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http断点续传简单实现(java)

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/* FvO,* r9  
**SiteFileFetch.java B|8|f(tsSa  
*/ /{[p?7x>  
package NetFox; q~Al[`K  
import java.io.*; FMhuCl2  
import java.net.*; )4.-6F7U?  
^FVmP d*1  
71ab&V il  
public class SiteFileFetch extends Thread { b'z\|jY  
XHOS"o$y  
lN0u1)'2  
SiteInfoBean siteInfoBean = null; //文件信息Bean #&fu"W+D96  
long[] nStartPos; //开始位置 HgBu:x?&  
long[] nEndPos; //结束位置 4sW~7:vU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cMoJHC,!  
long nFileLength; //文件长度 -t>"s'kv  
boolean bFirst = true; //是否第一次取文件 ]0[ot$Da6  
boolean bStop = false; //停止标志 %iJ}H6m  
File tmpFile; //文件下载的临时信息  ls7P$qq  
DataOutputStream output; //输出到文件的输出流 %o{IQ4Lz#  
TCIbPs E  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) @8+v6z  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ta/ u&t4  
{ *"4l}&  
siteInfoBean = bean; pU[yr'D.r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y$_]}<b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4S[)5su  
if(tmpFile.exists ()) }T AG7U*  
{ -_eG/o=M  
bFirst = false; $<Y%4LI  
read_nPos(); i[ws%GfEv  
} j)Kd'Va  
else Cud!JpL  
{ %tZrP$DQ  
nStartPos = new long[bean.getNSplitter()]; X#K;(.},h  
nEndPos = new long[bean.getNSplitter()]; 45$aq~%as  
} q)KOI` A  
{MTtj4$  
(d (>0YMv  
eT]*c?"  
} ry@p  
^tI&5S]nE  
<[K)PI  
public void run() m|t\w|B2  
{ N:S2X+}(  
//获得文件长度 $|T Lt{ K  
//分割文件 6Z2|j~  
//实例FileSplitterFetch 9_e_Ne`i`?  
//启动FileSplitterFetch线程 3(vm'r&5n>  
//等待子线程返回 ='_3qn.  
try{ i\gt @  
if(bFirst) 79-5 0}A  
{ x; -D}#  
nFileLength = getFileSize(); }UQ,B  
if(nFileLength == -1) @LDs$"f9=  
{ " vc4QH$  
System.err.println("File Length is not known!"); SBf=d<j 1)  
} mV)t  
else if(nFileLength == -2) hY !>>  
{ DUH_LnHw)  
System.err.println("File is not access!"); Q9B!0G.-bs  
} V0&7MY*  
else 01uj-!D$@  
{ 'Ffvd{+:8  
for(int i=0;i<nStartPos.length;i++) 7~'%ThUb$-  
{ LnN:;h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B., BP  
} 3Co1bY:  
for(int i=0;i<nEndPos.length-1;i++) YI> xxWA  
{ LU`)  
nEndPos = nStartPos[i+1]; w"#rwV&  
} ]gm3|-EiY  
nEndPos[nEndPos.length-1] = nFileLength; G"kX#k0S  
} Q~k|lTf  
} aNQ(xiskb  
r KdsVW  
k B4Fz  
//启动子线程 8 Gy*BpmJn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;l `Ufx  
for(int i=0;i<nStartPos.length;i++) @ 'N $5  
{ rOO10g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bFlI:R&<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), e7\gd\  
nStartPos,nEndPos,i); p=Le oc1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UvB\kIH  
fileSplitterFetch.start(); ]#rV]As  
} E}a.qM'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4^4T#f2=e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); B4+c3M\$V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pv&iJ7RN  
nEndPos = " + nFileLength); es\ qnq  
// fileSplitterFetch[nPos.length-1].start(); |TkicgeS  
@PhAg  
?hR0 MnP  
