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http断点续传简单实现(java)

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/* {&(bKQ  
**SiteFileFetch.java T{K+1SPy4  
*/ aEZn6k1  
package NetFox; p|%Y\!  
import java.io.*; l:+pO{7L  
import java.net.*; H "?-&>V-  
zT+yZA.L  
:S7yM8 b`  
public class SiteFileFetch extends Thread { skP_us~  
/C8(cVNZ  
W%Zyt:H`  
SiteInfoBean siteInfoBean = null; //文件信息Bean L@R%*-a  
long[] nStartPos; //开始位置 <^ )0M  
long[] nEndPos; //结束位置 1 }q[8q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 J&:0ytG  
long nFileLength; //文件长度 +TX p;6pA  
boolean bFirst = true; //是否第一次取文件 s_h <  
boolean bStop = false; //停止标志 ow`c B  
File tmpFile; //文件下载的临时信息 ;1OTK6  
DataOutputStream output; //输出到文件的输出流 8QZk0O  
z06pX$Q.<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) qaGIU`}:$A  
public SiteFileFetch(SiteInfoBean bean) throws IOException fW}H##b  
{ " Gn; Q-@  
siteInfoBean = bean; yZ)ScB^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =yNHJHRA#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #XY]@V\  
if(tmpFile.exists ()) c!\y\r  
{ $BBfsaJPT  
bFirst = false; ptq{$Y{_  
read_nPos(); u]MF r2  
} LA@}{hU  
else x}>tX  
{ hJ4.:  
nStartPos = new long[bean.getNSplitter()]; <,hBoHZSL  
nEndPos = new long[bean.getNSplitter()]; ze\~-0ks +  
} /7"1\s0U  
|95/'a*  
?H c A&  
246lFx G.  
} =L wX+c  
# nYGKZ  
YV940A-n  
public void run() qiF~I0_0  
{ t@JPnA7~  
//获得文件长度 ?RzT0HRd  
//分割文件 X9gC2iSs]  
//实例FileSplitterFetch ~D=@4(f8|  
//启动FileSplitterFetch线程 dO//  
//等待子线程返回 #"yf^*wX  
try{ 7ER 2 h*  
if(bFirst) ?Ru`ma\;  
{ I2DmM"-|  
nFileLength = getFileSize(); aQmL=9  
if(nFileLength == -1) B+DRe 8  
{ \j;uN#)28  
System.err.println("File Length is not known!"); p+7BsW.l  
} !^fJAtCN]  
else if(nFileLength == -2) ;VFr5.*x  
{ 7~Ga>BK  
System.err.println("File is not access!"); yl ;'Ru:  
} ^[Er%yr0  
else k"7eHSy,  
{ 4vQHr!$Ep  
for(int i=0;i<nStartPos.length;i++) F i/G, [q  
{ |O9=C`G_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Mqtp}<*@-  
} +r!h*4  
for(int i=0;i<nEndPos.length-1;i++) ?W|IC8~d')  
{ fDqXM;a"  
nEndPos = nStartPos[i+1]; =GVhAzD3  
} Xbtv}g<0c  
nEndPos[nEndPos.length-1] = nFileLength; (}}8DB  
} -d3y!| \>a  
} |\(/dXXP  
%UJ4wm  
)x7hhEk=^  
//启动子线程 *vO'Z &  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oX4uRc7wR  
for(int i=0;i<nStartPos.length;i++) GKtQ>39B  
{ 5#o,]tP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /_a *C.a6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L-R}O 8  
nStartPos,nEndPos,i); ] zY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WO9/rF_  
fileSplitterFetch.start(); bC{8yV=)  
}  :Y3?,  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m'B6qy!}6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MX0B$yc$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T!a[@,)_  
nEndPos = " + nFileLength); RGLA}|  
// fileSplitterFetch[nPos.length-1].start(); RHbp:Mlk  
R*0F)M  
6v#G'M#r  
//等待子线程结束 !v L :P2  
//int count = 0; `@D4?8_  
//是否结束while循环 !gf3%!%  
boolean breakWhile = false; UVJ(iNK"  
urB3  
[alXD_  
while(!bStop) 0cUt"(]  
{ ~m?~eJK#a  
write_nPos(); K-u/q6ufK  
Utility.sleep(500); B ,Brmn  
breakWhile = true; ? $ c  
5U jQLB  
kwR@oVR^  
for(int i=0;i<nStartPos.length;i++) vNSf:5H$  
{ z0[ZO1Fo(  
if(!fileSplitterFetch.bDownOver) >2 qP  
{ RWo B7{G  
breakWhile = false; B-|Zo_7  
break; UYOn p7R<  
} [1^wy#  
}  Vb 9N~v  
if(breakWhile) RA I&;"  
break; b1]_e'jj  
3rg^R"&  
5z ^UQ q  
//count++; 9%14k  
//if(count>4) x 4</\o  
// siteStop(); F5MPy[  
} 34kd|!e,  
[B @j@&  
l|em E ^  
System.err.println("文件下载结束!"); \q'fB?bS^  
} Z;\"pP:  
catch(Exception e){e.printStackTrace ();} 6ya87H'e@  
} WUS9zK  
m@u`$rOh  
E_1I|$  
//获得文件长度 AuipK*&g  
public long getFileSize() H<}eoU.  
