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http断点续传简单实现(java)

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/* '\&t3?;  
**SiteFileFetch.java 'mH9 O  
*/ h7}D//~p  
package NetFox; aBH!K   
import java.io.*; +E{'A7im8=  
import java.net.*; jlf.~ vt  
?D6?W6@  
c%5G3j  
public class SiteFileFetch extends Thread {  &Ow[  
.??[qBOTE  
K KPQ[3g  
SiteInfoBean siteInfoBean = null; //文件信息Bean !c;Z<@  
long[] nStartPos; //开始位置 #LGAvFA*_F  
long[] nEndPos; //结束位置 fO;#;p.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7kQZ$sLc  
long nFileLength; //文件长度 fG+/p 0sJ?  
boolean bFirst = true; //是否第一次取文件 |Sne\N>%  
boolean bStop = false; //停止标志 )YP"\E  
File tmpFile; //文件下载的临时信息 jO|D# nC  
DataOutputStream output; //输出到文件的输出流 y)s+/Teb  
*~t&Ux#hj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) * [\H)Lz  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0""t`y&  
{ pCE,l'Xa  
siteInfoBean = bean; :{(` ;fJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +zU[rhMk'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0gI^GJN%Y!  
if(tmpFile.exists ()) (iwZs:k-  
{ baD`k?](  
bFirst = false; l(o#N'!j4  
read_nPos(); PD- <D~7  
} tSP)'N<  
else n#{z"G  
{ 4\cJ}p}LZ{  
nStartPos = new long[bean.getNSplitter()]; ~HW}Wik  
nEndPos = new long[bean.getNSplitter()]; Znv3h  
} xJQ-k/`  
o@&Hc bN^  
5#DtaVz  
w?r   
} D4@'C4kL  
&!@7+'])  
J6WyFtlyLc  
public void run() ^7q qO%  
{ cZd9A(1"^  
//获得文件长度 @w8MOT$  
//分割文件 Kzj9!'0R  
//实例FileSplitterFetch lK}W%hzU  
//启动FileSplitterFetch线程 &YSjwRr  
//等待子线程返回 gPo3jwo$  
try{ |#y+iXTJ   
if(bFirst) 7j9X<8 *  
{ _'W en  
nFileLength = getFileSize(); J%Cn  
if(nFileLength == -1) @v#]+9F  
{  Uz;z  
System.err.println("File Length is not known!"); j4!g&F _y  
} &!kD81?Mm  
else if(nFileLength == -2) N"tEXb/,  
{ 3gUGfe di  
System.err.println("File is not access!"); BI BBp=+  
} mbij& 0  
else $CgJ+ua\8  
{ /nbHin#we  
for(int i=0;i<nStartPos.length;i++) ^an3&  
{ Gkc.HFn(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); *dTI4k  
} o7qZy |\4S  
for(int i=0;i<nEndPos.length-1;i++) qs["&\@  
{ TQor-Cymz  
nEndPos = nStartPos[i+1]; '@{'T LMCi  
} 2feiD?0  
nEndPos[nEndPos.length-1] = nFileLength; Vy- kogVt  
} u_;&+o2  
} LD.^.4{c:  
/2<1/[#  
y;.U-}e1  
//启动子线程 ,KfBG<3   
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; dbmty|d  
for(int i=0;i<nStartPos.length;i++) Y &G]M  
{ \Q CH.~]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I6jDRC0<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?3I93Bt7  
nStartPos,nEndPos,i); F!LVyY"w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -W#-m'Lvu  
fileSplitterFetch.start(); shn{]Y  
} e=8z,.Xk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &fyT}M A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); K}r@O"6*\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |i}5vT78  
nEndPos = " + nFileLength); _ ?\4k{ET  
// fileSplitterFetch[nPos.length-1].start(); O%>FKU>(?  
