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http断点续传简单实现(java)

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/* dOFxzk,g&R  
**SiteFileFetch.java EV@xUq!x .  
*/ JeJc(e  
package NetFox; 7K`A2  
import java.io.*; L44-: 3  
import java.net.*; a<[@p  
R4"g? e  
1e;^Mz B"  
public class SiteFileFetch extends Thread { 0j1I  
FxC@KZG  
_wg6}3  
SiteInfoBean siteInfoBean = null; //文件信息Bean LmLV2f  
long[] nStartPos; //开始位置 @>J4K#"  
long[] nEndPos; //结束位置 ?<Dinq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Rp)82- .  
long nFileLength; //文件长度 m&OzT~?_>N  
boolean bFirst = true; //是否第一次取文件 IN!m  
boolean bStop = false; //停止标志 M[0@3"}}  
File tmpFile; //文件下载的临时信息 w*ig[{ I  
DataOutputStream output; //输出到文件的输出流 Got5(^'c  
YXJjqH3  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ' hL\xf{  
public SiteFileFetch(SiteInfoBean bean) throws IOException p3*}!ez4  
{ S2" p(  
siteInfoBean = bean; laqW {sX^5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DY6wp@A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KX9+*YY,  
if(tmpFile.exists ()) ">kf X1LT  
{ X;T(?,,  
bFirst = false; :JqH.Sqk  
read_nPos(); Cl]E rg  
} ~?dPF;.6_  
else aU2O5z&  
{ {vAq08  
nStartPos = new long[bean.getNSplitter()]; a Kb2:1EQ  
nEndPos = new long[bean.getNSplitter()]; A1p;Ye>o~  
} JLRw`V,o7  
NrTQ}_3)  
" 7RQrz  
'?_;s9)  
} e.i5j^5u  
UR?[ba_h   
iwL\Ha  
public void run() 8@qYzSx[  
{ 8J%^gy>m]  
//获得文件长度 ;t@zH+*}  
//分割文件 . #;ZM[v  
//实例FileSplitterFetch `jJ5us  
//启动FileSplitterFetch线程 ~;|  
//等待子线程返回 GLL,  
try{ iy8U rgG;l  
if(bFirst) U\y];\~H  
{ [[?:,6I  
nFileLength = getFileSize(); RNiZ2:  
if(nFileLength == -1) b IcLMG s  
{ }(dhXOf\q  
System.err.println("File Length is not known!"); lx~!FLn  
} Ud:v3"1  
else if(nFileLength == -2) rU5gQq;  
{ (M6B$:  
System.err.println("File is not access!"); OUe@U;l{Z  
} Rw*l#cr=.  
else ^l ~i>:V  
{ S(Xab_DT)H  
for(int i=0;i<nStartPos.length;i++) K3TMTY<p  
{ M=e]v9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w:& m_z#M  
} C2,,+* v  
for(int i=0;i<nEndPos.length-1;i++) cxrUk$f  
{ 3t(nV4uDF  
nEndPos = nStartPos[i+1]; ./)A6O*#  
} Xf9<kbRw/  
nEndPos[nEndPos.length-1] = nFileLength; KQ xKU?b1  
} 1,Uv;s;{  
} x\!Qe\lE  
)`^t,x<S  
d$kGYMT"  
//启动子线程 VLN=9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :sFP{rFx~  
for(int i=0;i<nStartPos.length;i++) CfoSow-  
{ Ip( IGR"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), S?*v p=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N|T%cdh:/  
nStartPos,nEndPos,i); qp^O\>c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xRJv_=dT  
fileSplitterFetch.start(); "Q#/J)N  
} 'i{kuTv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _UYt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |SZRO,7x  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3.?PdK&C  
nEndPos = " + nFileLength); Ej ip%m  
// fileSplitterFetch[nPos.length-1].start(); 4\Y2{Z>P?  
