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http断点续传简单实现(java)

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/* P Ig)h-w?  
**SiteFileFetch.java sptDzVM  
*/ _9wX8fh3D  
package NetFox; G2U=*|  
import java.io.*; A!No:?S  
import java.net.*; sH(4.36+  
tzJdUZJ  
\,i9m9;y  
public class SiteFileFetch extends Thread { /<vbv  
: I28Zi*  
m+||t  
SiteInfoBean siteInfoBean = null; //文件信息Bean >xws  
long[] nStartPos; //开始位置 gEbe6!; q3  
long[] nEndPos; //结束位置 a H'iW)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QpwOrxI}  
long nFileLength; //文件长度 t/LQ|/xo  
boolean bFirst = true; //是否第一次取文件 fGHYs  
boolean bStop = false; //停止标志 _?kjIF  
File tmpFile; //文件下载的临时信息 p<*3mbgGO  
DataOutputStream output; //输出到文件的输出流 -gefdx6ES  
F]\(p=U.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) jt?4raNW  
public SiteFileFetch(SiteInfoBean bean) throws IOException !*ct3{m  
{ > $DMVtE0  
siteInfoBean = bean; wd2GKq!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3r!6Z5P7{'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); E1usxF)  
if(tmpFile.exists ()) :jB~rhZ~  
{ AHc:6v^  
bFirst = false; :oY u+ cQ  
read_nPos(); i-w^pv'  
} aa2&yc29hp  
else W\:!v%C  
{ @&t ';"AE  
nStartPos = new long[bean.getNSplitter()]; hJ\IE?+  
nEndPos = new long[bean.getNSplitter()]; 1r;]==  
} k'E3{8<!  
Mh"DPt9@J  
Y m=ihQ|  
2jV.\C k  
} losm<  
[Hw  
rXc-V},az8  
public void run() QE*O~Yj  
{ 16ahU$@-  
//获得文件长度 ~A2{$C  
//分割文件  \B) a57  
//实例FileSplitterFetch mIgc)"  
//启动FileSplitterFetch线程 iz!E1(z(  
//等待子线程返回 B/.+&AJw  
try{ *F0O*n*7W  
if(bFirst) g*?)o!_*  
{ ~sT/t1Rp  
nFileLength = getFileSize(); )zz^RB\p  
if(nFileLength == -1) H6%QM}t  
{ b9Jah  
System.err.println("File Length is not known!"); 8}z]B^?Fy  
} yH5^EY7rQ  
else if(nFileLength == -2) 5S`_q&  
{ XG FjqZr`  
System.err.println("File is not access!"); |b" h+  
} ]=\vl>W  
else ?3 {&"  
{ DKw%z8ft|  
for(int i=0;i<nStartPos.length;i++) C4wJSQl_I  
{ )Be?axI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V}gP'f07zy  
} G<n(\85X  
for(int i=0;i<nEndPos.length-1;i++) q)vdDdRe_  
{ zmd,uhNc:  
nEndPos = nStartPos[i+1]; 4.il4Qqy}i  
} X^;[X~g  
nEndPos[nEndPos.length-1] = nFileLength; %;ZWYj`]n  
} w/_n$hX  
} FN jT?*  
Cq\1t  
!wP |t#Sc9  
//启动子线程 hbl%<ItI49  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (1pI#H"f9  
for(int i=0;i<nStartPos.length;i++) /Iht,@%E  
{ \1|]?ZQ\K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aK>5r^7S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !kCMw%[  
nStartPos,nEndPos,i); b-4g HW  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZslH2#   
fileSplitterFetch.start(); k\->uSU9  
} V6l~Aj}/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :'1UX <&B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); lO=+V 6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", MO}J  
nEndPos = " + nFileLength); dQP7CP  
// fileSplitterFetch[nPos.length-1].start(); qZw4"&,j$  
pkTg.70wU  
GjTj..G/  
//等待子线程结束 Pf,S`U w;  
//int count = 0; s&(,_34  
//是否结束while循环 8/q6vk><  
boolean breakWhile = false; j7r!N^  
$p_FrN{  
[4qCW{x._  
while(!bStop) j{}-zQ]n  
{ A8Z2o\+  
write_nPos(); Cwo(%Wc  
Utility.sleep(500); 9 {&APxm  
breakWhile = true; },1**_#<Br  
vn oI.;H,  
0LI:R'P+P[  
for(int i=0;i<nStartPos.length;i++) [f`^+,U  
{ @ qFE6!  