{ :&)/vq  
int nFileLength = -1; ld}$Tsy0  
try{ {dXBXC/Ju  
URL url = new URL(siteInfoBean.getSSiteURL()); mS}x2 &  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `j}d=zZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); b|o!&9Yyr  
!o':\hex6  
!gfhEz Y  
int responseCode=httpConnection.getResponseCode(); lY*]&8/=  
if(responseCode>=400) O:tX0<6  
{ rOb"S*  
processErrorCode(responseCode); :yjK*"T|OD  
return -2; //-2 represent access is error F(~_L.  
} /&as)  
*/y]!<\v!k  
fbTw6Fde$  
String sHeader; Wx)U<:^e  
fR%1FXpK&  
2 U`W[  
for(int i=1;;i++) hUvuq,LH_  
{ >-5Gt  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 65#:2,s  
//Utility.log(in.readLine()); ?VP!1O=J  
sHeader=httpConnection.getHeaderFieldKey(i); !LOors za  
if(sHeader!=null) OrEuQ-,i@  
{ bTQa'y`3  
if(sHeader.equals("Content-Length")) g+ 1=5g  
{ /:{_|P\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); auTTvJ  
break; 56SS >b  
} f H|QAMfOu  
} =Z .V+4+  
else i(yAmo9h  
break; qJXsf M6  
} J7wQ=! g  
} F0'A/T'ht  
catch(IOException e){e.printStackTrace ();} 9Jy2T/l  
catch(Exception e){e.printStackTrace ();} ViwpyC'v  
@U3foL2\  
k;_KKvQ  
Utility.log(nFileLength); ,o@~OTja*  
-F+P;S  
O0wCb  
return nFileLength; ~K-*q{6Q  
} tG2OVRx8u  
Jp3di&x  
&M3ES}6  
//保存下载信息(文件指针位置) YG 5Z8@kH  
private void write_nPos() 0SY f<$  
{ Q|= Q]$d  
try{ G9n /S=R?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w-H%B`/  
output.writeInt(nStartPos.length); LX\*4[0%K  
for(int i=0;i<nStartPos.length;i++) C7 ]DJn  
{ F\=Rm  
// output.writeLong(nPos);  Ep\  
output.writeLong(fileSplitterFetch.nStartPos); fH e0W  
output.writeLong(fileSplitterFetch.nEndPos); FL#g9U>  
} (ND5CKCR^  
output.close(); r3H}*Wpf  
} Ur([L&  
catch(IOException e){e.printStackTrace ();} k'ZUBTRq!  
catch(Exception e){e.printStackTrace ();} 3_\{[_W  
} 2@3.xG  
}x?H ~QQT  
1KYbL8c  
//读取保存的下载信息(文件指针位置) p37zz4  
private void read_nPos() ,]uX:h-EM  
{ MO~~=]Y'  
try{ ..]*Ao2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +eBMn(7Cgv  
int nCount = input.readInt(); A!ioji+{[  
nStartPos = new long[nCount]; JU'WiR bcb  
nEndPos = new long[nCount]; &R'w-0k_  
for(int i=0;i<nStartPos.length;i++) MjQ[^%lfL  
{ N4a`8dS|  
nStartPos = input.readLong(); Z#4JA/c!  
