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http断点续传简单实现(java)

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/* A! ;meVUs  
**SiteFileFetch.java B/Ba5z"r$  
*/ %\yK5V5  
package NetFox; !Y%D 9  
import java.io.*; @Qo,p  
import java.net.*; D9ywg/Q91  
*o|p)lH  
;Prg'R[o;  
public class SiteFileFetch extends Thread { WTu{,Q  
^I./L)0= }  
H^v{Vo  
SiteInfoBean siteInfoBean = null; //文件信息Bean \DyKtrnm%  
long[] nStartPos; //开始位置 n1)'cS5}  
long[] nEndPos; //结束位置 M+UMR+K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <NL+9lR  
long nFileLength; //文件长度 L{K*~B-p  
boolean bFirst = true; //是否第一次取文件 &z0iLa4q)  
boolean bStop = false; //停止标志 'WzUu MCx  
File tmpFile; //文件下载的临时信息 v|To+ P6b  
DataOutputStream output; //输出到文件的输出流 ={xqNRVd  
g)N54WV  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) | /#'S&!U  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZE ^u.>5  
{ GFY-IC+fc  
siteInfoBean = bean; g$gVm:=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Y(W{Jd+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9H8=eJd  
if(tmpFile.exists ()) <mn-=#)  
{ "9 u-lcQ\  
bFirst = false; 9 G((wiE  
read_nPos(); }*OD M6  
} SZI7M"gf/+  
else .^GFy   
{ 1+FYjh!2t  
nStartPos = new long[bean.getNSplitter()]; o[2Y;kP3*P  
nEndPos = new long[bean.getNSplitter()]; M;> ha,x  
} 4&H+hN{3  
mf#fA2[  
+%x^RV}  
R$ v i!0  
} zAu}hVcW  
dY 6B%V  
Mf#2.TR  
public void run() "{mt?  
{ cyDiA(ot&  
//获得文件长度 .k p $oAL  
//分割文件 0\QYf0o   
//实例FileSplitterFetch ^CO#QnB @  
//启动FileSplitterFetch线程 _y|[Z;  
//等待子线程返回 iczs8gj*  
try{ %{=4Fa(Jux  
if(bFirst) kA1f[ AL  
{ Xk 5oybDI  
nFileLength = getFileSize(); S_`W@cp[  
if(nFileLength == -1)  9F/|`  
{ Hu[8HzJo  
System.err.println("File Length is not known!"); 9Zs #Ky/  
} I4A ;  
else if(nFileLength == -2) U[blq M  
{ cF-Jc}h  
System.err.println("File is not access!"); ngtuYASc  
} aA7S'[NjB  
else 5ENov!$H  
{ B'NS&7+].  
for(int i=0;i<nStartPos.length;i++) IJ+O),'  
{ _a?wf!4>P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tzx:*  
} r[Zg 2  
for(int i=0;i<nEndPos.length-1;i++) ajf_)G5X P  
{ oiIt3<BX  
nEndPos = nStartPos[i+1];  pb,{$A  
} /5Gnb.zN)  
nEndPos[nEndPos.length-1] = nFileLength; TG""eC!E  
} F Bd+=bx,Z  
} h#$ _<U  
:YkDn~@  
WBIQ%XB'  
//启动子线程 }])G Q@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .D>A'r8U  
for(int i=0;i<nStartPos.length;i++) @ J?-a m>  
{ D/+@d:-G  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NB~*sP-l&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C.DoXE7  
nStartPos,nEndPos,i); Pl`Bd0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s>[vT?  