//等待子线程结束 8m `Y  
//int count = 0; aG4 ^xOD  
//是否结束while循环 \Cin%S. C  
boolean breakWhile = false; "wKJ8  
@H( 7Mt  
QtW e,+WWV  
while(!bStop) #N64ZXz_  
{ Aw4)=-LKO  
write_nPos(); x_?K6[G&}  
Utility.sleep(500); ~i'!;'-_}  
breakWhile = true; ="%887e  
U2vb&Qu/  
fb^R3wd$ff  
for(int i=0;i<nStartPos.length;i++) nA.U'=`  
{ 4e; le&  
if(!fileSplitterFetch.bDownOver) _%B,^0;C  
{ 3DB= Xh  
breakWhile = false; ) hoVB  
break; W_Y56@7e  
} $vYy19z  
} a>,_o(]cW  
if(breakWhile) >uQjygjj  
break; *ezft&{)`  
{)!ua7GF0H  
5nceOG8  
//count++; {.o4U0+  
//if(count>4) >c5   
// siteStop(); ^gpd '*b  
} xS+xUi  
eoQt87VCU  
^nOh 8L;  
System.err.println("文件下载结束!"); p} eO  
} P *PJ  
catch(Exception e){e.printStackTrace ();} \VW":+  
} g/P1lQ)  
*`/4KMrq  
\9od*y  
//获得文件长度 b'R]DS{8  
public long getFileSize() .W2w/RayC  
{ \ :q@I]2  
int nFileLength = -1; Dvl\o;  
try{ Nt?=0X|M  
URL url = new URL(siteInfoBean.getSSiteURL()); r;H#cMj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `022gHYv  
httpConnection.setRequestProperty("User-Agent","NetFox"); _,UYbD\[J}  
6U%d3"T  
1<lf o^B  
int responseCode=httpConnection.getResponseCode(); 2\+N<-(F5  
if(responseCode>=400) 2.v`J=R  
{ $M4_"!  
processErrorCode(responseCode); 2_?VR~mA#  
return -2; //-2 represent access is error }XpZgd$  
} ,+gtr.  
K]7[|qf&   
r~fnK%|  
String sHeader; )qFqf<:yc  
*p0n^XZ% ?  
8. +f@wv  
for(int i=1;;i++) N}{V*H^0QU  
{ EBQ_c@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .N\t3\9}  
//Utility.log(in.readLine()); 7X> @r"9<  
sHeader=httpConnection.getHeaderFieldKey(i); X`eX+9  
if(sHeader!=null)  dBN:  
{ dpt P(H  
if(sHeader.equals("Content-Length")) (r}StR+  
{ \RFA?PuY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /; 21?o  
break; &f?JtpB  
} NxK.q)tj6  
} rfSEL 57'  
else 29|nt1Z  
break; L/vw7XNrX  
} N#R8ez`  
} GU Mf}y  
catch(IOException e){e.printStackTrace ();} 9]tW;?  
catch(Exception e){e.printStackTrace ();} M.)z;[3O  
$~ d6KFT  
wXBd"]G)C  
Utility.log(nFileLength); CR#-!_=4  
Z7e"4w A  
AAB_Ytf  
return nFileLength; ,MHF  
} o`'4EVw*  
I\j-  
Zny9TP  
//保存下载信息(文件指针位置) {%, 4P_m  
private void write_nPos() PtL8Kd0`C  
{ i-dosY`81  
try{ uLI;_,/:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JZ-64OT  
output.writeInt(nStartPos.length); ?"?AH/ED  
for(int i=0;i<nStartPos.length;i++) 'C:i5?zh(q  
{ Rx.5;2m  
// output.writeLong(nPos); h_\W7xt  
output.writeLong(fileSplitterFetch.nStartPos); Lc-Wf zT  
output.writeLong(fileSplitterFetch.nEndPos); &rG]]IO  
} YuzVh9jTI  
output.close(); {\LLiU}MJC  
} @|'9nPern  
catch(IOException e){e.printStackTrace ();} kKC] n   
catch(Exception e){e.printStackTrace ();}  Sb)}  
} {sq:vu@NC  
a/%qn-i|p  
s,Fts3+  
//读取保存的下载信息(文件指针位置) $V/Ke  
private void read_nPos() b1."mT!p  
{ wW<u)|>ye  
try{ uX1{K%^<TW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,eqRI>,\  
int nCount = input.readInt(); X?`mYoe  
nStartPos = new long[nCount]; Ggv*EsN/cC  
