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http断点续传简单实现(java)

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/* h=YY> x  
**SiteFileFetch.java JT&CJ&#[h  
*/ 5.F.mUO  
package NetFox; @no]*?Gpa  
import java.io.*; %m!o#y(hD`  
import java.net.*; h1G]w/.ws  
Y }'C'PR  
i;*c|ma1>  
public class SiteFileFetch extends Thread { zC!]bWsD  
l@4hBq  
|M  `B  
SiteInfoBean siteInfoBean = null; //文件信息Bean rAIX(2@cR_  
long[] nStartPos; //开始位置 8^&)A b  
long[] nEndPos; //结束位置 lF5;K c  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B o.x  
long nFileLength; //文件长度 xT{qeHeZ9,  
boolean bFirst = true; //是否第一次取文件 )QaI{ z  
boolean bStop = false; //停止标志 2{!'L'km  
File tmpFile; //文件下载的临时信息 a+szA};  
DataOutputStream output; //输出到文件的输出流 COc1np  
W!.UMmw`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Wt()DG|[  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,W5pe#n  
{ G{}E~jDi?  
siteInfoBean = bean; NwD*EuPF:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N+\#k*n?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 26>e0hBh&  
if(tmpFile.exists ()) gl:vJD  
{ !Qjpj KRy  
bFirst = false; t #MU2b  
read_nPos(); c)#b*k,lw<  
} B~-VGT 2o  
else ch1EF/"  
{ ./jkY7 k  
nStartPos = new long[bean.getNSplitter()]; mLPQ5`_  
nEndPos = new long[bean.getNSplitter()]; ~xGWL%og  
} HcUivC  
39S}/S)  
ii2X7Q  
a2v UZhkR  
} `hM`bcS  
~^$ONmI5  
H.XD8qi3W  
public void run() ^=bJ _'  
{ huWUd)Po%  
//获得文件长度  /8Bh  
//分割文件 jIv+=b#oT  
//实例FileSplitterFetch <tuh%k  
//启动FileSplitterFetch线程 ].pz  
//等待子线程返回 bPC {4l  
try{ [{6]iJ  
if(bFirst) \r^=W=  
{ K:z|1V  
nFileLength = getFileSize(); 2$yKa5SaX  
if(nFileLength == -1) Hlp!6\gukp  
{ Otj=vGr0  
System.err.println("File Length is not known!"); %bZ3^ ub}t  
} U|g4t=@ZR  
else if(nFileLength == -2) &at>pV3_  
{ KArf:d  
System.err.println("File is not access!"); M ioS  
} PkF B.  
else QB#f'X  
{ }h5pM`|1  
for(int i=0;i<nStartPos.length;i++) .^I,C!O#  
{ ETV|;>v  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )K -@{v^|  
} /XEcA 5C<  
for(int i=0;i<nEndPos.length-1;i++) eg~$WB;1  
{ vlw2dY@^  
nEndPos = nStartPos[i+1]; /8q7pwV  
} |iLeOztuE  
nEndPos[nEndPos.length-1] = nFileLength; DG O_fR5L  
} p+snBaAo}  
} J;+tQ8,AP  
S"CsY2;  
'1~mnmiP  
//启动子线程 0fxA*]h  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  ?Vbe  
for(int i=0;i<nStartPos.length;i++) 9Vxsv*OR,  
{ yrR<F5xge  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RQ y|W}d_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _:+W0YS  
nStartPos,nEndPos,i); J^hj R%H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S-gL]r3G8  
fileSplitterFetch.start(); ?#ndMv!$  
} ZL#4X*zT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \s`'3y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G2ZF`WQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Dgj`_yd  
nEndPos = " + nFileLength); Y gQ_P4B;  
// fileSplitterFetch[nPos.length-1].start(); } !pC}m  
$7jJV(B  
0h^upB#p  
//等待子线程结束 w?Nvm?_]  
//int count = 0; qXt2m  
//是否结束while循环 cm%QV?  
boolean breakWhile = false; Q {3"&  
@'?<9 2A  
_T6WA&;8  
while(!bStop) [`=|^2n?  
