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http断点续传简单实现(java)

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/* DC> R  
**SiteFileFetch.java [ R8BcO(  
*/ Ca?w"m~h  
package NetFox; ]Z\W%'q+  
import java.io.*; Rvf{u8W  
import java.net.*; %nq<nfDT  
Rl0"9D87z  
|zfFB7}v  
public class SiteFileFetch extends Thread { h7K,q  S  
Gl w|*{$  
91&=UUkK?  
SiteInfoBean siteInfoBean = null; //文件信息Bean FVP,$  
long[] nStartPos; //开始位置 ,Iz9!i J"  
long[] nEndPos; //结束位置 v_%6Ly  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8'3&z-  
long nFileLength; //文件长度 ?Q=(?yR0]  
boolean bFirst = true; //是否第一次取文件 [X@{xF^vBQ  
boolean bStop = false; //停止标志 rDwd!Jet  
File tmpFile; //文件下载的临时信息 B/lIn' =  
DataOutputStream output; //输出到文件的输出流 t'W6Fmwkx  
7u^wO<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,mCf{V]#  
public SiteFileFetch(SiteInfoBean bean) throws IOException F:<+}{Av  
{ jM6$R1HX  
siteInfoBean = bean; BDPE.8s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .L#4#IO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +N,Fq/x  
if(tmpFile.exists ()) twldwuN  
{ 6-?/kY6  
bFirst = false; Xu_1r8-|=b  
read_nPos(); 8aRmHy"9l  
} {*CG&-k2D  
else ~v/` `s  
{ }*-fh$QJ  
nStartPos = new long[bean.getNSplitter()]; cJwe4c6.m  
nEndPos = new long[bean.getNSplitter()]; fWfhs}_  
} r SoT]6/   
~/SLGyu  
G;t< dJ8  
|yOIC,5[JW  
} g0/ R\  
(1er?4  
]NWcd~"b!Z  
public void run() ;Cx`RF w  
{ SU7,uxF  
//获得文件长度 y\iECdPU  
//分割文件 7{S;~VH3  
//实例FileSplitterFetch FRPdfo37  
//启动FileSplitterFetch线程 }\N ~%?6D  
//等待子线程返回 5 8U[IGs(  
try{ l!j=em@  
if(bFirst) +['1~5  
{ /!"sPtIh  
nFileLength = getFileSize(); .bh 7  
if(nFileLength == -1) NgxJz ]b  
{ )r*F.m{&:  
System.err.println("File Length is not known!"); 5PpS/I:on  
} Ix=(f0|  
else if(nFileLength == -2) a{By U%  
{ 5wvh @Sc\  
System.err.println("File is not access!"); r:U<cL T[9  
} }.=wQ_  
else #.}&6ZP  
{ [zrFW g6N  
for(int i=0;i<nStartPos.length;i++) -"N vu  
{ $9Xn.,W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PEKXPF N  
} KAr5>^<zw  
for(int i=0;i<nEndPos.length-1;i++) O+Db#FW  
{ raP9rEs  
nEndPos = nStartPos[i+1]; -gb@BIV#  
} uD4W@*PYr  
nEndPos[nEndPos.length-1] = nFileLength; &y3;`A7,  
} _*t75e$-  
} gHWsKE  %  
sk t9mU  
7$L*nf  
//启动子线程 K1- 3!G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~>%% kQt  
for(int i=0;i<nStartPos.length;i++) gPpk0LZi  
{ [XA:pj;rg'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -BrJ5]T>*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @[ '?AsO  
nStartPos,nEndPos,i); \&v)#w  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8tT/w5  
fileSplitterFetch.start(); ge{%B~x  
} EhOB+Mc1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c8o2* C$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3HndE~_C&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A(JgAV1{  
nEndPos = " + nFileLength); !3*%-8bp  
// fileSplitterFetch[nPos.length-1].start(); R8j\CiV17  
~y:?w(GD  
*W4~.peoE  
//等待子线程结束 [5P1 pkZ  
//int count = 0; h& Ezhv2  
//是否结束while循环 "!o|^nN,  
boolean breakWhile = false; 2 3A)^j  
AT"!Ys|  
@Wzr rCpj  
while(!bStop) ((fFe8Rn)q  
{ !$,e)89  
write_nPos(); Vf$q3X  
Utility.sleep(500); zj;Ktgc E  
breakWhile = true; |OBZSk1jp  
6"o@d8>v  
YD;"_yH  
for(int i=0;i<nStartPos.length;i++) O6\t_.  