b|wCR%  
"Nn/vid;  
//等待子线程结束 NHUx-IqOX  
//int count = 0; G{i}z^n  
//是否结束while循环 \q(RqD  
boolean breakWhile = false;  s6rdQI]  
M/ 0!B_(R  
P8Fq %k  
while(!bStop) EMmNlj6  
{ y1(smZU  
write_nPos(); 9PVM06   
Utility.sleep(500); ,Zb]3  
breakWhile = true; *;(LKRV  
B[!wo  
ATv.3cy  
for(int i=0;i<nStartPos.length;i++) UW<V(6P  
{ qXkc~{W_  
if(!fileSplitterFetch.bDownOver) H jbC>*  
{ 0~H(GG$VH  
breakWhile = false; vL`wn=  
break; Ti!j  
} QSW62]=vV  
} pV(b>O  
if(breakWhile) C+cSy'VIK!  
break; @U_w:Q<9u  
kV(}45i]s  
9l@VxX68M  
//count++; `)& -;CMY  
//if(count>4) ddmTMfH  
// siteStop(); z"u4t.KpL  
} mZDrvTI'  
vAbMU  
=GTltFqI1  
System.err.println("文件下载结束!"); GNA:|x  
} Rgw\qOb  
catch(Exception e){e.printStackTrace ();} H*!j\|v0  
} =4"D8 UaHr  
Bl2y~fCA  
5. 5  
//获得文件长度 @>_`g=  
public long getFileSize() h)"PPI  
{ @H"~/m_o  
int nFileLength = -1; j08}5Eo  
try{ 0"(5\T  
URL url = new URL(siteInfoBean.getSSiteURL()); G)';ucs:,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <YP>c  
httpConnection.setRequestProperty("User-Agent","NetFox"); scCOiK)  
p)N=  
FRQ0tIp  
int responseCode=httpConnection.getResponseCode(); G,e>dp_cPu  
if(responseCode>=400) EkgS*q_  
{ lplEQ]J|  
processErrorCode(responseCode); WLQm|C,  
return -2; //-2 represent access is error P&V,x`<Z  
} mEmznA  
fmXA;^%  
&/d;4Eu  
String sHeader; 1D&Q{?RM  
]vMr@JM-G  
".O+";wk  
for(int i=1;;i++) x1W<r)A )r  
{ y5 $h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZMy0iQ@  
//Utility.log(in.readLine()); d_BECx <\  
sHeader=httpConnection.getHeaderFieldKey(i); YgNt>4K  
if(sHeader!=null) ^]3Y11sI  
{ sWP5=t(i+9  
if(sHeader.equals("Content-Length")) Yj|Oy  
{ ,`v)nwP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fHCLsI  
break; 5e~\o}]  
}  #:_qo  
} XMd-r8yYr  
else N W :_)1  
break; oJ\UF S  
} TYGUB%A  
} V.vA~a  
catch(IOException e){e.printStackTrace ();} t&T0E.kh*X  
catch(Exception e){e.printStackTrace ();} &[f.;1+C  
~0,Utqy  
s9>f5u?dK  
Utility.log(nFileLength); Q0i.gEwe  
iY1%"x  
H'Bor\;[>  
return nFileLength; Ol1[o  
} U8KB @E  
ATp7:Q  
l69&-Nyg  
//保存下载信息(文件指针位置) dR<sBYo  
private void write_nPos() ,4zwd@&O  
{ w$WN` =  
try{ 9"Oz-!Y4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >j5) MF{"  
output.writeInt(nStartPos.length); i\lur ET  
for(int i=0;i<nStartPos.length;i++) eVyXh>b*  
{ 4n @}X-)  
// output.writeLong(nPos); zV_U/]y  
output.writeLong(fileSplitterFetch.nStartPos); 'VcZ_m:  
output.writeLong(fileSplitterFetch.nEndPos); [,Q(~Qb  
} !qsk;Vk7Z  
output.close(); s!esk%h{K  
} !'o5X]s  
catch(IOException e){e.printStackTrace ();} XW w=3$  
catch(Exception e){e.printStackTrace ();} '^)Ve:K-.  