{ ?:s`}b  
write_nPos(); L=Dd`  
Utility.sleep(500); 5Jp@n .  
breakWhile = true; {ogGi/8  
VHM,W]  
|n=m8X  
for(int i=0;i<nStartPos.length;i++) p!AQ  
{ 2!~ j(_TA  
if(!fileSplitterFetch.bDownOver) 2etcSU(y>  
{ &1F)/$,v  
breakWhile = false; Q6_!I42Y`  
break; ul(1)q^  
} OC#oJwC  
} k^ B'W{  
if(breakWhile) 4sSQ nK  
break; !Lb9KDk  
Kk!D|NKLC  
r444s8Y  
//count++; J *.Nf)i  
//if(count>4) tU!"CX  
// siteStop(); .P# c/SQp  
} ``1#^ `  
P{)&#HXUVb  
5f=e JDo=x  
System.err.println("文件下载结束!"); FxKH?Rl  
} 7xVI,\qV  
catch(Exception e){e.printStackTrace ();} bo$xonV@y  
} b}9K"GT  
Xleoh2&M  
:)q/8 0@  
//获得文件长度 ykRKZYfsw(  
public long getFileSize() 4^w>An6  
{ RB\>$D  
int nFileLength = -1; bG^E]a/D  
try{ Cm JI"   
URL url = new URL(siteInfoBean.getSSiteURL()); G- Sw`HHo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xaoaZ3Ko  
httpConnection.setRequestProperty("User-Agent","NetFox"); A>%fE 6FY  
H[*.Jd  
HOsq _)K  
int responseCode=httpConnection.getResponseCode(); 67}y/C]<  
if(responseCode>=400) bRLmJt98P  
{ lR{eO~'~V  
processErrorCode(responseCode); #| A @  
return -2; //-2 represent access is error Y%^&aacZ  
} =5oFutg`  
}dAb} 0XK.  
Zul]ekv  
String sHeader; 2OAh7'8<  
"%A/bv\u  
VaZS_ qGe:  
for(int i=1;;i++) gpHI)1i'H  
{ o8KlY?hX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7w @.)@5  
//Utility.log(in.readLine()); ^\e:j7@z  
sHeader=httpConnection.getHeaderFieldKey(i); $* b>c:  
if(sHeader!=null) b-M[la}1"  
{ $Z+N*w~8  
if(sHeader.equals("Content-Length")) t<|=-  
{ hAfRHd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )}~k7bb}Y  
break; zXbTpm  
} vo!:uvy;2  
} dB<BEe\$g.  
else ZA1?'  
break; , y{o!w  
} _S,2j_R9  
} \&2GLBKpe  
catch(IOException e){e.printStackTrace ();} ;#EB0TK  
catch(Exception e){e.printStackTrace ();} cw/g1,p  
UmiW_JB  
^^jF*)DT@  
Utility.log(nFileLength); @2CYv>  
l"IBt:  
%Q1v8l.}  
return nFileLength; R@=ve %a-  
} Rk"VFe>r  
viD+~j18  
#ZCgpg$wM  
//保存下载信息(文件指针位置) 67 7p9{:  
private void write_nPos() 0w8Id . ,  
{ <rRm bFH#  
try{ 15iCJ p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vFL3eu#  
output.writeInt(nStartPos.length); ,":"Op61  
for(int i=0;i<nStartPos.length;i++)  Tx/  
{ :n0(gB  
// output.writeLong(nPos); >]T(}S~  
output.writeLong(fileSplitterFetch.nStartPos); +3s i=x\=/  
output.writeLong(fileSplitterFetch.nEndPos); [5)1 4% x  
} '3[Ecy#  
output.close(); &5(|a"5+G  
} ]AERi] B  
catch(IOException e){e.printStackTrace ();} $w[@L7'(  
catch(Exception e){e.printStackTrace ();} NvJu)gI%  
} z|+L>O-8  
o7/_a/  
]'~'V2Ey  
//读取保存的下载信息(文件指针位置) 1^!= J<`K;  
private void read_nPos() |]+m<Dpyr2  
{ Arir=q^2  
try{ 0Hff/~J  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H",yVD  
int nCount = input.readInt(); 73Mh65  
nStartPos = new long[nCount]; x:xKlPGd  
nEndPos = new long[nCount]; Ad@))o2  
for(int i=0;i<nStartPos.length;i++) F8_pwJUpf-  
{ P%' bSx1  
nStartPos = input.readLong(); "!E(= W?  