if(!fileSplitterFetch.bDownOver) K&1o!<|  
{ u=j|']hp#&  
breakWhile = false; 2hB';Dv  
break; Mou@G3  
} +Smt8O<N  
} Q2^~^'Y k  
if(breakWhile) YA(_*h  
break; <(|No3jx  
}m '= _u  
oh%kuO T[  
//count++; $E=t6WvA  
//if(count>4) aJh=4j~.  
// siteStop(); x0t&hY>P!  
} [s1Hd~$  
D@]gc&JN[  
VyRU_<xP  
System.err.println("文件下载结束!"); ZHPsGHA  
} TTNgnP  
catch(Exception e){e.printStackTrace ();} -KzU''  
} /cmnX'z  
G`!ff  
_W@SCV)yH  
//获得文件长度 7lP3\7wD@9  
public long getFileSize() fwR3=:5~  
{ /t "p^9!^  
int nFileLength = -1; JGmW>mH  
try{ M :m-iX  
URL url = new URL(siteInfoBean.getSSiteURL()); [,GXA)j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9ICC2%j|  
httpConnection.setRequestProperty("User-Agent","NetFox"); fX.V+.rj  
]>utLi5dX  
ZqI.n4:9  
int responseCode=httpConnection.getResponseCode(); x.>E7 +  
if(responseCode>=400) >{DHW1kF?  
{ .3;bUJ1  
processErrorCode(responseCode); @G/':N   
return -2; //-2 represent access is error $}[Tj0+:  
} P1P P#>E-2  
Salu[)+?  
[\9WqHs  
String sHeader; E\M{/.4 4  
DNgQ.lV  
1[k~*QS  
for(int i=1;;i++) 9JF*xXd>Q  
{ id^U%4J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2>{_O?UN  
//Utility.log(in.readLine()); \L#BAB6z  
sHeader=httpConnection.getHeaderFieldKey(i); uj.~/W1,!  
if(sHeader!=null) #=WDJ T:  
{ V/j]UK0$  
if(sHeader.equals("Content-Length")) a S- rng  
{ dEXHd@"H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Pn{yk`6E  
break; -KRHcr \  
} @5gZK[?|I  
} ?FRR";  
else Y^dVNC3vd  
break; T7;)HFGeW  
}  m8rz i:  
} 7R\!'`]\M  
catch(IOException e){e.printStackTrace ();} N0s)Nao4  
catch(Exception e){e.printStackTrace ();} vcB +h;x  
&`rV{%N"  
-`e=u<Y9@  
Utility.log(nFileLength); 0/.#V*KM  
"?j|;p@!>  
>Kl78w:  
return nFileLength; %EPqJ(T  
} *$(=I6b  
p71% -nV  
?o0#h  
//保存下载信息(文件指针位置) dRZor gar  
private void write_nPos() XEqg%f  
{ S(A0),  
try{ i_GE9A=h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A>L(#lz#ek  
output.writeInt(nStartPos.length); Fqzk/m  
for(int i=0;i<nStartPos.length;i++) JxQwxey{  
{ oB[3? e  
// output.writeLong(nPos); <$.KCLP  
output.writeLong(fileSplitterFetch.nStartPos); 4Uz:zB  
output.writeLong(fileSplitterFetch.nEndPos); #e%.z+7I  
} aMTY{  
output.close(); ]P0DPea  
} <.3@-z>w2,  
catch(IOException e){e.printStackTrace ();} tC+9W1o  
catch(Exception e){e.printStackTrace ();} b* Ipg8n+  
} k?Jzy  
(2@b ,w^  
4qda!%  
