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http断点续传简单实现(java)

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/* 1bjz :^  
**SiteFileFetch.java y t7>,  
*/ ;ik,6_/Y  
package NetFox; 2B^WZlx  
import java.io.*; bVzJOBe  
import java.net.*; !ST7@D  
{9* l  
T-h[$fxR_  
public class SiteFileFetch extends Thread {  T\#Gc4  
jrpki<D  
8n["/5,  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^\[c][fo  
long[] nStartPos; //开始位置 N,UUM|?9_  
long[] nEndPos; //结束位置 m6'9Id-:L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b7'l3mQjk  
long nFileLength; //文件长度 \Rs9B .  
boolean bFirst = true; //是否第一次取文件 SYh>FF"  
boolean bStop = false; //停止标志 @urZ  
File tmpFile; //文件下载的临时信息 ! ?>I  
DataOutputStream output; //输出到文件的输出流 SAdo9m'  
-q8l"i>h=  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ^j2ve's:  
public SiteFileFetch(SiteInfoBean bean) throws IOException L c )i  
{ o'Fyo4Qd  
siteInfoBean = bean; abv*X 1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l%xTF@4e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3h$E^"  
if(tmpFile.exists ()) ~7FS'!W,F  
{ 1CR\!?  
bFirst = false; YkE_7r(1  
read_nPos(); #^yOW^  
} m WHyk"l  
else !p76I=H%  
{ `+0dz,  
nStartPos = new long[bean.getNSplitter()]; e tL?UF$  
nEndPos = new long[bean.getNSplitter()]; |UB)q5I  
} ;kWWzg  
@n=&muC}  
vvs2:87zvJ  
`$XB_ o%@  
} + )z5ai0m  
X|&H2y|*7  
It<VjN9  
public void run() bxzx@sF2l  
{ HAo=t  
//获得文件长度 'nq~1 >i  
//分割文件 w~&#:F?  
//实例FileSplitterFetch 6(x53 y__  
//启动FileSplitterFetch线程 ;Qi!~VsP;  
//等待子线程返回 @.c[z D  
try{ ?JTTl;  
if(bFirst) [-i&)eX  
{ FS=LpvOG)  
nFileLength = getFileSize(); 1k^$:'  
if(nFileLength == -1) F|VKrH.  
{ ?|pP&8r  
System.err.println("File Length is not known!"); s:iBl/N}  
} c`&g.s@N\  
else if(nFileLength == -2) >ts}\.(]  
{ R]o0V*n  
System.err.println("File is not access!"); d`C$vj  
} NFP h}D  
else R*D5n>~  
{ gK(G1  
for(int i=0;i<nStartPos.length;i++) `'*4B_.  
{ :_]0 8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?6>*mdpl  
} 4q:8<*W=  
for(int i=0;i<nEndPos.length-1;i++) J}+N\V~  
{ ;(jL`L F  
nEndPos = nStartPos[i+1]; }K`KoM  
} j8 `7)^  
nEndPos[nEndPos.length-1] = nFileLength; M,X)rM}Q  
} }_F:]lI*R  
} GY.iCub  
&}0QnO_mj  
|@d}O8  
//启动子线程 23Dld+E&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Nr+~3:3  
for(int i=0;i<nStartPos.length;i++) OCJt5#e~A  
{ q@~{ g[   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^Sj;~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4P=1)t?tX  
nStartPos,nEndPos,i); ,G-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qa\,)<'D:  
fileSplitterFetch.start(); )_n(u3'  
} $CJf 0[|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cui%r!D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7ku=roPoF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m@lUJY  
nEndPos = " + nFileLength); %#PWD7a\  
// fileSplitterFetch[nPos.length-1].start(); ^TjC  
:475FPy]  
<}h <By)  
//等待子线程结束 tN_=&|{WE4  
//int count = 0; tIV{uVM[|D  
//是否结束while循环 2y|n!p T  
boolean breakWhile = false; $Ff6nc=  
<Rs$d0/  
fI2 y(p{?  
