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http断点续传简单实现(java)

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/* t*XN_=E$f  
**SiteFileFetch.java EZDy+6b  
*/ S9| a$3K'  
package NetFox; 6Jz^  
import java.io.*; LiQgR 6j  
import java.net.*; I5m][~6.?  
SHVWwoieT  
;gg\;i}^  
public class SiteFileFetch extends Thread { 13hE}g;.  
BB$oq'  
?sz)J 3  
SiteInfoBean siteInfoBean = null; //文件信息Bean l fZ04M{2  
long[] nStartPos; //开始位置 gB'fFkd  
long[] nEndPos; //结束位置 5ETip'<KT6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #/2$+x  
long nFileLength; //文件长度 4qi[r)G  
boolean bFirst = true; //是否第一次取文件 [K/m  
boolean bStop = false; //停止标志 tWeFEVg  
File tmpFile; //文件下载的临时信息 0\9K3  
DataOutputStream output; //输出到文件的输出流 o=J9  
Px FWJ?=  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) N_pUv   
public SiteFileFetch(SiteInfoBean bean) throws IOException V5F%_,No  
{ b</9Ai=  
siteInfoBean = bean; NB_ )ZEmF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vmTs9"ujF,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PQN@JaD  
if(tmpFile.exists ()) +HT1ct+dI  
{ -_ C#wtC  
bFirst = false; LUX*P7*B  
read_nPos(); !k3e\v|  
} yifY%!@Xu  
else :#~U<C@o  
{ KJ2Pb"s  
nStartPos = new long[bean.getNSplitter()]; &fa5laJb  
nEndPos = new long[bean.getNSplitter()]; 7CXW#H  
} C'yppl%  
nrm+z"7  
j^tW Iz  
XQ%4L-rhN  
} YKmsQ(q`N  
%WTEv?I{Ga  
8lF\v/vN  
public void run() 1NQbl+w#I  
{ lKWPTCU  
//获得文件长度 FTc.]laO  
//分割文件 mrIh0B:`  
//实例FileSplitterFetch 7\]E~/g  
//启动FileSplitterFetch线程 zmj"fN{\  
//等待子线程返回 t\P<X^d%  
try{ ;5-r_D;9  
if(bFirst) "tFxhKf  
{ P 3MhU;  
nFileLength = getFileSize(); .MQ^(  
if(nFileLength == -1) b45|vX+j  
{ Wq*b~Lw  
System.err.println("File Length is not known!"); D:^$4}h f  
} sJwyj D$b  
else if(nFileLength == -2) gz2\H}  
{ o8e?J\?  
System.err.println("File is not access!"); n1 6 `y}  
} n Ox4<Wk&  
else nJ4pTOc  
{ =K'cM=WM6  
for(int i=0;i<nStartPos.length;i++) QrO\jAZ{Ag  
{ {7TlN.(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -7J|l  
} ^7zu<lX  
for(int i=0;i<nEndPos.length-1;i++) 1I@8A>2^OX  
{ N7E$G{TT  
nEndPos = nStartPos[i+1]; _@S`5;4x  
}  |@NiW\O  
nEndPos[nEndPos.length-1] = nFileLength; T91moRv  
} @36u8pE  
} z [`@}}Q  
Zo1,1O  
,h"-  
//启动子线程 T\~x.aH`^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bR@p<;G|  
for(int i=0;i<nStartPos.length;i++) =X.LA%Sf=u  
{ Z{&cuo.@<]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [Nn`l,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }neY<{z  
nStartPos,nEndPos,i); c'/l,k  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |5Xq0nvCe  
fileSplitterFetch.start(); U9b?i$  
} ~4"qV_M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y0eE-5F,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4pw6bK,s2\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L(&&26Y  
nEndPos = " + nFileLength); quY:pqG38q  
// fileSplitterFetch[nPos.length-1].start(); ca+5=+X7  
%p%%~ewmx  
q, O$ %-70  
//等待子线程结束  H"A7Zo  
//int count = 0; %|s+jeUDn|  
//是否结束while循环 n:MdYA5,m  
boolean breakWhile = false; 6@DF  
J!5$,%v  
J:V?EE,\-  
while(!bStop) *_>Lmm.yh  
{ d!eYqM7-G  
write_nPos(); "DYJ21Ut4  
Utility.sleep(500); U&O: _>~  
breakWhile = true; N-lkYL-%\j  
vVOh3{e|  
'],J$ge  
for(int i=0;i<nStartPos.length;i++) @S|XGf  
{ 1GzAG;UUo6  
if(!fileSplitterFetch.bDownOver) y5!KXAQ%  
{ a+n0|CvF  
breakWhile = false; T=ev[ mS  
break; x7O-Y~[2  
} JtER_(.  