//读取保存的下载信息(文件指针位置) 4x'^?0H@  
private void read_nPos() 1elx~5v1.=  
{ =nnS X-x  
try{ yh_s(>sh  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I#l9  
int nCount = input.readInt(); ,Ucb)8a  
nStartPos = new long[nCount]; qn@Qd9Sf  
nEndPos = new long[nCount]; 7kn=j6I  
for(int i=0;i<nStartPos.length;i++) {CH\TmSz  
{ kt1f2cj  
nStartPos = input.readLong(); whKr3)  
nEndPos = input.readLong(); P7\(D`  
} kSNVI-Wzu  
input.close(); se_zCS4Y  
} ^F?H)[0  
catch(IOException e){e.printStackTrace ();} _0F6mg n  
catch(Exception e){e.printStackTrace ();} IJ, ,aCj4g  
} MbnV5b:X  
zi>f436-  
~s^&*KaA  
private void processErrorCode(int nErrorCode) [ur/`   
{ mC~W/KReA  
System.err.println("Error Code : " + nErrorCode); c%~'[W04\  
} {yyg=AMz  
svpWABO  
! # tRl  
//停止文件下载 ECkfFE`  
public void siteStop() |0f\>X I  
{ @7lZ{jV$  
bStop = true; jZv8X 5i  
for(int i=0;i<nStartPos.length;i++) s*k"-5  
fileSplitterFetch.splitterStop(); \g4\a?i  
&s/aJgJhp  
|r-<t  
} =X&h5;x'  
} V2/+SvB2  
//负责部分文件的抓取 6lT'%ho}B  
**FileSplitterFetch.java N83RsL "}_  
*/ ]VJcV.7`  
package NetFox; !+)$;`  
`*oLEXYN  
n^Z?u9VR  
import java.io.*; ;8 McG83  
import java.net.*; 4kXx(FE  
1Y9Ye?~jd  
{bETHPCf  
public class FileSplitterFetch extends Thread { M~662]Ekk  
OD1ns  
 j Mp{  
String sURL; //File URL b!.# `.  
long nStartPos; //File Snippet Start Position G|O"Kv6  
long nEndPos; //File Snippet End Position W>@%d`>o5  
int nThreadID; //Thread's ID L0&!Qct  
boolean bDownOver = false; //Downing is over V$v;lvt^Uq  
boolean bStop = false; //Stop identical M2xUs  
FileAccessI fileAccessI = null; //File Access interface bkOm/8k|4  
5 #kvb$97  
!d(!1fC  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g<.8iW 'c  
{ |e< U%v  
this.sURL = sURL; It_yh #s  
this.nStartPos = nStart; t*}<v@,  
this.nEndPos = nEnd; 8=nm`7(]  
nThreadID = id; }p- %~ Y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JAiV7v4&R  
} ;,4J:zvZdQ  
kT$4X0}  
H>7!+&M  
public void run() SiBbz4  
{ 3:;%@4f  
while(nStartPos < nEndPos && !bStop) b6/:reH{  
{ I(7gmCV  
/Cg/Rwl  
e1/|PgT(KM  
try{ L0_=R;.<  
URL url = new URL(sURL); dJ&s/Z/>E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >y8Z{ALQ5  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3o^V$N.  
String sProperty = "bytes="+nStartPos+"-"; 57MoO  
httpConnection.setRequestProperty("RANGE",sProperty); ?=4t~\g?  
