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http断点续传简单实现(java)

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/* 9g>)7Ne  
**SiteFileFetch.java O1bW, n(  
*/ cv G*p||  
package NetFox; Id&e'  
import java.io.*; ex6R=97uA  
import java.net.*; E&eY79  
0^sY>N"  
f 9Kt>2IN  
public class SiteFileFetch extends Thread { aU^6FI  
b?c/J {me  
6uT*Fg-G  
SiteInfoBean siteInfoBean = null; //文件信息Bean @Z2np{X:  
long[] nStartPos; //开始位置 Gx6%Z$2n  
long[] nEndPos; //结束位置 zRou~Kxi  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =/`]lY&  
long nFileLength; //文件长度 Tjhy@3  
boolean bFirst = true; //是否第一次取文件 cR_pC 9z  
boolean bStop = false; //停止标志 D}LM(s3li7  
File tmpFile; //文件下载的临时信息 6dV )pJd  
DataOutputStream output; //输出到文件的输出流 R TpNxr{[  
D>-r `  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -0x Q'1I  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8-Y*b89  
{ L!lmy&1  
siteInfoBean = bean; 28`s+sH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3%5a&b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p@nj6N.--  
if(tmpFile.exists ()) -5 D<zP/  
{ %1.F;-GdsW  
bFirst = false; YO$D-  
read_nPos(); %9a3$OGZX  
} BdF/(Pg  
else 5af0- hj  
{ brs`R#e \  
nStartPos = new long[bean.getNSplitter()]; IEMa/[n/  
nEndPos = new long[bean.getNSplitter()]; -v.\W y~\  
} ?5J#  
5l 3PAG  
_io'8X2K%  
Uq$/Q7  
} q]I aRho  
Dzf\m>H[  
PXkpttIE]M  
public void run() )Wr_*>xj  
{ 0hV#]`9`gN  
//获得文件长度 {;u,04OVK  
//分割文件 PPr Pj^%z=  
//实例FileSplitterFetch UZ2_FP  
//启动FileSplitterFetch线程 YLGE{bS  
//等待子线程返回 BEvY&3%l  
try{ bo/9k 4N3  
if(bFirst) CV.|~K0O  
{ %,_ZVgh0  
nFileLength = getFileSize(); Xt<1b  
if(nFileLength == -1) Q_|}~4_+  
{ 8c+V$rH_  
System.err.println("File Length is not known!"); "(7y% TFt:  
} A*?PH`bY  
else if(nFileLength == -2) )q-NE)  
{ Syy{ ^Ae}  
System.err.println("File is not access!"); 7I XWv-  
} j2<+[h-  
else ~TEn +  
{ {zvaZY|K"  
for(int i=0;i<nStartPos.length;i++) m^}|LB:5  
{ YHQ]]#'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3HpqMz  
} M7cD!s@'I  
for(int i=0;i<nEndPos.length-1;i++) r)pt(*KHo  
{ Sb/?<$>  
nEndPos = nStartPos[i+1]; Sv{n?BYq  
} peO@ZKmM  
nEndPos[nEndPos.length-1] = nFileLength; :5,~CtF5 `  
} 95z|}16UK  
} 1 >j,v+  
qBX_v5pvVA  
'-YiV  
//启动子线程 'E3T fM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1vj@ qw3  
for(int i=0;i<nStartPos.length;i++) 4d5c ]%  
{ Sk cK>i.[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X]p3?"7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OW4j!W  
nStartPos,nEndPos,i); qqf`z,u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X$we\t  
fileSplitterFetch.start(); #dUKG8-HJ  
} {MUiK 5:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,%*UF6B M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); BX0lk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Op ar+|p\  