{  11-?M  
if(!fileSplitterFetch.bDownOver) E@)9'?q  
{ Q~)A fa{  
breakWhile = false; %T~LK=m  
break; 6p~8(-nG  
} fSm|anuKZe  
} U0dhr;l  
if(breakWhile) {&)E$ M  
break; 24d{ol)  
>m`<AynJ  
m)xz_Plc  
//count++; NS^+n4  
//if(count>4) M}!E :bv'  
// siteStop(); \7tJ)[0aF  
} Wg=4`&F^  
x`zE#sD  
d)v'K5  
System.err.println("文件下载结束!"); 0"xD>ue&  
} `&o>7a;  
catch(Exception e){e.printStackTrace ();} oJor ]QYK  
} M[5fNK&nD  
~5wT|d  
43o!Vr/ S  
//获得文件长度 v\Xyz )  
public long getFileSize() G:!'hadw  
{ FK`M+ j  
int nFileLength = -1; :pg]0X;  
try{ IM&l%6[).  
URL url = new URL(siteInfoBean.getSSiteURL()); {{e+t8J??  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vI+X9C?  
httpConnection.setRequestProperty("User-Agent","NetFox"); tLe"i>  
G}gmkp]z  
eR:!1z_h  
int responseCode=httpConnection.getResponseCode(); WRfhxl  
if(responseCode>=400) )W$@phY(I  
{ {t QZqqdn@  
processErrorCode(responseCode); 'n4 iW  
return -2; //-2 represent access is error DeR C_ [  
} M07==R7  
s<fzk1LZ  
q b7ur;  
String sHeader; PitDk 1T  
3q:>NB<  
w2o5+G=  
for(int i=1;;i++) }C9P--  
{ Xmaj7*f>p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *S{fyYyM  
//Utility.log(in.readLine()); -4nSiI  
sHeader=httpConnection.getHeaderFieldKey(i); `{W>Dy  
if(sHeader!=null) '"o&BmF  
{ CxJkT2  
if(sHeader.equals("Content-Length")) {{ /-v3n  
{ ])uhm)U@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a;[=b p  
break; /;a b"b  
} 2g:V_%  
} +'QE-#%{=  
else =6LF_=}  
break; k&SI -jxj  
} 6F4OISy%3  
} 9a lMC  
catch(IOException e){e.printStackTrace ();} UfAN)SE"  
catch(Exception e){e.printStackTrace ();} w@"l0gm+u[  
a>XlkkX  
|\_d^U &`  
Utility.log(nFileLength); {|ChwM\x  
m03]SF(#3  
%q)*8  
return nFileLength; O[/l';i  
} -P7JaH/Q  
yi$Jk}w  
La#otuw+?  
