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http断点续传简单实现(java)

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/* /Bb\jvk-E  
**SiteFileFetch.java w \85D|u  
*/ g*8sh  
package NetFox; qA*QFQ'-  
import java.io.*; a-O9[?G/x  
import java.net.*; 8;+t.{  
)0/ D Y  
U^Hymgb%  
public class SiteFileFetch extends Thread { l&E-H@Pe  
RJ@d_~%U  
C[wnor!  
SiteInfoBean siteInfoBean = null; //文件信息Bean )LnHm  
long[] nStartPos; //开始位置 "bC8/^  
long[] nEndPos; //结束位置 `qX'9e3VP+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Lw-)ijBW  
long nFileLength; //文件长度 B<6*Ktc  
boolean bFirst = true; //是否第一次取文件 jLcW;7OAC  
boolean bStop = false; //停止标志 A D~\/V&+  
File tmpFile; //文件下载的临时信息 JTdK\A>l  
DataOutputStream output; //输出到文件的输出流 [7L1y) I(  
~!Onz wmO  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) '0w'||#1  
public SiteFileFetch(SiteInfoBean bean) throws IOException oXfLNe6>L  
{ y8 `H*s@  
siteInfoBean = bean; hC~lH eH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !+CRS9\D   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,]Hn*\@p[c  
if(tmpFile.exists ()) r?V\X7` +  
{ XnV|{X%]U  
bFirst = false; Z+Z`J; ,  
read_nPos(); 2<U5d`  
} dZv-lMYBE  
else `N2zeFG  
{ 'ApWYt  
nStartPos = new long[bean.getNSplitter()]; 5AQ $xm4  
nEndPos = new long[bean.getNSplitter()]; t5[{ihv~:  
} 82>zu}  
^'[Rb!Q8  
nqy\xK#.^  
%-H  
} BL,YJM(y  
%vn rLt$  
#^#N%_8  
public void run() c~z{/L  
{ Of Y>~d  
//获得文件长度 0=7C-A1(D  
//分割文件 ^yjc"r%B  
//实例FileSplitterFetch "l2_7ZXsPT  
//启动FileSplitterFetch线程 -KbT[]  
//等待子线程返回 sd.:PE <  
try{ }fL8<HM\'c  
if(bFirst) L@0DT&5  
{ 8[ :FU  
nFileLength = getFileSize(); RG#  
if(nFileLength == -1) Cz m`5  
{ Up)b;wR  
System.err.println("File Length is not known!"); WWH T;ST  
} \MX>=  
else if(nFileLength == -2) \S1WF ?<,  
{ Pgs4/  
System.err.println("File is not access!"); Ku56TH!Py  
} js'* :*7  
else Kl\A&O*{  
{ B1J+`R3OX  
for(int i=0;i<nStartPos.length;i++) vQYd!DSh  
{ N] }L*o&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @N"h,(^  
} ,$7LMTVDrE  
for(int i=0;i<nEndPos.length-1;i++) 2u/(Q>#  
{ DJT)7l{  
nEndPos = nStartPos[i+1]; ,]]*}4[r  
} U3Z-1G~*r  
nEndPos[nEndPos.length-1] = nFileLength; PTqia!  
} W|y;Kxy  
} k+vfZ9bD(J  
Rd|8=`)  
(.VS&Kv#U  
//启动子线程 P,F eF'J^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; wm_rU]  
for(int i=0;i<nStartPos.length;i++) mCG&=Fx  
{ *>1^q9M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k%Vprc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), _x|.\j  
nStartPos,nEndPos,i); (z?j{J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n?;rWq"  
fileSplitterFetch.start(); To5hVL<Ex"  
} H Ix%c5^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PB?2{Cj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =I@I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0!7p5  
nEndPos = " + nFileLength); Z# bO}!  