} w?)v#]<-  
6ziiV _p  
@d]I3?`  
//读取保存的下载信息(文件指针位置) sgp5b$2T.  
private void read_nPos() $_CE!_G&)  
{ =p,+a/*  
try{ W L$nchS9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v!n\A}^:  
int nCount = input.readInt(); d0$dQg  
nStartPos = new long[nCount]; 23 j{bK  
nEndPos = new long[nCount]; ~N2){0 j4  
for(int i=0;i<nStartPos.length;i++) j&6'sg;n)  
{ 2`hc0 IE  
nStartPos = input.readLong(); .}n,  
nEndPos = input.readLong(); WPi^;c8  
} YUU|!A8x  
input.close(); NWWag}  
} c Q:.V  
catch(IOException e){e.printStackTrace ();} -\6nT'P  
catch(Exception e){e.printStackTrace ();} ]#=43  
} H=Rqr  
xP%`QTl\  
9v>BP`Mg  
private void processErrorCode(int nErrorCode) g^ZsV:D  
{ eYZ{mo7  
System.err.println("Error Code : " + nErrorCode); hbRDM'  
} hfT HP  
~L$B]\/A5  
_i{$5JJ+K2  
//停止文件下载 S`HshYlE q  
public void siteStop() m99j]w r~c  
{ P=PcO>  
bStop = true; wQbN5*82  
for(int i=0;i<nStartPos.length;i++) 2 g5Ft  
fileSplitterFetch.splitterStop(); ^HYmi\`  
UQ6UZd37   
[ fvip_Pt  
} u3)Oj7cX  
} ],CJSA!5F  
//负责部分文件的抓取 #U45;idp  
**FileSplitterFetch.java 'zCJK~x`x  
*/ r2A%.bL#  
package NetFox; ,CqJ ((  
qOy3D~  
^*.S7.;2o  
import java.io.*; 9s\(yC8h  
import java.net.*; g&9E>wT  
;/+VHZP;  
 +]Ca_`  
public class FileSplitterFetch extends Thread { Y2709LWmP  
7|4hs:4mD  
Q WVH4rg  
String sURL; //File URL ;d$PQi  
long nStartPos; //File Snippet Start Position *fyC@fI>  
long nEndPos; //File Snippet End Position ^DVj_&~  
int nThreadID; //Thread's ID +p6cG\Gp  
boolean bDownOver = false; //Downing is over (qd$wv^ h  
boolean bStop = false; //Stop identical [=M0%"  
FileAccessI fileAccessI = null; //File Access interface F[PIo7?K  
[<SM*fQ>t  
\`?#V xz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .3WDtVE  
{ F7$x5h@  
this.sURL = sURL; 0sq?;~U  
this.nStartPos = nStart; 3Mw\}q  
this.nEndPos = nEnd; :N03$Tvl  
nThreadID = id; [0|g3K !A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UB[tYZ  
} JTbg8b  
hz#S b~g  
lU]/nKyd  
public void run() Kq!E<|yM  
{ vlYDhjZk#  
while(nStartPos < nEndPos && !bStop) sVP[7&vr~  
{ lF-;h{   
YT!QY@qw  
hnWo.5;$  
try{ Ar&]/X,WG  
URL url = new URL(sURL); 8B ZTHlUB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9F+i+(\,b  
httpConnection.setRequestProperty("User-Agent","NetFox"); P|}~=2J  
String sProperty = "bytes="+nStartPos+"-"; V_Z~$  
httpConnection.setRequestProperty("RANGE",sProperty); MgJiJ0y  
Utility.log(sProperty); mXZOkx{  
@Dc?fyY*o<  
\2cbZQx  
InputStream input = httpConnection.getInputStream(); tI50z khaB  
//logResponseHead(httpConnection); r,}U-S.w  
xK4b(KJj  
9>~UqP9  
byte[] b = new byte[1024]; T&Dt;CSF  
int nRead; W\09h Z6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j" wX7  
{ YrAaL"20  
nStartPos += fileAccessI.write(b,0,nRead); Mazjn?f  
//if(nThreadID == 1) }`k >6B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J }izTI  
} 8joJ e>9VJ  
+ $i-"^  
,arFR'u>  
Utility.log("Thread " + nThreadID + " is over!"); |k5uVhN  
bDownOver = true; d{_tOj$  
//nPos = fileAccessI.write (b,0,nRead); Oi{X \Y  
} y Q\K;  
catch(Exception e){e.printStackTrace ();} U9:?d>7  
} ,EPs>#d  
} sO7$b@"u.  