//保存下载信息(文件指针位置) b Q6<R4  
private void write_nPos() FF7  
{ UpIt"+d2&  
try{ `U[s d*C"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UOAL7  
output.writeInt(nStartPos.length); s`Z'5J;S  
for(int i=0;i<nStartPos.length;i++) .|Zt&5osI  
{ FqpUw<]6s  
// output.writeLong(nPos); ri?>@i-9=  
output.writeLong(fileSplitterFetch.nStartPos); Zr U9oy&!C  
output.writeLong(fileSplitterFetch.nEndPos); Q1?09  
} ?YTngIa  
output.close(); qS{E+)P  
} }HC6m{vH(  
catch(IOException e){e.printStackTrace ();} NHjZ`=J s  
catch(Exception e){e.printStackTrace ();} e;ej/)no`  
} vq&u19iP  
~xSAR;8  
8kwe._&)  
//读取保存的下载信息(文件指针位置) cun&'JOH?U  
private void read_nPos() G^Q8B^Lg  
{ :xz,PeXo7  
try{ 1ehl=WN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &>]c"?C*  
int nCount = input.readInt(); |q:p^;x  
nStartPos = new long[nCount]; .3QX*]{  
nEndPos = new long[nCount]; !QTfQ69Y0  
for(int i=0;i<nStartPos.length;i++) S[zX@3eZV  
{ ToVi;  
nStartPos = input.readLong(); _'"whZ)2  
nEndPos = input.readLong(); ^OWA   
} X/l{E4Ex  
input.close(); r%^l~PN  
} :g`j gn 0  
catch(IOException e){e.printStackTrace ();} >m-VBo  
catch(Exception e){e.printStackTrace ();} #OT8_D  
} Jiv%Opo/|  
s.p4+K J  
f*IC ZM  
private void processErrorCode(int nErrorCode) +Kz baBK  
{ 5UgxuuP4  
System.err.println("Error Code : " + nErrorCode); p]-\\o}  
} ?"o7x[  
K_" denzT+  
_3'FX# xc  
//停止文件下载 \69h>h  
public void siteStop() Z Vin+z  
{ R;]z/|8  
bStop = true; Uf ?._&:  
for(int i=0;i<nStartPos.length;i++) aA|<W g  
fileSplitterFetch.splitterStop(); z{N~AaY  
ruKm_j#J  
`v|w&ty*  
} oieJ7\h]m  
} Ddr.kXIpo  
//负责部分文件的抓取 1j!LK-  
**FileSplitterFetch.java t6+c"=P#  
*/ oE H""Bd  
package NetFox; D\ ;(BB  
uSl&d  
iiw\  
import java.io.*; xRI7_8Jpyn  
import java.net.*; !'jZ !NFO  
@X?7a]+;8  
e` QniTkT  
public class FileSplitterFetch extends Thread { g"dq;H  
=Lc!L !(,b  
U{JD\G 8m  
String sURL; //File URL S#{jyU9 ]  
long nStartPos; //File Snippet Start Position 0{q>'dv  
long nEndPos; //File Snippet End Position w1&\heSQ  
int nThreadID; //Thread's ID QCD MRh n  
boolean bDownOver = false; //Downing is over Tx19\\r  
boolean bStop = false; //Stop identical j TyR+#Wn  
FileAccessI fileAccessI = null; //File Access interface "?X,);5S  
~\oF}7l$  
]VkM)< +  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n ZbINhls  
{ MP3Vo|}3  
this.sURL = sURL; yd|roG/  
this.nStartPos = nStart; cs]h+yE  
this.nEndPos = nEnd; `B A'a" $  
nThreadID = id; 44x+2@&1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JqmxS*_P  
} a$AR  
CQANex4&\  
3n!f'" T  
public void run() /=(PMoZu  
{ lZr}F.7  
while(nStartPos < nEndPos && !bStop) Ym8 V)  
{ 2bnYYQ14:  
-\9K'8 C  
JE *d-  
try{ !\}X?G f  
URL url = new URL(sURL); )Ggv_mc h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (k^o[HF  
httpConnection.setRequestProperty("User-Agent","NetFox"); \:m1{+l  
String sProperty = "bytes="+nStartPos+"-"; 5<>"d :9  
httpConnection.setRequestProperty("RANGE",sProperty); Z_h-5VU-  
Utility.log(sProperty); I !J'  
YW2h#PV6_  
:OFs" bC  
InputStream input = httpConnection.getInputStream(); t }YT+S  
//logResponseHead(httpConnection); *6bO2LO"  
2j;9USZ p  
,(A $WT@e  
byte[] b = new byte[1024]; ZYS]Et[Q  
int nRead; o* ~aB_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {ldt/dl~  
{ lv>^P>S(O  
nStartPos += fileAccessI.write(b,0,nRead); we/sv9v}n  
//if(nThreadID == 1) >/4N:=.h  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]5r@`%9  
} 2}n7f7[/b  
Gsu?m  
b+CJRB1  
Utility.log("Thread " + nThreadID + " is over!"); pft-.1py  
bDownOver = true; !pZ<{|cH  
//nPos = fileAccessI.write (b,0,nRead); ?2%;VKN4  
} [jv+Of IZ  
catch(Exception e){e.printStackTrace ();} ox*>HkV  
} neQ~h4U"  
} bXi!_'z$  
Xp.$FJ1)  
K3iQ/j~aq  
//打印回应的头信息 W\2 ']7}e  
public void logResponseHead(HttpURLConnection con) <L+1 &H  
{ P1R5}i  
for(int i=1;;i++) Z(XohWe2  
{ ?>Ngsp>-P  
String header=con.getHeaderFieldKey(i); jU-aa+  
if(header!=null) IZLBv2m  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HbRvU}C1  
Utility.log(header+" : "+con.getHeaderField(header)); c'>_JlG~  
else 9a]{|M9  
break; #jh5%@  
} }K5okxio  
} la}cGZ; p.  