// fileSplitterFetch[nPos.length-1].start(); S!+>{JyQ  
:7mHPe }(  
/ *PHX@  
//等待子线程结束 w6WPfy(/2  
//int count = 0; ,?k1if(0[  
//是否结束while循环 .T3 m%n  
boolean breakWhile = false; a @d 15CN  
o. ;Vrc  
t(9q 6x3|e  
while(!bStop) Y#tur`N  
{ Q2uV/M1?  
write_nPos(); I.GoY[u_%  
Utility.sleep(500); f'H|K+bO  
breakWhile = true; !!H"B('m  
nSC2wTH!1  
@NqwJ.%g  
for(int i=0;i<nStartPos.length;i++) GNe^ ~  
{ "Y=`w,~~  
if(!fileSplitterFetch.bDownOver) \Z&Nd;o   
{ qc 5[ e  
breakWhile = false; H(rD*R[  
break; ^B% =P  
} !hhL",  
} nS*Y+Q^9a  
if(breakWhile) m<#12#D  
break; .\glNH1d  
V?1 $H  
qS FtQ4  
//count++; cgSN:$p(R  
//if(count>4) oSC'b%  
// siteStop(); $[n:IDa*@1  
} mpMAhm:  
ABX%oZ7[|o  
q1( [mHZ  
System.err.println("文件下载结束!"); dkZe.pv$j  
} g}xL7bTlI>  
catch(Exception e){e.printStackTrace ();} k[;)/LfhS  
} Y}N\|*ye-  
oDz|%N2s|  
P*O G`%y  
//获得文件长度 7MLLx#U  
public long getFileSize() y]m: {  
{ 7RL J  
int nFileLength = -1; `KFEzv  
try{ nQjpJ /=  
URL url = new URL(siteInfoBean.getSSiteURL()); -}|L<~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )hXTgUZa  
httpConnection.setRequestProperty("User-Agent","NetFox"); +*]$PVAFA  
< $0is:]  
pg4W?N`  
int responseCode=httpConnection.getResponseCode(); &uK(. @  
if(responseCode>=400) alaL/p{O  
{ ~v.mbh  
processErrorCode(responseCode); K8;SE !  
return -2; //-2 represent access is error ERpAV-Zf  
} .ybmJU*Hg  
[-])$~WfW  
A'DFY {  
String sHeader; hul,Yd) Z  
CO='[1"_5  
4]h/t&ppq  
for(int i=1;;i++) olE(#}7V  
{ dFy$w=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g X!>ef  
//Utility.log(in.readLine()); )!2@v@SQ  
sHeader=httpConnection.getHeaderFieldKey(i); nF<K84  
if(sHeader!=null) _x,X0ncv]@  
{ f+cb83}n]  
if(sHeader.equals("Content-Length")) 5H0qMt P  
{ IzpE|8l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~)U50. CH  
break; >1j#XA8  
} lYG`)#T  
} 4X+xh|R:U  
else <fvu) f  
break; I%YwG3uR  
} 5n3yc7NPP  
} ys9:";X;}  
catch(IOException e){e.printStackTrace ();} r1L@p[>  
catch(Exception e){e.printStackTrace ();} ;g0Q_F@;p  
B$ eM  
hIe.Mv-I)  
Utility.log(nFileLength); YEu+kBlcQ  
s2O()u-  
QLY;@-jF$  
return nFileLength; COh#/-`\1  
} x%viCkq  
jY=y<R_oK  
YSP\+ZZ  
//保存下载信息(文件指针位置) ZmsYRk~@-  
private void write_nPos() b Hr^_ogN  
{ Fv^zSoi2  
try{ $${I[2 R)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); w}3N!jNDv  
output.writeInt(nStartPos.length); 3``JrkPI  
for(int i=0;i<nStartPos.length;i++) |+ F ~zIu'  
{ t2d sYU/  
// output.writeLong(nPos); w-K A~  
output.writeLong(fileSplitterFetch.nStartPos); 1-y8Hy_a2  
output.writeLong(fileSplitterFetch.nEndPos); d A)T>  
} rfwJLl/  
output.close(); ~B;}jI]d[  
} ,Cr%2Wg-  
catch(IOException e){e.printStackTrace ();} `etw[#~N  