} |\pbir  
if(breakWhile) #U14-^7  
break; 3Z1CWzq(  
O({2ivX  
`V##Y  
//count++; .V,@k7U,V  
//if(count>4) FSND>\>  
// siteStop(); p, #o<W  
} ob8qe,_'  
4:FK;~wM&x  
V:y'Qf2M  
System.err.println("文件下载结束!"); F w?[lS  
} `nu''B H  
catch(Exception e){e.printStackTrace ();} Ofs <EQ  
} $< JaLS  
9 AJ(&qY(  
4 r45i:  
//获得文件长度 A}l3cP; `#  
public long getFileSize() dkz=CY3p%X  
{ q.;u?,|E/  
int nFileLength = -1; s7F.sg  
try{ 4t=G   
URL url = new URL(siteInfoBean.getSSiteURL()); PUUwv_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wRVUu)  
httpConnection.setRequestProperty("User-Agent","NetFox"); uA< n  
ez| )ph7  
]9^sa-8  
int responseCode=httpConnection.getResponseCode(); ~sh`r{0  
if(responseCode>=400) ?32&]iM oW  
{ w(L4A0K[  
processErrorCode(responseCode); E 7{U |\  
return -2; //-2 represent access is error H*}y^ )x  
} ~A\GT$  
1eF3`  
LcTP #  
String sHeader; )P sY($ &  
Bx< <~[Ws}  
lN Yt`xp  
for(int i=1;;i++) @u6B;)'l  
{ a!v1M2>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZpQ)IHA.  
//Utility.log(in.readLine()); cPlZXf  
sHeader=httpConnection.getHeaderFieldKey(i); ]Gsv0Xk1  
if(sHeader!=null) s*.hl.k.  
{ T{-CkHf9Q  
if(sHeader.equals("Content-Length")) ~UP[A'9jJ  
{ Jcd-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J| w>a  
break; VZKvaxIk6  
} Wi)_H$KII  
} 9dx/hFA  
else |Y ,b?*UF  
break; <eWf<  
} ZbdZ rE$  
} X aMJDa|M  
catch(IOException e){e.printStackTrace ();} ,?^ p(w  
catch(Exception e){e.printStackTrace ();} , s"^kFl  
N2;B-UF 7  
f6&iy$@   
Utility.log(nFileLength); 0Qf,@^zL*  
P/W XaE4  
[M=7M}f;  
return nFileLength; "ut39si  
} z7fp#>uw  
I 7{T  
#Lh;CSS  
//保存下载信息(文件指针位置) *nkoPVpC  
private void write_nPos() R {SF(g3  
{ inMA:x}cF1  
try{ _Tm3<o.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'a@/vx&J  
output.writeInt(nStartPos.length); KW pVw!  
for(int i=0;i<nStartPos.length;i++) <h0?tv]  
{ rlOAo`hd  
// output.writeLong(nPos); t-tg-<  
output.writeLong(fileSplitterFetch.nStartPos); ia!y!_L\'  
output.writeLong(fileSplitterFetch.nEndPos); g}1B;zGf  
} V17%=bCZ5[  
output.close(); iP ->S\  
} r@H /kD  
catch(IOException e){e.printStackTrace ();} "#2a8#  
catch(Exception e){e.printStackTrace ();} nFHUy9q  
} "R;U/+  
@@Kp67Iv  
8V`WO6*  
//读取保存的下载信息(文件指针位置) 6d<r= C=  
private void read_nPos() &5B'nk"  
{ vXrx{5gz  
try{ YYBDRR"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (c=6yV@  
int nCount = input.readInt(); ];[}:f  
nStartPos = new long[nCount]; Nk? ^1n$  
nEndPos = new long[nCount]; dy%;W%  
for(int i=0;i<nStartPos.length;i++) ; F"g$_D0  
{ *&^Pj%DX  
nStartPos = input.readLong(); B" 1c  
nEndPos = input.readLong(); yg<R=$n,Q  
} rr],DGg+B]  
input.close(); /~%&vpF-L  
} U ]H#MiC!  