Bi2 c5[3  
wB bCGU  
public void splitterStop() d%UzQ*s  
{ d N$,AOT  
bStop = true;  fDloL  
}  !TivQB  
PXyv);#Q`  
9Z21|5  
} _RIlGs\.  
!,dp/5 V  
Y]7503J  
/* wBvVY3VQ^  
**FileAccess.java )Gm9x]SVl  
*//文件访问(定位,写) $H)Q UFyC  
package NetFox; p="0Y<2l  
import java.io.*; `yP`5a/  
M!kSt1  
|;7mDhj=  
public class FileAccessI implements Serializable{ m8;w7S7,j~  
M\/hK2J# #  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 t>AOF\  
RandomAccessFile oSavedFile; 3@qv[yOE  
long nPos; d]Y;rqjue  
WrSc@j&Ycv  
co~NXpqg  
public FileAccessI() throws IOException lm 96:S  
{ Q`W2\Kod]  
this("",0); k qL.ZR  
} 3C<G8*4);/  
!:m.-TE  
0ki- /{;  
public FileAccessI(String sName,long nPos) throws IOException vc&v+5Y  
{ b _<n]P*)  
oSavedFile = new RandomAccessFile(sName,"rw"); i6KB\W2  
this.nPos = nPos; SDC'S]{ew  
oSavedFile.seek(nPos); DnFzCJ  
} N<8\.z5:<  
1C8xJ6F  
l'/`2Y1  
public synchronized int write(byte[] b,int nStart,int nLen) rD~/]y)t  
{ Hf@4p'  
int n = -1; ":8\2Qp  
try{ DtFHh/X  
oSavedFile.write(b,nStart,nLen); vMB61 |O  
n = nLen; kqm(D#  
} K<wFr-z  
catch(IOException e) xy]O8> b  
{ 7;o:r$08&}  
e.printStackTrace (); 7H5VzV  
} P*A+k"DU1  
fJ[ ^_,O  
C[<}eD4bV  
return n; +7}^Y}(  
} XZb=;tYo  
tkT,M,]?9  
X7huc*  
} "t&=~eOe3  
J`U]Ux/L  
lG\uJxV  
/* s|e.mZk/  
**SiteInfoBean.java TvDSs])  
*/ }bv+^#  
package NetFox; B=TUZ)  
1H-Y3G>jN  
Qc3d<{7\~  
public class SiteInfoBean { T0tX%_6`  
bE/|&8  
S-S%IdL  
private String sSiteURL; //Site's URL Xx{| [2`  
private String sFilePath; //Saved File's Path `/PBZnj  
private String sFileName; //Saved File's Name bW6| &P}X  
private int nSplitter; //Count of Splited Downloading File p>7qyZ8  
dn#I,xa`  
KVa{;zBwl  
public SiteInfoBean() k~8-E u1  
{//nSplitter的缺省值为5 /P*XB%y  
//default value of nSplitter is 5 wuH*a3(  
this("","","",5); Vc(4d-d5  
} !0,q[|m  
w 0_P9g:  
R'k `0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8OZj24*'DS  
{ EfEgY|V0  
sSiteURL= sURL; KEOk%'c,  
sFilePath = sPath; &u2;S?7m  
sFileName = sName; teJt.VA7)  
this.nSplitter = nSpiltter; :hZM$4  
IE`3I#v  
UH!(`Z\C  
} rtuaU=U  
KV_/fa~Ry  
Fa%1] R  
public String getSSiteURL() YCbvCw$Ob  
{ *6/IO&y1a  
return sSiteURL; 61S;M8tNv  
} #hxYB  
Zk=,`sBC  
s(=wG|   
public void setSSiteURL(String value) A9.TRKb=8  
{ 7[1Lh'u  
