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http断点续传简单实现(java)

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/* c<=`<!FS[  
**SiteFileFetch.java 4|> rwQ~t  
*/ p^KlH=1n.6  
package NetFox; Rwc[:6;fn  
import java.io.*; I&TTr7  
import java.net.*; JrCf,?L^  
L_THU4^j  
mL:m;>JJ n  
public class SiteFileFetch extends Thread { 2^)D .&  
c*x J=Gz6d  
QKp+;$SE'  
SiteInfoBean siteInfoBean = null; //文件信息Bean a>o"^%x  
long[] nStartPos; //开始位置 k4qLB1&,  
long[] nEndPos; //结束位置 BIxV|\k  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h8f!<:rTS  
long nFileLength; //文件长度 '1W!xQ}E  
boolean bFirst = true; //是否第一次取文件 IajD;V  
boolean bStop = false; //停止标志 (KT38RhA  
File tmpFile; //文件下载的临时信息 n-b>m7O(  
DataOutputStream output; //输出到文件的输出流 S}oG.r 9  
7?6xPKQ)H  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5h`m]#YEG  
public SiteFileFetch(SiteInfoBean bean) throws IOException NuC-qG#  
{ %f3c7\=C  
siteInfoBean = bean; *QbM*oH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5f;n<EP y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FU_fCL8yA  
if(tmpFile.exists ()) t8+?U^j  
{ LP.HS'M~u  
bFirst = false; Sm$p\ORa  
read_nPos(); 2y3?!^$  
} O&`U5w  
else UWQtvQ f  
{ f{)+-8  
nStartPos = new long[bean.getNSplitter()]; +7| [b  
nEndPos = new long[bean.getNSplitter()]; /xl4ohL$a  
} .)LZ`Ge3F  
9{_8cpm4  
vuYO\u+ud  
}1QI"M*  
} J.1O/Pw!.a  
S5uJX#*;  
2dHM  
public void run() u?Fnln e4@  
{ p86~~rvq[  
//获得文件长度 R'rTE  
//分割文件 >%-Hj6%  
//实例FileSplitterFetch ,"~WkLI~\t  
//启动FileSplitterFetch线程 TQ; Z.)L  
//等待子线程返回 "yg.hK`  
try{ *8z"^7?^=  
if(bFirst) [/ AIKZM<  
{ <f%ujrX  
nFileLength = getFileSize(); +"jl(5Q  
if(nFileLength == -1) "gFxfWIA  
{ s(Z(e %  
System.err.println("File Length is not known!"); hT?6sWa  
} a "R7JjH  
else if(nFileLength == -2) z)}3**3'y  
{ j7K5SS_]  
System.err.println("File is not access!"); \ jE CSV|  
} ToV6lS"  
else 4w 'lu"U  
{ `,+#!)  
for(int i=0;i<nStartPos.length;i++) GxxDY]!  
{ ~|h lE z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b`$yqi<[  
} lK0s=4c{  
for(int i=0;i<nEndPos.length-1;i++) d:A}CBTSY  
{ e|yX QTlvL  
nEndPos = nStartPos[i+1]; J0=7'@(p  
} |~z3U>  
nEndPos[nEndPos.length-1] = nFileLength; Odm#wL~E  
} xdPcsox~  
} YQ; cJ$  
)T9;6R$b  
Rq) 0i}F  
//启动子线程 d^PD#&"g  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :4|M jn  
for(int i=0;i<nStartPos.length;i++) 2+z1h^)W  
{ )B6# A0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uS~#4;R   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4CLsY n?  
