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http断点续传简单实现(java)

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/* rXP~k]tC  
**SiteFileFetch.java 2F :8=_sA  
*/ gCq'#G\Z  
package NetFox; T>68 ,; p  
import java.io.*; ,&.$r/x|?  
import java.net.*; +/ rt'0o  
C),i#v  
Z+=M_{`{  
public class SiteFileFetch extends Thread { lg +>.^7k  
R*/s#*gmL  
F3[,6%4v  
SiteInfoBean siteInfoBean = null; //文件信息Bean sGa}Cf;H@g  
long[] nStartPos; //开始位置 Ad&VOh+0  
long[] nEndPos; //结束位置 6n^@Ps  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RdBIbm  
long nFileLength; //文件长度 u4j"U6"]M  
boolean bFirst = true; //是否第一次取文件 Y>6N2&Q  
boolean bStop = false; //停止标志 -Xx4:S  
File tmpFile; //文件下载的临时信息 pX+4B=*  
DataOutputStream output; //输出到文件的输出流 V503  
Y (p Ud3y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T+e*'<!O  
public SiteFileFetch(SiteInfoBean bean) throws IOException .cm2L,1h  
{ ocu,qL)W  
siteInfoBean = bean; m?kyAW'|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [ ou$*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); y @S_CB 47  
if(tmpFile.exists ()) iX[g  
{ k.z(.uc=  
bFirst = false; <RKT |  
read_nPos(); "}V_.I* +  
} @VPmr}p:{  
else u*/+cT  
{ uP+VS>b  
nStartPos = new long[bean.getNSplitter()]; PMUW<UI  
nEndPos = new long[bean.getNSplitter()]; *YSRZvD<\  
} |nE4tN#J<  
/3&MUB*z&y  
SA7(EJ95  
Re&"Q8I.8  
} M*f]d`B  
P?S]Q19Q4  
s VHk;:e>x  
public void run() sn"z'=ch  
{ .G#li(NWH  
//获得文件长度 hD=.rDvO  
//分割文件 bF6J>&]!  
//实例FileSplitterFetch }wkY`"  
//启动FileSplitterFetch线程 yM~bUmSg  
//等待子线程返回 FWA?mde  
try{ $1g1Bn  
if(bFirst) C!|LGzs0  
{ z;!"i~fFK  
nFileLength = getFileSize(); tj$[szo  
if(nFileLength == -1) s&Y"a,|Z  
{ K8R>O *~  
System.err.println("File Length is not known!"); -Caj>K  
} Q;J( 5;  
else if(nFileLength == -2) ?xrOhA9  
{ {`G d  
System.err.println("File is not access!"); d$jwh(Ivs  
} }opw_h+/F  
else a ydNSgu  
{ ^ H&U_  
for(int i=0;i<nStartPos.length;i++) g/fpXO\  
{ k%FA:ms|k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +FAj30  
} s8)`wH ?  
for(int i=0;i<nEndPos.length-1;i++) UKQ"sC  
{ 4(8tr D6  
nEndPos = nStartPos[i+1]; Z`u$#<ukX  
} xP!QV~$>  
nEndPos[nEndPos.length-1] = nFileLength; FF~r&h8H  
} %4f.<gz~r|  
} +D:8r|evH  
-rn6ZSD)  
'It8h$^j  
//启动子线程 xhOoZ-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; tM^4K r~o,  
for(int i=0;i<nStartPos.length;i++) "L:4 7!8  
{ <l $ d>,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X.#)CB0c1Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P6R_W  
nStartPos,nEndPos,i); RFy MRE!?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y;uR@{  
fileSplitterFetch.start(); z V\+za,  
} t2s/zxt  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 10i$b<O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o$buoGSPc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  +l/v`=C  
nEndPos = " + nFileLength); {BT/P!  
