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http断点续传简单实现(java)

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/* lC2xl(#!  
**SiteFileFetch.java D^u{zZy@e  
*/ 7%<jZ =  
package NetFox; ^KlOD_GN|  
import java.io.*; h~1QmEat  
import java.net.*; &A9+%kOk>  
cnj_tC=zt  
Gnw>%f1@u  
public class SiteFileFetch extends Thread { nGf@zJDb  
E|TzrH  
3_-#  
SiteInfoBean siteInfoBean = null; //文件信息Bean  O~S}u  
long[] nStartPos; //开始位置 }_;nl n?t(  
long[] nEndPos; //结束位置 N.<hZ\].=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c;e ,)$)-|  
long nFileLength; //文件长度 Grqs*V &|g  
boolean bFirst = true; //是否第一次取文件 }dxdxnVt  
boolean bStop = false; //停止标志 pr?/rXw  
File tmpFile; //文件下载的临时信息 l{R)yTO  
DataOutputStream output; //输出到文件的输出流 Pv'x|p*  
4{R`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) bcZonS  
public SiteFileFetch(SiteInfoBean bean) throws IOException X*~YCF[_  
{ yx-"YV}5  
siteInfoBean = bean; e,BJD>N ?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jyC6:BNust  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $_VD@YlAp  
if(tmpFile.exists ()) zk]~cG5dT/  
{ WIghP5%W  
bFirst = false; 8ah]D  
read_nPos(); pGFocw  
} g:EU\  
else h(L5MZs  
{ 9+:Trc\%N  
nStartPos = new long[bean.getNSplitter()]; Wama>dy%  
nEndPos = new long[bean.getNSplitter()]; lO *Hv9#  
} 4L0LT>'M\  
c"xaN  
pI`Ke"  
,?qS#B+>  
} .DQ]q o]OG  
Ojs\2('u  
L:<'TXsRA  
public void run() ;1%a:#5  
{ [>0r'-kI  
//获得文件长度 +M*a.ra0OF  
//分割文件 N_<n$3P\?f  
//实例FileSplitterFetch >O _  
//启动FileSplitterFetch线程 X]!@xlwF\  
//等待子线程返回 8vo} .JIl  
try{ fCfY.vd5  
if(bFirst) m ";gD[m  
{ !S:@x.n@iR  
nFileLength = getFileSize(); IFY !3^;zO  
if(nFileLength == -1) K"1J1>CHQ  
{ kD>vQ?  
System.err.println("File Length is not known!"); [wR8q,2  
} >W<5$.G  
else if(nFileLength == -2) U*@_T3N  
{ _X[c19q  
System.err.println("File is not access!"); z -D pLV  
} DkIF vsLK  
else [xPE?OD  
{ Pz 'Hqvd  
for(int i=0;i<nStartPos.length;i++) ,3j7Y5v  
{ Ce:ds%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b~gF,^w  
} F'I6aE%  
for(int i=0;i<nEndPos.length-1;i++) K="+2]{I  
{ ;qMlGXW*q  
nEndPos = nStartPos[i+1]; v,0DGR~  
} wLbngO=VG  
nEndPos[nEndPos.length-1] = nFileLength; i`qh|w/b_  
} `2PT 8UM  
} > =H8>X  
X\%3uPQ  
U&R$(k0zS  
//启动子线程 ^= G+]$8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _HsvF[\[  
for(int i=0;i<nStartPos.length;i++) sYpogFfV  
{ [w f12P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [78 .%b'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %*OJRL`  
nStartPos,nEndPos,i); ,)1e+EnV&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1*h7L<#|mQ  
fileSplitterFetch.start(); "puz-W'n  
} Xdt+ \}\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K }BX6dA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w C"%b#(}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S41>VbtEp  
nEndPos = " + nFileLength); P{18crC[1  
// fileSplitterFetch[nPos.length-1].start(); DF2&j!  
Ysu/7o4  
5ov%(QI  
//等待子线程结束 :(Bi {cw  
//int count = 0; ^~l<N@  
//是否结束while循环 3;:V1_JA  
boolean breakWhile = false; ^q\zC%.  