catch(Exception e){e.printStackTrace ();} 0AO^d[v  
} ~+\=X`y  
"'v+*H 3  
+f/ I>9G  
//读取保存的下载信息(文件指针位置) EH844k8 p  
private void read_nPos() MLd; UHU  
{ #}^waYAk)  
try{ :!aLa}`@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); v`|]57?A  
int nCount = input.readInt(); g{N}]_%Uh  
nStartPos = new long[nCount]; BM!ZdoKrKt  
nEndPos = new long[nCount]; -}6ew@GE  
for(int i=0;i<nStartPos.length;i++) x1 |/  
{ @aS)=|Ls\  
nStartPos = input.readLong(); l[E^nh>  
nEndPos = input.readLong(); yQhO-jT  
} }; '@'   
input.close(); dj0%?g>  
} T1Py6Q,-  
catch(IOException e){e.printStackTrace ();} {"]!zL  
catch(Exception e){e.printStackTrace ();} ~R|9|k  
} FAM{p=t]HT  
-E}X`?WhD  
dXTD8 )&  
private void processErrorCode(int nErrorCode) #da{3>z:  
{ V*n$$-5 1-  
System.err.println("Error Code : " + nErrorCode); 63E6nW M  
} Ek<Qz5)  
h3`}{ w  
Z#.d7B"  
//停止文件下载 Ck/44Wfej  
public void siteStop() WOn53|GQK  
{ 'HW l_M  
bStop = true; 6k hBT'n  
for(int i=0;i<nStartPos.length;i++) 3wfcGQn|sD  
fileSplitterFetch.splitterStop(); EV( F!&  
|:C0_`M9  
~ky;[  
} |3~m8v2-  
} ]njNSn  
//负责部分文件的抓取 Pg}QRCB@  
**FileSplitterFetch.java v*V( hMy  
*/ cvsH-uAp  
package NetFox; eKOEOm+  
Fv]6 a n.  
l 73% y  
import java.io.*; 8y27O  
import java.net.*; Q\4tzb]  
kl]V_ 7[  
%?[gBf[y  
public class FileSplitterFetch extends Thread { 9]v,3'QI  
CT'4.  
;B@#,6t/  
String sURL; //File URL S${%T$>  
long nStartPos; //File Snippet Start Position 8gavcsVE[  
long nEndPos; //File Snippet End Position &pY '  
int nThreadID; //Thread's ID zg ,=A?  
boolean bDownOver = false; //Downing is over t{c:<nN  
boolean bStop = false; //Stop identical +.~K=.O)  
FileAccessI fileAccessI = null; //File Access interface x\'3UKQP+^  
X{x(p  
(kR NqfX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |m KohV qr  
{ n{N0S^h  
this.sURL = sURL; =6U5^+|d  
this.nStartPos = nStart; \lG)J0  
this.nEndPos = nEnd; dm}1"BU<  
nThreadID = id; m]V#fRC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sl-wNIQ  
} ,Vq$>T@z  
E"'u2jEG^  
/)kJ iV  
public void run() f_)#  
{ }vh <x6  
while(nStartPos < nEndPos && !bStop) Ub\^3f  
{ (-$5YKm  
y7/4u-_c  
&wlD`0v  
try{ :4AIYk=q  
URL url = new URL(sURL); z00X ?F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FdE?uw  
httpConnection.setRequestProperty("User-Agent","NetFox"); eGT&&Y  
String sProperty = "bytes="+nStartPos+"-"; NxF:s,a6  
httpConnection.setRequestProperty("RANGE",sProperty); Z-lhJ<0/Pa  
Utility.log(sProperty); AM=> P 7  
9ye!kYF,  
j5DCc,s  
InputStream input = httpConnection.getInputStream(); :xHKbWz6j  
//logResponseHead(httpConnection); T;3qE1c  
4!Radl3`  
Lxv;[2XsW)  
byte[] b = new byte[1024]; 9n is8  
