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http断点续传简单实现(java)

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/* GsO(\hR6^  
**SiteFileFetch.java "kFNOyj3\  
*/ NVQ.;"2w  
package NetFox; pSAtn  
import java.io.*; ,n%b~.$:v5  
import java.net.*; O,7S1  
le_a IbB"P  
3;jx Io$,  
public class SiteFileFetch extends Thread { 83]m/Iz  
]D~Ibv{Y  
;wJe%Nw?  
SiteInfoBean siteInfoBean = null; //文件信息Bean -~RGjx  
long[] nStartPos; //开始位置 60n>FQ<  
long[] nEndPos; //结束位置 2WLLI8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ` ,SNqi  
long nFileLength; //文件长度 3zmbx~| =\  
boolean bFirst = true; //是否第一次取文件 u)zv`m  
boolean bStop = false; //停止标志 tYgHJ~1L*  
File tmpFile; //文件下载的临时信息 DBGU:V,85  
DataOutputStream output; //输出到文件的输出流 K8&) kfyI  
!ni 1 qM  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) P B-x_D  
public SiteFileFetch(SiteInfoBean bean) throws IOException oP T)vN?  
{ ?x 0gI   
siteInfoBean = bean; : &nF>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 48S NI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); yIr0D 6L  
if(tmpFile.exists ()) # bjK]+  
{ l['p^-I  
bFirst = false; FzSL[S4i  
read_nPos(); Oc,HnyV+  
} BK)<~I  
else *Ej;}KSv  
{ 0nBDF79  
nStartPos = new long[bean.getNSplitter()]; }%c>Hh  
nEndPos = new long[bean.getNSplitter()]; |Y6;8e`H  
} _B^X3EOc  
Xk'Pc0@a  
pyX:$j2R+%  
B[h^]k  
} LN.*gG l  
\N-3JOVy  
x|AND]^Q  
public void run() .nNZ dta&=  
{ MSBrI3MqQ  
//获得文件长度 mJ(ElDG  
//分割文件 3.P7GbN  
//实例FileSplitterFetch Xf"< >M  
//启动FileSplitterFetch线程 1he5Zevm}  
//等待子线程返回 v>nBdpjXh  
try{ o7Z 8O,;  
if(bFirst) 2yFT` 5+H4  
{ \1#]qs -  
nFileLength = getFileSize(); W2v'2qAs  
if(nFileLength == -1) xCWS  
{ 4i&Rd1#0dI  
System.err.println("File Length is not known!"); PJ&L7   
} $0OOH4  
else if(nFileLength == -2) b>i5r$S8G  
{ S[hyN7sI  
System.err.println("File is not access!"); T*8 S7l  
} T~L V\}h  
else gMZ+kP`  
{ _NwHT`O[  
for(int i=0;i<nStartPos.length;i++) br TP}A  
{ 9@IL547V  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); NX8hFwR  
} 2"shB(:z>  
for(int i=0;i<nEndPos.length-1;i++) Z'uiU e`&  
{ rH,@"( p\  
nEndPos = nStartPos[i+1]; j+3rS  
} ?WqaT)l~  
nEndPos[nEndPos.length-1] = nFileLength; 5`:d$rv  
} 0y/31hp  
} g)ZMU^1  
sV5") /~  
yZm=#.f  
//启动子线程 @^ti*`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f52P1V]  
for(int i=0;i<nStartPos.length;i++) d-m.aP)y:  
{ $%M]2_W(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |v : )9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XjP;O,x  
nStartPos,nEndPos,i); imzPVGCD{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u)r:0;5  
fileSplitterFetch.start(); SsZSR.tD  
} Ac*J;fI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \/\w|j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .m\0<8C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Wb cm1I)  
nEndPos = " + nFileLength); <Uj9~yVN]  
// fileSplitterFetch[nPos.length-1].start(); 7hu7rWY`E  
b5Q>e%i#  
kw#-\RR_c  
//等待子线程结束 %QGw`E   
//int count = 0; l1O"hd'~s  
//是否结束while循环 uM,Ps}  
boolean breakWhile = false; E,K>V:P*  
eV(9I v[  
0b n%L~KU  
while(!bStop) ,LSiQmV5  
{ 4$ihnb`DQN  
write_nPos(); 34N~<-9AY  
Utility.sleep(500); wYV>Qd Z  
breakWhile = true; ITn PF{N  
3Z me?o*bY  
~LOE^6C+~o  
for(int i=0;i<nStartPos.length;i++) IFS_DW  
{ q3h& V  
if(!fileSplitterFetch.bDownOver) dT?3Q;>B?  