nEndPos = input.readLong(); n_$lRX5  
} :Q+ rEjw+  
input.close(); 9VV  
} H$(%FWzQ%  
catch(IOException e){e.printStackTrace ();} "}7K>|a  
catch(Exception e){e.printStackTrace ();} kVkV~  
} >5/dmHPc  
&m>`+uVBP  
CyzvQfpZr  
private void processErrorCode(int nErrorCode) *r:8=^C7S  
{ 3c@Cb`w@  
System.err.println("Error Code : " + nErrorCode); kL*Q})  
} n3isLNvIp  
ETSBd[  
Vfg144FG'  
//停止文件下载  ;lW0p8  
public void siteStop() 0u'2f`p*  
{ TQE3/IL  
bStop = true; hS*3yCE"8  
for(int i=0;i<nStartPos.length;i++) zoC/Hm  
fileSplitterFetch.splitterStop(); >AN`L`%2  
U lj2 Py}  
i&mu=J[  
} EZ1H0fm  
} 5SR 29Z[  
//负责部分文件的抓取 ;]Y.2 J  
**FileSplitterFetch.java ZS>}NN  
*/ m[ay  
package NetFox; K`(STvtM  
g@MTKqs  
{n$9o  
import java.io.*; eW\7X%I  
import java.net.*; ll[U-v{  
KDRIy@[e  
a3R#Bg(  
public class FileSplitterFetch extends Thread { u;!CQ w/  
7k+UCi u>  
lsJ'dS  
String sURL; //File URL tz1iabZ{  
long nStartPos; //File Snippet Start Position h(GgkTj4+  
long nEndPos; //File Snippet End Position "*%=k%'  
int nThreadID; //Thread's ID cQ*:U@  
boolean bDownOver = false; //Downing is over oIoJBn  
boolean bStop = false; //Stop identical Iimz  
FileAccessI fileAccessI = null; //File Access interface f*W<N06EZ  
l:j9lBS  
[ {lF1+];@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {s=QwZdR  
{ d?b2jZ$r]  
this.sURL = sURL; )l[ +7  
this.nStartPos = nStart; UbY-)9==  
this.nEndPos = nEnd; `hM ]5;0  
nThreadID = id; j#-ZL-N  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -a&wOn-W  
}  <gf:QX!  
?v8RY,Q30  
\&@Tq-o  
public void run() #^!oP$>1  
{ RX?Nv4-  
while(nStartPos < nEndPos && !bStop) Zp- Av8  
{ g 4Vt"2|  
1swh7  
d /Zt}{  
try{ lNqXx{!k  
URL url = new URL(sURL); S3)JEZi  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S U2`H7C*  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6M+~{9(S  
String sProperty = "bytes="+nStartPos+"-"; *=@Z\]"?  
httpConnection.setRequestProperty("RANGE",sProperty); ;&Eu< %y  
Utility.log(sProperty); |=jgrm1yj  
p_B,7@Jl  
<| Xf4.  