nEndPos = new long[nCount]; %Z*)<[cIE0  
for(int i=0;i<nStartPos.length;i++) ;oVOq$ql  
{ n \&H~0X  
nStartPos = input.readLong(); wg:\$_Og  
nEndPos = input.readLong(); v9t'CMU  
} sULsUt#  
input.close(); "`Xbi/i  
} YNp-A.o W@  
catch(IOException e){e.printStackTrace ();} V%zo[A  
catch(Exception e){e.printStackTrace ();} >+:cTQ|q  
} ##1/{9ywy  
,hT**(W  
xz +;1JAL3  
private void processErrorCode(int nErrorCode) {q~N$"#  
{ tejpY  
System.err.println("Error Code : " + nErrorCode); 'Ir   
} (4rHy*6  
KyqP@ {  
AF{@lDa1h  
//停止文件下载 RyWfoLc  
public void siteStop() YnCuF0>  
{ lfR}cx  
bStop = true; `sd H q  
for(int i=0;i<nStartPos.length;i++) V*@&<x"E  
fileSplitterFetch.splitterStop(); ,1v FX$  
v Et+^3=  
7p{uRSE4._  
} OO,%zwgt  
} #N y+6XM  
//负责部分文件的抓取 ;9Wimf]G,E  
**FileSplitterFetch.java cBCC/n  
*/ %8P6l D  
package NetFox; @?0))@kPc3  
RE]*fRe7#  
_u~`RlA  
import java.io.*; scrss  
import java.net.*; *WWDwY@!u  
JX{rum  
{L M Q  
public class FileSplitterFetch extends Thread { /}5)[9GC  
%GMCyT  
C MGDg}  
String sURL; //File URL +)_DaL E  
long nStartPos; //File Snippet Start Position :8?l=B9("g  
long nEndPos; //File Snippet End Position CXi:?6OG  
int nThreadID; //Thread's ID f\Q_]%^W  
boolean bDownOver = false; //Downing is over )|Ka'\xr  
boolean bStop = false; //Stop identical kn&BGYt  
FileAccessI fileAccessI = null; //File Access interface N[yS heT  
Qv8 =CnuOT  
`vf]C'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C2DAsSw  
{ Kzwe36O;?  
this.sURL = sURL; yv$hIU2X  
this.nStartPos = nStart; $5Rx>$~+d  
this.nEndPos = nEnd; G^/8^Zi  
nThreadID = id; )31xl6@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C7&L9k~jf  
} ;iUO1t)^  
Go[anf  
~ D/1U)kt  
public void run() b~TTz`HZ  
{ A[:(#iR5-E  
while(nStartPos < nEndPos && !bStop) fvA167\  
{ \GGyz{i  
W!* P  
;9vY5CxzC  
try{ #aKUD  
URL url = new URL(sURL); JPg^h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x3nUKQtk:8  
httpConnection.setRequestProperty("User-Agent","NetFox"); nKjT&R  
String sProperty = "bytes="+nStartPos+"-"; &uf|Le4  
httpConnection.setRequestProperty("RANGE",sProperty); x5M+\?I<2  
Utility.log(sProperty); g}*p(Tp9:  
)k4&S{=  
~!/agLwY  
InputStream input = httpConnection.getInputStream();  ?H8dyQ5"  
//logResponseHead(httpConnection); ]tmMk7  
veS) j?4  
"R% RI( y{  
byte[] b = new byte[1024]; xhMAWFg|  
int nRead; NK%Ok  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) FbW$H]C$  
{ ;i ?R+T  
nStartPos += fileAccessI.write(b,0,nRead); iD>H{1 h  
//if(nThreadID == 1) bj?=\u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <J.q[fd1*  
} (Hs,Tj  
V&lx0Dy  
6Z@T /"mU(  
Utility.log("Thread " + nThreadID + " is over!"); V2'5doo  
bDownOver = true; hXD/  
//nPos = fileAccessI.write (b,0,nRead); 6E_YUk?KW  
} =(v'8?--  
catch(Exception e){e.printStackTrace ();} 65rf=*kz:  
} Mh@n>+IR  
} LeNSjxB  
s Dsq:z  
7{NH;U t  
//打印回应的头信息 C87 9eeJ  
public void logResponseHead(HttpURLConnection con) @r\{iSg&g.  