fileSplitterFetch.start(); gDUoc*+h  
} BV_a-\Sa=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6%Cna0x:&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @U7U?.p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (7 ]\p  
nEndPos = " + nFileLength); arpJiG~JR  
// fileSplitterFetch[nPos.length-1].start(); /9t*CEu\  
gwkZk-f\p  
v= 8~ZDY  
//等待子线程结束 ,cl"1>lp  
//int count = 0; 5VY%o8xXa  
//是否结束while循环 z^SN#v$  
boolean breakWhile = false; K~9 jin  
T`0`]z!~  
}K qw\]`  
while(!bStop) }b\ipA,~  
{ d- _93  
write_nPos(); KJ05Zx~uma  
Utility.sleep(500); J}93u(T5  
breakWhile = true; Z:}2F^6  
g tSHy*3]  
!E(J ]a  
for(int i=0;i<nStartPos.length;i++) [jmAMF<F  
{ Y }g6IK}  
if(!fileSplitterFetch.bDownOver) f/|a?n2\hm  
{ d<^6hF  
breakWhile = false; \t 7zMp  
break; Jg?pW:}R  
} Sd/d [  
} Vo58Nz:%  
if(breakWhile)  _j?=&tc  
break; 55)ep  
]mDsUZf<  
LVz%$Cq,0  
//count++; kk>0XPk  
//if(count>4) M4$4D?  
// siteStop(); z8rh*Rfxd  
} w{UKoU  
1OJD\wc  
G5Dji_|  
System.err.println("文件下载结束!"); r+WPQ`Ar  
} 5la]l  
catch(Exception e){e.printStackTrace ();} )SO1P6  
} ob()+p.kK  
. KSr@Gz  
5&7?0h+I  
//获得文件长度 5;uX"z G  
public long getFileSize() M<me\s)  
{ 2QQYXJ^  
int nFileLength = -1; - G2M;]Cn  
try{ T;vPR,]rz  
URL url = new URL(siteInfoBean.getSSiteURL()); ?. 'oxW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ri_6 wbPp  
httpConnection.setRequestProperty("User-Agent","NetFox"); x'PjP1  
X0J]6|du.  
j~<iTLM  
int responseCode=httpConnection.getResponseCode(); 0}3'h#33=  
if(responseCode>=400) 7=[O6<+o  
{ D +%k1  
processErrorCode(responseCode); '/)_{Ly  
return -2; //-2 represent access is error k*+ZLrT  
} tfU3 6PR  
YSUH*i/%  
t 1'or  
String sHeader; XhkL)) FcG  
aLo>Yi  
[A/+tv  
for(int i=1;;i++) !ES#::;z?  
{ 761"S@tf$}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4BL,/(W] x  
//Utility.log(in.readLine()); u+T, n  
sHeader=httpConnection.getHeaderFieldKey(i); ;DWp>jgy  
if(sHeader!=null) .0/Z'.c 8  
{ @G-k]IWi  
if(sHeader.equals("Content-Length")) YQd&rkr  
{ A>,fG9pR  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,,-3p#P bw  
break; "4- Nnm  
} m<HjL  
} *y@]zNPD  
else w%u[~T7OI  
break; yxq!. 72  
} S6:gow(wU  
} y#W8] <dS"  
catch(IOException e){e.printStackTrace ();} s+t eYL#Zi  
catch(Exception e){e.printStackTrace ();} KFrmH  
~Q\uP(!D  
]$*_2V3VA$  
Utility.log(nFileLength); `SbX`a0p2  
3W WxpTU  
@WE$%dr  
return nFileLength; /JY i^rZ  
} enepAu-="p  
jpS#'h  
fxa^SV   
//保存下载信息(文件指针位置) <]`2H}*U'  
private void write_nPos() aM1JG$+7G  
{ |n%N'-el  
try{ 4r!40^:2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yXmp]9$  
output.writeInt(nStartPos.length); Za?&\  
for(int i=0;i<nStartPos.length;i++) +u.L6GcB  
{ ps J 1J  
// output.writeLong(nPos); lO@Ba;x  
output.writeLong(fileSplitterFetch.nStartPos); >QPS0Vx[  
output.writeLong(fileSplitterFetch.nEndPos); 0pz X!f1~  
} . 2Q/D?a  
output.close(); \Ki#"%S  
} 3xY]Lqwv  
catch(IOException e){e.printStackTrace ();} (9%%^s]uPT  
catch(Exception e){e.printStackTrace ();} t0(hc7`  
} o%7yhCY  
wAPdu y[  
] lTfi0}g_  
//读取保存的下载信息(文件指针位置) \`x'g)z(i  
private void read_nPos() ttRH[[E(  
{ S?<Qa;  
try{ 5eJd$}Lbc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )2hoO_l:  
int nCount = input.readInt(); zD|W3hL2&  
nStartPos = new long[nCount]; BW[K/l~"$:  
