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http断点续传简单实现(java)

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/* }^|g|xl!  
**SiteFileFetch.java a=(D`lQ8  
*/ '@4M yg* b  
package NetFox; N?cvQR{r9  
import java.io.*; S0,q@LV  
import java.net.*; W?y7mw_S  
K%NNw7\A  
ZL!,s#  
public class SiteFileFetch extends Thread { Ze `=n  
bf1Tky=/  
+tsF.Is!t  
SiteInfoBean siteInfoBean = null; //文件信息Bean _5<d'fBd  
long[] nStartPos; //开始位置 p mv6m  
long[] nEndPos; //结束位置 XO[S(q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W5C8$Bqm  
long nFileLength; //文件长度 {wUbr^  
boolean bFirst = true; //是否第一次取文件 _v~c3y).  
boolean bStop = false; //停止标志 +ucj>g1(#  
File tmpFile; //文件下载的临时信息 G- _h 2  
DataOutputStream output; //输出到文件的输出流 Y"Y%JJ.J  
W 7xh  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) zNAID-5K;  
public SiteFileFetch(SiteInfoBean bean) throws IOException ' i- 6JG%  
{ m9yi:zT%  
siteInfoBean = bean; ?D 8<}~Do  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EPEy60Rx5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M%(B6};J  
if(tmpFile.exists ()) 'p%aHK{  
{ N.\?"n   
bFirst = false; ;/ wl.'GA  
read_nPos(); X<:B"rPuK  
} ~_l@ _P5yz  
else -PfBL8  
{ 54[#&T$S  
nStartPos = new long[bean.getNSplitter()]; Sq#AnD6To  
nEndPos = new long[bean.getNSplitter()]; x/BtB"e*5  
} VU8EjuOetb  
c@SNbY4}%  
}sy^ed  
GvAP  
} U}#3 LFr.?  
%"<|u)E  
Y.}"<{RQ  
public void run() /l.:GH36f  
{ 4OX2GH=W  
//获得文件长度 hc"l^a!7ic  
//分割文件 AN193o   
//实例FileSplitterFetch { XI0KiE  
//启动FileSplitterFetch线程 Lzr&Q(mL  
//等待子线程返回 F~bDA~  
try{ v,T :V#f^  
if(bFirst) " V[=U13  
{ 9Hu;CKs  
nFileLength = getFileSize(); }I}/e v  
if(nFileLength == -1) .[8! E_  
{ /,C;fT<R  
System.err.println("File Length is not known!"); {oXU)9vj  
} 3(2WO^zX {  
else if(nFileLength == -2) H1bHQB  
{ fnXYp !  
System.err.println("File is not access!"); <x!q! ;  
} (-}:'5|Yj  
else GG0H3MSc  
{ ppm =o4`s[  
for(int i=0;i<nStartPos.length;i++) _sp, ,gz  
{ ;s*   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jF$bCbAUce  
} z6IOVQ*r  
for(int i=0;i<nEndPos.length-1;i++) _h6j, )  
{ <QuIXA  
nEndPos = nStartPos[i+1]; V8w7U:K  
} 8+f{ /  
nEndPos[nEndPos.length-1] = nFileLength; rCK   
} %>p[;>jW  
} G_m$?0\  
]!c59%f=  
r5RUgt  
//启动子线程 J# >)+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a/\SPXQ/9  
for(int i=0;i<nStartPos.length;i++) x5w5xw  
{ &nV/XLpG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lQS(\}N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^cUmLzM  
nStartPos,nEndPos,i); "h@=O c  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #r|qi tL3  
fileSplitterFetch.start(); R\a6 #u3  
} <<=.;`(/v  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aM7e?.rU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); cyMvjzzRN  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", u1}/SlCp  
nEndPos = " + nFileLength); K N Y  
// fileSplitterFetch[nPos.length-1].start(); )_&P:;N  
%K`th&331  
bIWSNNV0F  
//等待子线程结束 JpRn)e'Z  
//int count = 0; 4Wd H!z  
//是否结束while循环 adcH3rV  
boolean breakWhile = false; A`B>fI  
U F&B7r  
/~(T[\E<  
while(!bStop) 6%a9%Is!O  
{ -Qy@-s $  
write_nPos(); ]x1;uE?1J  
Utility.sleep(500); &lCOhP#  
breakWhile = true; a1>Tz  
sSLV R^  
P5JE = &M  
for(int i=0;i<nStartPos.length;i++) bJ"}-s+Dx  
{ :[:*kbWN-  
if(!fileSplitterFetch.bDownOver) UVd ^tg  
{ `@<~VWe5  
breakWhile = false; dc dVB>D  
break; &wX568o  
} Ia[4P8Z  
} \wKnX]xGf  
if(breakWhile) $$ 9!4  
break; p uZY4}b_  
Yu}[RXC(=  
'uW&AD p  
//count++; Z=m5V(9  
//if(count>4) Gw$Y`]ipy  
// siteStop(); 4wkmgS  
} A-eRL`  
!X5LgMw^;  
aBd>.]l?  