int nRead; 7vXP|8j  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) LpY{<:y  
{ 8Tg1 >q<  
nStartPos += fileAccessI.write(b,0,nRead); AmC9qk8Q  
//if(nThreadID == 1) `Kg!aN  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XY{N"S8  
} {96MfhkeBv  
Ce-= -  
D} B?~Lls  
Utility.log("Thread " + nThreadID + " is over!"); OIj.K@Kr  
bDownOver = true; UF^[?M =  
//nPos = fileAccessI.write (b,0,nRead); Y=|p}>.}  
} 7[P-;8)tq  
catch(Exception e){e.printStackTrace ();} "Y^j=?1k  
} S`YT"|~  
} r+m.! +  
HI{q#  
'k]~Q{K$  
//打印回应的头信息 }F0<8L6%  
public void logResponseHead(HttpURLConnection con) kJl^,q  
{ u=Ik&^v Wq  
for(int i=1;;i++) s<"|'~<n  
{ 'm`}XGUBS  
String header=con.getHeaderFieldKey(i); UapU:>!"`  
if(header!=null) 5?H wM[`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); B-_b.4ND)  
Utility.log(header+" : "+con.getHeaderField(header)); @gb W:  
else l'q%bi=f  
break; OQfFS+6  
} .]h/M,xg  
} G=[<KtWa  
f6K.F  
,ja!OZ0$  
public void splitterStop() pt"9zkPj  
{ niCK(&z  
bStop = true; a(6h`GHo  
} `1P|<VbZ  
al}J^MJ  
 s&pnB  
} vE^tdzAG  
@Q,Q"c2  
N,K/Ya)1  
/* s !?uLSEdb  
**FileAccess.java mrRid}2  
*//文件访问(定位,写) 8Yk*$RR9  
package NetFox; -t S\  
import java.io.*; d/yF}%0QI  
4@{?4k-cq  
OWwqCPz.  
public class FileAccessI implements Serializable{ +'c+X^_  
W9w*=W )Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 FfM^2`xP  
RandomAccessFile oSavedFile; sw}O g`U  
long nPos; (o IGp  
S=-$:65  
8u~  
public FileAccessI() throws IOException 7Q&-ObW  
{ Kw`CN  
this("",0); `K5*Fjx  
} xrvM}Il  
m=l'9j"D  
DNq(\@x[!  
public FileAccessI(String sName,long nPos) throws IOException pml33^*<U  
{ >-N(o2j3  
oSavedFile = new RandomAccessFile(sName,"rw"); sq`Xz 8u  
this.nPos = nPos; pAatv;Ex  
oSavedFile.seek(nPos); "."(<c/3  
} <9ucpV  
LE<J<~2Z  
O_1[KiZ  
public synchronized int write(byte[] b,int nStart,int nLen) 7?R600OA  
{ la+Cra&xL  
int n = -1; o:Kw<z,$H  
try{ A811VL^  
oSavedFile.write(b,nStart,nLen); *p $0(bz  
n = nLen; 4{kH;~ z$  
} `5@F'tKQ  
catch(IOException e) vi,hWz8WB  
{ ]O@$}B];)  
e.printStackTrace (); ,;)ZF  
} 9njl,Q:  
2c9?,Le/;  
[^5\Ww  
return n; 4%(Ji  
} y?$DDD  
V ;T :Q%  
N^Re  
} P49\A^5S!  
(`tRJWbdz  
c3vb~l)  
/* *%j$i_  
**SiteInfoBean.java #.Rn6|V/4  
*/ 5~*)3z^V  
package NetFox; y~SVD@  
t[^$F,  
8H!QekQZ]\  
public class SiteInfoBean { xA] L0h]  
GtA`0B  
)g0fN+Mb  
private String sSiteURL; //Site's URL AU{"G  
private String sFilePath; //Saved File's Path oaoTd$/5  
private String sFileName; //Saved File's Name )pnyVTKt  
private int nSplitter; //Count of Splited Downloading File tdy2ZPVtTV  
+a1x;  
-3I3 X  
public SiteInfoBean() M([#Py9h  
{//nSplitter的缺省值为5 MY&Jdmga  
//default value of nSplitter is 5 Uzu6>yT  
this("","","",5); "LMj,qZ1!  