nEndPos = new long[nCount]; wtyu"=  
for(int i=0;i<nStartPos.length;i++) XCoOs<O:@  
{ .? / J  
nStartPos = input.readLong(); i{0_}"B  
nEndPos = input.readLong(); omu&:) g  
} W=:+f)D  
input.close(); 64@s|m*  
} c^%k1pae(  
catch(IOException e){e.printStackTrace ();} r Y.:}D  
catch(Exception e){e.printStackTrace ();} ]y e &#  
} *WG}K?"/  
Qa+gtGtJ  
fZC,%p  
private void processErrorCode(int nErrorCode) ?;Qk!t2U  
{ cCs:z   
System.err.println("Error Code : " + nErrorCode); .}wir,  
} i :72FVo  
\8ZNXCP  
n66 _#X  
//停止文件下载 }z #8vE;  
public void siteStop() 71InYIed  
{ DFMWgBL  
bStop = true; ~r3g~MCHS  
for(int i=0;i<nStartPos.length;i++) 0Og =H79<  
fileSplitterFetch.splitterStop(); Ns_d10rZ.  
3IIlAzne;  
l(W3|W#P  
} ^8)d8?}  
} @U5o;X!qU  
//负责部分文件的抓取 DQd&:J@?  
**FileSplitterFetch.java 5o*x?P!$  
*/ \T?O.  
package NetFox; J4 <*KL~a  
[sBD|P;M  
l3,|r QD  
import java.io.*; ge|}'QKow  
import java.net.*; 5h&8!!$[  
:Pv{ E  
Nbda P{{  
public class FileSplitterFetch extends Thread { _wMz+<7bY  
-c tZ9+LL  
}PVB+i M  
String sURL; //File URL ;FU d.vg{  
long nStartPos; //File Snippet Start Position _F9 c.BH  
long nEndPos; //File Snippet End Position J7H1<\=cJb  
int nThreadID; //Thread's ID y< 84Gw_  
boolean bDownOver = false; //Downing is over PuWF:'w r  
boolean bStop = false; //Stop identical #oaX<,  
FileAccessI fileAccessI = null; //File Access interface c!c!;(  
btOC\bUMfD  
y =CemJ[~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]Q+Tm2{  
{ Q["}U7j  
this.sURL = sURL; <M=K!k  
this.nStartPos = nStart; OP@PB|  
this.nEndPos = nEnd; |<E%hf  
nThreadID = id; 28-@Ga4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "(5M }5D  
} yR&E6o.$z  
F[lHG,g-  
ppxu\a  
public void run() MkQSq MU=  
{ F~m tE8B:  
while(nStartPos < nEndPos && !bStop) 5%9& 7  
{ Wl1%BN0>  
B=f{`rM)~W  
/<@oUv  
try{ GB0] |z5  
URL url = new URL(sURL); }Vt5].TA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2`; 0y M  
httpConnection.setRequestProperty("User-Agent","NetFox"); `Tab'7  
String sProperty = "bytes="+nStartPos+"-"; h' 16"j>  
httpConnection.setRequestProperty("RANGE",sProperty); ]5^u^  
Utility.log(sProperty); QDU^yVa_  
PffRV7qU0  
 hHdC/mR  
InputStream input = httpConnection.getInputStream(); 9 eP @}C6  
//logResponseHead(httpConnection); B!,})F$x  
$]O\Ryf6  
UXd\Q''  
byte[] b = new byte[1024]; Ji=E 1R  
int nRead; zU(U^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q*2ljcb55  
{ 3]wV`mD  
nStartPos += fileAccessI.write(b,0,nRead); &AW?!rH  
//if(nThreadID == 1) 6,k}v:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b.$Gc!g  
} wsM5T B  
T\OLysc  
67d0JQTu  
Utility.log("Thread " + nThreadID + " is over!"); ^Xh9:OBF  
bDownOver = true; 0%vXPlfnY  
//nPos = fileAccessI.write (b,0,nRead); tvP"t{C6,  
} KnlVZn[3t  
catch(Exception e){e.printStackTrace ();} tvI~?\Ylj  
} )5hS;u&b  
} 4rv3D@E  
D9JT)a  
c" yf>0  
//打印回应的头信息 "xw2@jGpG  
public void logResponseHead(HttpURLConnection con) -B R&b2  
{ 2&dtOyxo>  
for(int i=1;;i++) 9hcZbM]  
{ 0?k/vV4  
String header=con.getHeaderFieldKey(i); (ZDRjBth[  
if(header!=null) (G:$/fK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Krz[ f  
Utility.log(header+" : "+con.getHeaderField(header)); ]e R1 +Nl  
else Si!W@Jm  
break; jh9^5"vQ  
} `XQM)A  
} 'H:lR1(,  
iz>a0~(K  
Aqq%HgY:t  
public void splitterStop() G.1pg]P!  
