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http断点续传简单实现(java)

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/* h7wm xa;  
**SiteFileFetch.java #,0%g 1  
*/ ?s dVd  
package NetFox; tz6d}$  
import java.io.*; ix=HLF-0zC  
import java.net.*; @c9VCG D  
ezY _7  
"'~'xaU!=a  
public class SiteFileFetch extends Thread { F9^8/Z  
H"N o{|^<  
Z1wN+Y.CA  
SiteInfoBean siteInfoBean = null; //文件信息Bean oL2|@WNj,  
long[] nStartPos; //开始位置 _}vD?/$L  
long[] nEndPos; //结束位置 FQ*4?D,A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9P#E^;L  
long nFileLength; //文件长度 _iO,GT=J-  
boolean bFirst = true; //是否第一次取文件 =P<gZ-Cm  
boolean bStop = false; //停止标志 Wt"fn&R}  
File tmpFile; //文件下载的临时信息 :CNHN2 J  
DataOutputStream output; //输出到文件的输出流 a<B[ ~J4i  
X@*$3z#Z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5P ,{h  
public SiteFileFetch(SiteInfoBean bean) throws IOException l(-6pP5`  
{ .:B] a7b  
siteInfoBean = bean; ?J<Y]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \`Db|D?oy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?a+tL'D[  
if(tmpFile.exists ()) &~29%Ns  
{ *Sm$FMWQ  
bFirst = false; FYFP 6ti  
read_nPos(); Em N0K'x  
} Bmm#5X@*  
else >%h_ R:  
{ %fGS< W;  
nStartPos = new long[bean.getNSplitter()]; #joGIw  
nEndPos = new long[bean.getNSplitter()]; ;H9d.D8  
} :<Yc V#!P  
@kK${  
vd c k  
3)^-A4~E  
} TPZZln'3   
/d ?)  
rDX_$,3L  
public void run() Z$ {I 4a  
{ ,^3eMn  
//获得文件长度 {s6;6>-kPW  
//分割文件 Iw(deD  
//实例FileSplitterFetch [cv7s=U%  
//启动FileSplitterFetch线程 (%ra~s?  
//等待子线程返回 jhr{JApbJv  
try{ :vz_f$=  
if(bFirst) .Wv2aJq  
{ T^x7w+  
nFileLength = getFileSize(); !j#Z48=&  
if(nFileLength == -1) J*Dj`@`4`g  
{ -9Wx;u4]o  
System.err.println("File Length is not known!"); @%q0fj8b  
} lR\=] ]7I>  
else if(nFileLength == -2) 6UXa 5t  
{ (Hb i+IHV  
System.err.println("File is not access!"); 8zS't2 u  
} Ad xCP\S&  
else !([Q1r{u  
{ $`W .9  
for(int i=0;i<nStartPos.length;i++) U$@p"F@P  
{ )sWdN(E3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); axW3#3#`  
} -yHVydu=  
for(int i=0;i<nEndPos.length-1;i++) RUC V!L  
{ *lRP ZN  
nEndPos = nStartPos[i+1]; /Y_F"GQ  
} TK<~ (Dk  
nEndPos[nEndPos.length-1] = nFileLength; dPwe.:  
} 3 [: x#r  
} $=uyZTYF)}  
T>2)YOx  
d?C8rkV'  
//启动子线程 qRT1Wre 3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +/y 3]}  
for(int i=0;i<nStartPos.length;i++) M)C. bo{p  
{ }2:/&H'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *Nloa/a&9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Sd'!(M^k3  
nStartPos,nEndPos,i); dtw1Am#Ci  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ; {$9Sc $  
fileSplitterFetch.start(); SUsD)!u_H  
} s,XKl5'+8e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +QT(~<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3YVG|Bc~_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n0q5|ES  
nEndPos = " + nFileLength); r e.chQ6  
// fileSplitterFetch[nPos.length-1].start(); Nlemb:'eP3  
rT9<_<  
uUu]JDdz  
//等待子线程结束 ?W-J2tgss{  
//int count = 0; [0U!Y/?6lA  
//是否结束while循环 ;A7HEx  
boolean breakWhile = false; Ymkk"y.w  
5<\&7P3y  
Y0fX\6=h  
while(!bStop) o_ka'|  
{ `VX]vumG  
write_nPos(); >MZWm6M8  
Utility.sleep(500); ac%%*HN,  
breakWhile = true; L\_MZ*<0[  
R`q*a_  
mk.:V64 >;  
for(int i=0;i<nStartPos.length;i++) +a_eNl,  
{ ":E 7#9  
if(!fileSplitterFetch.bDownOver) mJe;BU"y]  
{ /{Ksi+q  
breakWhile = false; .q$HL t  
break; G{ ~pA4  
} 0 1<~~6A  
} 12BTZ  
if(breakWhile) 0j\?zt?  