nStartPos,nEndPos,i); UH[<&v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uKv&7p@|_)  
fileSplitterFetch.start(); hi!`9k  
} qP7G[%=v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WJfES2N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2UiR~P]%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", GD!- qH  
nEndPos = " + nFileLength); 9CB\n  
// fileSplitterFetch[nPos.length-1].start(); ]bm=LA  
"f4<B-9<$  
5y]io Jc9-  
//等待子线程结束 >-M ]:=L  
//int count = 0; #b'N}2'p#V  
//是否结束while循环 ^5>s7SGB"  
boolean breakWhile = false; $_sYfU9  
C}q>YRubZ  
.jA\f:u#  
while(!bStop) ld.7`)  
{ joqWh!kv7U  
write_nPos(); pE2QnNr'  
Utility.sleep(500); Ea-bC:>  
breakWhile = true; 4jQ'+ 2it  
b^x07lO  
/t*YDWLg  
for(int i=0;i<nStartPos.length;i++) WfZF~$li`  
{ C ZJV_0  
if(!fileSplitterFetch.bDownOver) Vo\H<_=G  
{ >)NQH9'1  
breakWhile = false; eX"''PA  
break; \6o\+OQk  
} 3+ =I;nj  
} YGp)Oy}:  
if(breakWhile) /;Yy@oc  
break; nU2V]-qY  
'f+NW &   
)s)_XL  
//count++; NgVR,G|1  
//if(count>4) R(G\wqHUT3  
// siteStop(); v8m`jxII64  
}  x0A7O  
/_)l|<k+V  
<*<U!J-i  
System.err.println("文件下载结束!"); z}+i=cAN  
} RP! X8~8  
catch(Exception e){e.printStackTrace ();} )u*^@Wo  
} GKZN}bOm\  
*)'Vvu<  
[k$efwJ  
//获得文件长度 =xL)$DTg)  
public long getFileSize() _7"5wB?|+  
{ n *<v]1  
int nFileLength = -1; .po>qb6  
try{ o_f-GO  
URL url = new URL(siteInfoBean.getSSiteURL()); e\F} q)_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \K7t'20  
httpConnection.setRequestProperty("User-Agent","NetFox"); F}36IM9/:  
9pL g+6O  
~jN'J+_$  
int responseCode=httpConnection.getResponseCode(); ~}'F887f  
if(responseCode>=400) SJk>Jt=  
{ o r2|O#=  
processErrorCode(responseCode); )K;]y-Us[  
return -2; //-2 represent access is error kccWoU,  
} Y/fJQ6DY  
k_ Y~;P@  
Dz;HAyPj  
String sHeader; Mzkkc QLK  
bcH_V| 5}  
BMFF=  
for(int i=1;;i++) Q`ME@vz  
{ S_ b/DO  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Xj@+{uvQB  
//Utility.log(in.readLine()); ^A9 M;q  
sHeader=httpConnection.getHeaderFieldKey(i); p=Y>i 'CG  
if(sHeader!=null) .tnkT;T  
{ ;a r><w  
if(sHeader.equals("Content-Length")) y 9L14  
{ %w ) +V  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); d ~`V7B2Y  
break; g`0moXz  
} [sy j#  
} 3^,QIG  
else G$bJ+  
break; !yJICjXj  
} ,SUT~oETP  
} )d`mvZBn1  
catch(IOException e){e.printStackTrace ();} I :l01W;  
catch(Exception e){e.printStackTrace ();} +v7) 1y  
Kct@87z  
28I^$> [  
Utility.log(nFileLength); K pHw-6"  
BPv>$ m+.  
@S^ASDuQU7  
return nFileLength; fjG&`m#"  
} wTc)S6%7  
`yO'[2  
HrM$NRhu  
//保存下载信息(文件指针位置) q7\Ovjs0  
private void write_nPos() F<|t\KOW  
{ swcd&~9r  
try{ >IfV\ w32  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZDt?j   
output.writeInt(nStartPos.length); k N7Bd}  
for(int i=0;i<nStartPos.length;i++) ztll}  
{ 5B4Ssrs5W~  
// output.writeLong(nPos); %,P >%'0  
output.writeLong(fileSplitterFetch.nStartPos); *ZrSiIPP  
output.writeLong(fileSplitterFetch.nEndPos); 0~Gle:  
} WFTvOFj  
output.close(); ravyiO L  
} aZS7sV28  
catch(IOException e){e.printStackTrace ();} A8r^)QJP{  
catch(Exception e){e.printStackTrace ();} /F)H\*  
} K> g[k_  
}G V X>p  
GVGlVAo|@  
//读取保存的下载信息(文件指针位置) V3Z]DA  
private void read_nPos() x;s0j"`Jb  
{ p@ NaD=9  
try{ pzZk\-0R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #5} wuj%5  
int nCount = input.readInt(); YJV%a  
nStartPos = new long[nCount]; .a'f|c6  
nEndPos = new long[nCount]; 4rg2y]  
for(int i=0;i<nStartPos.length;i++) Xf[kI  
{ yx38g ca  
nStartPos = input.readLong(); zeb=8 Dg :  
nEndPos = input.readLong(); \M<3}t  
} 4T6 {Y  
input.close(); I:98 $r$  
} 64>krmVIe  
catch(IOException e){e.printStackTrace ();} (V:E2WR  
catch(Exception e){e.printStackTrace ();} V!_71x\-Q  
} zP\7S}p7%  
R%Y`=pK>}  
W~1~k{A  
private void processErrorCode(int nErrorCode) avQJPB)}Sb  
{ "R>FqX6FB  
System.err.println("Error Code : " + nErrorCode); CusF/>  
} j=RRfFg)  
o\b-_E5"?  