nEndPos = " + nFileLength); k773h`;  
// fileSplitterFetch[nPos.length-1].start(); ES&u*X:  
J 7R(X  
J&>@ >47  
//等待子线程结束 6+IhI?lI=  
//int count = 0; I]v2-rB&-  
//是否结束while循环 P);s0Y|@H  
boolean breakWhile = false; DJ,LQj  
i *.Y  
z_ $c_J  
while(!bStop) g2|Myz)  
{ i"0Bc{cQ  
write_nPos(); 5p[}<I{  
Utility.sleep(500); QPDh!A3T  
breakWhile = true; "kyCY9) %  
wS*r<zj  
#XDgvX >  
for(int i=0;i<nStartPos.length;i++) q>2bkcGY#  
{ Z)`)9]*  
if(!fileSplitterFetch.bDownOver) o{sv<$  
{ xR0T' @q  
breakWhile = false; eut2x7Z(c  
break; iQgg[ )  
} %;k Hnl  
} `s CwgY+  
if(breakWhile) w+ R/>a( ]  
break; 2F:qaz  
}8ubGMr,Y  
.d1ff] ;  
//count++; 9;e!r DW,#  
//if(count>4) kP ]Up&'  
// siteStop(); f$xXR$mjf  
} n^4R]9U  
2CzhaO  
(?|M'gZ  
System.err.println("文件下载结束!"); p"ytt|H  
} aV'bI  
catch(Exception e){e.printStackTrace ();} ;t{q]"? W  
} o6[.$C  
ApCU|*r)  
]$@a.#}  
//获得文件长度 xak)YOLRV  
public long getFileSize() }L_YpG7  
{ xQu|D>kv87  
int nFileLength = -1; JI5o~; }m  
try{ t@qf/1  
URL url = new URL(siteInfoBean.getSSiteURL()); t5-O-AI[b{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]y0Y(  
httpConnection.setRequestProperty("User-Agent","NetFox"); }<04\t?  
F^u12R)  
>NKJ@4Y  
int responseCode=httpConnection.getResponseCode(); =8\.fp  
if(responseCode>=400) ?R)]D:`  
{ P1-eDHYw  
processErrorCode(responseCode); bC<W7qf]}  
return -2; //-2 represent access is error HT;^u"a~  
} ]3_b3@k  
,;`f* #  
Y,}_LS$f  
String sHeader; Jl/wP   
=fcg4h5(  
KxkBP/`3Q  
for(int i=1;;i++) yq%5h[M  
{ Za:j;u Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gg/`{  
//Utility.log(in.readLine()); ?_NKyiu95  
sHeader=httpConnection.getHeaderFieldKey(i); h[mT4 e3c  
if(sHeader!=null) bF"l0 jS  
{ R/+$ :  
if(sHeader.equals("Content-Length")) v-1}&K  
{ &xnQLz:#  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); vF27+/2+R  
break; S+T/(-W  
} h aAY=:  
} vY4sU@+V  
else AQ~ xjU  
break; N6Mr#A-{  
} G *CPj^O  
} W7S~~  
catch(IOException e){e.printStackTrace ();} FnO@\{M"A  
catch(Exception e){e.printStackTrace ();} C-&ymJC|  
f<YYo  
Q\$3l'W  
Utility.log(nFileLength); %2\Hj0JQQ  
<3;p>4gN  
n Nt28n@  
return nFileLength; .IeO+RDQ  
} bKQho31a'  
2e`}O  
jxog8 E  
//保存下载信息(文件指针位置) 23}` e  
private void write_nPos() jf9+H!?^N  
{ bv+u7B6,  
try{ ){;XI2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QZzamT)"  
output.writeInt(nStartPos.length); _ \D %  
for(int i=0;i<nStartPos.length;i++) q(KjhM  
{ g>lZs  
// output.writeLong(nPos);  - vvyG  
output.writeLong(fileSplitterFetch.nStartPos); @-$8)?`q  
output.writeLong(fileSplitterFetch.nEndPos); #<*Vc6pC  
} AC,RS 7  
output.close(); $^]K611w9  
} =Hi@q "  
catch(IOException e){e.printStackTrace ();} GcBqe=/B!  