{ T,>L  
breakWhile = false; nfGI4ZE  
break; kQlwl9  
} %.$7-+:7A  
} S++~w9}  
if(breakWhile) Yc_(g0NK  
break; H=f| X<8  
SA=>9L,2  
M3|G^q:l  
//count++; :Y1;= W  
//if(count>4) y@LiUe5  
// siteStop(); esx/{j;<u  
} SZ$WC8AX  
W-&V:S{<  
10c.#9$  
System.err.println("文件下载结束!"); ,5ZQPICF  
} =8<~pr-NO  
catch(Exception e){e.printStackTrace ();} 3b]M\ F9  
} R)\^*tkz7  
+DR$>a  
=Tl_~OR  
//获得文件长度 T{f$S  
public long getFileSize() Qe ip h  
{ ]PoWL;E'  
int nFileLength = -1; B {:a,V7  
try{ 0{8L^ jB/  
URL url = new URL(siteInfoBean.getSSiteURL()); dY~z6bT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p)?6#~9$  
httpConnection.setRequestProperty("User-Agent","NetFox"); fxr#T'i  
{N/%%O.b  
a\}MJ5]  
int responseCode=httpConnection.getResponseCode(); xz5A[)N  
if(responseCode>=400) c>^(=52Q  
{ 3T gX]J@  
processErrorCode(responseCode); 2ag8?#  
return -2; //-2 represent access is error vxI9|i  
} PcU~1m1  
0('ec60u  
Q3&q%n|<  
String sHeader; !8cV."~  
>-<iY4|[d  
^V96l Kt/  
for(int i=1;;i++) hEsi AbTyF  
{ {)!>e  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +FqE fY4j  
//Utility.log(in.readLine()); ,#&7+e!]>P  
sHeader=httpConnection.getHeaderFieldKey(i); 5Lej_uqF   
if(sHeader!=null) 51#OlvD  
{  +)e|>  
if(sHeader.equals("Content-Length")) (?JdiY/  
{ ]SRpMZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /9I/^i~  
break; urjf3h[%  
} 3)\fZYu)  
} X|eZpIA45  
else )S2yU<6oOt  
break; _(kaaWJ  
} 0.n[_?<(  
} lNa+NtQu  
catch(IOException e){e.printStackTrace ();} 1nskf*Z  
catch(Exception e){e.printStackTrace ();} %>i:C-l8  
y*vSt^  
PMB4]p%o  
Utility.log(nFileLength); Uza '%R  
:Z6j5V;s  
>5L_t   
return nFileLength; ~qGW9 4  
} 9N}\>L)_  
5Q"w{ n  
`a|&aj0  
//保存下载信息(文件指针位置) !.$L=>:V  
private void write_nPos() Op ?"G  
{ ^sLx3a  
try{ Y6 sX|~Zy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8iJB'#''*  
output.writeInt(nStartPos.length); x}?<9(nE c  
for(int i=0;i<nStartPos.length;i++) Wx{E\ l  
{ IyyBW2  
// output.writeLong(nPos); p,$N-22a  
output.writeLong(fileSplitterFetch.nStartPos); {.{Wl,|7  
output.writeLong(fileSplitterFetch.nEndPos); |9c~kTjK  
} #H>{>0q  
output.close(); PKSfu++Z  
} @3O)#r}\  
catch(IOException e){e.printStackTrace ();} y-1e(:GF  
catch(Exception e){e.printStackTrace ();} *<($.c  
} ^1bslCe   
M }d:B)cz  
M[YFyM(  
//读取保存的下载信息(文件指针位置) \BXzmok  
private void read_nPos() +C{-s  
{ mSxn7LG  
try{ HN{c)DIm]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3$k#bC  
int nCount = input.readInt(); e;6K xvX~  
nStartPos = new long[nCount]; UDg' s  
nEndPos = new long[nCount]; K ?!qNK  
for(int i=0;i<nStartPos.length;i++) IL %]4,  
{ s51$x M  
nStartPos = input.readLong(); J @"#  
nEndPos = input.readLong(); 5h#h>0F  
} .w.:o2L  
input.close(); S v>6:y9?G  
} k5.5$<< T  
catch(IOException e){e.printStackTrace ();} e}e8WR=B  
catch(Exception e){e.printStackTrace ();} ns8s2kYcm  
} x 6`!  