{ eo"6 \3z  
bStop = true; r'-)@|  
} TR| G4l?  
3. fIp5g  
RytQNwv3  
} !\^c9Pg|v  
u.R:/H<>~  
bNj| GIf  
/* "@DCQ  
**FileAccess.java &!a[rvtZ+  
*//文件访问(定位,写) (q*Za  
package NetFox; p\~ lPXK  
import java.io.*; + ,0RrD )  
pJ1GB  
a'rN&*P  
public class FileAccessI implements Serializable{ 4, 8gf2  
8g^OXZ   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yD$rls:v<  
RandomAccessFile oSavedFile; USfOc  
long nPos; OiZPL"Q(K  
aV,>y"S  
h{VCx#!]  
public FileAccessI() throws IOException o0_RU<bWN  
{ % =br-c  
this("",0); rer=o S  
} pu=Q;E_f[  
+(QGlRd  
qJKD| =_  
public FileAccessI(String sName,long nPos) throws IOException 4L(axjMYU  
{ 2>_6b>9]  
oSavedFile = new RandomAccessFile(sName,"rw"); JIQS'r  
this.nPos = nPos; |U>BXX P  
oSavedFile.seek(nPos);  \|L@  
} !Yz~HO,u+  
: DCj2"  
K3M<%  
public synchronized int write(byte[] b,int nStart,int nLen) Z ~:S0HDP  
{  ZOi8)Y~  
int n = -1; bo4 :|Z  
try{ 1BmevE a)  
oSavedFile.write(b,nStart,nLen); ,yNPD}@v>  
n = nLen; ]4@_KKP  
} % Lhpj[C  
catch(IOException e) nxA Y]Q  
{ >t2 0GmmN  
e.printStackTrace (); ;lB%N t<,  
} Y7zg  
i-vhX4:bd  
9N:Bu'j&/  
return n; FAzshR  
} `_N8A A  
f nX!wN  
!vHnMY~AG  
} n{6XtIoYq  
Ks(+['*S  
k3da*vwE  
/* @kenv3[Lc  
**SiteInfoBean.java .9#4qoM'  
*/ T2P0(rEz  
package NetFox; q&B'peT  
0m(/hK  
{OL*E0  
public class SiteInfoBean { f<= #WV  
J^R))R=  
mnzamp  
private String sSiteURL; //Site's URL #'^!@+)  
private String sFilePath; //Saved File's Path |FHeT*"  
private String sFileName; //Saved File's Name [rC-3sGar  
private int nSplitter; //Count of Splited Downloading File Ek~Qp9B  
"WdGY*r  
( \{9W  
public SiteInfoBean() E ~<SEA  
{//nSplitter的缺省值为5 B.-5$4*s  
//default value of nSplitter is 5 BNw^ _j1  
this("","","",5); ,A[40SZA  
} o7i/~JkTP  
PspH[db  
!@{_Qt1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) OkGg4X|9  
{ ^3B{|cqf  
sSiteURL= sURL; qL091P\F  
sFilePath = sPath; .+t{o [  
sFileName = sName; Oh9wBV  
this.nSplitter = nSpiltter; 4(o: #9I  
~O;!y%  
=G]} L<  
} R"Nvnpm  
=24)`Lyb  
[X ]\^   
public String getSSiteURL() PwU}<Hrl]  
{ TS^(<+'  
return sSiteURL; }jBr[S5  
} l~!Tnp\M  
<?kr"[cQeP  
jhjGDF  
public void setSSiteURL(String value) W?mn8Y;{`  
{ 9:4PJ%R9  
sSiteURL = value; *M\Qt_[  
} [X0Wfb}{  
Ap9CQ h=!  