// fileSplitterFetch[nPos.length-1].start(); 0=#>w_B  
S.)Jp -&K  
}&t>j[  
//等待子线程结束 avL_>7q  
//int count = 0; r]UF<*$  
//是否结束while循环 V@!)Pw  
boolean breakWhile = false; \1Xk[%  
dniU{v  
eM:J_>7t  
while(!bStop) Iz5NA0[=2  
{ _BmObXOp.  
write_nPos(); #5Z`Q^  
Utility.sleep(500); X 3$ W60Q  
breakWhile = true; yjg&/6  
6FQi=}O1  
*Bq}.Yn  
for(int i=0;i<nStartPos.length;i++) s:Ml\['x  
{ 1XMR7liE  
if(!fileSplitterFetch.bDownOver) 8&)v%TX  
{ 1(Ta*"(0Ip  
breakWhile = false; G$+v |z  
break; $KO2+^%y  
} uI)twry]@  
} Z0jgUq`r  
if(breakWhile) /}(d'@8p  
break; +t+<?M B  
:q]9F4im  
^k;]"NR  
//count++; fq]PKLW'  
//if(count>4) RhH 1nf2UR  
// siteStop(); |zYOCDFf  
} { K]5[bMT  
{O^u^a\m  
|4Q*4s  
System.err.println("文件下载结束!"); 9)ALJd,M  
} )ODF6Ag  
catch(Exception e){e.printStackTrace ();} ]~KLdgru_  
} Jpj=d@Of70  
vRmn61  
3KkfQ{  
//获得文件长度 XiE`_%NW  
public long getFileSize() pn gto  
{ TZAd{EZa  
int nFileLength = -1; G @..?>  
try{ t?W}=%M[  
URL url = new URL(siteInfoBean.getSSiteURL()); {`QHg O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X#lNS+&='  
httpConnection.setRequestProperty("User-Agent","NetFox"); P5h|* ?=  
.B# .   
(Q^sK\  
int responseCode=httpConnection.getResponseCode(); DK)W ,z|  
if(responseCode>=400) K^shTh8k  
{ " B#|C'   
processErrorCode(responseCode); Yf w>x[#e  
return -2; //-2 represent access is error 50W+!'  
} ["Ltqgx  
5^u$zfR  
`hi=y BO  
String sHeader; <+i(CGw  
vxOqo)yO  
gBm'9|?  
for(int i=1;;i++) _\ToA9m  
{ sjr,)|#[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;u UFgDi  
//Utility.log(in.readLine()); :8A+2ra&  
sHeader=httpConnection.getHeaderFieldKey(i); Ey&H?OFiP  
if(sHeader!=null) elOeXYO0  
{ G%<}TI1}  
if(sHeader.equals("Content-Length")) wA=r ]BT  
{ ,#A(I#wL~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $ J`O-"M  
break; h:YD $XE  
} oJz2-P mX  
} bbK};u  
else @ _Ey"k<  
break; r ]DiB:.  
} }TmOoi(X@  
} FzT.9Vz7  
catch(IOException e){e.printStackTrace ();} U(#<D7}  
catch(Exception e){e.printStackTrace ();} {ez $kz  
t4WB^dHYp  
5p;AON  
Utility.log(nFileLength); 'o >)E>  
M"~jNe|  
;b$P*dSG}  
return nFileLength; 1i76u!{U  
} _ E;T"SC  
MtLWpi u@[  
XO <wK  
//保存下载信息(文件指针位置) Z*%;;&?  
private void write_nPos() RP4/:sO  
{ yB b%#GW  
try{ /`*{57/3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =}^NyLE?  
output.writeInt(nStartPos.length); ,XD" p1(|G  
for(int i=0;i<nStartPos.length;i++) Jl Do_}  
{ > ;,S||  
// output.writeLong(nPos); 9u B?-.  