ca>6r`  
l!Q |]-.@  
//打印回应的头信息 [s?H3yQ.  
public void logResponseHead(HttpURLConnection con) A#9@OWV5f  
{ I"awvUP]a[  
for(int i=1;;i++) Y9F78=Q  
{ SI_{%~k*B  
String header=con.getHeaderFieldKey(i); M$O}roOa  
if(header!=null) c-nBB  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y- S]\tu  
Utility.log(header+" : "+con.getHeaderField(header)); I}oxwc  
else K{[ySB  
break; dRg1I=|{_  
} 51.! S  
} rAqg<fR*  
(1e;7sNG@  
+ >o/Ob  
public void splitterStop() e-<fkU9^W  
{ i9}n\r0=c  
bStop = true; b~\gV_Z  
} zo66=vE!  
FG8genCH@  
4xLU15C  
} 3\eb:-B:@  
iN%\wkx*N  
x#yL&+'?Mj  
/* ]9z{ 95  
**FileAccess.java ;c73:'e  
*//文件访问(定位,写) f:L%th  
package NetFox; uiq)?XUKv  
import java.io.*; i|u3Qt5  
.v [8ie  
[sG=(~BU  
public class FileAccessI implements Serializable{ U(5(0r  
>O[# 661  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *LJN2;  
RandomAccessFile oSavedFile; BBw]>*  
long nPos; 'qBg^c  
:HhLc'1Jw  
oD_'8G}  
public FileAccessI() throws IOException eN]0]9JO  
{ Qg  
this("",0); btb-MSkO  
} k!E`Xeob  
SPA_a\6_  
A S;ra,x  
public FileAccessI(String sName,long nPos) throws IOException q[]EVs0$ew  
{ (1\!6  
oSavedFile = new RandomAccessFile(sName,"rw"); jM1|+o*Wr  
this.nPos = nPos; $5nOiaQL  
oSavedFile.seek(nPos); rly3f  
} s$xctIbm?,  
w#_xV =  
3$+|nP:U  
public synchronized int write(byte[] b,int nStart,int nLen) ~V3pj('/)'  
{ Y}(#kqh>  
int n = -1; ]5D?Sc#-  
try{ DV +DJcF  
oSavedFile.write(b,nStart,nLen); #9z\Wblr  
n = nLen; (_-<3)q4  
} 'LIJpk3J  
catch(IOException e) Q%~b(4E^7P  
{ {>>ozB.  
e.printStackTrace (); p"ht|x  
} FCQIfJ#  
8^j u=  
^.jIus5  
return n; PIP2(-{ai  
} SiHZco I  
k <ds7k1m  
R^P~iAO  
} [0N==Ym1  
dix\hqZ  
3EB8ls2  
/* q.i@Lvu#  
**SiteInfoBean.java Q)yhpwrX  
*/ mJ0nyjX^  
package NetFox; ?1}1uJMj-  
j['Z|Am"l  
LKY4rY!|@d  
public class SiteInfoBean { MdT'xYomzQ  
tDFN *#(  
2Xk(3J!!'a  
private String sSiteURL; //Site's URL F>&Q5Kl R  
private String sFilePath; //Saved File's Path Oa\!5Pw1  
private String sFileName; //Saved File's Name '#[U7(lIQ  
private int nSplitter; //Count of Splited Downloading File A:[La#h|p  
DIodQkF  
2H fP$.  