{ q/qig5Ou  
for(int i=1;;i++) h)z2#qfc  
{ #E_<}o  
String header=con.getHeaderFieldKey(i); #+|0o-  
if(header!=null) U/h@Q\~U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); STPRC&7;  
Utility.log(header+" : "+con.getHeaderField(header)); Lw<.QMN%f  
else Y6(= cm  
break; NGW:hgf  
} bE3mOml  
} 9A9T'g)Du  
&/g^J\0M)  
Ss\FSEN!/  
public void splitterStop() F|8;Swb5  
{ 8T"kQB.Zv  
bStop = true; y-"QY[  
} :kd]n$]  
8wn{W_5a  
t8*NldC  
} }?sC1]-j&  
 EIPXq  
6wZ)GLW[  
/* =RQI5 nHdw  
**FileAccess.java $\PU Y8  
*//文件访问(定位,写) \(r$f!`  
package NetFox; ; {v2s;  
import java.io.*;  #J  
f|~X}R  
}eveNPB{5  
public class FileAccessI implements Serializable{ >G As&\4hs  
9q\_UbF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CW]Th-xc  
RandomAccessFile oSavedFile; @R(Op|9  
long nPos; A>_,tt  
Y) l=r^Ap>  
J :KU~`r  
public FileAccessI() throws IOException q)J5tBfJ  
{ 1Afy$It/{  
this("",0); j}6h}E&dEr  
} V~do6[(  
tjx|;m7  
Z EvK  
public FileAccessI(String sName,long nPos) throws IOException )g KC}_h=  
{ ?F*I2rt#  
oSavedFile = new RandomAccessFile(sName,"rw"); %al 5 {  
this.nPos = nPos; S27s Rxfr  
oSavedFile.seek(nPos); zU_ dk'&,  
} %OP|%^2  
iU(B#ohW"  
@ 'U`a4  
public synchronized int write(byte[] b,int nStart,int nLen) 6Xbf3So  
{ Q2F20b  
int n = -1; Q8$;##hzt  
try{ {uJ"%  
oSavedFile.write(b,nStart,nLen); SIc~cZ!Yu  
n = nLen; _CBMU'V  
} "/Gw`^t  
catch(IOException e) c:<a"$  
{ m7i(0jd +  
e.printStackTrace (); }{Ra5-PY  
} ):y^g:  
V/zmbo)  
*p9k> )'J  
return n; N7YCg  
} B![:fiR`  
<qEBF`XP=  
:[0)Uu{  
} 9~jS_Y)"  
1qBE|PwBp  
X-J85b_e  
/* *kcc]*6@s  
**SiteInfoBean.java 6~x a^3G:  
*/ t D4-Llj6  
package NetFox; eC L_c>3!  
$RUK<JN$6  
u! dx+vd  
public class SiteInfoBean { ^Y5I OX:  
#rNc+  
UT[{NltH  
private String sSiteURL; //Site's URL $xcZ{C  
private String sFilePath; //Saved File's Path {L [   
private String sFileName; //Saved File's Name hMUUnr"8;i  
private int nSplitter; //Count of Splited Downloading File -= izu]Fb,  
$1Zr.ERL|(  
S(CVkCP  
public SiteInfoBean() 'f CSP|  
{//nSplitter的缺省值为5 LXPO@2QF  
//default value of nSplitter is 5 2A9crL $  
this("","","",5); C%CgWO`Xj  
} %5nEyZOq  
%~,Fe7#p  
R.vOYzo  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y O,Jgn  
{ 1}+b4 "7]  
sSiteURL= sURL; n$9Xj@  +  
sFilePath = sPath; E&5S[n9{3  
sFileName = sName; o wb+,Gk(  
this.nSplitter = nSpiltter; ^7Z;=]8J  
S4-jFD)U  
t)rPXvx}!  