output.writeLong(fileSplitterFetch.nStartPos); :!`"GaTy  
output.writeLong(fileSplitterFetch.nEndPos); Da=EAG-{7  
} Mt[yY|Ec|  
output.close(); QU"WpkO  
} kRp]2^}\s\  
catch(IOException e){e.printStackTrace ();} 22`^Rsb,6L  
catch(Exception e){e.printStackTrace ();} k ut=( ;  
} ZZw`8 E  
-Zt!H%U  
{Su?*M2y  
//读取保存的下载信息(文件指针位置) i"2OsGT  
private void read_nPos() "TV'}HH  
{ 4CNrIF@  
try{ $*yYmF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *]6g-E?:@  
int nCount = input.readInt(); D'"  T'@  
nStartPos = new long[nCount]; BuJo W@)  
nEndPos = new long[nCount]; $ V^gFes  
for(int i=0;i<nStartPos.length;i++) p@m0 Oi,=  
{ n ~t{]if"  
nStartPos = input.readLong(); qpjY &3SI  
nEndPos = input.readLong(); O\5%IfB'"  
} /k#-OXP~  
input.close(); #@XBHJD\#  
} dGIdSQ~ _  
catch(IOException e){e.printStackTrace ();} Rn1oD3w  
catch(Exception e){e.printStackTrace ();} OxlA)$.hpu  
} '%N?r,x C  
Pf*6/7S:  
N'Gq9A  
private void processErrorCode(int nErrorCode) M&Uy42,MR  
{ /x<g$!`X  
System.err.println("Error Code : " + nErrorCode); [BWq9uE  
} 54 lD+%E  
*FS8]!Qg  
`KJ( .m  
//停止文件下载 a:kAo0@":j  
public void siteStop() D31X {dJ  
{ %( )d$.F  
bStop = true; %go2tv:|W  
for(int i=0;i<nStartPos.length;i++) 7#V7D6j1  
fileSplitterFetch.splitterStop(); @= -(H<0  
P"YdB|I  
eV;r /4  
} _:x]' w%  
} i_Kwxn$  
//负责部分文件的抓取 i2F7O"f.  
**FileSplitterFetch.java d t/AAk6  
*/ o3J#hQrl  
package NetFox; dbp\tWaW  
:6n#y-9^1  
E)"19l|}B  
import java.io.*; peQwH  
import java.net.*; ~# -?V[  
&5 CRXf  
5ut| eD`3  
public class FileSplitterFetch extends Thread { nL@'??I1  
XJ18(Q|w'  
=|t-0'RsN  
String sURL; //File URL &?<uR)tl  
long nStartPos; //File Snippet Start Position X Xque-  
long nEndPos; //File Snippet End Position (lk9](;L  
int nThreadID; //Thread's ID Z}W{ iD{  
boolean bDownOver = false; //Downing is over --yF%tRMP  
boolean bStop = false; //Stop identical ER0 Yl  
FileAccessI fileAccessI = null; //File Access interface vygzL U^  
' \JE>#  
]#tB[G  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !3Q0Ahf  
{ ~#_~DqbMZ5  
this.sURL = sURL; q+g,?;Yx  
this.nStartPos = nStart; b--=GY))F  
this.nEndPos = nEnd; F%OP,>zl  
nThreadID = id; *ap,r&]#F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (q)}`1d'  
} eYOY   
1\}vU  
F O!Td  
public void run() 5`;SI36"  
{ !_QI<=X  
while(nStartPos < nEndPos && !bStop) f|[7LIdh-  
{ Sj+H{xJi  
g4K+AK  
iw@rW5%'~  
try{ Q(|@&83].  
URL url = new URL(sURL); A8{jEJ=)P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yD\q4G  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1w,_D.1'  
String sProperty = "bytes="+nStartPos+"-"; +! 1_Mt6  
httpConnection.setRequestProperty("RANGE",sProperty); K'A+V  
Utility.log(sProperty); lriezI  
|9* Rnm_  
~7m`p3W@  
InputStream input = httpConnection.getInputStream(); ? <?Ogq"<  
//logResponseHead(httpConnection); XlppA3JON|  
g~lv/.CnA+  
?]Yic]$n  
byte[] b = new byte[1024]; ot0teNF  
int nRead; |t,sK aL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'gwh:  
{ T:^.; ZY  
nStartPos += fileAccessI.write(b,0,nRead); sh/ ,"b2!P  
//if(nThreadID == 1) |G j.E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _@5Xmr  
} _3/u#'m0  
L+t / E`  
]U?nYppV  
Utility.log("Thread " + nThreadID + " is over!"); }$ y.qqG  
bDownOver = true; *zrT;j G  
//nPos = fileAccessI.write (b,0,nRead); m&)/>'W   
} Dri6\/0  
catch(Exception e){e.printStackTrace ();} u[a-9^&g  
} Nr|Gw @+  
} {^]qaQ[5N  
UZdnsG7  
hf`y_H+\7  
//打印回应的头信息 x39tnf/F  
public void logResponseHead(HttpURLConnection con) N,`@Q7  
{ h ldZA  
for(int i=1;;i++) xP8/1wd.  