Utility.log(sProperty); &YMVoyVD  
Y-{spTI  
WI~%n  
InputStream input = httpConnection.getInputStream(); VmT5? i  
//logResponseHead(httpConnection); ^X;>?_Bk  
a0LX<}   
"Q J-IRt &  
byte[] b = new byte[1024]; '+QgZ>q"  
int nRead; #xo&#FIH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) (@#Lk"B  
{ +es6c')  
nStartPos += fileAccessI.write(b,0,nRead); ut,"[+ J  
//if(nThreadID == 1) L%8"d6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); plIx""a^h  
} 'K"*4B^3  
QA9vH'  
z"vgwOP su  
Utility.log("Thread " + nThreadID + " is over!"); >5gzo6j/  
bDownOver = true; 6FmgK"t8  
//nPos = fileAccessI.write (b,0,nRead); 2bC%P})m  
} PJ.jgN(r  
catch(Exception e){e.printStackTrace ();} pxC5a i  
} f 0#V^[%Q  
} ^R$dG[Qf  
DtN6.9H2`  
!'MD8  
//打印回应的头信息 nc{ <v  
public void logResponseHead(HttpURLConnection con) hWu)0t  
{ 3gh^a;uC  
for(int i=1;;i++) OlJj|?z $  
{ ]a%Kn]HI&2  
String header=con.getHeaderFieldKey(i); N~kYT\$b#  
if(header!=null) P3|<K-dFAK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +]zP $5_e  
Utility.log(header+" : "+con.getHeaderField(header)); '[E_7$d  
else xr2:bu  
break; vJ' 93 h  
} LYF vzw>M  
} -XyuA:pxx  
H}~^,B2;  
OE"Bb   
public void splitterStop() *Wau7  
{  M:$nL  
bStop = true; }.vy|^X  
} s#fmGe"8  
9|m  L  
Z}C%%2Iz  
} :F\f}G3  
E;Hjw0M'k  
{cI<4><  
/* Ye6O!,R  
**FileAccess.java *~L]n4-  
*//文件访问(定位,写) t*#&y:RG  
package NetFox; I$LO0avvH2  
import java.io.*; jY.%~Y1y  
e- CW4x  
eH8.O  
public class FileAccessI implements Serializable{ jYF3u0 )  
iT"Itz-^#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AVWrD[ wD2  
RandomAccessFile oSavedFile; J#]y KgT  
long nPos; 4\3t5n  
jayoARUB  
:<gk~3\  
public FileAccessI() throws IOException GZt] 38V)g  
{ Jx<  
this("",0); -tdG} Gu  
} wp*1HnWj8Y  
( -@>  
do,X{\  
public FileAccessI(String sName,long nPos) throws IOException y|se^dn  
{ Hdx|k=-Q^  
oSavedFile = new RandomAccessFile(sName,"rw"); Z(eSnV_RL  
this.nPos = nPos; NZ5~\k  
oSavedFile.seek(nPos); nE;gM1I  
} ?OyW|jL  
(c2\:hvy  
3lN+fQ>)S  
public synchronized int write(byte[] b,int nStart,int nLen) Gp+XM  
{ U;@jl?jnG  
int n = -1; Se`N5hQ  
try{ oUSG`g^P(M  
oSavedFile.write(b,nStart,nLen); ^ym{DSx  
n = nLen; ^aCYh[=  
} WRyLpTr-  
catch(IOException e) J.l%H U  
{ a)Ek~{9  
e.printStackTrace (); nW_  
} ~2431<YV  
PEIr-qs%D  
dDbC0} x/  
return n; T7~v40jn|  
} AUde_ 1hi  
 )S;ps  
"r"An"  
} ~7a BeD  
 &7&*As  
6DW|O<k^j  
/* R <\Yg3m8  
**SiteInfoBean.java 9m4rNvb  
*/ Wp3l>:  
package NetFox; SGd.z6"H  
pe})A  
Q{hOn]"  
public class SiteInfoBean { n0pe7/Ai  
VBJ]d|  
, ~X;M"U  
private String sSiteURL; //Site's URL qu+2..3  
private String sFilePath; //Saved File's Path TWEqv<c  
private String sFileName; //Saved File's Name ;@ X   
private int nSplitter; //Count of Splited Downloading File J*X.0&Toc  
J9.p8A^^2  
E(_I3mftm  
public SiteInfoBean() ! hr@{CD  
{//nSplitter的缺省值为5 (Nb1R"J `  
//default value of nSplitter is 5 >L`mF_WG  
this("","","",5); ;_5 =g  
} ~HRWKPb  
3y B6]U  
#!,`EU  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p|V1Gh<  
{ ZMg9Qt  
sSiteURL= sURL;  7`@?3?  
sFilePath = sPath; 0\nhg5]?  
sFileName = sName; 5yi q#  
this.nSplitter = nSpiltter; .@-]A   
 89=JC[c  
'|N4fbZd  
} IFofF Xv_  
O>5u5n  
NOp=/  
public String getSSiteURL() u>6/_^iq  
{ 1>x@1Mo+K  
return sSiteURL; `f+g A  
} `1<3Hu_  
x>" JWD  
-L?% o_  
public void setSSiteURL(String value) 8z8SwWS?  