R*DQm  
3U_,4qf  
//等待子线程结束 c`F~vrr)X  
//int count = 0; 2l8TX#K  
//是否结束while循环 3 ;N+5*-  
boolean breakWhile = false; tn"n~;Bh?:  
Hq>"rrVhx  
T|/B}srm  
while(!bStop) O%$XgEJ8p  
{ {<p-/|Z52  
write_nPos(); zUe)f~4  
Utility.sleep(500); 9b8kRz[ c  
breakWhile = true; _olhCLIR-  
3BTXX0yx  
|X'Pa9u  
for(int i=0;i<nStartPos.length;i++)  Uu<Tn#nb  
{ "EE=j$8u+  
if(!fileSplitterFetch.bDownOver) wG, "ZN  
{ S~Z`?qHWh  
breakWhile = false; pE^jUxk6  
break; tH}$j  
} _:ORu Vk  
} 5UTIGla  
if(breakWhile) o:.6{+|N  
break; P ]prrKZe,  
f`[gRcZ-  
KBb{Z;%  
//count++; %+1;iuDL  
//if(count>4) T##_?=22I  
// siteStop(); 09r0Rb  
} jOE~?{8m  
`X=2Ff  
5@:c6(5$  
System.err.println("文件下载结束!"); bR0z$~  
} R3[H#*gF<  
catch(Exception e){e.printStackTrace ();} AzfYw'^&9  
} /IkSgKJiz\  
%.zcE@7*  
^<}>]F_  
//获得文件长度 A18&9gY  
public long getFileSize() PGj?`y4  
{ bSKe@4C  
int nFileLength = -1; ]xYm@%>6  
try{ X-Q;4M-CJ  
URL url = new URL(siteInfoBean.getSSiteURL()); /.[;u1z"^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1 Ar6hA  
httpConnection.setRequestProperty("User-Agent","NetFox"); knPo"GQW  
:We}l;.jQ  
lwhVP$q}  
int responseCode=httpConnection.getResponseCode(); Z,? T`[4B  
if(responseCode>=400) --32kuF&(  
{ f"wm]Q59  
processErrorCode(responseCode); OFyZY@B-C~  
return -2; //-2 represent access is error 7wm9S4+|  
} e@GR[0~  
\N?,6;%xB  
R24ZjbKL  
String sHeader; (ohza<X;6  
Za&.sg3RG  
us:V\V  
for(int i=1;;i++) jW?siQO^  
{ L'*P;z7<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); l$:.bwXXO  
//Utility.log(in.readLine()); fuwv,[m  
sHeader=httpConnection.getHeaderFieldKey(i); 7n_'2qY  
if(sHeader!=null) N@z+h  
{ ]Q%|69H}B  
if(sHeader.equals("Content-Length")) [T5z}!_y  
{ +yh-HYo`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E@f2hW2  
break; 6*cY[R|q!  
} @ eQo  
} w'Cn3b)`  
else 5T,In+~Kd  
break; P/'9k0zs)  
} -d|VXD5N  
} "n4' \ig  
catch(IOException e){e.printStackTrace ();} N~w4|q!]  
catch(Exception e){e.printStackTrace ();} Fp`MX>F  
bc".R]  
@`</Z)  
Utility.log(nFileLength); F$;vPAxbK"  
=> PBdW  
* MJl(  
return nFileLength; @k~_ w#  
} }iK_7g`yKa  
pxF<L\L?:  
E8:4Z$|c  
//保存下载信息(文件指针位置) *@C4~Zo  
private void write_nPos() N1O& fMz  
{ jv"^_1  
try{ V&' :S{i  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =Wl*.%1 b  
output.writeInt(nStartPos.length); SSS)bv8m  
for(int i=0;i<nStartPos.length;i++) Fe4QWB6\U  
{ >/kwy2  
// output.writeLong(nPos); 7= o2$  
output.writeLong(fileSplitterFetch.nStartPos); m^8KHa  
output.writeLong(fileSplitterFetch.nEndPos); wR"4slY_%  
} 4s Vr]p`  
output.close(); m-~eCFc  
} $S"QyAH~-a  
catch(IOException e){e.printStackTrace ();} WF6'mg^^?  