catch(IOException e){e.printStackTrace ();} ) j#`r/  
catch(Exception e){e.printStackTrace ();} FpmM63$VN[  
} 2*;~S4 4  
H)kwQRfu  
9<6;Hr,>G  
private void processErrorCode(int nErrorCode) |6sp/38#p  
{ q376m-+  
System.err.println("Error Code : " + nErrorCode); 823Y\x~>  
} Q4#m\KK;i9  
_{YWXRC#  
/K@XzwM  
//停止文件下载 ;PF<y9M  
public void siteStop() {4<C_52t  
{ N2^=E1|_  
bStop = true; c<B/V0]  
for(int i=0;i<nStartPos.length;i++)  MzdV2.  
fileSplitterFetch.splitterStop(); & p  
/|6N*>l)y  
/$Nsd  
} /=nJRC3.  
} }c,}V  
//负责部分文件的抓取 24 'J  
**FileSplitterFetch.java z% ?+AM)P  
*/ @e.C"@G  
package NetFox; X:"i4i[}{9  
Cn34b_Sbd  
|.: q  
import java.io.*; RB7tmJ c  
import java.net.*; ^,TO#%$iE  
]nn98y+  
!Iy_UfW  
public class FileSplitterFetch extends Thread { i &nSh ]KK  
]g3JZF-  
@alK;\  
String sURL; //File URL zZPO&akB"  
long nStartPos; //File Snippet Start Position _}Ac n$  
long nEndPos; //File Snippet End Position =7=]{Cx[  
int nThreadID; //Thread's ID o q Xg  
boolean bDownOver = false; //Downing is over Ju@c~Xm  
boolean bStop = false; //Stop identical EHJ.T~X  
FileAccessI fileAccessI = null; //File Access interface g*AWE,%=|  
*a M=Z+  
,q`\\d  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Xx~Bp+  
{ jp%S3)  
this.sURL = sURL; `KoV_2|  
this.nStartPos = nStart;  ~^:A{/  
this.nEndPos = nEnd; T4Uev*A  
nThreadID = id; <44G]eb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hD 82tr  
} lfow1WRF  
*w`sM%]Rq  
vH@ds k  
public void run() 2*& ^v  
{ pI\]6U  
while(nStartPos < nEndPos && !bStop) UcHJR"M~c  
{  R B  
yS'I[l  
-$ls(oot  
try{ rpha!h>w1%  
URL url = new URL(sURL); q"lSZ; 'E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -=Q*Ml#I  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~!d\^Z^i  
String sProperty = "bytes="+nStartPos+"-"; 9s q  
httpConnection.setRequestProperty("RANGE",sProperty); dFB]~QEK  
Utility.log(sProperty); GR_-9}jQP  
(mpNcOY<D  
l ukB8  
InputStream input = httpConnection.getInputStream(); CY5Z{qiX  
//logResponseHead(httpConnection); A}9`S6@@  
xJ]\+ 50  
}o(-=lF  
byte[] b = new byte[1024]; Q(?#'<.#  
int nRead; kVMg 1I@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &U#|uc!+  
{ B~ GbF*j  
nStartPos += fileAccessI.write(b,0,nRead); .*Y  
//if(nThreadID == 1) 5|s\* bV`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 013x8!i  
} #=A)XlZMd  
e X|m  
AQvudx)@"  
Utility.log("Thread " + nThreadID + " is over!"); 6A-|[(NS  
bDownOver = true; 904}Jh,  
//nPos = fileAccessI.write (b,0,nRead); G5 WVr$  
} O<?R)NH-P  
catch(Exception e){e.printStackTrace ();} 14yv$,  
} ^6V[=!& H  
} "ze|W\Bv!  