while(!bStop) hoM%|,0  
{ SIKaDIZ  
write_nPos(); Hz[1c4)'F  
Utility.sleep(500); Yk)fBPHr  
breakWhile = true; DU)q]'[u  
m/jyc# L:u  
eK5~gnv,  
for(int i=0;i<nStartPos.length;i++) 2{Dnfl'k  
{ zUDXkG*Lv  
if(!fileSplitterFetch.bDownOver) Qds:*]vGS  
{ UZmUYSu;  
breakWhile = false; B0A y  
break; Mw"[2PA  
} 8a]g>g  
} 7=yjd)Iy9m  
if(breakWhile) w ^^l,  
break; ,3iD/8_  
0v9i43[S|J  
n/ :#:  
//count++; Iw`|,-|  
//if(count>4) jcvq:i{  
// siteStop(); l:bbc!3  
} |Kjfh};-C  
8B-mZFXpK  
n7Bv~?DM  
System.err.println("文件下载结束!"); Cg%Owe/E?0  
} ki}Li*)7  
catch(Exception e){e.printStackTrace ();} Y~Vc|zM^(  
} |pbetA4&  
kP/<S<h,g  
&cTOrG  
//获得文件长度 ?u;m ],w!  
public long getFileSize() f2pA+j5[  
{ ^c/3 !"wK  
int nFileLength = -1; "w0~f6o  
try{ )E7wBNV   
URL url = new URL(siteInfoBean.getSSiteURL()); L[<Y6u>m!1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =Ti@Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); z_'!?K{  
t^>P,%$  
lq]8zm<\)]  
int responseCode=httpConnection.getResponseCode(); rZ5xQ#IA  
if(responseCode>=400) ?(Tin80=r  
{ =./PY10'  
processErrorCode(responseCode); :f%kk atO  
return -2; //-2 represent access is error 2~7*jA+Ab  
} (CH6Q]Wi_!  
yiXb<g+B  
aIQC[ry  
String sHeader; @Q{:m)\  
nT2b"wkTT  
#`U?,>2q  
for(int i=1;;i++) Y,yU460T8  
{ s]`6u yW"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2 M\7j  
//Utility.log(in.readLine()); n@h$V\&\iM  
sHeader=httpConnection.getHeaderFieldKey(i); 6/Yo0D>M$  
if(sHeader!=null) 4+nZ4a>LH?  
{ $Q}L*4?]  
if(sHeader.equals("Content-Length")) p,|)qr:M  
{ @jjxgd'%&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 92R,o'#  
break; F7w\ctUP  
} OC-d5P  
} wu11)HFL|z  
else 7J`v#  
break; ;;rx)|\<R  
} .HGK  3  
}  t5S|0/f  
catch(IOException e){e.printStackTrace ();} J}4RJ9  
catch(Exception e){e.printStackTrace ();} &'i>d&  
p\#;(pf}s  
'rFLG+W  
Utility.log(nFileLength); ]TUoXU2<x  
/X0<2&v  
l x0BKD?n  
return nFileLength; L0H^S)g  
} :SO4@JT{W  
-:Fr($^  
b"}ya/  
//保存下载信息(文件指针位置) O'^AbO=,  
private void write_nPos() Oml3=TV  
{ [T)>RF  
try{ >Wx9a"H^(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q>;Aq!mr=  
output.writeInt(nStartPos.length); W>Pcj EI  
for(int i=0;i<nStartPos.length;i++) 4T"L#o1  
{ V4CA*FEA  
// output.writeLong(nPos); D'{ o3Q,%K  
output.writeLong(fileSplitterFetch.nStartPos); 'Z,7{U1P  
output.writeLong(fileSplitterFetch.nEndPos); *%_M?^  
} Au/'|%2#(  
output.close(); \>EUa}%xn  
} g2}aEfp!H  
catch(IOException e){e.printStackTrace ();} v;g,qO!LJ  
catch(Exception e){e.printStackTrace ();} qz Hsqlof  
} RtxAIMzh?  