catch(Exception e){e.printStackTrace ();} =uYz4IDB  
} )BuS'oB  
is3nLm(  
Y'.WO[dgf  
//读取保存的下载信息(文件指针位置) 4E Hb  
private void read_nPos() NjTVinz  
{ sH^?v0^a  
try{ h-XMr_F  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wGqQR)a  
int nCount = input.readInt(); _t:l:x.;T  
nStartPos = new long[nCount]; a=55bEn  
nEndPos = new long[nCount]; ~~.v*C[  
for(int i=0;i<nStartPos.length;i++) U#B,Q6~  
{ n&. bs7N2  
nStartPos = input.readLong(); T4W"!4[  
nEndPos = input.readLong(); jU#/yM "Y  
} doCWJ   
input.close(); kXj%thDx  
} IZm_/  
catch(IOException e){e.printStackTrace ();} iwHy!Vi-5  
catch(Exception e){e.printStackTrace ();} _HT*>-B  
} 0I.9m[<Fc  
3X+uJb2  
g5EdW=Dt,  
private void processErrorCode(int nErrorCode) 0d-w<lg9  
{ b}G4eXkuj  
System.err.println("Error Code : " + nErrorCode); a<.7q1F  
} >.D0McQg  
;w(]z  
+ *YGsM`E9  
//停止文件下载 BO5gwvyI  
public void siteStop() %j].' ;  
{ QK5y%bTSA  
bStop = true; 728}K^7:  
for(int i=0;i<nStartPos.length;i++) iA~b[20&  
fileSplitterFetch.splitterStop(); imx/hz!  
u_aln[oIv  
dVDQ^O&  
} 9<An^lLK*  
} /`iBv8!  
//负责部分文件的抓取 TA47lz q  
**FileSplitterFetch.java 7'[C+/:  
*/ #]s>  
package NetFox; gT K5z.]  
8s4y7%,|  
Nxu 10  
import java.io.*; TQ? D*&  
import java.net.*; H=vrF-#  
DPfP)J:~  
nL}bCX{  
public class FileSplitterFetch extends Thread { k'N `5M)  
U! F~><  
}2Lh'0 xY  
String sURL; //File URL )x.}B4z  
long nStartPos; //File Snippet Start Position k_9tz}Z  
long nEndPos; //File Snippet End Position p[(VhbN  
int nThreadID; //Thread's ID Ejdw"P"  
boolean bDownOver = false; //Downing is over >G2o  
boolean bStop = false; //Stop identical rK*s/mX <  
FileAccessI fileAccessI = null; //File Access interface +#5nk,1c>  
j+3~  
]JX0:'x^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s,TKC67.%+  
{ 5/Ng!bW  
this.sURL = sURL; H/_R!G8 \  
this.nStartPos = nStart; r}i<cyL  
this.nEndPos = nEnd; %$j)?e  
nThreadID = id; EXDtVa Ot  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j%iz>  
} dbkccO}WB  
%3e}YQe)  
\ ?[#>L4  
public void run() 5_+vjV;5  
{ -OpI,qyS  
while(nStartPos < nEndPos && !bStop) 4#uWj ?u  
{ PsDks3cG  
?)#dP8n  
M}4%LjD  
try{ O6P0Am7s  
URL url = new URL(sURL); \5^#5_<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /"?y @;Y~  
httpConnection.setRequestProperty("User-Agent","NetFox"); omM*h{z$$  
String sProperty = "bytes="+nStartPos+"-"; buo_H@@p{s  
httpConnection.setRequestProperty("RANGE",sProperty); rt%.IQdY  
Utility.log(sProperty); *b?C%a9  
?H7*?HV  
KQ3]'2q  
InputStream input = httpConnection.getInputStream(); FxSBxz<N-A  