break; Se7NF@>9_  
xvOGE]n  
j_Pt8{[  
//count++; U?97yc\$  
//if(count>4) c'B6E1}sx  
// siteStop(); v1%rlP  
} )X2=x^u*U  
u~FXO[b  
rt)70=  
System.err.println("文件下载结束!"); &^$dHr6v  
} fr kDf-P  
catch(Exception e){e.printStackTrace ();} t<s:ut)Q!  
} zBD ?O!  
T;K,.a8bU  
L1ZhH3}X  
//获得文件长度 yo]!Zn  
public long getFileSize() %> Z;/j|#r  
{ pi7Fd\A  
int nFileLength = -1; (]7&][  
try{ yk OJhd3  
URL url = new URL(siteInfoBean.getSSiteURL()); Lsv[@Rl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]Tk3@jw+b  
httpConnection.setRequestProperty("User-Agent","NetFox"); #ky]@vyO  
l6Wa~E  
2Pn  
int responseCode=httpConnection.getResponseCode(); /T&z :st0  
if(responseCode>=400) TD:NL4dm  
{ |;3Ru vX?+  
processErrorCode(responseCode); Lh.?G#EM  
return -2; //-2 represent access is error ?;Dh^mc  
} /4{ 6`  
ZD\`~I|gp  
YCZl1ry:V=  
String sHeader; cr Hd$~q,  
&TYTeJ]  
q8%T)$!  
for(int i=1;;i++) )HbsUm#  
{ $/^DY&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~?i;~S  
//Utility.log(in.readLine()); 7pH`"$  
sHeader=httpConnection.getHeaderFieldKey(i); (8DJf"}  
if(sHeader!=null) ZYDLl8  
{ a_Y*pOu  
if(sHeader.equals("Content-Length")) dU%Q=r8R  
{ <?UbzT7X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1%~yb Q  
break; EUH&"8 L  
} ^_W+  
} &5>R>rnB  
else G?D7R/0)  
break; l",JN.w  
} *6D0>F  
} _aa3;kT_  
catch(IOException e){e.printStackTrace ();} 1|$V  
catch(Exception e){e.printStackTrace ();} 5u +U^D  
'q%56WAJ  
 pleLdGq  
Utility.log(nFileLength); ArWMbT>Zqw  
6[fpe  
xG:eS:iT  
return nFileLength;  eX7dyM  
} ~/Gx~P]  
=kvfe" N0e  
HE GMwRJG  
//保存下载信息(文件指针位置) g-`HKoKe  
private void write_nPos() C "XvspJ  
{ G|eY$5!i  
try{ hu}`,2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V5w00s5?%  
output.writeInt(nStartPos.length); tGHZU^B:}  
for(int i=0;i<nStartPos.length;i++) `x%v& >  
{ jo 0 d#  
// output.writeLong(nPos); 'z$BgXh\  
output.writeLong(fileSplitterFetch.nStartPos); r}kQ<SRx  
output.writeLong(fileSplitterFetch.nEndPos); &)`xlIw}  
} i#Tm] ++  
output.close(); &:1PF.)N  
} So>P)d$8+  
catch(IOException e){e.printStackTrace ();} x\taG.'zX  
catch(Exception e){e.printStackTrace ();} (A!+$}UR  
} X"_,#3Ko!  