{  .OS?^\  
sSiteURL = value; )}\@BtcjA]  
} )ZyuF(C&  
VhIIW"1  
gD+t'qg$  
public String getSFilePath() 59BHGvaF  
{ c$:=d4t5$  
return sFilePath; Pt0}9Q  
} (G%gVk]  
s{J!^q  
WTv\HI2X !  
public void setSFilePath(String value) I jztj  
{ i=H>D  
sFilePath = value; H6S vU  
} gs8@b5 RSb  
9Sl|l.;!  
SH$cn,3F8  
public String getSFileName() `oRs-,d|<  
{ 8yz((?LrDh  
return sFileName; ff./DMDafI  
} cBR8HkP~  
(DP9& b  
MGyB8(  
public void setSFileName(String value)  Is6 _  
{ l@/kPEh  
sFileName = value; aC Lg~g4  
} y&=19 A#  
[P c[{(  
$SGA60q  
public int getNSplitter() o/9LK  
{  53*, f  
return nSplitter; 7RC096 ?}  
} Il`k]XM  
EQOP?>mWx!  
p't:bR  
public void setNSplitter(int nCount) 4FE@s0M,  
{ >AX~c jo  
nSplitter = nCount; ;(0$~O$3u  
} AD%D ,l  
} bKMR7&e.Ep  
~TFYlV  
bd P,Zqd  
/* ?&<o_/`-H5  
**Utility.java c[RL Yu  
*/ a(DZGQ-as  
package NetFox; Y{2d4VoW6  
`CEj 4  
=>z tBw\  
public class Utility { <CKmMZ{  
OC>_=i$ '  
U;Ll.BFP  
public Utility() grxl{uIC8  
{ P:, x?T?J^  
T\ }v$A03  
?-::{2O)  
} LSu^#B  
>"<k8wn  
//线程睡眠 46P6Bwobh  
public static void sleep(int nSecond) 69j~?w)^  
{ &<|-> *v  
try{ FJ(B]n[>  
Thread.sleep(nSecond); [aM'  
} oBNX8%5w  
catch(Exception e) K7xWE,y  
{ YyJ{  
e.printStackTrace (); 'tu@`7*  
} /sT ^lf=  
} 4,F3@m:<  
Cq*}b4^;  
//日志 9kX=99kf[  
public static void log(String sMsg) =e!l=d|/  
{ )dIfr  
System.err.println(sMsg); g?[& 0r1  
} Ph+X{|  
z(` }:t  
bA<AG*  
public static void log(int sMsg) r -q3+c^+  
{ iA3>X-x   
System.err.println(sMsg); W\qLZuQ  
} {`H<=h__  
} M9s43XL(&  
I' ! r  
$~,}yh;  
/* ]C ~1]7vb  
**TestMethod.java bH\C5zt6(  
*/ mYh5#E41J  
package NetFox; :`Uyn!w  
oO#xx)b  
mo;)0Vq2l  
public class TestMethod { p>:ef<.i  
G=Hf&l  
)b&-3$?  
public TestMethod() GT'7,+<?N  
{ ///xx/weblogic60b2_win.exe Zv|p>q`R2  
try{ 09 39i_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hH1lgc  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EzIs@}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2T@L{ql  
fileFetch.start(); 1O7]3&L@  
} 0Ws;|Yg  
catch(Exception e){e.printStackTrace ();} :/v,r=Y9p  
```d:f  
1X::0;3  
} 7k] RO  
?AnjD8i  
2<'`^AO@  
public static void main(String[] args) e`Co,>W/  
{ ?jri!]ux#  
new TestMethod(); *!g 24  
} /BMtcCPG!  
} ms}f>f=  
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