} 0WYu5|  
'2|P-/jU  
Mc!LC .8  
public String getSSiteURL() (U_HX2f  
{ bOp%  
return sSiteURL; D5f[:  
} (h g6<`  
8Op^6rX4  
jzBW'8  
public void setSSiteURL(String value) 0,Ib74N'w  
{ .yFO] r1aL  
sSiteURL = value; KWAd~8,mk  
} oe0YxSauL  
Q]3]Z/i  
=1'WZp}D5  
public String getSFilePath() bf {_U%`  
{ 9)o@d`*  
return sFilePath; (: ?bQA'Td  
} )=MK&72r  
?~E"!  
*ZFF$0}  
public void setSFilePath(String value) J9DI(`  
{ {9.UeVz  
sFilePath = value; 3IB9-wG  
} *X ;ch55\  
8eYEi  
=tP^vgfQ  
public String getSFileName()  + #E?)  
{ 7J ?s&x  
return sFileName; B([-GpZt[  
} 'J5F+, \Ka  
K2e *AE*  
^u1Nbo  
public void setSFileName(String value) 8#- Nx]VM  
{ uXLZ!LJo  
sFileName = value; %e3E}m>  
} V0W4M%  
V\opC6*L_e  
DS>&|zF5l  
public int getNSplitter() :Ea|FAeK8  
{ ;Bj&9DZd  
return nSplitter; z!18Jh  
} `h'=F(v(}  
,S(s  
8oXp8CC  
public void setNSplitter(int nCount) q9{)nU  
{ 1s(]@gt  
nSplitter = nCount; m<kJH<!j  
} yNn=r;FZQ  
} v+`'%E  
)pT5"{  
"#-iD  
/* aR('u:@jHi  
**Utility.java Il(o[Q>jJ3  
*/ 96QY0  
package NetFox; CSq|R-@< U  
c00rq ~<K  
vCSC:  
public class Utility { 5U4V_*V  
9y;}B y  
\AA9 m'BZ  
public Utility() NH}o`x/  
{ _>kc:  
g,M-[o=Fk  
d;wq@ e  
} "`cPV){]  
b=pk;'-  
//线程睡眠 J:>o\%sF  
public static void sleep(int nSecond) zwJ&K;"y(  
{ J'7;+.s(  
try{ GEh(pJ  
Thread.sleep(nSecond); vM5/KrW  
} e@TwZ6l  
catch(Exception e) %6 GM[1__  
{ *AGf'+j*z  
e.printStackTrace (); ?eX/vqk  
} yt="kZ  
} W} H~ka  
Y)1J8kq_  
//日志 qGEp 6b H  
public static void log(String sMsg) a%si:_  
{ ty rP[y  
System.err.println(sMsg); (l-= /6-  
} Zl3e=sg=  
~yw]<{?  
~LV]cX2J(  
public static void log(int sMsg) >dm9 YfQ  
{ Q1x&Zm1v  
System.err.println(sMsg); Lw_|o[I}  
} <bSPKTKL  
} J` GL_@$q  
$,U/,XA {E  
?Z?(ky!  
/* x4L3Z__  
**TestMethod.java q{f\_2[  
*/ RJerx:]  
package NetFox; PQSmBTs.  
KA?%1s(kJ  
sCrP+K0D  
public class TestMethod { ,zHL8SiTX  
tcv(<0  
V,d\Wkk/  
public TestMethod() O_4B> )zd  
{ ///xx/weblogic60b2_win.exe jaKW[@<  
try{ x< 2]UB`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R<6y7?]bZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Qg(;>ops  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ; YQB  
fileFetch.start(); g@4~,  
} :?g+\:`/0j  
catch(Exception e){e.printStackTrace ();} ,@?9H ~\  
rXD:^wUSc  
Fb%?qaLmCv  
} K|-m6!C!7  
GP hhg  
l7^^Mnk C  
public static void main(String[] args) B; e<.M)e  
{ Q8m%mJz~]  
new TestMethod(); j8[U}~*^  
} M kJBKS  
} qAH^BrJ  
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