gc``z9@Xg  
`o~ dQb/k+  
//读取保存的下载信息(文件指针位置) Ia_I~ U$  
private void read_nPos() *Ju$A  
{ Q72}V9I9  
try{ WJH-~,u  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f Z8%Z   
int nCount = input.readInt(); ' >a(|  
nStartPos = new long[nCount]; { FVLH:{U^  
nEndPos = new long[nCount]; )I7~ <$w  
for(int i=0;i<nStartPos.length;i++) 4C@ .X[r  
{ 3ZdheenK9  
nStartPos = input.readLong(); b=nQi./f  
nEndPos = input.readLong(); =`RogjbP  
} #[ZF'9x  
input.close(); Ik[aiz  
} =!}n .  
catch(IOException e){e.printStackTrace ();} Uedzt  
catch(Exception e){e.printStackTrace ();} &o{=  
} 'Cw&9cL9w  
b[5$$_[  
/ZC/yGdIS_  
private void processErrorCode(int nErrorCode) -L%J,f[&,  
{ qKoD*cl)Za  
System.err.println("Error Code : " + nErrorCode); Uc oVp}vl  
} kLc}a5;  
%eJolztKZ  
,H6*9!Dv2  
//停止文件下载 qm RdO R  
public void siteStop() u!kC+0Y  
{ I*,!zym  
bStop = true; tBR"sBiws  
for(int i=0;i<nStartPos.length;i++) V>"nAh]}.  
fileSplitterFetch.splitterStop(); hf5yTs  
80qSPitj  
yX%q7ex  
} >q W_%  
} c6 O1Z\M@\  
//负责部分文件的抓取 kmfz=q?  
**FileSplitterFetch.java J<K- Yeph  
*/ -+1_ 1!  
package NetFox; 7G,{BBB  
1Z9_sd~/6  
\#1*r'V8  
import java.io.*; ]/byz_7]  
import java.net.*; Fh2$,$ 2  
xd[GJ;xvs  
e,j2#wjor  
public class FileSplitterFetch extends Thread { 5R^e  
)ro3yq4??  
~W?F.  
String sURL; //File URL o }EipTL  
long nStartPos; //File Snippet Start Position >%qk2h>  
long nEndPos; //File Snippet End Position -P I$SA,  
int nThreadID; //Thread's ID DeqTr:  
boolean bDownOver = false; //Downing is over kR+xInDM*  
boolean bStop = false; //Stop identical CKC%|xke  
FileAccessI fileAccessI = null; //File Access interface ii0{$}eoh  
:X1~  
3O{*~D&n  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?&qa3y)wX:  
{ 1oD1ia#  
this.sURL = sURL; |jh&a+4W  
this.nStartPos = nStart; 4k}3^.#  
this.nEndPos = nEnd; UNx|+  
nThreadID = id; .I~#o$6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZkbaUIQ  
} Gk"o/]Sf  
7d9kr?3(U  
~3]ZN'b\  
public void run() 93Z/|7  
{ f?KHp|  
while(nStartPos < nEndPos && !bStop) p]/qf \E  
{ U`{'-L.  
"Jd!TLt\x  
P'EPP*)q  
try{ n^} -k'l  
URL url = new URL(sURL); {_#~&IQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #Az#dt]H  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z )Imj&;  
String sProperty = "bytes="+nStartPos+"-"; |r5e#3w  
httpConnection.setRequestProperty("RANGE",sProperty); kNC.^8ryz[  
Utility.log(sProperty); XUI9)Ne  
$-HP5Kj(k-  
F0 yvV6;  
InputStream input = httpConnection.getInputStream(); g43j-[j)  
//logResponseHead(httpConnection); 5AX AIPn)  
{2|[7oNT6  
 z]/;?  
byte[] b = new byte[1024]; j41)X'MgJ  
int nRead; M4%u~Z:4h+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uc0 1{t0,  
{ bfjC:"!H  
nStartPos += fileAccessI.write(b,0,nRead); 0F"W~OQ6  
//if(nThreadID == 1) ~&zrDj~FI  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7(ni_|$|  
} [w0@7p"7  
,r=9$i_  
U8f!yXF'  
Utility.log("Thread " + nThreadID + " is over!"); +XaRwcLC.  
