//日志 ~zyQ('  
public static void log(String sMsg) RWikJ   
{ `d*b]2  
System.err.println(sMsg); ,!>fmU`E4  
} 6V;:+"BkJ  
:6u~aT/  
kF-TG3  
public static void log(int sMsg) :`J>bHE  
{ O71BM@2<  
System.err.println(sMsg); s.y}U5Ty?P  
} g1qi\axm  
} 8]C1K Zs  
7) 0q--B  
2U%qCfh6|  
/* }n95< {  
**TestMethod.java [TCRB`nTQF  
*/ _,Q[2gQ5N  
package NetFox; !$r9C/k  
3bts7<K=  
^s*\Qw{Ii  
public class TestMethod { 0N VI +Z$  
:bv|Ah  
q6&67u0  
public TestMethod() -eL'KO5'  
{ ///xx/weblogic60b2_win.exe /f&By p  
try{ b *9-}g:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *?N<S$m  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <E}N=J'uJ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t/ eo]  
fileFetch.start(); PYieD}'  
} RbAt3k;y  
catch(Exception e){e.printStackTrace ();} J wFned#T  
o?dR\cxj  
la702)N{  
} PP-kz;|  
xt))]aH  
kY!C_kFcn  
public static void main(String[] args) i4VK{G~g"  
{ $e1:Q#den2  
new TestMethod(); V6+Zh>'S  
} %MuaW(I o  
} oCA(FQ6  
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