{i0SS  
//停止文件下载 ]:M0Kj&h  
public void siteStop() O^Q7b7}y  
{ 8.AR.o  
bStop = true; kRCQv-*  
for(int i=0;i<nStartPos.length;i++) /AY4M;}p  
fileSplitterFetch.splitterStop(); F,BOgWwP  
'xY@x-o  
"\C$   
} Yb3mP!3q8Z  
} GzXUU@p  
//负责部分文件的抓取 N["W I r  
**FileSplitterFetch.java nAIo{ F  
*/ *g}Yw  
package NetFox; YHkcWz  
GPz(j'jU  
JF&$t}  
import java.io.*; K.<.cJE  
import java.net.*; i 9<pqQ  
Q_-_^J  
JxE53ev  
public class FileSplitterFetch extends Thread { y$FW$Ka  
Z;Ez"t&U  
[qUN4x5b  
String sURL; //File URL }D411228  
long nStartPos; //File Snippet Start Position jp8@vdRg  
long nEndPos; //File Snippet End Position . o7m!  
int nThreadID; //Thread's ID `nM/l @  
boolean bDownOver = false; //Downing is over I-y#Ks1p+  
boolean bStop = false; //Stop identical KqBk~-G  
FileAccessI fileAccessI = null; //File Access interface  McH>"`  
9EDfd NN  
3$.deYa$R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0R{dNyh{  
{ X[ q+619  
this.sURL = sURL; 3vhnwDcK  
this.nStartPos = nStart; {"oxJ`z4  
this.nEndPos = nEnd; "Ve.cP,7(  
nThreadID = id; eAv4FA4g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wO ?+Nh  
} U*Ge<(v$  
m8'C_U^89  
L^2FQti>  
public void run() dm0QcW4  
{ wW>zgTG  
while(nStartPos < nEndPos && !bStop) xh7cVE[UM  
{ f` =CpO*  
_XJ2fA )  
(" LQll9  
try{ kt`nbm|aw  
URL url = new URL(sURL); ];.pK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7+X:LA~U  
httpConnection.setRequestProperty("User-Agent","NetFox"); "k]CW\H6z  
String sProperty = "bytes="+nStartPos+"-"; G9g1hie@%  
httpConnection.setRequestProperty("RANGE",sProperty); O"Ku1t!  
Utility.log(sProperty); O+g3X5f+  
* #jsgj[  
mPI8_5V8]  
InputStream input = httpConnection.getInputStream(); 0/S_e)U  
//logResponseHead(httpConnection); }ci#>  
3"o"fl  
'smWLz}  
byte[] b = new byte[1024]; 8} =JKR^cK  
int nRead; ono4U.C9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PH"n{lW.T  
{ :Y9NLbv  
nStartPos += fileAccessI.write(b,0,nRead); f$NMM >z  
//if(nThreadID == 1) NR;1z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ml\4xp,  
} T,| 1g6  
X[f=h=|  
 r.4LU  
Utility.log("Thread " + nThreadID + " is over!"); !r# ?C9Sq  
bDownOver = true; V&-~x^JK  
//nPos = fileAccessI.write (b,0,nRead); M\yT).>z  
} Neg,qOt  
catch(Exception e){e.printStackTrace ();} oc8:r  
} =Umw$+fJr  
} sB;@>NY  
8_T6_jL<  
!\&;h  
//打印回应的头信息 sC9&Dgkk  
public void logResponseHead(HttpURLConnection con) TMY d47  
{ A&nU]R8S  
for(int i=1;;i++) PO 6&bIr  
{ m0v:\?S:  
String header=con.getHeaderFieldKey(i); &f&z_WU  
if(header!=null) J_s>N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LX^u_Iu   
Utility.log(header+" : "+con.getHeaderField(header)); u_ABt?'  