bDownOver = true; YY! Lv:.7>  
//nPos = fileAccessI.write (b,0,nRead); [r[IWy(}  
} .f1  
catch(Exception e){e.printStackTrace ();} }OQaQf9V{  
} U9?fUS  
} % oPt],>  
tl:V8sYTP  
d|P,e;m-  
//打印回应的头信息 @W4tnM,#  
public void logResponseHead(HttpURLConnection con) .G ^-. p  
{ #hp 7@ Tu  
for(int i=1;;i++) 'H19@b5rx  
{ gD13(G98  
String header=con.getHeaderFieldKey(i); gdPPk=LD  
if(header!=null) e8WuAI86  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J^!2F}:  
Utility.log(header+" : "+con.getHeaderField(header)); RA%=_wPD +  
else :i{Svb*_'  
break; >i6sJ)2?>  
} l**gM  
} k-:wM`C  
q <, b  
11'^JmKA  
public void splitterStop() J AQ y  
{ d8)ps,  
bStop = true; p`dH4y]D  
} `Z#0kpXk_  
#9( 0.!v  
@3^D[  
} ?%|w?Fdx-  
_u[2R=h  
1g{-DIOmn  
/* Nldy76|g  
**FileAccess.java u<g0oEs)  
*//文件访问(定位,写) r<%ua6@  
package NetFox; H^VNw1.   
import java.io.*; S7B7'[ru  
/?ZO-]q  
|w{}h6 a  
public class FileAccessI implements Serializable{ ?Iin/<y  
9wTN *y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >3C4S  
RandomAccessFile oSavedFile; {h}0"5  
long nPos; z[cs/x  
c\Z.V*o  
Y94 ^mt-  
public FileAccessI() throws IOException s~z~9#G(6  
{ }&*wJ]j`L  
this("",0); *(,zPn,  
} { R`"Nk  
]ZMFK>"^%  
Qm"&=<  
public FileAccessI(String sName,long nPos) throws IOException ?rJe"TOIy  
{ 8 t)?$j$  
oSavedFile = new RandomAccessFile(sName,"rw"); @TQzF-%#7  
this.nPos = nPos; 18HmS>Qo  
oSavedFile.seek(nPos); A2 r\=for  
} eT'Z;ZO  
hZ[(Ik]*Zd  
|zkZF|-  
public synchronized int write(byte[] b,int nStart,int nLen) zao=}j?  
{ cIS?EW]S%X  
int n = -1; A_4.>g  
try{ A6?!BB=]  
oSavedFile.write(b,nStart,nLen); tl=H9w&@  
n = nLen; 1_jd1 UT  
} NimW=X;c  
catch(IOException e) G<$ N*3  
{ ;4'pucq5/  
e.printStackTrace (); x+;a2yE~  
} F"ua`ercI  
n^t!+  
/$U< S"  
return n; W5^<4Ya!  
} ${F4x"x  
+F4SU(T  
q`0wG3  
} -cONC9 =  
BN~gk~t_  
S8dX8,qg  
/* d7]~t|  
**SiteInfoBean.java Yo*.? Mq'  
*/ E]0}&YG  
package NetFox; 9 WO|g[Y3  
ls@j8bVv^  
PB(q9gf"1}  
public class SiteInfoBean { BY5ODc$  
{8pN]=SaJ~  
#]kO/Mr  
private String sSiteURL; //Site's URL R_zQiSwG<  
private String sFilePath; //Saved File's Path h]jy):9L  
private String sFileName; //Saved File's Name a;h.I}*]  
private int nSplitter; //Count of Splited Downloading File V#,jUH|  
5hvg]w95;  
UOa n  
public SiteInfoBean() :pCv!g2  
{//nSplitter的缺省值为5 P#l"`C /  
//default value of nSplitter is 5 MJM<  
this("","","",5); *~\R0ddz  
} [e`e bn[C  
)>]@@Trx  
J=t@2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) SMn(c  
{ 'Z8=y[l  
sSiteURL= sURL; #8/pYQ;  
sFilePath = sPath; V^%P}RFMc  
sFileName = sName; od-yVE&  
this.nSplitter = nSpiltter; fZgEJsr  
L}\ oFjVju  
EM7Z g 65  
} b[rVr J  
a{@gzB  
Db K(Rh_ K  
public String getSSiteURL() >pm`(zLn  
{ E0)43  
return sSiteURL; D$U`u[qjtS  
} Pk{%2\%&2  
d#CAP9n;'  
&e \UlM22  
public void setSSiteURL(String value) X.GK5Phd  
{ uZml.#@4  
sSiteURL = value; phi9/tO\u  
} z'9U.v'M)  
+`f3_Xd  
<lgX=wx L  
public String getSFilePath() vLs*}+f  
{ c->.eL%   
return sFilePath; (b8ZADI*  
} :pdl2#5H^  
85_Qb2<'r  
[?55vYt  
public void setSFilePath(String value) )m$MC25  
{ ;-^8lWt  
sFilePath = value; ~7>D>!!  