LS'=>s"  
U@nwSfp:G  
while(!bStop) E6M: ^p*<  
{ #9OP.4  
write_nPos(); *.g?y6d  
Utility.sleep(500); P hu| hx<  
breakWhile = true; ISew]R2  
VKz<7K\/  
c ?XUb[  
for(int i=0;i<nStartPos.length;i++) UI C? S  
{ M7,MxwZ0k  
if(!fileSplitterFetch.bDownOver) 0h4}RmS  
{ -QDgr`%5  
breakWhile = false; 0(x@ NGb>{  
break; o[hP&9>q  
} #Ca's'j&f  
} N1~$ +  
if(breakWhile) ~-wJ#E3g  
break; 9'g{<(R]  
/g'-*:a  
Ws)X5C=A  
//count++; ue<<Y"NR  
//if(count>4) WG}CPkj  
// siteStop(); - oBas4J  
} yX3H&F6  
Ba|}C(Ws?  
i0Q _f!j  
System.err.println("文件下载结束!"); Eu.qA9,@U  
} @H0%N53nE  
catch(Exception e){e.printStackTrace ();} #l#[\6  
} MmH_gR  
KxmPL  
fMPq  
//获得文件长度 Q0Qm0B5eY  
public long getFileSize() k<zGrq=8J  
{ 2Q|*xd4B^  
int nFileLength = -1; UMQW#$~C{g  
try{ 3}{5 X'  
URL url = new URL(siteInfoBean.getSSiteURL()); 5'Jh2r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N('DIi*or  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,9wenr  
}, &,Dt  
<<5 :zlb  
int responseCode=httpConnection.getResponseCode(); |!5T+H{Sj  
if(responseCode>=400) 9w;J7jgOT!  
{ :;q_f+U  
processErrorCode(responseCode); .y9rM{h}b  
return -2; //-2 represent access is error fhIj+/{_O  
} }lUpC}aq_  
XqS*;Zj0  
Ty0T7D   
String sHeader; 8t: &#h  
1idjX"'  
w <>6>w@GZ  
for(int i=1;;i++) OMI!=Upz  
{ pkfOM"5'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Po11EZa$a  
//Utility.log(in.readLine()); \*!%YTZ~  
sHeader=httpConnection.getHeaderFieldKey(i); ^}/ E~Sg7\  
if(sHeader!=null) o/ g+Z  
{ 6Y_O^f  
if(sHeader.equals("Content-Length")) k.xv+^b9Q  
{ =>}.W:=  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); GHC?Tp   
break; uj9tr`Zh  
} 7M#$: Fdb  
} u4,X.3V]A  
else b}&7~4zw  
break; +}XL>=-5  
} ciGpluQF  
} tZu*Asx7  
catch(IOException e){e.printStackTrace ();} N' $DE  
catch(Exception e){e.printStackTrace ();} v7<S F  
Prb_/B Dd  
h9BD ^j  
Utility.log(nFileLength); a;'E}b{`F  
x #X#V\w=  
A6UdWK  
return nFileLength; a}qse5Fr  
} M`+e'vdw  
k CW!m  
_E1]cbIo  
//保存下载信息(文件指针位置) Hdbnb[e  
private void write_nPos() UK~B[=b9  
{ 9p\Hx#^  
try{ 7hN6IP*so  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Dj ]Hgg  
output.writeInt(nStartPos.length); q"LJwV}W  
for(int i=0;i<nStartPos.length;i++) y }&4HrT&  
{ <% 7P  
// output.writeLong(nPos); xngeV_xc2  
output.writeLong(fileSplitterFetch.nStartPos); N{ V5 D  
output.writeLong(fileSplitterFetch.nEndPos); &!DZW 5  
} F;Q_*0mIQ  
output.close(); MX`Wg  
} j*H;a ?Y  
catch(IOException e){e.printStackTrace ();} \5_P5q:`  
catch(Exception e){e.printStackTrace ();} h%1~v$W`  
} `gt&Y-  
Q3Z%a|3W  
H#|Z8^ *Ds  
//读取保存的下载信息(文件指针位置) }} ``~  
private void read_nPos() x?f0Hk+  
{ 3Zaq#uA  
try{ L* k hj3;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8yE%X!E  
int nCount = input.readInt(); bQXc IIa{  
nStartPos = new long[nCount]; iz9\D*or  
nEndPos = new long[nCount]; X"TUe>cM  
for(int i=0;i<nStartPos.length;i++) T\2) $  
{ M2;%1^  