else H54 R8O$  
break; &|/| ''A)  
} 5 ~TdD6}  
} [Q=dC X9%  
@}u9Rn*d;  
_YF%V;X  
public void splitterStop() X7s `U5'l  
{ (V4 ~`i4V  
bStop = true; ]c! ;L5  
} .A6(D$ O k  
K)J(./  
7b<yVP;{  
} ULQMG'P^D  
hWX% 66  
\Gc+WpS(  
/* Z)jw|T'X  
**FileAccess.java "HPB!)C8(  
*//文件访问(定位,写) i&VsW7  
package NetFox; _cXqAo  
import java.io.*; qh`t-  
XLH0 ;+CL{  
_-EyT  
public class FileAccessI implements Serializable{ 3YVi" k?2  
-|E!e.^7:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;VWAf;U;B  
RandomAccessFile oSavedFile; $sEy%-  
long nPos; 'Fmvu   
o<N  nV  
EVoE szR  
public FileAccessI() throws IOException /iX+R@  
{ 0{= `on;  
this("",0); ,T2G~^0  
} -;'1^  
7}X[ 4("bB  
3D2E?$dX  
public FileAccessI(String sName,long nPos) throws IOException U~pV)J  
{ () j =5KDu  
oSavedFile = new RandomAccessFile(sName,"rw"); )kP5u`v  
this.nPos = nPos; '_V2!?+RU+  
oSavedFile.seek(nPos); t^w"w`v\u  
} p\bDY  
xXM{pd  
utIX  %0  
public synchronized int write(byte[] b,int nStart,int nLen) Nqu>6^-z0  
{ }K&7%N4LZ  
int n = -1; e d<n9R  
try{ ]w.;4`l*  
oSavedFile.write(b,nStart,nLen); 78/Zk}I]  
n = nLen; 9]@A]p!  
} d+'p@!W_  
catch(IOException e) bFW=ylF9  
{ @7B$Yy#  
e.printStackTrace (); .C--gQpIv  
} (;q;E\Ej q  
rYbpih=x  
({q?d[q[  
return n; 6q{HU]N+  
} 6Udov pl  
B&@?*^.  
oZAB_A)[-  
} <TP=oq?I/  
l6d$V 9A  
IP(Vr7-v  
/* L|,!?cSAT  
**SiteInfoBean.java ;UfCj5`Q)4  
*/ ypy68_xyW  
package NetFox; PS[+~>%  
mFi&YpH u3  
S;)w.  
public class SiteInfoBean { 6Aku1h  
tQjLOv+?=  
@~%r5pz6  
private String sSiteURL; //Site's URL kOed ]>H  
private String sFilePath; //Saved File's Path (JM5`XwM  
private String sFileName; //Saved File's Name 9o+)?1\  
private int nSplitter; //Count of Splited Downloading File QDhOhGK  
JhLgCnm  
T7#W0^tj  
public SiteInfoBean() 07[_.i.l  
{//nSplitter的缺省值为5 o}$ EG  
//default value of nSplitter is 5 VSSu &Q  
this("","","",5); Ba!J"b]  
} *3?'4"B{8  
Dp':oJC  
iB498t  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3J5!oF{H  
{ 'JRvP!]  
sSiteURL= sURL; 2'W<h)m)z  
sFilePath = sPath; >Vwc3d  
sFileName = sName; hK_LEwd;  
this.nSplitter = nSpiltter; <?@NRFTe  
rsy'q(N[  
F 9@h|#an  
} sn)3Z A  
zaK#Z?V}  
{$wjO7Glp  
public String getSSiteURL() D`$hPYK|_  
{ -&-Ma,M?  