 ]SL+ZT  
PR(KDwsT&l  
//读取保存的下载信息(文件指针位置) Uvi@HB HJ  
private void read_nPos() *Sbc 8Y  
{ SX =^C  
try{ =%>E8)Jb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jJ@@W~/)B  
int nCount = input.readInt(); @n9iOf~<  
nStartPos = new long[nCount]; rTJU)4I^h  
nEndPos = new long[nCount]; $ntC{a>&  
for(int i=0;i<nStartPos.length;i++) v$q\3#5|'  
{ .{bT9Sc5  
nStartPos = input.readLong(); :x3DuQP  
nEndPos = input.readLong(); qT4`3nH:  
} n[v`F  
input.close(); @Xh8kvc81  
} ,O^kZ}b  
catch(IOException e){e.printStackTrace ();} -)bu&  
catch(Exception e){e.printStackTrace ();} %wu,c e]*  
} ;F71f#iY  
" ;8kKR  
)liNjY@  
private void processErrorCode(int nErrorCode) =KnHa.%  
{  s-&i!d  
System.err.println("Error Code : " + nErrorCode); Zw/??Tq b  
} K7(GdKZe  
eISHV.QV  
AGVipI #  
//停止文件下载 aK,\e/Oo  
public void siteStop() m{lS-DlRg  
{ $SniQ  
bStop = true; @}+B%R  
for(int i=0;i<nStartPos.length;i++) -wNhbV2  
fileSplitterFetch.splitterStop();  Spo[JQ%6  
CJ#Yu3}  
chE}`I?  
} %F;uW[4r  
} eR3MU]zF  
//负责部分文件的抓取 +K;%sAZy  
**FileSplitterFetch.java RzLeR%O  
*/ OQyZ'  
package NetFox; 3A\Hiy!{F  
%6@m~;c0  
A/j'{X!z  
import java.io.*; ,p..h+l  
import java.net.*; XFww|SG$  
MpIP)bdq7  
IY2f$YV  
public class FileSplitterFetch extends Thread { 1gYvp9Ma  
:ZM=P3QZ  
]tbl1=|  
String sURL; //File URL }k8&T\V!  
long nStartPos; //File Snippet Start Position _.,"`U; H  
long nEndPos; //File Snippet End Position n!NA}Oa  
int nThreadID; //Thread's ID  Zzr  
boolean bDownOver = false; //Downing is over n0^3F1Z  
boolean bStop = false; //Stop identical . ve a[  
FileAccessI fileAccessI = null; //File Access interface -#AO4xpI  
eN<?rVZl  
IF?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $')Uie<!8  
{ #N\<(SD/  
this.sURL = sURL; #q?:Act  
this.nStartPos = nStart; HuD~(CI.  
this.nEndPos = nEnd; *NI hYg6  
nThreadID = id; 5*$z4O:Aa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [{+ZQd  
} lJ4/bL2I/  
MPsm)jqX  
jSvo-  
public void run() fEyc3K'5V  
{ GsE =5A8  
while(nStartPos < nEndPos && !bStop) $[(FCS  
{ elP#s5l4  
%Vsg4DRy  
H<`7){iG  
try{ o-]8)G>~M  
URL url = new URL(sURL); o1<Z; 2#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \&Oc}]  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]#$r TWMl'  
String sProperty = "bytes="+nStartPos+"-"; ob(~4H-  
httpConnection.setRequestProperty("RANGE",sProperty); k@2@%02o9C  
Utility.log(sProperty); NX<Q}3cC  
#~qY%X  
9z?B@;lMc  
InputStream input = httpConnection.getInputStream(); FzFP 0  
//logResponseHead(httpConnection); o7:"Sl2AD  
~T'$gl  
AiV1 vD`  
byte[] b = new byte[1024]; M j |"+(  
int nRead; : DBJ2n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8PW3x-+  
{ sH)40QmO{  
nStartPos += fileAccessI.write(b,0,nRead); Xm.["&  
//if(nThreadID == 1) I;?np  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |\q@XCGei  
} 9 J~KM=p  
=Xb:.  