InputStream input = httpConnection.getInputStream(); $'?CY)h{  
//logResponseHead(httpConnection); jpm}EOq<%  
8{%/!ylJz  
L!mQP  
byte[] b = new byte[1024]; akJ{-   
int nRead; mQ VduG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1m}'Y@I  
{ rZ:  
nStartPos += fileAccessI.write(b,0,nRead); ?kE2 S6j5  
//if(nThreadID == 1) W 86S)+h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'qQ DM_+  
} !Aunwq^  
}-: d*YtK  
() b0Sh=  
Utility.log("Thread " + nThreadID + " is over!"); =*8"ci $  
bDownOver = true; !QcgTW)T  
//nPos = fileAccessI.write (b,0,nRead); lS XhHy  
} }! zjj\g^  
catch(Exception e){e.printStackTrace ();} XRP/E_4  
} a ^4(7  
} F_YZV)q!W  
z7HC6{g%X  
0e:KiUr  
//打印回应的头信息 J +<|8D  
public void logResponseHead(HttpURLConnection con) ;PG'em  
{ clG3t eC  
for(int i=1;;i++) 4sNM#]%|  
{ 4J94iI>S.l  
String header=con.getHeaderFieldKey(i); jD H)S{k  
if(header!=null) I`Rxijz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )bPNL$O  
Utility.log(header+" : "+con.getHeaderField(header)); u`E_Q8  
else ~g1@-)zYxK  
break; Qbt fKn95  
} |])%yRAGQ  
} ,1^)JshZ~  
zs[t<`2  
^C<dr}8  
public void splitterStop() h>bmHQ  
{ 5'+g'9  
bStop = true; Og30&a!~F  
} xv4nYm9  
r8^1JJ~\  
7@+0E 2'  
} s_D7?o  
K8284A8v  
FY#`]124*  
/* }@ 1LFZx  
**FileAccess.java ^Ud`2 OW;2  
*//文件访问(定位,写) tet  
package NetFox; "TN}=^A\F  
import java.io.*; 2R<1  ^  
6D0uLh  
nU`vj`K   
public class FileAccessI implements Serializable{ \Cx3^ i X  
->8n.!F}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nqiy)ZN#R  
RandomAccessFile oSavedFile; Y*w< ~m  
long nPos; -pg7>vOq  
4XX21<yn  
M7jDV|Go  
public FileAccessI() throws IOException sI*( MhU  
{ b-~`A;pr  
this("",0); :4(7W[r6  
} e5veq!*C?  
6"ZQN)7  
hrEKmRmF-  
public FileAccessI(String sName,long nPos) throws IOException 3bE^[V8/  
{ VMHiuBz:  
oSavedFile = new RandomAccessFile(sName,"rw"); $JX_e  
this.nPos = nPos; x%cKTpDh!  
oSavedFile.seek(nPos); M{O2O(  
} 5 0~L(<  
s2w .V O  
\ZCc~muR  
public synchronized int write(byte[] b,int nStart,int nLen) )o9CFhFB  
{ /SN.M6~  
int n = -1; ^z0[{1  
try{ [gQ~B1O  
oSavedFile.write(b,nStart,nLen); 3@6f%Dyj  
n = nLen; @jwUH8g1  
} 6 D!,vu  
catch(IOException e) ;]<$p[m  
{ mRQ F5W6  
e.printStackTrace (); cC4*4bMm  
} DPy"FQYZb  
nNBxT+3*i  
KwpNS(]I  
return n; 7sHtJr  
} {wA@5+[  
BT`/O D@  
< >f12pu  
} hr]NW>;  
1iF |t5>e  
WGp81DNS|  
/*  0m*0I >  
**SiteInfoBean.java *pI3"_  
*/ W&+UF'F2  
package NetFox; ly, d =  
F_V~UX1D  
0 w@~ynW[  
public class SiteInfoBean { 2!&:V]  
9O}YtX2  
,YH^jc  
private String sSiteURL; //Site's URL p1X lni%=  
private String sFilePath; //Saved File's Path Ev$?c9*>  
private String sFileName; //Saved File's Name B;G|2um:$  
private int nSplitter; //Count of Splited Downloading File oleRQ=  
LX*T<|c`'  
`"-)ObOj}  
public SiteInfoBean() OmKT}D~ 4  
{//nSplitter的缺省值为5 ShGR !r<  
//default value of nSplitter is 5 HESwz{eSS  
this("","","",5); }>)"!p;t_  
} ;O{AYF?,N  
.bnoK  
CXA)Zl5#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fyQAQZT  
{ ?CmW{9O  
sSiteURL= sURL; _Vp9Y:mX2  
sFilePath = sPath; LZ\}Kgi(!T  
sFileName = sName; qx`*]lX  
this.nSplitter = nSpiltter; ,Sz*]X  
 /H!I90  
M-|4cd]6  
} oSy[/Y44a  
+-8uIqZ  
CE*@CkC0z  
public String getSSiteURL() 7b'XQ/rs  
{ K mL PWj  
return sSiteURL; 5^P)='0*  
} w6#hsRq[C  
i ]F,Y;&|  
/=Q7RJ@P  
public void setSSiteURL(String value) D ZLSn Ax  
{ Cww$ A %}  
sSiteURL = value; _W?}%;  
} oN)K2&M0  
:X2B+}6_&  
c&F"tLl  
public String getSFilePath() >@y5R^B`  
{ >`s2s@Mx  
return sFilePath; PiAA,  
} p^~lQ8t  
? )0U!)tK  
*,pG4kh!  