}bjZeh.  
FoyYWj?,R  
private void processErrorCode(int nErrorCode) 3N+lWuE}K  
{ cj8cV|8@  
System.err.println("Error Code : " + nErrorCode); ,94<j,"  
} zzQWHg]/  
:;7I_tb  
fo@^=-4A-  
//停止文件下载 [s {!  
public void siteStop() St-uE |8  
{ y!77gx?-  
bStop = true; WVy'f|3;  
for(int i=0;i<nStartPos.length;i++) ~hLan&T  
fileSplitterFetch.splitterStop(); ~-BF7f 6C  
Yv;s3>r  
lrT2*$ w3  
} \j>7x  
} 37/n"\4  
//负责部分文件的抓取 ?0VR2Yb${b  
**FileSplitterFetch.java yJm"vN  
*/ aKbmj  
package NetFox; %T{]l;5  
HB/V4ki  
WVbrbs4  
import java.io.*;  Z.6dL  
import java.net.*; hi0HEm\  
' [ 4;QYw  
G21o @38e  
public class FileSplitterFetch extends Thread { yp.K-  
z*eBjHbF  
ATNOb  
String sURL; //File URL +$,Re.WnP  
long nStartPos; //File Snippet Start Position pE4a~:  
long nEndPos; //File Snippet End Position k&]nF,f  
int nThreadID; //Thread's ID Z',!LK!  
boolean bDownOver = false; //Downing is over Ma[EgG  
boolean bStop = false; //Stop identical &7aWVKon  
FileAccessI fileAccessI = null; //File Access interface e`D}[G#  
/~[Lr   
1sQIfX#2f  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~7P)$[  
{ W7i|uTM  
this.sURL = sURL; IU%|K~_n  
this.nStartPos = nStart; NI >%v  
this.nEndPos = nEnd; ):D"L C  
nThreadID = id; ,^#Jw`w^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yGZsNd {a&  
} S(Yd.Sp  
*U?O4E9  
NB"S ,\M0  
public void run() HGDrH   
{ l90mM'[  
while(nStartPos < nEndPos && !bStop) 200yN+ec  
{ ~U9K<_U  
u epyH  
qLN^9PdEE  
try{ ,5}U H  
URL url = new URL(sURL); }htjT/Nm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jVj5; }  
httpConnection.setRequestProperty("User-Agent","NetFox"); tMIYVHGy  
String sProperty = "bytes="+nStartPos+"-"; ]A#lV$  
httpConnection.setRequestProperty("RANGE",sProperty); ^:eZpQ [,  
Utility.log(sProperty); RK>Pe3<  
K7+yU3  
BM%wZ: s  
InputStream input = httpConnection.getInputStream(); h+f>#O+:  
//logResponseHead(httpConnection); 0B NLTRv  
> VG  
H",B[ YK  
byte[] b = new byte[1024]; AZtS4]4G)  
int nRead; a|aVc'j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bLgH3[{  
{ kNEEu! G  
nStartPos += fileAccessI.write(b,0,nRead); Lsmcj{1d  
//if(nThreadID == 1) C|(A/b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nV;'UpQw  
} RgE`Hr  
\oQ]=dDCd%  
DDg\oGLp  
Utility.log("Thread " + nThreadID + " is over!"); @ D+ftb/  
bDownOver = true; 'Wonz<{'  
//nPos = fileAccessI.write (b,0,nRead); ^u /%zL  
} a^|DD#5  
catch(Exception e){e.printStackTrace ();} dhl[=Y ` Q  
} g*| j+<:7  
} %\As  
\{,TpK.  