nStartPos = input.readLong(); OK M\"A4  
nEndPos = input.readLong(); OAW=Pozr9  
} D%;wVnU w  
input.close(); (0OSGG9  
} J@ktj(  
catch(IOException e){e.printStackTrace ();} \'; t*  
catch(Exception e){e.printStackTrace ();} pcRF: ~TE  
} W>}Qer4  
e0v9uQ%F5  
` $.X[\*U  
private void processErrorCode(int nErrorCode) [j:}=:feQ  
{ d s|8lz,  
System.err.println("Error Code : " + nErrorCode); tp1KP/2w[  
} 9Qt)m fqM  
2I]]WBW#:  
.8T\Nr\~2  
//停止文件下载 eW%L$I  
public void siteStop() I"8d5a}  
{ 6P%<[Z  
bStop = true; ilDJwZg#  
for(int i=0;i<nStartPos.length;i++) < -Hs<T|tW  
fileSplitterFetch.splitterStop(); :b<-[8d&  
mD D4_E2*  
_l#3]#  
} ERp:EZ'  
} oF%^QT"R  
//负责部分文件的抓取 gB/;clCdX)  
**FileSplitterFetch.java }yx=(+jP  
*/ /e.FY9  
package NetFox; ur/Oc24i1n  
H o4B   
r+p@X  
import java.io.*; d3EjI6R*z  
import java.net.*; tSEA999  
(@ %XWg  
"C:rTIH  
public class FileSplitterFetch extends Thread { PU^[HC*K  
W:VW_3  
F3r S6_  
String sURL; //File URL 8`:M\*  
long nStartPos; //File Snippet Start Position `j"4:  
long nEndPos; //File Snippet End Position u{g]gA8s  
int nThreadID; //Thread's ID 5*JV )[  
boolean bDownOver = false; //Downing is over }x:\69$  
boolean bStop = false; //Stop identical 2-8YSHlh  
FileAccessI fileAccessI = null; //File Access interface "NxOOLL  
pGY [f@_x-  
t *o7,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException m5e\rMN~>\  
{ ?D1x;i9<  
this.sURL = sURL; tegOT]|  
this.nStartPos = nStart; 8'3"uv  
this.nEndPos = nEnd; i Bi7|  
nThreadID = id; /t$rX3A  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~J%R-{U9  
} jZa25Z00  
zTkFX67)  
'GrRuT<  
public void run() h^['rmd  
{ $TR=3[j  
while(nStartPos < nEndPos && !bStop) L5R `w&Up  
{ ov1Wr#s  
1T!cc%ah  
+*n] tlk  
try{ "=9-i-K9B  
URL url = new URL(sURL); 3b<: :t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c L?\^K)  
httpConnection.setRequestProperty("User-Agent","NetFox"); xy2\'kS`G  
String sProperty = "bytes="+nStartPos+"-"; h{\t*U 54'  
httpConnection.setRequestProperty("RANGE",sProperty); DD2adu^  
Utility.log(sProperty); )i&%cyZw  
,r@xPZPz:e  
*:?QB8YJ  
InputStream input = httpConnection.getInputStream(); *f{7  
//logResponseHead(httpConnection); g+igxC}2z  
/d[Mss  
>g=^,G}y  
byte[] b = new byte[1024]; TKK,Y{{  
int nRead; 1d`cTaQ-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z|uOJ0uK  
{ ]n~yp5Nbr  
nStartPos += fileAccessI.write(b,0,nRead); 4/b(Y4$,[r  
//if(nThreadID == 1) 5n:nZ_D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !zU/Hq{wcK  
} N A8 sN  
_jW>dU^B  
9p5= _  
Utility.log("Thread " + nThreadID + " is over!"); yGRR8F5>(  
bDownOver = true; M/*Bh,M`  
//nPos = fileAccessI.write (b,0,nRead); *K`x;r  
} iM8sX B  
catch(Exception e){e.printStackTrace ();} ^#2xQ5h  
} Umij!=GPG^  
} nZ~kZ |VS  
[@ILc*2O  
1^S'sWwe  
//打印回应的头信息 Xj%,xm>}!u  
public void logResponseHead(HttpURLConnection con) en%J!<&W{K  
{ NJk)z&M  
for(int i=1;;i++) ^ s=*J=k  
{ \/n+j!  