return sSiteURL; apu4DAy&8  
} o/+13C  
SF>c\eTtx  
c5u@pvSP  
public void setSSiteURL(String value) cj1cZ-  
{ ekWePL;rR2  
sSiteURL = value; f>N!wgo[  
} wwyPl  
#N`~xZ|$  
*exS6@N]  
public String getSFilePath() e8GEoD  
{ K~| 4[\  
return sFilePath; * iF]n2g:  
} !y@6Mm  
CW,Wx:Y  
l\@)y4 +  
public void setSFilePath(String value) ::}{_ Z  
{ s;6CExH  
sFilePath = value; FgB& b  
} l=v4Fa0^jF  
}Nf%n@  
H{=21\a\  
public String getSFileName() uLWh |   
{ E(Z8  
return sFileName; mD^ jd+  
} n\^Tq<] a  
LILQ\I<<'  
3GUZ;jdn  
public void setSFileName(String value) /\4'ddGU  
{ C,v(:ZE$J7  
sFileName = value; vy\RcP  
} .8by"?**  
D F*:_B )  
,f[>L|?e  
public int getNSplitter() Z )SY.iK.  
{ +Zaj,oEE  
return nSplitter; `1bv@yzq  
} !Rhl f.x  
,}K7Dg^1  
>kW@~WDMu  
public void setNSplitter(int nCount) oz}+T(@O  
{ 9f<MQ6_UU  
nSplitter = nCount; }<9cL'  
} TzNn^ir=HX  
} $3s@}vLd  
{/ BT9|LI  
"gDb1h)8  
/* =*r]) Vg^  
**Utility.java osX8eX]\  
*/ RsY3V=u  
package NetFox; 'qOREN  
fmb} 2h  
"HDcmIXg&  
public class Utility { @tZ&2RY1  
^h"`}[+  
?'KL11@R  
public Utility() @NNq z  
{ SV~cJ]F  
#0y)U;dA+w  
\cUC9/ b  
} +O*/"]h  
+7=K/[9p  
//线程睡眠 z <##g  
public static void sleep(int nSecond) mjKS{  
{ Yd#/1!A7u  
try{ B(n{e53 9f  
Thread.sleep(nSecond); hHT_V2*  
} z$?~Y(EY  
catch(Exception e) f]\CD<g3|E  
{ <U!`J[n%  
e.printStackTrace (); 4Za7^c.  
} 8&)DE@W  
} WRrd'{sB  
vJ-q*qM1  
//日志 ~;#Y9>7\\'  
public static void log(String sMsg) >o7n+Rb:  
{ 29?,<bB)  
System.err.println(sMsg); 3tZ]4ms}  
} 98uV6b~g  
2gCX}4^3b  
'8{N e!y  
public static void log(int sMsg) -\ EP.Vtz  
{ +/)#( j@  
System.err.println(sMsg); S|]X'f  
} 4'!c*@Y  
} ?C&z]f3(:  
K0 }p i +=  
JU^lyi!  
/* ]Zyur`  
**TestMethod.java dAkgR~  
*/ VBcy9|lD  
package NetFox; :"xzj<(  
y*tZ !m2Gg  
2M68CE  
public class TestMethod { 7]||UuF<  
S'_-G;g.  
7:)n$,31FW  
public TestMethod() s3R(vd  
{ ///xx/weblogic60b2_win.exe %sX$ nmi3  
try{ =p=rg$?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d\ 1Og\U|A  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qT`k*i?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %Ntcvp)  
fileFetch.start(); N#DYJ-~*  
} &' Ne! o8  
catch(Exception e){e.printStackTrace ();} b;cdIl!3  
C0}IE,]  
bdF.qO9  
} /$'AjIg4:&  
3~ S8!nx  
EioB%f3  
public static void main(String[] args) 9&` 2V  
{ b/{t|io{  
new TestMethod(); .tzG_  
} :]^P1sH[  
} [5+}rwm&W  
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