public void setSFilePath(String value) 0XXu_f@]9  
{ X$%RJ3t e  
sFilePath = value; uCUQxFp  
} ?~u"w OH'  
{!6!z,  
qZA?M=NT?  
public String getSFileName() Ibpk\a?A{  
{ G9}[g)R*  
return sFileName; =_Qt&B)  
} \zgRzO'N  
fqvA0"tv  
N}\$i&Vi  
public void setSFileName(String value) 3go!P])  
{ rq2XFSXn  
sFileName = value; o.Q |%&1  
} E: XzX Fxx  
#7gOtP#{  
&\c$s  
public int getNSplitter() #sNa}292"  
{ i"|'p/9@q  
return nSplitter; `2S%l, >)#  
} M,cI0i  
MLa]s* ; d  
BflF*-s ^  
public void setNSplitter(int nCount)  bQ  
{ (:E^} &A  
nSplitter = nCount; Jq?ai8  
} Ep?a1&b  
} ,'82;oP4  
Zf(ucAhL  
8]2S'm xE  
/* #M{}Grg  
**Utility.java 4S03W  
*/ 1N:eM/a  
package NetFox; d![EnkyL;  
@@!t$dD  
)"j_ NlO  
public class Utility { TKj9s'/  
% J+'7'g  
^R K[-tVV  
public Utility() "$ u"Py  
{ nQ/(*d  
8!:4m"Y  
YZ/mTQn_D  
} MO/l(wO  
L`];i8=I  
//线程睡眠 c5O1h8  
public static void sleep(int nSecond) NIV&)`w  
{ 4my8 p Fk  
try{ FC vR  
Thread.sleep(nSecond); H(n_g QAX  
} 6,cyi|s  
catch(Exception e) w3,QT}WvY  
{ PksHq77  
e.printStackTrace (); lc[\ S4  
} QN*'MA"M  
} tJ'U<s  
( 8H "'  
//日志 |@V<}2zCZ  
public static void log(String sMsg) %H%>6z x  
{ ?t?!)#X  
System.err.println(sMsg); Vf O0 z5&  
} D>LdDhNn,`  
k('2K2P  
|A5]hL   
public static void log(int sMsg) gqG l>=.m  
{ 9)mJo(  
System.err.println(sMsg); AL,|%yup  
} 7j._3'M=Kc  
} K$f~Fft  
ob-be2EysH  
`?`\!uP"  
/* ?vM{9!M  
**TestMethod.java Hyc19|  
*/ Xj|j\2$ 0  
package NetFox; ;QW)tv.y  
3%k@,Vvt  
FnL~8otPF'  
public class TestMethod { |A0kbC.  
3osAWSCEL  
okr'=iDg  
public TestMethod() o2F6K*u}  
{ ///xx/weblogic60b2_win.exe coU`2n/  
try{ zXp{9P\c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \s+ <w3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s )_sLt8?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 9SMM%(3, r  
fileFetch.start(); u3c e\  
} ><^A4s  
catch(Exception e){e.printStackTrace ();} tXPS@4F  
i[WTp??Uv  
U4^dDj  
} rK)%n!Z  
S(/@.gI:f  
5E}0 <&  
public static void main(String[] args) d4A}BTs1  
{ 6t*=.b,N  
new TestMethod(); 8fZ\})t  
} qdO^)uJJ  
} N=:yl/M  
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