String header=con.getHeaderFieldKey(i); ~)_K"h.DY  
if(header!=null) b(/j\NWC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *u}'}jC1X  
Utility.log(header+" : "+con.getHeaderField(header)); f`,-b  
else 7"#f!.E  
break; u >4ArtF  
} GKCM|Y  
} +N7"EROc  
J||E;=%f-Q  
zOL;"/R  
public void splitterStop() wE?CvL  
{ >:%BNeO  
bStop = true; 02(h={  
} ZvH?3Jy  
0 k9<&  
CG.,/]_  
} S"Kq^DN  
f9a$$nb3`  
RtwUb(wn6  
/* |U EC  
**FileAccess.java "-P/jk  
*//文件访问(定位,写) f}2;N  
package NetFox; Je 31".  
import java.io.*; lY8`5Uz  
g>yry}>04%  
(vnoP< 0  
public class FileAccessI implements Serializable{ &sdx`,  
"H$@b`)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ctHEEFWm  
RandomAccessFile oSavedFile; |kseKZ3  
long nPos; *,&S',S-  
9n"V\e_R  
Kr]z]4.d@  
public FileAccessI() throws IOException 4v Lw?_".  
{ >L=;"+B0U&  
this("",0); modC6d%  
} t0.;nv@A0  
e}e6r3faz  
r%|A$=[Q  
public FileAccessI(String sName,long nPos) throws IOException @D]lgq[  
{ \E77SO,$  
oSavedFile = new RandomAccessFile(sName,"rw"); 0<Q*7aY  
this.nPos = nPos; o,*=$/or  
oSavedFile.seek(nPos); x6v,lR  
} BPewc9RxV  
P$OUi!"  
xCq'[9oU  
public synchronized int write(byte[] b,int nStart,int nLen) tDt :^Bc  
{ <h@]Ri  
int n = -1; SO_>c+Dw  
try{ s4bv;W  
oSavedFile.write(b,nStart,nLen); -?z\5 z  
n = nLen; @$c!/  
} @Z q[e   
catch(IOException e) G\ex^&M  
{ ,56;4)cv  
e.printStackTrace (); WqQU@sA  
} Ha218Hy0W  
MMd.0JuaO  
`XgFga)  
return n;  n}OU Y  
} ?-,6<K1  
96}eR,  
1qZG`Vz  
} >pdnCv_c  
O:YJ%;w  
ZLrHZhP-+  
/* GW/WUzK  
**SiteInfoBean.java RX>2~^  
*/ *)D1!R<\,R  
package NetFox; :j,}{)5=  
$DE&J4K  
" #v%36U  
public class SiteInfoBean { PIxjM>  
p9iu:MucD<  
P)hi||[  
private String sSiteURL; //Site's URL esI'"hVJ  
private String sFilePath; //Saved File's Path I_>`hTiR  
private String sFileName; //Saved File's Name kceyuD$3G  
private int nSplitter; //Count of Splited Downloading File y/tSGkMv  
#xp(B5  
Mk5RHDh  
public SiteInfoBean() sLhDO'kM  
{//nSplitter的缺省值为5 RRzP* A%=  
//default value of nSplitter is 5 W;TJenv  
this("","","",5); = F<:}Tx)C  
} x7$ax79ly  
Hi8Y6|y$D  
t!qwxX*$T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y-a|Lu*  
{ ^l(^z fsZ  
sSiteURL= sURL; ^P$7A]!  
sFilePath = sPath; HeozJ^u\?  