} O_ d[{e=5`  
lw43|_'G-t  
%j/}e>$"Nk  
public String getSFileName() lSG]{  
{ a];1)zVA6  
return sFileName; Ku?1QDhrF*  
} rcz9\@M  
vMzBp#MT  
i:|e#$x  
public void setSFileName(String value) _>E=.$  
{ @y2cC6+'t  
sFileName = value; oc"7|YG  
} \DcO .`L  
J,*+Ak ~  
hr W2#v  
public int getNSplitter() 8 .t3`FGH  
{ %J8uVD.2  
return nSplitter; Ip |=NQL>  
} k_`h (R  
U&W/Nj  
snYyxi  
public void setNSplitter(int nCount) [nf 5<  
{ L:\>)6]Ls  
nSplitter = nCount; CrB4%W:{  
} g&rz*)|/  
} TPn#cIPG  
PsM8J  
cAq5vAqmg  
/* p$}/~5b}4  
**Utility.java X<Ag['r  
*/ <+Gf!0i  
package NetFox; jJD*s/o  
e5d STc`  
{dYz|O<  
public class Utility { $;rvKco)%  
?&=JGk^eJ  
"?^#+@LV  
public Utility() M<r]a{Yv  
{ Gkm {b[  
W~FU!C?]  
*|ef#-|D  
} 1&RB=7.h  
 Vqr]Ui  
//线程睡眠 ar _@"+tZ  
public static void sleep(int nSecond) jLn|zK  
{ !JtM`x/yR  
try{ B,] AfH  
Thread.sleep(nSecond); 3oV2Ek<d  
} pV O{7I  
catch(Exception e) Y+h ?HS  
{ f!F5d1N  
e.printStackTrace (); 1\J9QZX0  
} |rI;OvZ\  
} 29zMs9oKPP  
\U<d)j/  
//日志 5w%[|%KG:L  
public static void log(String sMsg) VRTJKi  
{ Z23T 2  
System.err.println(sMsg); [6Q1yNE  
} M)~sL1)  
]X> I(p@  
BO2s(8  
public static void log(int sMsg) R$`%<Y3)  
{ xDNXI01o  
System.err.println(sMsg); &eb8k2S  
} s>)?MB*vb  
} h; 6G~D  
fw5+eTQ^  
PQUJUs  
/* Z3U%Afl2{  
**TestMethod.java 3WpQzuHPT  
*/ 5uV_Pkb?8  
package NetFox; w '9!%mr  
7\N }QP0"u  
Y`3\Z6KlV  
public class TestMethod { [+L!c}#  
RKZBI?@4  
i-9W8A  
public TestMethod() jX0^1d@  
{ ///xx/weblogic60b2_win.exe <fE ^S  
try{ R@#xPv4o%  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eVd:C8q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?*.:*A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $y{.fjy3  
fileFetch.start(); ;p7R~17  
} T-h[$fxR_  
catch(Exception e){e.printStackTrace ();} q/Zs]Gz  
nzZs2  
Sk-Q 4D^  
} Ly z8DwZ  
U'u_'5 {  
~NB|BwAh  
public static void main(String[] args) CM7NdK?I  
{ \58bz<u"  
new TestMethod(); U "r)C;5  
} ;NQ}c"9  
} '<QFf  
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