} D&@]  
%,$n^{v  
[|}IS@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yIMqQSt79z  
{ *H>rvE.K?  
sSiteURL= sURL; \8`?ir q"  
sFilePath = sPath; kB\{1;  
sFileName = sName; @-N` W9  
this.nSplitter = nSpiltter; / HTY>b  
 N;7/C  
wj|Zn+{"nF  
}  6@S6E(^  
1>!LK_  
sp9gz~Kq  
public String getSSiteURL() .])prp8  
{ }aCa2%  
return sSiteURL; O] _4pP  
} QrZ#<{,J5  
EE/mxN(<  
!3ggQG!e  
public void setSSiteURL(String value) LF<&gC  
{ k9|5TLXq?  
sSiteURL = value; my=f}%k=  
} Yo-}uTkw  
DSGcxM+  
2_o#Gx'  
public String getSFilePath() Bf_$BCyGW  
{ rr<E#w  
return sFilePath; <=uYfi3,  
} v* ;d  
V7ph^^sC}  
ITu19WG  
public void setSFilePath(String value) &hCbXs=  
{ M>Q]{/V7T  
sFilePath = value; "L~(%Nx3  
} /@os*c|je  
_KT!OYH  
H'+7z-% G  
public String getSFileName() 98m|&7  
{ S63 Zk0(25  
return sFileName; ^5mc$~1`  
} L'e_?`!:  
N<EVs.7  
?RRO  
public void setSFileName(String value) n|`3d~9$&  
{ \-<BUG]=  
sFileName = value; NnZW@ln"|  
} ^0VL](bD>  
_|HhT^\P  
{]vD@)k  
public int getNSplitter() '\Xkvi  
{ voWH.[n^_  
return nSplitter; 8hRcB[F~S  
} O5\r%&$xd  
>rG>Bz^Pu  
`-NK:;^  
public void setNSplitter(int nCount) *zfgO pK  
{ :_{8amO  
nSplitter = nCount; d@%"B($nR  
} V0ze7tSG[f  
} ,'#TdLe  
)U^=`* 7  
M  .#}  
/* W{p}N  
**Utility.java 7Z-j'pq  
*/ _vQ52H,  
package NetFox; g40Hj Y  
L"_X W no  
1/_g36\l$  
public class Utility { jnH\}IB  
{@Wv@H+4  
m 0HK1'  
public Utility() _0/unJl`  
{ Lx"GBEkt7  
X -pbSq~5  
"CJVtO  
} Z:4/lx7Bq  
nF3}wCe)  
//线程睡眠 sEhvx +(  
public static void sleep(int nSecond) ?HEqv$n  
{ Y\xEPh  
try{ ^BsT>VSH6  
Thread.sleep(nSecond); 1$E(8"l  
} nep#L>LP$x  
catch(Exception e) (f/(q-7VWt  
{ "k zKQ~  
e.printStackTrace (); 3o.x<G(  
} gF6> /  
} ^z,3#gK  
0cG'37[  
//日志 ]ua3I}_B6v  
public static void log(String sMsg) l{By]S  
{  F/Goq`  
System.err.println(sMsg); LIg1U  
} .#EU@Hc  
72HA.!ry  
E^8|xT'h6  
public static void log(int sMsg) *P mZqe  
{ :X>Wd+lY:_  
System.err.println(sMsg); F)3+IuY  
} tBo\R?YRs  
} y^2#;0W  
E@}F^0c  
*V>?m6y/  
/*  ?kjQ_K  
**TestMethod.java !gh8 Qs  
*/ /9vi  
package NetFox; ]#0 (  
zJQh~)  
2mLZ4 r>WE  
public class TestMethod { YQ0#j'}/  
N8A)lYT]_u  
Nt>^2Mv   
public TestMethod() *s6 x  
{ ///xx/weblogic60b2_win.exe vCa8`m  
try{ {}$9 70y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }[0nTd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Okq,p=D6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mK:gj&N7X|  
fileFetch.start(); @SfQbM##%  
} Xv1vq -cM  
catch(Exception e){e.printStackTrace ();} .Fb#j+Lq  
'-wmY?ZFxy  
b]u$!W  
} 91OxUVd  
@3`5(xwzm  
b{0a/&&1O  
public static void main(String[] args) c 4z&HQd  
{ !73y(Y%TE  
new TestMethod(); 9r%fBiSk  
} 161P%sGx2  
} uq5?t  
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