catch(Exception e){e.printStackTrace ();} Yuv i{ 0  
} ]5ZXgz  
GK@OdurAR  
Su#0 F0  
//读取保存的下载信息(文件指针位置) !}&|a~U@`k  
private void read_nPos() `'YX>u/  
{ > i/jqT/  
try{ q/i2o[f'n  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b($hp%+yJ  
int nCount = input.readInt(); |+#Zuq  
nStartPos = new long[nCount]; V b0T)C  
nEndPos = new long[nCount]; zxyl+tU &  
for(int i=0;i<nStartPos.length;i++) :`bC3Mr  
{ XM$ ~HG  
nStartPos = input.readLong(); gmGK3am  
nEndPos = input.readLong(); $Z]&3VxxY  
} :{7+[LcH7  
input.close(); Xg)8}  
} ">H*InF  
catch(IOException e){e.printStackTrace ();} {9x_E {  
catch(Exception e){e.printStackTrace ();} o<G 9t6~  
} }9fa]D-a?  
jI-a+LnEm  
?.~1%l!  
private void processErrorCode(int nErrorCode) 7N$2N!I(  
{ \-\>JPO~<  
System.err.println("Error Code : " + nErrorCode); Ew8@{X y  
} I ]m  
y'R}  
nS+Rbhs  
//停止文件下载 <:S qMf  
public void siteStop() $RD~,<oEm  
{ ?cV,lak  
bStop = true; /$~1e7 W  
for(int i=0;i<nStartPos.length;i++) qmrT d G  
fileSplitterFetch.splitterStop(); WTSh#L  
yaUtDC.|  
1NZ"\9=U  
} F y+NJSG  
} z0 "DbZ;d  
//负责部分文件的抓取 >*-%:ub  
**FileSplitterFetch.java :j\7</uu  
*/ &jqaW 2  
package NetFox; gQnr.  
3jx%]S^z|  
pKSCC"i&j  
import java.io.*; u?^V4 +V  
import java.net.*; oRV}Nz7hr  
({uW-%  
]Ry9{:  
public class FileSplitterFetch extends Thread { }[p{%:tP  
PgBEe @.  
{:X'9NEE  
String sURL; //File URL vX+oZj   
long nStartPos; //File Snippet Start Position ^FVdA1~/  
long nEndPos; //File Snippet End Position i)i>Ulj*i  
int nThreadID; //Thread's ID opcanl9pSW  
boolean bDownOver = false; //Downing is over Hm-#Mpw  
boolean bStop = false; //Stop identical '/\  
FileAccessI fileAccessI = null; //File Access interface `+H=3`}X  
}lZEdF9GhG  
GBJL B  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cO?*(e1m=  
{ QPlU+5Cx  
this.sURL = sURL; i<QDV W9  
this.nStartPos = nStart; `4"8@>D  
this.nEndPos = nEnd; W}(A8g#6  
nThreadID = id; ]S2rqKB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )2f#@0SVL  
} u6|C3,!z"  
oF%m  
)G P;KUVae  
public void run() \/ bd  
{ J Enjc/  
while(nStartPos < nEndPos && !bStop) %cF`x_h[j  
{ ~D52b1f  
P\U<,f  
qt8Y3:=8l  
try{ OSu&vFKz  
URL url = new URL(sURL); >M<3!?fW)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <8r"QJY/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8P n  
String sProperty = "bytes="+nStartPos+"-"; +B ?qx Q  
httpConnection.setRequestProperty("RANGE",sProperty); is.t,&H4P]  
Utility.log(sProperty); =EJ&=t  
I%T+H[,  
pbMANZU[  
InputStream input = httpConnection.getInputStream(); iOfm:DTPr  
//logResponseHead(httpConnection); l}nVWuD  
}x'*3zI  
6)INr,d  
byte[] b = new byte[1024]; AL]gK)R  
int nRead; l+ }=D@l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f:;-ZkIU ?  
{ N_Us6 X  
nStartPos += fileAccessI.write(b,0,nRead); G]lGoa}]`u  
//if(nThreadID == 1) &PMQ]B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [gW eD  
} :jiEn y  
kWzp*<lWe  
~ 'ZwD/!e  
Utility.log("Thread " + nThreadID + " is over!"); dSDZMB sd  
bDownOver = true; *|rdR2R!  