RsP^T:M}$  
Utility.log("Thread " + nThreadID + " is over!"); 95  X6V  
bDownOver = true; fu`|@S  
//nPos = fileAccessI.write (b,0,nRead); th|TwD&mO  
} ebB8.(k9G3  
catch(Exception e){e.printStackTrace ();} YR68'Sft[  
} GG`;c?d@  
} 6C*4' P9>  
jR,3 -JQ  
Jb` yK@x  
//打印回应的头信息 At8^yF   
public void logResponseHead(HttpURLConnection con) 6b=7{nLF  
{ >zcp(M98  
for(int i=1;;i++) 5%XEybc2  
{ ]4-t*Em  
String header=con.getHeaderFieldKey(i); CLY>M`%?+p  
if(header!=null) ]=0$-ImQ@x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fmk(}  
Utility.log(header+" : "+con.getHeaderField(header)); -gLU>I7wV  
else * n>YS  
break; |K$EULzz  
} tumYZ)nW  
} i.>d#S  
>]l7AZ:,  
Gv }~  
public void splitterStop() <o&\/uO~H  
{ $PKUcT0N9  
bStop = true; Y\7/`ty  
} uF\f>E)/N%  
l#%G~c8x  
% KmhR2v  
} )u_[cEJHO  
~px)Jd  
r*4@S~;  
/* #jR1ti)p  
**FileAccess.java *6 P)HU@  
*//文件访问(定位,写) {(qH8A  
package NetFox; wg 6  
import java.io.*; _,]@xFCOH  
a6.0 $'  
,zH\&D$>u  
public class FileAccessI implements Serializable{ )u(Dqu\t  
/c-%+Xd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Y^J/jA0\B  
RandomAccessFile oSavedFile; -&_;x&k /  
long nPos; +^@6{1  
_'DZoOH|VE  
\jThbCb  
public FileAccessI() throws IOException 7 `& NB]  
{ g|V0[Hnq6  
this("",0); YXjWk),  
} ( G#W6  
^6I8a"  
Q?TXM1Bp  
public FileAccessI(String sName,long nPos) throws IOException ^B7C8YP  
{ QDJ:LJz\  
oSavedFile = new RandomAccessFile(sName,"rw"); w `r)B`!g  
this.nPos = nPos; 1:d,8  
oSavedFile.seek(nPos); j+>&~  
} ? ;)F_aHp  
:~+m9r  
w?zY9Fs=s  
public synchronized int write(byte[] b,int nStart,int nLen) tR% &.,2  
{ i$W=5B>SO  
int n = -1; 14;lB.$p  
try{ Z:s:NvFX  
oSavedFile.write(b,nStart,nLen); Pi:=0,"XOp  
n = nLen; xSoXf0zq:  
} |F^h >^ x  
catch(IOException e) aXO|% qX  
{ /0I=?+QSo  
e.printStackTrace (); ~`Xu 6+1o  
} %G>V .d  
u9R:2ah&K  
U/I+A|S[  
return n; y1 53ax  
} 1$G'Kg/  
>On"BP# U  
Ks-aJ+}  
} h9 &V   
nH^RQ'19  
v"a.%" oN8  
/* O:3DIT1#>  
**SiteInfoBean.java i(@<KH  
*/ esVZ2_eL  
package NetFox; '=eE6=m^K  
MW6KEiQ"  
fKZgAISF  
public class SiteInfoBean { <E.$4/T  
{Lm%zdk*k  
;NzS;C'  
private String sSiteURL; //Site's URL Nt#a_  
private String sFilePath; //Saved File's Path lKF<]25  
private String sFileName; //Saved File's Name o{&UT VyGs  
private int nSplitter; //Count of Splited Downloading File PofHe  
\9t6 #8  
/i)1BaF  
public SiteInfoBean() nmrYBw>  
{//nSplitter的缺省值为5 %[C-KQH  
//default value of nSplitter is 5 3V`.<  
this("","","",5); _z3YB  
} `Gp!Y  
edy6WzxBcm  
oPA [vY  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fCxF3m(O  
{ *PVv=SU  
sSiteURL= sURL; +w pe<T  
sFilePath = sPath; dECH/vJ^  
sFileName = sName; |6.1uRFE2  
this.nSplitter = nSpiltter; : 'LG%E:b  
=wy3h0k^  
^."HD(  
} c_r&)8  
/Aq):T T  
2dF:;k k  
public String getSSiteURL() N%.Dj H  
{ 5{&<X.jv  
return sSiteURL; Z/ypWoV(  
} ].eY]o}=  
)tV^)n[w  
\!tS|h  
public void setSSiteURL(String value) Lx"a#rZ  
{ mTW@E#)n  
sSiteURL = value; `1[GY){?)  