System.err.println("文件下载结束!"); qOTo p-  
} j5gL 67B  
catch(Exception e){e.printStackTrace ();} `Hx JE"/  
} _ea|E  8  
wX4gyr  
+h)1NX;o1  
//获得文件长度 U]]ON6Y&F  
public long getFileSize() ae#Qeow`  
{ S l`F`  
int nFileLength = -1; 1 )H;}%[  
try{ FvJkb!5*e_  
URL url = new URL(siteInfoBean.getSSiteURL()); cCuK?3V4K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O@>ZYA%  
httpConnection.setRequestProperty("User-Agent","NetFox"); &R))c|>OT&  
 /M@[ 8  
FfX*bqy  
int responseCode=httpConnection.getResponseCode(); NI:3hfs  
if(responseCode>=400) YO9ofT  
{ C"0vMUZ  
processErrorCode(responseCode); K8JshF Ie  
return -2; //-2 represent access is error 5^97#;Q;J"  
} ,_UTeW6M  
1{<r~  
`J$7X  
String sHeader; M1q_gHA  
#Y0ru9  
6u9?  
for(int i=1;;i++) Fr_6pEH]}  
{ q`|rS6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0iV~MQZ(  
//Utility.log(in.readLine()); Ov#G7a"  
sHeader=httpConnection.getHeaderFieldKey(i); d}2(G2z^  
if(sHeader!=null) 7lx]`u>  
{ rhDiIO_  
if(sHeader.equals("Content-Length")) 3Ct:AJeg  
{ 6 u1|pX8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); goOw.~dZ'  
break; -cWGF  
} oh7tE$"c  
} iOtf7.@  
else }Oq P`B  
break; xnDst9%  
} 6@;sOiN+  
} ,FwJ0V  
catch(IOException e){e.printStackTrace ();} HF<h-gX  
catch(Exception e){e.printStackTrace ();} z~th{4#E ;  
e!ql8wbp  
LvCX(yjZ*  
Utility.log(nFileLength); v"l8[::  
&bigLe  
r3+   
return nFileLength; ( e#f  
} .JBTU>1]_n  
*LEI@  
}"&Ye  
//保存下载信息(文件指针位置) 6!C>J#T  
private void write_nPos() M0t9`Z9  
{ #fDM{f0]R  
try{ B%WkM\\!^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); lf\^!E:  
output.writeInt(nStartPos.length); ; Kh!OBZFo  
for(int i=0;i<nStartPos.length;i++) nwVW'M]r  
{ 4>Y*owa4  
// output.writeLong(nPos); Nj.;mr<  
output.writeLong(fileSplitterFetch.nStartPos); l(HxZlHr  
output.writeLong(fileSplitterFetch.nEndPos); r&_e3#]*  
} Wjli(sT#-  
output.close(); $|N\(}R  
} ?ph>:M  
catch(IOException e){e.printStackTrace ();} MvTp%d.  
catch(Exception e){e.printStackTrace ();} x@@bC=iY$  
} 6$K@s  
3:>hHQi  
qJJ}, 4}  
//读取保存的下载信息(文件指针位置) vwzElZ{C:v  
private void read_nPos() 89m9iJ=  
{ ?z0W1a  
try{ yG^pND>_df  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `i!fg\qnK  
int nCount = input.readInt(); V ONC<wC  
nStartPos = new long[nCount]; P5W58WxT'  
nEndPos = new long[nCount]; -56gg^Pnr  
for(int i=0;i<nStartPos.length;i++) y@r0"cvz9  
{ m%b# B>J,n  
nStartPos = input.readLong(); $WO{!R  
nEndPos = input.readLong(); @SI,V8i  
} dsg-;*%  
input.close(); /CUBs!  