nEndPos = input.readLong(); ~IlF*Zz#}6  
} oI_oz0nHk  
input.close(); -v;n"Zy1  
} aJ6#=G61l  
catch(IOException e){e.printStackTrace ();} s-C!uq  
catch(Exception e){e.printStackTrace ();} cXk6e.Uz  
} llHc=&y#  
.Na&I)udX.  
PG6[lHmi  
private void processErrorCode(int nErrorCode) X(GmiH /E  
{ C#Hcv*D  
System.err.println("Error Code : " + nErrorCode); (!ZQ  
} Ig1lol:;  
1KTabj/C  
@PPR$4  
//停止文件下载 a{]g+tGH  
public void siteStop() ]~ !X iCqu  
{ *?_qE  
bStop = true; cc|CC Zl  
for(int i=0;i<nStartPos.length;i++) *.m{jgi1X  
fileSplitterFetch.splitterStop(); Pqy-gWOv  
N>d|A]zH  
/~i.\^HX  
} Ky[bX  
} kqVg2#<@M  
//负责部分文件的抓取 8^/+wa+G  
**FileSplitterFetch.java [ 8F \;  
*/ LkJ$aW/  
package NetFox; T&1-eq>l  
]u rK$   
2#z=z d  
import java.io.*; ";PG%_(  
import java.net.*; AH&9Nye8  
>j50 ;</  
|Du,UY/  
public class FileSplitterFetch extends Thread { >vlQ|/C  
r0F_;  
RVc)") hQj  
String sURL; //File URL Q0V^PDF  
long nStartPos; //File Snippet Start Position 0jR){G9+  
long nEndPos; //File Snippet End Position  5ZnSA9?  
int nThreadID; //Thread's ID Y 3o^Euou  
boolean bDownOver = false; //Downing is over $d'CBsu|<  
boolean bStop = false; //Stop identical {]&R8?%  
FileAccessI fileAccessI = null; //File Access interface JAc@S20v\  
pO"m~mpA  
`FUFK/7 w\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException DVObrL)znL  
{ S?*^>Y-e;  
this.sURL = sURL; z*6$&sS\>  
this.nStartPos = nStart; ZV!R#Xv  
this.nEndPos = nEnd; "@.Z#d|Y  
nThreadID = id;  QTVa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |]^l^e 6m  
} R=`U4Ml;  
0/ut:RV0  
QT#b>xV)1  
public void run() y0,Ft/D  
{ #hIEEkCp +  
while(nStartPos < nEndPos && !bStop) &oA~ Tx  
{ k_]\(myq  
7egq4gN]2Y  
lZ}P{d'f.  
try{ !q!"UMiG  
URL url = new URL(sURL); ,# ]+HS^B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r+o_t2_b*  
httpConnection.setRequestProperty("User-Agent","NetFox"); X*0k>j  
String sProperty = "bytes="+nStartPos+"-"; 4Mk8Cpz  
httpConnection.setRequestProperty("RANGE",sProperty); Y|mW.  