W .7rHa  
//打印回应的头信息 {|+Y;V`  
public void logResponseHead(HttpURLConnection con) GP|=4T}Bf  
{ R$awgSE  
for(int i=1;;i++) IP~!E_e}\  
{ ^4y]7 p  
String header=con.getHeaderFieldKey(i); =8kmFXo  
if(header!=null) US6_5>/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 092t6D}  
Utility.log(header+" : "+con.getHeaderField(header));  R$a<=  
else \INH[X#>  
break; !QUY (  
} j =_rUc'Me  
} K~x,so  
&K)8  
weitDr6  
public void splitterStop() wucdXj{%  
{ VSj!Gm0LB  
bStop = true; ~xH&"1  
} +Q*`kg'  
!,WGd|oJ  
TBhM^\z  
} 30Yis_l2h  
bdUPo+  
"}]`64?  
/* # kI>  
**FileAccess.java cH]tZ$E`  
*//文件访问(定位,写) dn6B43w  
package NetFox; KWwtL"3  
import java.io.*; T X`X5j  
xS18t="  
 )vr@:PE  
public class FileAccessI implements Serializable{ j)1yv.  
@u3`lhUcT  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^6 6!f 5^W  
RandomAccessFile oSavedFile; LHAlXo;  
long nPos; :NzJvI<  
Ycm)PU["  
R+sT &d  
public FileAccessI() throws IOException @nxo Bc !P  
{ R{hX--|j  
this("",0); bIKg>U'5d  
} o3ZN0j69|  
'Pz%c}hJ  
]AP1+ &9fN  
public FileAccessI(String sName,long nPos) throws IOException GnV0~?  
{ <?jd NM  
oSavedFile = new RandomAccessFile(sName,"rw"); yu?5t?vf  
this.nPos = nPos; XGlt^<`  
oSavedFile.seek(nPos); Fc[KIG3@  
} $o"nTl  
k<1yv$/mW  
QWmE:F[M~  
public synchronized int write(byte[] b,int nStart,int nLen) @|!4X(2  
{ |J`EM7qMK  
int n = -1; TyxIlI4"  
try{ :-&|QVH  
oSavedFile.write(b,nStart,nLen); -"(*'hD  
n = nLen; U%{GLO   
} G#iQX`  
catch(IOException e) A#u U ]S  
{ WlL(NrVA@@  
e.printStackTrace (); 2FcL-?  
} 4Nm>5*]  
>hKsj{=R7  
3f|}p{3  
return n; mDD.D3RS  
} fV:15!S[  
c0Ug5Vr  
gW, [X(  
}  a+h$u  
<+8'H:wz  
K/4@ 2vF  
/* ^ 5 >e  
**SiteInfoBean.java U}v`~' K  
*/ :I"CQ C[Z  
package NetFox; 2 a<\4w'  
3WV(Ok  
ycGY5t@K@  
public class SiteInfoBean { *0WVrM06?  
Tw~R-SiS`s  
:\T Mm>%q  
private String sSiteURL; //Site's URL >T$0*7wF  
private String sFilePath; //Saved File's Path W? 7l-k=S  
private String sFileName; //Saved File's Name G1:}{a5i_  
private int nSplitter; //Count of Splited Downloading File s"(RdJ-,  
*k$[/{S1-  
~cz}C("Z  
public SiteInfoBean() !}*N';  
{//nSplitter的缺省值为5 <H[w0Z$  
//default value of nSplitter is 5 \u=d`}E  
this("","","",5); `At.$3B  
} 2Gyq40  
$CcjuPsK  
%wD#[<BGn>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  yCX5 5:  
{ l\U Q2i  
sSiteURL= sURL; 'Kelq$dn#  
sFilePath = sPath; 68%aDs  
sFileName = sName; *4O=4F)x  
this.nSplitter = nSpiltter; Wzq W1<*`  
5C w( 4.  