} Bh&dV%'  
catch(IOException e){e.printStackTrace ();} a+j"8tHu$  
catch(Exception e){e.printStackTrace ();} O"#/>hmv-  
} Ed+jSO0  
lx7]rkWo|a  
e|q~t {=9S  
private void processErrorCode(int nErrorCode) B}J0 d  
{ V{ fG~19  
System.err.println("Error Code : " + nErrorCode); j@{B 8  
} TiR00#b  
0es\ j6c  
j9X|c7|  
//停止文件下载 vnS8N  
public void siteStop() tns4e\  
{ f@k.4aS  
bStop = true; !="8ok+  
for(int i=0;i<nStartPos.length;i++) <*9(m  
fileSplitterFetch.splitterStop(); bwa*|{R  
>uDC!0)R  
&}t8O?!  
} )iJv?Y\]  
} xz~Y %Y|Z  
//负责部分文件的抓取 av_ +M;G  
**FileSplitterFetch.java z0%tBgqY(  
*/ hVl@7B~  
package NetFox; vpC?JXz=H  
/t*Q"0X5  
fYW9Zbov-  
import java.io.*; n:f&4uKoG<  
import java.net.*; =G !]_d0  
l&5Tft  
IG:2<G  
public class FileSplitterFetch extends Thread { 13 %: 3W(  
!L<z(dV|(  
rs,'vV-2\  
String sURL; //File URL hZw8*H^tP  
long nStartPos; //File Snippet Start Position 7* [  
long nEndPos; //File Snippet End Position N( f0,  
int nThreadID; //Thread's ID QP<.~^ao  
boolean bDownOver = false; //Downing is over zN=s]b=/  
boolean bStop = false; //Stop identical yMC6 Gvp  
FileAccessI fileAccessI = null; //File Access interface de;CEm<n  
Vt,P.CfdC  
zZP/C   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5#y_EpL"  
{ 13*S<\  
this.sURL = sURL; D]5j?X'  
this.nStartPos = nStart; aj/+#G2  
this.nEndPos = nEnd; d%RH]j4  
nThreadID = id; IVVX3RI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >nvnU`\  
} +"1-W> HV  
J/3$I  
skU }BUK6  
public void run() ]u:_r)T  
{ 64vj6 &L  
while(nStartPos < nEndPos && !bStop) Ktu~%)k%  
{ a!f71k r  
%xKZ" #Z#K  
+~=j3U  
try{ 4P"XT  
URL url = new URL(sURL); itg"dGDk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0g~Cdp  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3E0C$v KM  
String sProperty = "bytes="+nStartPos+"-"; Z{/GT7 /  
httpConnection.setRequestProperty("RANGE",sProperty); x&"P^gh)  
Utility.log(sProperty); p/G9P +?  
5m;BL+>YE  
GDb V y)&  
InputStream input = httpConnection.getInputStream(); g9=_^^Tg  
//logResponseHead(httpConnection); \}X[0ct2!  