//logResponseHead(httpConnection); (Q !4\Gy  
<@n/[ +3  
Q3#- q> ;7  
byte[] b = new byte[1024]; @oC8:  
int nRead; h0NM5   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ZLdvzH@'  
{ ;$@7iL  
nStartPos += fileAccessI.write(b,0,nRead); u~yJFIo  
//if(nThreadID == 1) |KF X0*70  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'v4#mf  
} m~9Qx`fi`  
2q J}5  
m~~_iz_*  
Utility.log("Thread " + nThreadID + " is over!"); `rC9i5:  
bDownOver = true; 1oaiA/bq  
//nPos = fileAccessI.write (b,0,nRead); .-+_>br~  
} v?rjQ'OP  
catch(Exception e){e.printStackTrace ();} gZgb-$b  
} )((Jnm D  
} 2%N$Y]  
nBL7LocvR  
~C< X~$y&  
//打印回应的头信息 693J?Yah[  
public void logResponseHead(HttpURLConnection con) \pZ,gF;y  
{ w!)B\l^+c  
for(int i=1;;i++) o)'T#uK  
{ x^}kG[s  
String header=con.getHeaderFieldKey(i); T[s_w-<7$  
if(header!=null) bL (g$Yi  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !<]%V]5[_  
Utility.log(header+" : "+con.getHeaderField(header)); ys:1%D,,_  
else `pzp(\lc  
break; e0"R7a  
} tfj6#{M5  
} i$)bZr\  
=,KRZqz  
&TE=$a:d&  
public void splitterStop() 9 )u*IGj  
{ 6 k+FTDL  
bStop = true; CJk$o K{Q  
} H r?G_L  
*. l,_68  
O^hWG ~o  
} zu<b#Wv  
EtJyI&7VK  
* 7.!"rb8A  
/* Gvv~P3Dm  
**FileAccess.java i4 KW  
*//文件访问(定位,写) 7 2ux3D  
package NetFox; VYkOJAEBg  
import java.io.*; -_.)~ )P  
*PE 1)bF  
Oi&.pY:X-  
public class FileAccessI implements Serializable{ !7@IWz(, "  
_)Q) tOW  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ed4:r/Dpo  
RandomAccessFile oSavedFile; 8I04Nx  
long nPos; >>=lh  
}N(-e$88  
E"bYl3  
public FileAccessI() throws IOException G>&=rmK"  
{ ZO{uG(u  
this("",0); KZzOs9 s  
} jDI O,XuF  
|Y"q. n77  
5b3Wt7  
public FileAccessI(String sName,long nPos) throws IOException <~t38|Ff@  
{ H1rge<  
oSavedFile = new RandomAccessFile(sName,"rw"); z$oA6qB)  
this.nPos = nPos; Z+)R%Z'aL  
oSavedFile.seek(nPos); <",4O  
} 4m$nVv  
,x!P|\w.G{  
[sp=nG7i&  
public synchronized int write(byte[] b,int nStart,int nLen) Rv ?G o2  
{ 2Ch!LS:+  
int n = -1; g !w7Yv  
try{ LEvdPG$)  
oSavedFile.write(b,nStart,nLen); G`PSb<h\oc  
n = nLen; mm\Jf  
} `o yz"07m  
catch(IOException e) NqvL,~1G  
{ H7?C>+ay  
e.printStackTrace (); 048BQ  
} v5i[jM8  
!OekN,6  
TAl py$  
return n; &K2[>5 mG  
} } WY7!Y  
PcC9)x  
p>h B&h  
} 2<)63[YO  
Fh9`8  
.,(bDXl?  
/* e4u$+  
**SiteInfoBean.java qCOv4b`  
*/ >/nS<y>  
package NetFox; VS@o_fUx)  
kX."|]  
Lw\ANku  
public class SiteInfoBean { "12.Bi.O"[  
@4Z>;  
$Ll]h</Z  
private String sSiteURL; //Site's URL kc^ Q ?-?  