Utility.log(sProperty); MzcB3pi  
x'@W=P 7   
^>-+@+( r  
InputStream input = httpConnection.getInputStream(); i wUv`>l&  
//logResponseHead(httpConnection); PmHd9^C  
aZ$/<|y~:_  
FIH@2zA  
byte[] b = new byte[1024]; C?,*U  
int nRead; M3ZOk<O<R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) TZe+<~4*i%  
{ wY/bA}%  
nStartPos += fileAccessI.write(b,0,nRead); d$}&nV/A)  
//if(nThreadID == 1) sTiYf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q*gnAi&.#  
} oWI!u 5  
(}G!np  
Ddb-@YD&+0  
Utility.log("Thread " + nThreadID + " is over!"); 4iwf\#  
bDownOver = true; v{r1E]rY  
//nPos = fileAccessI.write (b,0,nRead); |7y6 pz  
} [~COYjp  
catch(Exception e){e.printStackTrace ();} d [r-k 2  
} J<rlz5':  
} :i.t)ES  
f_rp<R>Uu  
Wj&nUp{  
//打印回应的头信息 $|k%@Q>  
public void logResponseHead(HttpURLConnection con) l_6eI  
{ z?)He)d  
for(int i=1;;i++) ^CUSlnB\(  
{ )#a7'Ba  
String header=con.getHeaderFieldKey(i); }B`Ku5 M  
if(header!=null) *,17x`1e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); t ^m~  
Utility.log(header+" : "+con.getHeaderField(header)); >Co)2d]  
else " CM ucK  
break; opXDm\  
} "e@n:N!  
} 7{4w 2)  
%yfE7UPS]  
Y3k[~A7X  
public void splitterStop() e gI&epN  
{ L"^OdpOs  
bStop = true; k=`$6(>Fz  
} "CBRPp  
}-74 f  
:> SLQ[1  
} FI$XSG  
g rspt}  
t{zBC?c R  
/* *jE;9^  
**FileAccess.java ->h5T%sn  
*//文件访问(定位,写) h,t:]  
package NetFox; P3!Atnv2  
import java.io.*; q6R Eh;$  
Cc Y7$D  
w.z<60%},0  
public class FileAccessI implements Serializable{ ~@D/A/|  
A @2Bs 5F  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5rloK"  
RandomAccessFile oSavedFile; RJhK$\  
long nPos; ?`H[u7*%  
P#MK  
et` 0Je  
public FileAccessI() throws IOException QD$Gw-U-l=  
{ FAw1o  
this("",0); <: :VCA%  
} $Asr`Q1i   
g5Hr7K m  
/OG zt  
public FileAccessI(String sName,long nPos) throws IOException R&*@@F-dx  
{ {n&Uf{  
oSavedFile = new RandomAccessFile(sName,"rw"); dxCPV6 XI  
this.nPos = nPos; H O*YBL  
oSavedFile.seek(nPos); Ys3uPs  
} 35_)3 R)  
e>AXXUEf  
|@wyC0k!  
public synchronized int write(byte[] b,int nStart,int nLen) f@d9Hqr+l;  
{ yQ%"U^.m  
int n = -1; Us=eq "eu  
try{ `eR 7H>I  
oSavedFile.write(b,nStart,nLen); I3(d<+M  
n = nLen; !),t"Ae?>  
} oL-2qtv  
catch(IOException e) psUE!~9,  
{ nZ E)_  
e.printStackTrace (); %j5ywr:  
}  to>  
o2naVxetE  
Skxd<gv  
return n; `N'V#)Pi  
} (`c G  
:h*a rT4{  
<#*.}w~  
} 3{ "O,h  
wd+K`I/v7h  
I 8z G~L%"  
/* u-:Ic.ZV  
**SiteInfoBean.java }`_(<H  
*/ cP rwW 6  
package NetFox; vFhz!P~  
e.8$ga{  
y vI<4F  
public class SiteInfoBean { :FHA]oec1  
Ej"u1F14J  
B(,:haAr  
private String sSiteURL; //Site's URL ue\t,*KYd  
private String sFilePath; //Saved File's Path |`0n"x7  
private String sFileName; //Saved File's Name pW|u P8#  
private int nSplitter; //Count of Splited Downloading File tTuX\;G  
|]sx+NlNc  
{dzoEM[ 1s  
public SiteInfoBean() =;ICa~`C;  
{//nSplitter的缺省值为5  3+U]?7t  
//default value of nSplitter is 5 >cgpajx*  
this("","","",5); =w%Oa<  
} ej^3Y Nh&  
e fO jTA%  
k\aK?(.RC7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ahGT4d`)9  
{ Ia4)uV8  
sSiteURL= sURL; #fDs[  
sFilePath = sPath; *C2R`gpBI  
sFileName = sName; {HrZ4xQnpV  
this.nSplitter = nSpiltter; q>s`uFRg(  
27#5y_ `  
D$q'FZH  
} RN9;kB)c  
:L:&t,X  
:dwt1>  
public String getSSiteURL() :Li/=>R^  
{ r:g9Z_  
return sSiteURL; +ts0^;QO2{  
} ue{xnjw>U  
,={t8lN  
{' 5qv@3  
public void setSSiteURL(String value) m;,xmEp  
{ $kPHxD!"  