.&`apQD}  
QjD=JC+  
byte[] b = new byte[1024]; 1f'msy/  
int nRead; 6!N2B[9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &C)97E  
{ gGN 6Yqj0  
nStartPos += fileAccessI.write(b,0,nRead); LDYa{w-t  
//if(nThreadID == 1) H/Rzs$pnv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  z:   
} OmK4 \_.  
nrX+  '  
i r'C(zD=  
Utility.log("Thread " + nThreadID + " is over!"); '&2-{Y [!  
bDownOver = true; 27}7 n  
//nPos = fileAccessI.write (b,0,nRead); %;|dEY  
} 6{0MprY  
catch(Exception e){e.printStackTrace ();} U9*< dR  
} ;lS sy  
} 7j29wvSp5  
z@ `u$D$n  
EWY'E;0@5  
//打印回应的头信息 ZE= Yn~XM  
public void logResponseHead(HttpURLConnection con) *xITMi  
{ Xbrc_ V\_  
for(int i=1;;i++) WJ LqH<  
{ }%<_>b\  
String header=con.getHeaderFieldKey(i); 9XhH*tBn7(  
if(header!=null) M%RH4%NZ0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &pR 8sySu  
Utility.log(header+" : "+con.getHeaderField(header)); TA qX f_  
else l?YO!$  
break; >YsM'.EFD  
} 3g5r}Ug  
} 0Wc_m;  
2m} bddS  
e,Y<$kPV  
public void splitterStop() .}uri1k"@k  
{ Y9&na&vY?  
bStop = true; x34GRe!!  
} B|8|f(tsSa  
HL dHyK/S  
nJ/}b/A{  
} rl&.|;5uH;  
)4.-6F7U?  
^FVmP d*1  
/* K4+|K:e  
**FileAccess.java 71ab&V il  
*//文件访问(定位,写) b'z\|jY  
package NetFox; XHOS"o$y  
import java.io.*; `%EcQ}Nr  
*-uzsq.W  
O{Mn\M6  
public class FileAccessI implements Serializable{ cMoJHC,!  
-t>"s'kv  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]0[ot$Da6  
RandomAccessFile oSavedFile; %iJ}H6m  
long nPos;  ls7P$qq  
%o{IQ4Lz#  
TCIbPs E  
public FileAccessI() throws IOException @8+v6z  
{ Ta/ u&t4  
this("",0); *"4l}&  
} pU[yr'D.r  
{`T^&b k  
,nGQVb   
public FileAccessI(String sName,long nPos) throws IOException TtKKU4yp  
{ ez)Ks`  
oSavedFile = new RandomAccessFile(sName,"rw"); RCxwiZaf33  
this.nPos = nPos; E H%hL5(  
oSavedFile.seek(nPos); td23Z1Elk#  
} KmM:V2@A$  
NV@$\ <  
m6]6 !_  
public synchronized int write(byte[] b,int nStart,int nLen) %DA`.Z9 #  
{ 9sd}Z,l  
int n = -1; l4(FM}0X5}  
try{ &-X51O C  
oSavedFile.write(b,nStart,nLen); 8V9OMOt!  
n = nLen; =dQ/^C_hj  
} 8.7q -<Q  
catch(IOException e) ;DVg[#  
{ :^xNHMp!  
e.printStackTrace (); *[BtW5 6-  
} P=\Hi.]%  
gW9`k,U  
|.&GmP  
return n; rKd|s7l  
} mZmEE2h  
(/!@ -]1  
~C>Q+tR8  
} _-^mxC|M  
[TFp2B~)#  
@LDs$"f9=  
/* " vc4QH$  
**SiteInfoBean.java SBf=d<j 1)  
*/ mV)t  
package NetFox; hY !>>  
ccp9nXv  
$J,$_O6  
public class SiteInfoBean { J&}1=s  
V@TA~'$|  
~l{Qz0&  
private String sSiteURL; //Site's URL LnN:;h  
private String sFilePath; //Saved File's Path B., BP  
private String sFileName; //Saved File's Name 3Co1bY:  
private int nSplitter; //Count of Splited Downloading File Msfxce  
HDKY7Yr  
Fp [49  
public SiteInfoBean() ]gm3|-EiY  
{//nSplitter的缺省值为5 G"kX#k0S  
//default value of nSplitter is 5 Q~k|lTf  
this("","","",5); : yq2 XE%r  
} wL^x9O|`p9  
; C(5lD&\5  
i[{*(Y$L  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  >;%QW  
{ lA;^c)  
sSiteURL= sURL; lN{>.q@V`r  
sFilePath = sPath; VGu(HB8n#  
sFileName = sName; .;.Zbhm  
this.nSplitter = nSpiltter; 5MZv!N   
UvB\kIH  
]#rV]As  
} E}a.qM'  
4^4T#f2=e  
B4+c3M\$V  
public String getSSiteURL() pv&iJ7RN  
{ es\ qnq  
return sSiteURL; |TkicgeS  
} @PhAg  
-U?%A:,a|  
Br&&#  
public void setSSiteURL(String value) 9F6dKPN:  
{ zb02\xvf  
sSiteURL = value; &jQqlQ j  
} a|[f%T<<  
3u^wK  
#N64ZXz_  
public String getSFilePath() :,R>e}lM  
{ fQg^^ZXe"  
return sFilePath; zxx9)I@?A  
} A&%7Z^Pp  
SkVah:cF-  
DB_oRr[oj  
public void setSFilePath(String value) (b&Z\?"  