} %g>{m2o  
PNbs7f  
f1RfNiW.  
public String getSFilePath() /:}z*a  
{ ohA@Zm8O  
return sFilePath; t!Uc, mEV]  
} q|A-h'  
-^JGa{9*  
rpNe8"sh  
public void setSFilePath(String value) >5jHgs#  
{ [}OL@num  
sFilePath = value; *ppb 4R;CW  
} j;k(AM<  
92k}ON  
7BX%z$_)A  
public String getSFileName() e]+ [lq\p@  
{ c[Mz#BWG  
return sFileName; (Rc 0l;  
} U "qO&;m  
-0) So  
~"*;lT5KX  
public void setSFileName(String value) B43o_H|s  
{ r]=3aebR.  
sFileName = value; UI4Xv  
} Vo%UiVHy  
diLjUC`69  
,QpDz{8  
public int getNSplitter() A_t<SG5  
{ O;A/(lPW+  
return nSplitter; ]rh)AE!Y(  
} "iof -b=ys  
?ExfxR!~  
\\D~Yg\#  
public void setNSplitter(int nCount) A*h)p@3t<  
{ [^gSWU  
nSplitter = nCount; bz~-uHC  
} _l?5GLl_F$  
} ^/Hj^4~_U  
wBcDL/(>  
y^C; ?B<  
/* *4zVK/FJ  
**Utility.java "z }bgy  
*/ /Ki :6  
package NetFox; N[}XLhbt  
z^4\?R50yO  
_W: S>ij(  
public class Utility { TBQ`:`g^m  
rrSA.J{  
 FFgy=F  
public Utility() Jz#ZDZkm  
{ ^}8_tZs8\  
f ( `.q  
)^!-Aj\x  
} )_EobE\  
Ze$:-7Czl  
//线程睡眠 7l Aa6"Y68  
public static void sleep(int nSecond) P|.KMtG  
{ 2597#O  
try{ >t8eVMMa  
Thread.sleep(nSecond); r/Pg,si  
} S$"A[  
catch(Exception e) 7$GP#V1r/  
{ @fpxGMy&  
e.printStackTrace (); "`:#sF9S  
} qc\o>$-:`  
} }7$\F!R  
!*%3um  
//日志 !9o8v0ZI  
public static void log(String sMsg) )K2n!Fbd  
{ NUL~zb  
System.err.println(sMsg); #G#gB   
} O!f* @  
yB. 6U56  
McnP>n  
public static void log(int sMsg) m$J'nA  
{ raJyo>xXb5  
System.err.println(sMsg); `T9<}&=!  
} o7 !@WOeZ3  
} n?,fF(  
bM^'q  
72-@!Z0e  
/* `hlyN]L  
**TestMethod.java uR"]w7=  
*/ +[2lS54"W4  
package NetFox; 00pHnNoxW  
1shvHmrV  
!#iP)"O  
public class TestMethod { f\(Kou$  
jv0e&rt  
>8NQ8i=]V1  
public TestMethod() 5. l&nt'  
{ ///xx/weblogic60b2_win.exe q>omCk%h  
try{ |J}~a8o  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [1vrv(u>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NM]6  o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I3s}t$`y(  
fileFetch.start(); 8'cDK[L  
} -`?V8OwY]  
catch(Exception e){e.printStackTrace ();} d'-^ VxO0  
Dkdm~~Rr  
\aW5V:?  
} Hh@mIusj  
Y66 vJ<lM  
A`r&"i OKA  
public static void main(String[] args) Y2$ % %@  
{ 3]VTQl{P  
new TestMethod(); t1~*q)!Mo  
} #-V Kk  
} w|5}V6WD  
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