private String sFilePath; //Saved File's Path ,,S5 8\x  
private String sFileName; //Saved File's Name 'W usEME  
private int nSplitter; //Count of Splited Downloading File sh[Yu  
\Xc6K!HJM  
{EGiGwpf  
public SiteInfoBean() KG6ki_  
{//nSplitter的缺省值为5 &10vdAnBRC  
//default value of nSplitter is 5 Ke,UwYG2~G  
this("","","",5); 55MsF}p  
} 8:0QIkqk  
3]WIN_h  
=_I2ek  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `DIIJ<;g  
{ ^-c j=on=Q  
sSiteURL= sURL; hNmC(saMGm  
sFilePath = sPath; A U9Y0<  
sFileName = sName; GLQ1rT  
this.nSplitter = nSpiltter; JDfkm+}uY  
G$ XvxJ  
~V[pu  
} B-ReBtN  
)+RTA y[k  
1O*5>dkX;%  
public String getSSiteURL() $wH{snX  
{ b>=MG8  
return sSiteURL; ^ '!]|^  
} "8%B (a 5A  
hH[UIe  
xK9"t;!C&  
public void setSSiteURL(String value) uS<7X7|!0  
{ =z'- B~  
sSiteURL = value; h2ewYe<87`  
} Z0g3> iItM  
]N_(M   
f1(V~{N,+  
public String getSFilePath() 5p}Y6Lc\j  
{ DZ5%-  
return sFilePath; s$css{(ek  
} :TJv<NZi'  
<8yzBp4gZ  
rlk0t159  
public void setSFilePath(String value) no`c[XY  
{ ]c]rIOTN  
sFilePath = value; asb-syqU  
} *,5V;7OR  
i`)bn 1Xm  
35B G&;C  
public String getSFileName() @G[P|^B  
{ 0b+OB pqN  
return sFileName; r/'9@oM  
} cP%mkh_ri  
Kj,C 9  
h!ZEZ|{  
public void setSFileName(String value) ."Wdpf`~  
{ Da*=uW9  
sFileName = value; /2pf*\u  
} 0"7 xCx  
e^Q$Tog<  
y`wTw/5N  
public int getNSplitter() >;kCcfS3ct  
{ L ?g|:  
return nSplitter; *`OgwMr)M  
} $ r)+7i  
xZW6Hk _  
*CZvi0&  
public void setNSplitter(int nCount) md:$O C3  
{ Y~EKMowI&e  
nSplitter = nCount; {i y[8eLg  
} 3 XdN \xc  
} @-nCK Yj  
Yh)yp?  
S/G6NBnbS  
/* 4zs1BiMG  
**Utility.java ,}2yxo;i  
*/ H$TYp  
package NetFox; 0KO_bF#EB=  
q+f]E&':  
lMz5))Rr  
public class Utility { La9v97H:  
sc'QNhrW  
*t J+!1  
public Utility() __r]@hY   
{ |&B.YLx  
T`KH7y|bv  
YYU Di@K  
} <jE6ye(R  
l[lUmE  
//线程睡眠 yPrp:%PS  
public static void sleep(int nSecond) UOHU 1.3$T  
{ rU<NHFGj4  
try{ s'' ?: +  
Thread.sleep(nSecond); hNs970i  
} D,%R[F? 5O  
catch(Exception e) g\;AU2?p7  
{ 3kFSu  
e.printStackTrace (); <6^MVaD  
} {WUW.(^]G  
} y>wrm:b-O  
>FED*C4  
//日志 ?#?[6t  
public static void log(String sMsg) ks|[`FH  
{ BqC, -gC  
System.err.println(sMsg); LW6&^S?4{  
} =S/$h}Vi  
maQE Bi,  
>yFEUD:  
public static void log(int sMsg) 3"=% [  
{ 0jCYOl  
System.err.println(sMsg); ^{&Vv(~!Q  
} WF\ hXO  
} +shT}$cb1  
;@p2s'(  
OrP-+eg  
/* G0Zq:kJ  
**TestMethod.java #k2&2W=x  
*/ j~,7JJ (y  
package NetFox; )R$+dPu>  
7uG@ hL36  
_"n1"%Ns  
public class TestMethod { $O"S*)9  
$G/h-6+8  
"+3p??h%Rq  
public TestMethod() z3+y|nx!  
{ ///xx/weblogic60b2_win.exe AY4ZU CqI  
try{ Q!K@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YSwAu,$jf  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !Cxo4Twg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [^xLK  
fileFetch.start(); iTsmUq<b]l  
} "3o{@TdU  
catch(Exception e){e.printStackTrace ();} cmgI,n-o?  
*Wk y#  
,9<}V;(  
} 2%4dA$H#4w  
_[;>V*?zp5  
<>$`vuU  
public static void main(String[] args) )&:4//}a  
{ =H6"\`W  
new TestMethod(); p\I,P2on  
} %7=B?c |  
} ,73 kh  
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