public SiteInfoBean() wG2lCv`d  
{//nSplitter的缺省值为5 ON _uu]=  
//default value of nSplitter is 5 G\tTwX4  
this("","","",5); ]OZZPo  
} 0wXfu"E{  
^Qz8`1`;Z  
vjaIFyj  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GEfX,9LF&  
{ ?rXh x{vD  
sSiteURL= sURL; 3(%hHM7DM  
sFilePath = sPath; !cT#G  
sFileName = sName; =K{$?%"  
this.nSplitter = nSpiltter; YFOK%7K  
-QCo]:cp  
Z'<=06  
}  (:].?o  
bG67TWY)  
?I)-ez  
public String getSSiteURL() ~|@aV:k  
{ ~;#J&V@D  
return sSiteURL; \ntmD?kA  
} )ruC_)  
r|cl6s!P  
EaFd1  
public void setSSiteURL(String value) pm B}a7  
{ ja70w:ja  
sSiteURL = value; MX6*waQ-<  
} b_cnVlN[  
J7t5 B}}  
#*#4vMk<  
public String getSFilePath() +[`N|x<  
{ )mxY]W+  
return sFilePath; Ki}PO`s  
} }qT @.  
Hkg^  
6G7B&"&  
public void setSFilePath(String value) z,}1K!  
{ `23&vGk}  
sFilePath = value; )y'`C@ijI  
} r vVU5zA4H  
e{U`^ao`F8  
\bqNjlu  
public String getSFileName() j{>E.F2.  
{ k!t5>kPSQ  
return sFileName; nVw]0Yl  
} REB8_H"  
?(>7v[=iT  
<|k!wfHL  
public void setSFileName(String value) D}vgXzD  
{ 6Z ~>d;&9  
sFileName = value; >FFZ8=  
} ?tE}89c  
^i&/k  
^2|gQ'7<  
public int getNSplitter() uCF+Mp  
{ 7<x0LW  
return nSplitter; AUcq\Ys  
} |OF<=GGO+  
;#78`x2  
t= "EbPE  
public void setNSplitter(int nCount) ^v*ajy.>  
{ 6Bmv1n[X^h  
nSplitter = nCount; }lML..((1  
} 7'7bIaJk  
} %>Z=#1h/a  
03J,NXs  
pK1P-!c  
/* qi`*4cas*A  
**Utility.java B@e,3:  
*/ *58<.L|  
package NetFox; @jN!j*Y H  
|;6FhDW+'  
?0hk~8c  
public class Utility { zN#$eyt  
LPb43  
5dT-{c%w4  
public Utility() LTS3[=AB  
{ ] $$ciFM  
-WE pBt7*  
IpGq_TU  
} fC.-* r  
%Gl,V5z&  
//线程睡眠 Y<:%_]]  
public static void sleep(int nSecond) ktU98Bk]  
{ Sq/M %z5'  
try{ ml.l( 6A  
Thread.sleep(nSecond); f?#:@ zcL  
} s#&jE GBug  
catch(Exception e) kR7IZo" q  
{ x% k4Lm  
e.printStackTrace (); Ig"Krz  
} RR{]^g51  
} 63UAN0K%  
@]6)j&  
//日志 ^TVy :5Ag  
public static void log(String sMsg) <5@+:7Dv  
{ 50rCW)[#  
System.err.println(sMsg); =bded(3Z  
} W>K2d  
!-2nIY!  
r-^Ju6w{  
public static void log(int sMsg) i cQsA  
{ ?qAX *j  
System.err.println(sMsg); S"CsY2;  
} 1m|Oi%i4  
} }<uD[[FLB  
gmLGK1  
9Vxsv*OR,  
/* $.R$I&U  
**TestMethod.java r&A#h;EQX2  
*/ 3lM mSKN  
package NetFox; g v&xC 6>  
3*CF!Y%  
<\8dh(>  
public class TestMethod { Yt++  ?  
;EW]R9HCH  
93kSBF#  
public TestMethod()  h#^IT  
{ ///xx/weblogic60b2_win.exe @NlnZfMu  
try{ @bmu4!"d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7F4$k4r<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dZ9[wkn  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Os*,@N3t  
fileFetch.start(); yi"V'Us  
} %&c[g O!Za  
catch(Exception e){e.printStackTrace ();} *oY59Yf  
QJTGeJ Y  
_T6WA&;8  
} L,[0*h  
p W:[Q\rSj  
Q pz01x  
public static void main(String[] args) 8~ .r/!wfy  
{ >sm< < gVb  
new TestMethod(); A{: a kK  
} Z=z'j8z3  
} |08tQ  
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