XeX0\L')R  
public String getSFilePath() %Js3Y9AL C  
{ zuUf:%k}I  
return sFilePath; $'btfo4H  
} e;~[PYeu  
%Ez%pT0TQ#  
.",E}3zn  
public void setSFilePath(String value) `=Pn{JaD  
{ } R!-*Wk  
sFilePath = value; hAi50q;z  
} fp|!LU  
y;<^[  
ugcWFB5|  
public String getSFileName() SoeL_#+^W  
{ 7\@[e, ^9  
return sFileName; ^$f} s,09  
} 6f,#O8]#5  
"]>JtK  
>i7zV`eK  
public void setSFileName(String value) z #c)Q  
{ :$."x '  
sFileName = value; zm4Okg)w@  
} P9; =O$s  
h~{TCK+I  
Qc#<RbLL  
public int getNSplitter() w^e<p~i!^E  
{ 9i GUE  
return nSplitter; qFp }+s  
} / >c F  
3Xyu`zS&   
+#7 e?B  
public void setNSplitter(int nCount) ,0O9!^  
{ URS6 LM  
nSplitter = nCount; Ae R3wua  
} #8iRWm0*6  
} 4^\5]d!  
&QFg=  
<seb,> :  
/* 4%>iIPXi.(  
**Utility.java eFS;+?bu  
*/ *-"DZ  
package NetFox; BS*IrH H  
2<53y~Yi%  
,pL%,>R5  
public class Utility { ':YFm  
%_C!3kKv~  
FJJ+*3(  
public Utility() 7.7P>U  
{ N GP}Z4  
21i?$ uU  
/KGVMBifM  
} e<o{3*%p)  
[)UL}vAO\q  
//线程睡眠 YLs%u=e($  
public static void sleep(int nSecond) @H[)U/.  
{ s8;/'?K  
try{ d Bn/_  
Thread.sleep(nSecond); VBV y3fnj  
} Wg X9k J  
catch(Exception e) @%Y$@Qb{  
{ j_L1KB*  
e.printStackTrace (); 2\Bt~;EIx  
} w5zr Ek#  
} =_~bSEqyRI  
8+'9K%'@qX  
//日志 W$&{jr-p  
public static void log(String sMsg) m/}(dT;  
{ 'MZX"t  
System.err.println(sMsg); AA$+ayzx9{  
} S5B12P  
4rkj$  
\$;Q3t3  
public static void log(int sMsg) nO-1^HUl  
{ EG=~0j~  
System.err.println(sMsg); 8K(3{\J[V  
} S ?v^/F  
} 9PpPAF  
?O]iX;2vM  
D$ >gAv  
/* vCPiT2G  
**TestMethod.java I eQF+Xz  
*/ {;iG}jK  
package NetFox; EPY64 {  
dWg09sx  
.6@qU}  
public class TestMethod { qTGEi  
6" s}<  
RsY7F;  
public TestMethod() `#X\@?'5  
{ ///xx/weblogic60b2_win.exe jK#[r[q{  
try{ ;bC163[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4bT21J37  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )\iO wA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sz5&P )X  
fileFetch.start(); > @Ux8#  
} -ZmccT"8  
catch(Exception e){e.printStackTrace ();} O{sb{kk  
3Pb]Of#  
E"EBj7<s  
} (A6 -9g>  
e``X6=rcG  
4h|48</  
public static void main(String[] args) |"7^9(  
{ QasUgZ  
new TestMethod(); N*k`'T  
} z[7j`J|Kk  
} ;:w?&4  
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