&j"?\f?  
g}cq K  
//打印回应的头信息 yR{3!{r3(  
public void logResponseHead(HttpURLConnection con) #q=Efn'  
{ +a+Om73B2  
for(int i=1;;i++) ^hM4j{|&M  
{ *.t 7G  
String header=con.getHeaderFieldKey(i); Zb>?8  
if(header!=null) <\^8fn   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f2`2,?  
Utility.log(header+" : "+con.getHeaderField(header)); VY4yS*y  
else sDlO#  
break; aEeodA<(  
} Z@!+v 19^  
} e*NnVys  
/nA{#HY  
YNF k  
public void splitterStop() BW4J>{  
{ htF] W|z  
bStop = true; T(Eugl"  
} NZ0;5xGR  
"+G8d' %YV  
2^ nxoye  
} !Wnb|=j  
0 M[EEw3  
'5$b-x6F  
/* >|UOz&  
**FileAccess.java j A%u 5V  
*//文件访问(定位,写) /*mI<[xb  
package NetFox; ^<2p~h0 \  
import java.io.*; 8&slu{M- t  
/a4{?? #e  
4|DWOQ':  
public class FileAccessI implements Serializable{ (O3nL.  
2P0*NQ   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F={a;Dvrn  
RandomAccessFile oSavedFile; UP,c|  
long nPos; 83#mB:^R  
}o`76rDN  
(f"4,b^]  
public FileAccessI() throws IOException _q-*7hCQ`  
{ `b$.%S8uj=  
this("",0); !+v$)3u9  
} o>pJPV  
SwMc pNo  
oCz/HQoBk  
public FileAccessI(String sName,long nPos) throws IOException vEJbA  
{ 9\7en%(M  
oSavedFile = new RandomAccessFile(sName,"rw"); cbTm'}R(G  
this.nPos = nPos; i9x+A/ o[  
oSavedFile.seek(nPos); /j.9$H'y  
} ;:NJCuG  
Q\Vgl(;lX  
gg2( 5FPP  
public synchronized int write(byte[] b,int nStart,int nLen) w\O;!1iU  
{ 4o[{>gW  
int n = -1; sfl<qD+?  
try{ \'O"~W  
oSavedFile.write(b,nStart,nLen); )Pv%#P-<  
n = nLen; o`-msz  
} 6Z"X}L,*  
catch(IOException e) }N52$L0[  
{ Z *x'+X  
e.printStackTrace (); j0q&&9/Jj  
} CpT jJXb  
3u0RKLc\  
r9?Mw06Wc5  
return n; dSHDWu&  
} TB31- ()  
^U/O !GK  
ZbKg~jdF  
} `Urhy#LC  
FGzwhgy  
0w7DsPdS  
/* ;!Fn1|)  
**SiteInfoBean.java q!@4~plz  
*/ pd$[8Rmj_  
package NetFox; _lq`a\7e  
Tw<q,O  
6_B]MN!(  
public class SiteInfoBean { ,PD QzJY  
MF'JeM;H  
6ik$B   
private String sSiteURL; //Site's URL o)/ 0a  
private String sFilePath; //Saved File's Path "#g}ve,  
private String sFileName; //Saved File's Name iWR)ke  
private int nSplitter; //Count of Splited Downloading File <F'\lA9  
J<lW<:!3]  
JW&gJASGC  
public SiteInfoBean() gjlx~.0d  
{//nSplitter的缺省值为5 !5!<C,U  
//default value of nSplitter is 5 {{!-Gr  
this("","","",5); Q+{n-? :  
} %(Icz ?  
*0ro0Z|Iq  
r.U`Kh]K  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^<6[.)  