sSiteURL = value; Z_q+Ac{p  
} CeYhn\m5K0  
1B4Qj`:+0  
r^~+ <"  
public String getSFilePath() ai_ve[A  
{ <,M"kF:  
return sFilePath; 3(WijtH  
} KoERg&fY  
9^}&PEl  
f7x2"&?vg  
public void setSFilePath(String value) !/}3/iU  
{ p3M!H2W  
sFilePath = value; " @D  
} `dZ|Ko%k  
h$02#(RHJ  
v6*0@/L M  
public String getSFileName() uN`/&_$c  
{ >jI.$%L$  
return sFileName; s)E  \  
} 3k1e  
GKt."[seV  
AQ'%}(#0  
public void setSFileName(String value) q/ljH_-  
{ bT ,_=7F  
sFileName = value; m Q9dF,  
} Cy;UyZ  
;XN|dq  
8c9HJ9vk  
public int getNSplitter() QC+ Z6WS;  
{ }Fjbj5w0  
return nSplitter; cw<I L  
} XKWq{,Ks  
I8bM-k):9R  
PJ5}c!o[  
public void setNSplitter(int nCount) q94;x|63  
{ ?%6oM  
nSplitter = nCount; 11oNlgY&  
} tj13!Cc}e`  
} >5FTB e[D  
Fl`U{03  
ng%[yY  
/* dxX`\{E  
**Utility.java IJ Jp5[w  
*/ hY&Yp^"}]^  
package NetFox; ^-"Iw y  
mh3S?Uc  
h&'|^;FM  
public class Utility { G Aj%o]}u  
;E.]:Ia~  
0+CcNY9  
public Utility() cUR :a @  
{ &>\;4E.O5  
ve d]X!  
O)q4^AE$  
} W![K#r5T  
!y d B,S  
//线程睡眠 vfkF@^D  
public static void sleep(int nSecond) D kWp  
{ F!X0Wo=  
try{ nCq'=L,m  
Thread.sleep(nSecond); Ih.+-!w  
} NVMn7H}>  
catch(Exception e) ,8 4|qI  
{ Q5ASN"_  
e.printStackTrace (); e4z~   
} MqZ"Js  
} _pTcSp 3  
,iyy2  
//日志 0f@+o}i=)  
public static void log(String sMsg) :M"+  
{ . Vb|le(7  
System.err.println(sMsg); F+hV'{|w`  
} 6\7c:  
pq) =  
3;v)f":[  
public static void log(int sMsg) j#//U2VdN  
{ 0 PYYG  
System.err.println(sMsg); z/J?!ee  
} "&={E{pQ  
} d~<$J9%  
O<$w-(  
NZ1B#PG,c  
/* ClKWf\(ii6  
**TestMethod.java }eLApFHEDg  
*/ "p O  
package NetFox;  :tZsSK  
Tr?p/9.m  
cP?GRMX@}  
public class TestMethod { @(#vg\UH  
0cmd +`  
UCVYO. 9"  
public TestMethod() OL\-SQ&  
{ ///xx/weblogic60b2_win.exe #m U\8M,  
try{ % G!!0V!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F${sEtH  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .!4'Y}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r-T1^u  
fileFetch.start(); `/WxEu3  
} VrW]|jIu*  
catch(Exception e){e.printStackTrace ();} *<^C0:i(  
~3s ?.[}d  
__}SHU0R  
} "[ S[vkI  
7u"Q1n(h/  
W"%n5)  
public static void main(String[] args) jsAx;Z:QT  
{ a?W5~?\9  
new TestMethod(); 2(d  
} L!JC)p.  
} N-l`U(Z~P  
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