{ 0h-NT\m  
String header=con.getHeaderFieldKey(i); gtKih  
if(header!=null) D*l(p5[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fB2ILRc  
Utility.log(header+" : "+con.getHeaderField(header)); ak7%  
else  \XDiw~0  
break; \f,<\mJ#  
} ?1Nz ,Lc$  
} kQ\GVI11?  
]TvMT  
j.M]F/j  
public void splitterStop() 757&bH|a  
{ l)r\SE1  
bStop = true; y-pdAkDh  
} :zW? O#aL-  
Z$z-Hx@%  
[* xdILj  
} 7F`\Gz_2  
qlhc"}5x }  
FPc `J  
/* <IrhR,@M,L  
**FileAccess.java Q%CrB>|@  
*//文件访问(定位,写) Q Xd`P4a  
package NetFox; (Mc{nFqS  
import java.io.*; !t%1G.  
fh#:j[R4e  
\`.v8C>vG  
public class FileAccessI implements Serializable{ :3F[!y3b  
^EIuGz1@0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0fc;H}B*  
RandomAccessFile oSavedFile; \Z.r Pq  
long nPos; CvIuH=,  
= MByD&o`  
b+Q{Z*  
public FileAccessI() throws IOException +2[0q% i  
{  Wvb ~j  
this("",0); /&6{}n  
} [3dGHf;miw  
@(R=4LL  
g0f4>m  
public FileAccessI(String sName,long nPos) throws IOException VEV?$R7;  
{ 6AIqoX*p  
oSavedFile = new RandomAccessFile(sName,"rw"); y[J9"k(@  
this.nPos = nPos; XT/t\\Z`U  
oSavedFile.seek(nPos); :E W1I>}_  
} RFM;?!S  
A6z2KVk  
 II'.vp  
public synchronized int write(byte[] b,int nStart,int nLen) fhi}x(  
{ ?0)K[Kd'Y  
int n = -1; 4(8c L?J`0  
try{ UDHOcb  
oSavedFile.write(b,nStart,nLen); NXD-  
n = nLen; y,?=,x}o#  
} >4g!ic~O  
catch(IOException e) C\{A|'l!x  
{ m9h<)D'>  
e.printStackTrace (); =2q#- ,t  
} S6bW r0XR  
rL<N:@HL  
<ppdy,j:  
return n; 4{>r_^8  
} s<*+=aIfu  
e;v7!X  
dPO"8HQ  
} CLND[gc  
0}GO$%l  
7<LuL  
/* YM#' +wl}`  
**SiteInfoBean.java "s@Hg1  
*/ 1PVZGZxAgv  
package NetFox; 'qVlq5.  
G/ si( LK  
p*K #s1  
public class SiteInfoBean { +wG *qI  
y/@Bhzc  
oW OR7)?r  
private String sSiteURL; //Site's URL !I|_vJ@<  
private String sFilePath; //Saved File's Path ; FI'nL  
private String sFileName; //Saved File's Name HRTNIx  
private int nSplitter; //Count of Splited Downloading File Qfp4}a=  
^5Y<evjm  
7(5d$W  
public SiteInfoBean() uj;iE 9  
{//nSplitter的缺省值为5 rHk(@T.]  