sFileName = sName; l"\uf(0K  
this.nSplitter = nSpiltter; U=m=1FYaG  
m&/=&S  
Mudrg[@ `  
} g>n0z5&TNF  
A[JM4x   
ir&.Z5=  
public String getSSiteURL() "DpKrVuG  
{ I$j|Rq  
return sSiteURL; J-XTN"O  
}  zy>}L #  
ch })ivFP[  
>nM%p4E  
public void setSSiteURL(String value) UA(;fZ@  
{ ]w[ThHRJ  
sSiteURL = value; 6fGK (r  
} J?D\$u:  
rQj~[Y.c  
BIfi:7I;Q  
public String getSFilePath() 2f..sNz  
{ hSMV&Cs  
return sFilePath; P%)b+H{$h  
} 38Efp$)  
X| <yq  
fj+O'X  
public void setSFilePath(String value) !^v\^Fc  
{ WQKj]:qk0  
sFilePath = value; OKPJuV`y6  
} % rcFT_  
jBRPR R0  
1X&B:_  
public String getSFileName() vGN3 YcH  
{ ;J=:IEk  
return sFileName; l &Z(K,6  
} MZ~.(&  
1VLLo~L%  
SdI1}&  
public void setSFileName(String value) KY+]RxX  
{ ipZHSA  
sFileName = value; w+_Wc~f  
} @a(oB.i  
3_zSp.E\l  
W4vBf^eC  
public int getNSplitter() o](.368+4  
{ x)R0F\_  
return nSplitter; F$yeF^\g  
} . r `[  
T2|:nC)@  
ML= z<u+  
public void setNSplitter(int nCount) 5-w:c>  
{ 9h&yuS'Yj  
nSplitter = nCount; NvHN -^2  
} X9~p4ys9{  
} {^m5#f 0"  
P(;Mb{  
|-61(X.  
/* %nQmFIt  
**Utility.java %3G;r\|r]  
*/ P) 1 EA;  
package NetFox; HNMBXXf, B  
6"%2,`Nu  
/ O)6iJ  
public class Utility { >{XScxaB`  
m6MaX}&zv  
-*3(a E  
public Utility() ]l&'k23~p  
{ -tyaE  
ke6n/ h5`  
X6kaL3L}  
} SQ<f  
j_c+.iET  
//线程睡眠 `M]BhW)  
public static void sleep(int nSecond) PL@7 KD Q  
{ UABbcNW  
try{ tJm{I)G  
Thread.sleep(nSecond);  MYx88y  
} 4)nt$fW  
catch(Exception e) aAcKwCGq\  
{ }) 7K S?  
e.printStackTrace (); /7vE>mSY  
} ]]y[t|6  
} PbN3;c3  
hBy*09Sv  
//日志 ,qu:<  
public static void log(String sMsg) s41adw>  
{ T#r=<YH[C  
System.err.println(sMsg); {(0Id!  
} +XQP jg  
tqhh<u;  
'!@A}&]  
public static void log(int sMsg) Pz1G<eh#{g  
{ mu>] 9ZW  
System.err.println(sMsg); UR,?!rJ^B  
} }.t^D|  
} {*fUJmao"  
W5X7FEW  
=mLeMk/7 w  
/* Xi+n`T'i  
**TestMethod.java KBj@V6Q  
*/ r0uJ$/!  
package NetFox; )f[C[Rd  
kQ[Jo%YT?E  
WKOI\  
public class TestMethod { y($EK(cb  
i'iO H|s  
t%HI1eO7h  
public TestMethod() Y{j7Q4{  
{ ///xx/weblogic60b2_win.exe /+29.1#|  
try{ m{O Dz :  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PJ;.31u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '}CN?f|.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); SctJxY(}!  
fileFetch.start(); $>![wZ3  
} SdSgn|S  
catch(Exception e){e.printStackTrace ();} A$ J9U3+O  
yWmrdvL  
9BO|1{  
} ,3k@L\$.x  
0}D-KvjyP  
4uPH  
public static void main(String[] args) H7}g!n?  
{ >~^`5a`$uI  
new TestMethod(); iel-<(~   
} 6N?#b66  
} 1y~L8!: L  
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