{ W[]|Uu/%  
sFilePath = value; [fb9;,x`  
} ^^tTA^  
c'Z)uquvP  
TL7qOA7^X  
public String getSFileName() h^`@%g9 S  
{ MBKF8b'k  
return sFileName; kApDD[ N  
} 8oRq3"  
P c5C*{C  
|E||e10wR  
public void setSFileName(String value) d7zZ~n  
{ B> \q!dX3  
sFileName = value; 0oBAJP  
} 0]]OE+9<c  
ba ,n/yH  
o_kZ  
public int getNSplitter() _ D8 zKp  
{ ;p fN  
return nSplitter; FYefn3b  
} .'2I9P\!  
x;~@T9.  
AE`{k-3=%  
public void setNSplitter(int nCount) Qm"~XP  
{ ;:J"- p  
nSplitter = nCount; /7,@q?v  
} `_ZbA#R,  
} 48G^$T{  
BC1smSlJ  
$ kMe8F_  
/* /~fu,2=7  
**Utility.java erTly2-SJ  
*/ 5xNOIOpDB  
package NetFox; a[sdYZ  
S==0/  
0QrRG$<4X  
public class Utility { R3)ccom  
AxTFV ot  
o: > (Tv  
public Utility() mRGr+m  
{ nKtRJ,>  
 :fy,%su  
_z.CV<  
} p}wysVB  
j>v8i bS(  
//线程睡眠 T xpj#JD  
public static void sleep(int nSecond) hg'eSU$J  
{ d& v 7l  
try{ J<Ki;_=I  
Thread.sleep(nSecond); O(.eHZ=  
} h2:TbQ  
catch(Exception e) qxZf!NX5  
{ np}0O  X  
e.printStackTrace (); Tgi7RAY  
} <dBz]W  
} vQ $"|8,  
1 un!  
//日志 1}ifJ~)5S  
public static void log(String sMsg) tO"AeZe%|  
{ 4U'sBaY!K  
System.err.println(sMsg); HyYJ"54  
} q_BMZEM  
IM2<:N%'  
#E<~WpP  
public static void log(int sMsg) j{=}?+M  
{ I\j-  
System.err.println(sMsg); Zny9TP  
} {%, 4P_m  
} ;9J6)zg !n  
61HJ%  
5,|{|/  
/* Fy.!amXu  
**TestMethod.java N"~P$B1 X  
*/ r(n>N0:0Ls  
package NetFox; v6=X]Ji{YA  
^hT2 ed +  
V$u:5"qu0  
public class TestMethod { I_`NjJ;61  
/@DJf\`vM  
$h=v ;1"  
public TestMethod() vJx( lU`Y  
{ ///xx/weblogic60b2_win.exe (gcy3BX;  
try{ |&bucG=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @|'9nPern  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V^}$f3\B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6bf!v  
fileFetch.start(); ~ySsv  
} ZR{YpLFQ  
catch(Exception e){e.printStackTrace ();} evVxzU&  
8S[bt@v  
u`!Dp$P  
} ~= otdJ  
U2Ky4UFm  
%y)hYLOJ  
public static void main(String[] args) i.-2 w6  
{ CWd &  
new TestMethod(); O\%0D.HEz  
} v&f\ Jv7  
} <fMQ#No  
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