//nPos = fileAccessI.write (b,0,nRead); .UK0bxoa  
} 2BccE  
catch(Exception e){e.printStackTrace ();} WK%cbFq(  
} XYcZ;Z9:  
} I9?\Jbqg  
+M j 6.X  
;lMvxt:  
//打印回应的头信息 @-@Coy 4Tt  
public void logResponseHead(HttpURLConnection con) t3L>@NWG  
{ /~LE1^1&U  
for(int i=1;;i++) ,np=m17  
{ P\"kr?jZP  
String header=con.getHeaderFieldKey(i); T?3Q<[SmI  
if(header!=null) {&1L &f<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cy%M$O|hX5  
Utility.log(header+" : "+con.getHeaderField(header)); _}[ Du/c  
else }?[];FB  
break; gM96RY  
} ]E9iaq6Z  
} (-C)A-Uo&  
e@3SF  
( 5LCy?-6  
public void splitterStop() C[FHqo9M?H  
{ Ym'h vK  
bStop = true; 8h] TI_  
} f&-`+V}U  
1]xmOx[mb  
n_kwtWX(  
} d1~#@6CIz  
.@H:P  
pGie!2T E  
/* '54\!yQ<{  
**FileAccess.java /-M:6  
*//文件访问(定位,写) @pH2"k| @  
package NetFox; #`Su3~T=S  
import java.io.*; eWH0zswG  
~WA@YjQ]  
:Xw|v2z%3  
public class FileAccessI implements Serializable{ QK_5gD`$a,  
VEps|d3,,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |\(uO|)ju  
RandomAccessFile oSavedFile; a`wjZ"}'[  
long nPos; [ycX)iM  
|/,S NE  
"uH>S+%|b  
public FileAccessI() throws IOException 0i~U(qoI  
{ l7QxngWw  
this("",0); I%d=c0>%  
} -y.cy'$f  
>LBA0ynh {  
e-dkvPr  
public FileAccessI(String sName,long nPos) throws IOException S,5ok0R  
{ t$BjJ -G  
oSavedFile = new RandomAccessFile(sName,"rw"); x?AG*' h&  
this.nPos = nPos; yY VR]HH  
oSavedFile.seek(nPos); p]aEC+q  
} J3yK^@&&  
f:-)S8OJ  
sH6;__e  
public synchronized int write(byte[] b,int nStart,int nLen) (.-4Jn  
{ -XYvjW,|  
int n = -1; D07M!U  
try{ hQ#e;1uD  
oSavedFile.write(b,nStart,nLen); l>6tEOXt  
n = nLen; #*h\U]=VS  
} Vb,V N?l  
catch(IOException e) %a/3*vz/I%  
{ SaPE 1^}  
e.printStackTrace (); SVU>q:ab  
} joY7Vk!<o  
k9k39`t  
xs= ~N  
return n; 7I3_$uF  
} CX]1I|T5  
rXB;#ypO  
9=>q0D2  
} :^7w  
ZvRa"j  
JxIJxhA>  
/* W9SU1{*9  
**SiteInfoBean.java (?e%w}  
*/ Ph3;;,v '  
package NetFox; +O/b[O'0  
2^r~->  
5FOMh"!z\  
public class SiteInfoBean { bZxN]6_  
o[>d"Kp  
-6[DQB  
private String sSiteURL; //Site's URL v,<14w  
private String sFilePath; //Saved File's Path R"W}\0k  
private String sFileName; //Saved File's Name Lt*P&  
private int nSplitter; //Count of Splited Downloading File G9:XEEN  
=WTSaC  
 2U)n^  
public SiteInfoBean() !q\8`ss  
{//nSplitter的缺省值为5 d:)#-x*h7  
//default value of nSplitter is 5 fJS:46  
this("","","",5); =x<N+vjXY  
} dlYpbw}W&<  
fo ~uI(rk  
wm~7`&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |62` {+  
{ =RB {.%  
sSiteURL= sURL; n&[CTOV  
sFilePath = sPath; vPDw22L;'  
sFileName = sName; Fi``l )Tt  
this.nSplitter = nSpiltter; P%2v(  
qFmw9\Fn  
)] @h}K}  
} Im;%.J  
;e?M;-  
?[JP[ qS  
public String getSSiteURL() J*;RL`  
{ 8?Zhh.  