egmUUuO  
} zcpL[@B  
u#05`i:Z  
!_glZ*tL  
public String getSSiteURL() Q+CJd>B  
{ ; :e7Z^\/k  
return sSiteURL; [V}vd@*k  
} :4AQhn^;"  
Fwm$0=BXL  
QE]@xLz   
public void setSSiteURL(String value) l;F"m+B!$  
{ ZvY"yl?e  
sSiteURL = value; x/QqG1q  
} s|YH_1r  
h y rPu_  
0 _!0\d#c  
public String getSFilePath() uJ`N'`Z  
{ M-WSdG[AJ  
return sFilePath; ulR yt^bx|  
} SH*'<  
^Z (cV g  
/E>;O47a  
public void setSFilePath(String value) zzG=!JR  
{ PW*Vfjf4  
sFilePath = value; DJ ru|2  
} B<W}:>3  
+'H[4g`  
X[z;P!U  
public String getSFileName() ^} j~:EZb  
{ ODJ"3 J  
return sFileName; N=mvr&arP  
} KFM[caKeJO  
q 4BXrEOw  
'r'=%u$1C  
public void setSFileName(String value) &oL"AJU  
{ xvGYd,dlK  
sFileName = value; z/Lb1ND8  
} 88Pt"[{1  
hV3]1E21"  
g4W$MI  
public int getNSplitter() (lsG4&\0F  
{ b+s'B4@rb  
return nSplitter; ui]iO p  
} q NGR6i  
4S(G366  
6v@Prw@.b  
public void setNSplitter(int nCount) /N0mF< P  
{ +o+f\!  
nSplitter = nCount; K#FD$,c~  
} L1IF$eC  
} vbJ<|#|r-  
6/!:vsa"3  
288mP]a(v_  
/* mF gqM:  
**Utility.java zJ`u>:*$  
*/ ,7nu;fOT[  
package NetFox; (nqhX<T>  
jMT[+f  
r$<!?Z  
public class Utility { -J]?M  
%6ckau1_;  
}3 /io0"D  
public Utility() J~x]~}V&  
{ t!D'ZLw  
rpk8  
St;9&A  
} M]8>5Zx.  
AB=%yM7V*  
//线程睡眠 `n+uA ~  
public static void sleep(int nSecond) !&%KJS6p4  
{ pI@71~|R  
try{ kn#?+Q  
Thread.sleep(nSecond); 9WHE4'Sa  
} l4gH]!/@  
catch(Exception e) q\tr&@4iC  
{ ?M90K)&g{  
e.printStackTrace (); +kI}O*s  
} 6>?qBWW  
} qMaO1cE\  
hC-uz _/3  
//日志 P, x" ![6  
public static void log(String sMsg) |E13W  
{ k(f),_  
System.err.println(sMsg); 1P]J3o  
} F%L"Q>aHW  
Eu |/pH=:  
fMwF|;  
public static void log(int sMsg) lB}?ey   
{ s.(.OXD&  
System.err.println(sMsg); y9}qB:[bR  
} W *0!Z:?  
} 4n#u?)  
H Qj,0#J)  
y^r'4zN'  
/* ]n=z(2Z9lD  
**TestMethod.java ?`TQ!m6y  
*/ o. $ 48h(  
package NetFox; .p{lzI9  
h`Jc%6o  
<mX5VGY9^  
public class TestMethod { J rK{MhO  
dC<%D'L*  
h5{//0 y  
public TestMethod() >MJ %6A>  
{ ///xx/weblogic60b2_win.exe hMupQDv/I  
try{ {F_>cyR  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *b;)7lj0h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 2?(/$F9X,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $d1ow#ROgy  
fileFetch.start(); xpZ@DK;  
} l>jrY1u  
catch(Exception e){e.printStackTrace ();} %n]jsdE^|  
+R?E @S  
`LH9@Z{  
} t:dvgRJt*  
QAI=nrlp  
,T;sWl  
public static void main(String[] args) bLTX_ R  
{ d% @0xsU1  
new TestMethod(); VK4UhN2  
} l=" (Hp%b  
} qY&(O`?m&  
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