sSiteURL = value; ^3~e/PKM  
} ^?GmrHC)  
]l;*$2w)  
1[PMDS_X  
public String getSFilePath() a`c:`v2o  
{ z&}-8JykH  
return sFilePath; go'j/4Tp  
} /'wF2UR  
:dnJY%/q  
T@ YGB]*Y  
public void setSFilePath(String value) h{'t5&yY  
{ }NCL>l;q  
sFilePath = value; /aqEJGG>  
} +%0z`E\?M#  
bS!\#f%9"  
K5 KyG  
public String getSFileName() ,6"l(]0  
{ 8e2?tmWM  
return sFileName; U[\Vj_?(I  
} z5 m>H;P  
>n*\bXf  
J/x2qQ$9  
public void setSFileName(String value) N4!<Xj  
{ [f{VIE*?%  
sFileName = value; 4. qtp`  
} I;MD>%[W,  
fiDl8=~@  
V5mTu)tp5  
public int getNSplitter() /-M@[p&  
{ ,kM)7!]N  
return nSplitter; '%;\YD9  
} #x@eDnb_  
=Lp7{09u  
27Emm c  
public void setNSplitter(int nCount) ccJM>9  
{ [\e@_vY@OH  
nSplitter = nCount; EbQa?  
} z\!K<d"Xv  
} X[3}?,aqL  
Ip *g'  
wdas1  
/* c j$6  
**Utility.java }}{Yw  
*/ H=^K@Ti:  
package NetFox; <V&5P3)d9  
Ey `h1 Y  
Gc,_v3\  
public class Utility { K|r Lkl9  
5/0j}_pP  
1DJekiWf  
public Utility() (p)!Mq "^  
{ )A8v];.]3  
`BXS)xj  
hZ$t$3  
} dp5cDF}l  
ku&k'V  
//线程睡眠 HIvZQQW|  
public static void sleep(int nSecond) j}JZ  
{ q6d~V] 4:  
try{ _e<o7Y@_  
Thread.sleep(nSecond); T6BFX0$  
} A#y@`} ]!'  
catch(Exception e) n6Z|Q@F  
{ Y3U9:VB  
e.printStackTrace (); +cu^%CXT  
} k!L@GQ  
} \?fIt?  
} p:%[  
//日志 6" B%)0  
public static void log(String sMsg) 5<YzalNf  
{ V9%aBkf8w  
System.err.println(sMsg); ?&+9WJ<M  
} o^p  
M[]A2'fS  
5"KlRuv%  
public static void log(int sMsg) 2umv|]n+l|  
{ v3[@1FQ"  
System.err.println(sMsg); TLa]O1=Bf.  
} o*S"KX $  
} Tl("IhkC  
>bo'Y9C  
_GYMPq\%L#  
/* w Iv o"|%  
**TestMethod.java Vm1-C<V9  
*/ % ZU/x d  
package NetFox; 0#p/A^\#7M  
e]8,:Gd(  
Am4lEvb  
public class TestMethod { 6sfwlT  
5g5'@vMN  
umEVy*hc  
public TestMethod() va)%et0!  
{ ///xx/weblogic60b2_win.exe n~IVNB*  
try{ 1 OaXo!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W8WXY_yJt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (8a#\Y[b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B 9dt=j3j2  
fileFetch.start(); 1 jb/o5n;  
} F\JUx L@8  
catch(Exception e){e.printStackTrace ();} K95;rd  
MjL)IgT  
} ?@5W,  
} e&<yX  
0ezYdS~o  
{Tp2H_EG  
public static void main(String[] args) +>f<EPGn  
{ Q 9F)  
new TestMethod(); W&Y"K)`  
} VyLH"cCv  
} (=x"Y{%  
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