//default value of nSplitter is 5 ~LI}   
this("","","",5); e!=7VEB  
} w#2apaz  
>'n[B    
sct 3|H#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -Tvnd,  
{ |Ja5O  
sSiteURL= sURL; qo:Zc`t(R  
sFilePath = sPath; {^ BZ#)m|  
sFileName = sName; zEjl@Kf  
this.nSplitter = nSpiltter; ys!O"=OJ  
Dh m ;K$T  
4~Q<LEly  
} p7+>]sqX  
!pfpT\i]N:  
E9Kp=3H  
public String getSSiteURL() "[/W+&z[~  
{ (]k Q9}8  
return sSiteURL; S#CaJ}M  
} ?i_2ueVR  
Vuy%7H  
t(<k4ji,  
public void setSSiteURL(String value) /?BTET  
{ IUAe6  
sSiteURL = value;  irh Z  
} 2K3j3|T  
l_2Xao$  
&n]v  
public String getSFilePath() BZOl&G(  
{ Z9H2! Cp  
return sFilePath; ^0"fPG`  
} GRpwEfG  
t<+>E_Xw  
Z$i?p;HnW  
public void setSFilePath(String value) n=f?Q=h\3  
{ "4KyJ;RA*  
sFilePath = value; Na]ITCVR  
} Tb^1#O  
1A93ol=  
MF$Dx| Tcj  
public String getSFileName() 'oGMr=gp<&  
{ a^G>|+8  
return sFileName; ">B&dNrt  
} s o: o b}  
}.u[';q ]S  
gdAd7 T  
public void setSFileName(String value) .R)Ho4CE  
{ j!L7r'AV5  
sFileName = value; BGNZE{K4"  
} xn=mS!"1Zo  
&]f8Xd  
)#Ecm<.^  
public int getNSplitter() !#1UTa  
{ p]e.E`'S  
return nSplitter; ! qtj1.w  
} /2r&ga&  
fyZtwl@6w#  
dXWG`G_  
public void setNSplitter(int nCount) E-X02A  
{ @CPkP  
nSplitter = nCount; :3se/4y}  
} R4D$)D  
} -R$Q`Xw  
Us6~7L00  
*Qngx  
/* %YuFw|wO  
**Utility.java 0m4#{^Y  
*/ [ P*L`F  
package NetFox; ee<'j~{A  
?<OE|nb&  
](+u'8  
public class Utility { @Rd`/S@  
E)'T;%  
u#ocx[  
public Utility() '*U_!RmQ  
{ _0&U'/cs  
#pD=TMefC  
uYE"O UNWL  
} QVb{+`.7  
ju.`c->k"  
//线程睡眠 x {R j2~KC  
public static void sleep(int nSecond) ? _[ q{i{  
{ H_iQR9Ak7  
try{ ?U:c\TA,m  
Thread.sleep(nSecond); @q|c|X:I  
} gsIp y  
catch(Exception e) Rs'mk6+  
{ vN6)Szim  
e.printStackTrace (); (^ J2(  
} 7*+tG7I @  
} JFRbW Q0  
U d+6=Us{  
//日志 6m9\0)R  
public static void log(String sMsg) DI :  
{ `'rvDaP  
System.err.println(sMsg); xM&`>`;^e  
} 4SkCV  
0sq?>$~Kc*  
Z4k'c+  
public static void log(int sMsg) (>\4%(pnD  
{ ;MO,HdP;  
System.err.println(sMsg); =EHKu|rX~  
} P!R`b9_U  
} ?R@u'4yK  
V4*/t#L/  
bM,%+9oz;  
/* Z%{`j!!p  
**TestMethod.java [Z[ p@Ux  
*/ bz\nCfU  
package NetFox; H9=8nLb.  
Q-e(>=Gv_  
|pT[ZT|}G  
public class TestMethod { @ +>>TGC  
nI`9|W  
5N#Sic M  
public TestMethod() (]"`>, ray  
{ ///xx/weblogic60b2_win.exe >)F)@KAuN4  
try{ [WR*u\FF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V4<f4|IL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "6WE6zq   
SiteFileFetch fileFetch = new SiteFileFetch(bean); &7w*=f8I  
fileFetch.start(); ,u5iiR  
} {>yy3(N  
catch(Exception e){e.printStackTrace ();} .UUT@ w?  
.A7ON1lc^C  
%G, d&%f  
} +qa^K%K  
!$0ozDmD  
e$-Y>Dd  
public static void main(String[] args) "2 qivJ  
{ F,xFeq$/{  
new TestMethod(); 239g pf]}  
} d?[8VfAnh  
} GS,}]c=  
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