{ gRzxLf`K  
sSiteURL= sURL; VIbq:U  
sFilePath = sPath; E{vbO/|kf  
sFileName = sName; N2o7%gJw  
this.nSplitter = nSpiltter; *m(=V1"  
4skD(au8  
%a7$QF]  
} e|r`/:M  
~}Pfu  
B#R|*g:x  
public String getSSiteURL() EdX$(scu~B  
{ NHE18_v5  
return sSiteURL; !VzC&>'v^9  
}  ~$J2g  
o+VQ\1as?(  
B)UZ`?>c  
public void setSSiteURL(String value) w32y3~  
{ 9- # R)4_  
sSiteURL = value; fN2lLn9/u  
} y1#1Ne_  
-:rUw$3J  
wuo,kM  
public String getSFilePath() 8 FhdN  
{ iURe([@  
return sFilePath; B-mowmJ3dg  
} 5lum$5  
|':{lH6+1  
Y4YJJYvD  
public void setSFilePath(String value) T> p&$]OG  
{ ;FEqe 49  
sFilePath = value; pK4)yu+  
} 1.>m@Slr>  
ptaKf4P^r  
lLIA w$  
public String getSFileName() @}ZVtrz  
{ 6dYMwMH  
return sFileName; "Y.y:Vv;  
} V.2_i*  
e}W)LPR!  
phz&zl D  
public void setSFileName(String value) FGkVqZ Y2?  
{ |l!aB(NW  
sFileName = value; 7[wPn`v2  
} dF2RH)Ud  
D/' dTrR  
Qg/rRiV  
public int getNSplitter() ss-D(K"  
{ e:W{OIz:  
return nSplitter; 6MI8zRX  
} 8b=_Y;  
5LMw?P.<  
LH6 vLuf  
public void setNSplitter(int nCount) }PpUAt~g  
{ _ x*3PE  
nSplitter = nCount; >R=|Wo`Ri  
} wKHBAW[i]  
} #A.@i+Zv  
54qFfN8O  
fc@A0Hf  
/* 13 wE"-  
**Utility.java 048kPXm`  
*/ DV{=n C  
package NetFox; Hx:;@_g q  
hv+zGID7  
$od7;%  
public class Utility { %XTI-B/K  
x)VJFuqy  
=\d?'dII:  
public Utility() Xm&L B X  
{ \`"ht  
']oQ]Yx0  
w*Ihk)  
} {>;R?TG]$  
L0]_X#s>#  
//线程睡眠 92-I~ !d  
public static void sleep(int nSecond) WPDyu.QD  
{ O H7FkR  
try{ =w^M{W.w  
Thread.sleep(nSecond);  S[QrS 7  
} E)3NxmM#  
catch(Exception e) C*lJrFpB  
{ 9>$p  
e.printStackTrace (); -Qe Z#w|  
} A\;U3Zu  
} .sA.C] f  
'ig'cRD6N  
//日志 :H[6Lg\*  
public static void log(String sMsg)  z$Qbj  
{ 0(btA~'*  
System.err.println(sMsg); SY8C4vb'h  
} U<-D(J  
CH/rp4NeSy  
^W@5TkkBQq  
public static void log(int sMsg) "h ^Z  
{ )CyS#j#=  
System.err.println(sMsg); 2BobH_ H  
} J-4:H gx  
} 'W#D(l9nI  
1nOCQ\$l  
bN88ua}k{  
/* |Ds=)S" K  
**TestMethod.java A(N4N  
*/ \di=  
package NetFox; R GX=)  
c"xK`%e  
UZ$/Ni  
public class TestMethod { E!AE4B1bd  
c:g'.'/*  
8i,K~Bu=  
public TestMethod() kNL\m[W8$  
{ ///xx/weblogic60b2_win.exe 0?M:6zf_iv  
try{ [8*)8jP3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _tXlF;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); . [ mR M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *9i{,I@  
fileFetch.start(); KGpA2Nx  
} ]:\dPw`A  
catch(Exception e){e.printStackTrace ();} .x1NWGDn  
KY N0  
E~:x(5'%d  
} jA/w|\d!  
D,ln)["xm  
Q3SS/eNP  
public static void main(String[] args) Y4(  
{ K4);HJ|=  
new TestMethod(); m#F`] {  
} ],v=]+R  
} o8vug$=Z  
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