return sSiteURL; ]PS`"o,pF$  
} 9@|52dz%  
5%jhVys23  
.!3e$mhV  
public void setSSiteURL(String value) zsp%Cz7T  
{ %7ngAIg  
sSiteURL = value; hTDK[4e  
} {s8c@-'  
w;lpJ B\  
/h>g-zb  
public String getSFilePath() z:\9t[e4  
{ p@jw)xI  
return sFilePath; i.mv`u Dm  
} re*}a)iL  
=Dn <DV  
!Se0&Ob  
public void setSFilePath(String value) %#2$B+  
{ 03~ ADj  
sFilePath = value; I!hh_  
} l5D)UO  
5f*_K6,v  
D40 vCax^J  
public String getSFileName() 3"x_Y  
{ _ $a3lR  
return sFileName; iVFOOsJ@  
} Cx TAd[az  
R,3cJ Y_%  
1GYZ1iA  
public void setSFileName(String value) Yc7 YNC.  
{ G'JHimP2j  
sFileName = value; {w2] Is2F  
} HPphTu}`  
|^Iox0A  
WZ'Z"'  
public int getNSplitter() 1Dr&BXvf]8  
{ 7(84j5zb  
return nSplitter; W\l&wR  
} YYQvt  
F{x+1hct0  
sa'1hX^@  
public void setNSplitter(int nCount) /"X_{3dq?  
{ IAO5li3  
nSplitter = nCount; 5_(\Cd<#  
} `vBBJ@f4)  
} Wj.t4XG!  
QXb2jWz  
L"b&O<N o  
/* Bt<)1_  
**Utility.java S)U*1t7[  
*/ ^+yz}YFM  
package NetFox; c5^HGIe1  
$9G& wH>{  
PMAz[w,R~  
public class Utility { s[8. l35|  
Y:DopKRD  
JvO1tA]ij  
public Utility() :SaZhY  
{ z"4 q%DC  
5Cdn j  
]o'o v  
} &GLDoLk6[  
MG=E 6:  
//线程睡眠 ,-6Oma -  
public static void sleep(int nSecond) :|bL2T@>[  
{ vm@V5oH  
try{ ) ^ En  
Thread.sleep(nSecond); rD}g9?ut  
} p)SW(pS  
catch(Exception e) mOJdx-q?r  
{ BeUyt  
e.printStackTrace (); ] hT\"5&6  
}  }#m9Q[  
} vaeQ}F  
-@XSDfy7S  
//日志 pN^g.  
public static void log(String sMsg) #aX#gh}1  
{ HR-'8?)R.A  
System.err.println(sMsg); nL?P/ \  
} Z=&|__ +d  
[K A^+n  
sTd@/>S?p  
public static void log(int sMsg) t~L4wr{B  
{ J_7w _T/  
System.err.println(sMsg); TJv .T2|  
} :of([e|u6  
} @1o X&#  
Z#}sK5s  
%UI^+:C  
/* j/aJDE(+  
**TestMethod.java kEh\@x[  
*/ 4ior  
package NetFox; ovp/DM  
M+:5gMB'  
d dgDq0N1j  
public class TestMethod { !SK`!/7c?  
at?I @By  
I7_lKr3  
public TestMethod() 48 -j  
{ ///xx/weblogic60b2_win.exe  ;Ci:d*  
try{ 76D$Nm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L"jA#ULg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qIJc\,'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B=OzP+  
fileFetch.start(); !\#Wq{p>W*  
} DCp8rvUI  
catch(Exception e){e.printStackTrace ();} P6_Hz!vE  
V< F &\  
I3>8B  
} N'y<<tTA  
+2{ f>KZ  
rfonM~3?'  
public static void main(String[] args) f:M^q ;  
{ '=;e# C`<{  
new TestMethod(); F`4W5~`  
} x:-NTW -g  
} :Fhk$?/r  
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