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http断点续传简单实现(java)

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/* {j!+\neL  
**SiteFileFetch.java oasEG6OI8  
*/ 5*P+c(=  
package NetFox; w_hN2eYo&e  
import java.io.*; =>en<#[\:  
import java.net.*; >Ndck2@  
#cdrobJ  
~;uc@GGo  
public class SiteFileFetch extends Thread { m2h@*  
unZYFA}(  
RwyRPc _  
SiteInfoBean siteInfoBean = null; //文件信息Bean `Eq~W@';Q0  
long[] nStartPos; //开始位置 MeMSF8zSQ  
long[] nEndPos; //结束位置 NPY\ >pf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f&ri=VJY\T  
long nFileLength; //文件长度 U2TR>0l  
boolean bFirst = true; //是否第一次取文件  VsR8|Hn$  
boolean bStop = false; //停止标志 L^><APlX  
File tmpFile; //文件下载的临时信息 DJ.n8hne  
DataOutputStream output; //输出到文件的输出流 M>LgEc-v67  
Vq>$ZlvS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 4k4 d%  
public SiteFileFetch(SiteInfoBean bean) throws IOException G,fh/E+  
{ 'En|-M5  
siteInfoBean = bean; " s3eO  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *uG!U%jY)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eemw I  
if(tmpFile.exists ()) D_2~ 6  
{ 9Impp5`/B  
bFirst = false; uW4wTAk;qh  
read_nPos(); A$ Tp0v`t  
} H68~5lJY^]  
else S#{gCc  
{ |b^+= "  
nStartPos = new long[bean.getNSplitter()]; T\3a T  
nEndPos = new long[bean.getNSplitter()]; /t"F Z#  
} O4lHR6M2  
vn"+x_  
p^>_VE[S  
m?)REE  
} x_VD9  
y Nc"E  
14Y<-OO: k  
public void run() @B#\3WNt  
{ s. ]<r5v7  
//获得文件长度 n4%ZR~9WH  
//分割文件 4SDUTRo a  
//实例FileSplitterFetch ~>-MVp  
//启动FileSplitterFetch线程 *JT,]7>  
//等待子线程返回 tkj QSz  
try{ ":!7R<t  
if(bFirst) NcMohpkq  
{ vj,OX~|  
nFileLength = getFileSize(); 43m@4Yb  
if(nFileLength == -1) 6#gS`X23Y  
{ d.Im{-S  
System.err.println("File Length is not known!"); aTLu7C\-e  
} INjr$'*  
else if(nFileLength == -2) 8;\  
{ m]Gxep0%  
System.err.println("File is not access!"); ewrs D'?  
} x,81#=m^h  
else ::`#qa4!  
{ $LkTu  
for(int i=0;i<nStartPos.length;i++) 734f &2  
{ 0s'h2={iI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); bpgvLZb>s  
} z}z 6Vg  
for(int i=0;i<nEndPos.length-1;i++) T0TgV  
{ ($or@lfs  
nEndPos = nStartPos[i+1]; =9yh<'583  
} T j(MIFi|5  
nEndPos[nEndPos.length-1] = nFileLength; Z`]r)z%f  
} ms%RNxU4:  
} hteAuz4H  
4}xw&x  
<reALC  
//启动子线程 0Fc^c[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0ub0 [A  
for(int i=0;i<nStartPos.length;i++) >K;DBy*  
{ =IH~:D\&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o|G[/o2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XDQ5qfE|  
nStartPos,nEndPos,i); c$P68$FB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A}3dx!?7j  
fileSplitterFetch.start(); 7U647G(Sg  
} `p'682xI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +S6(Fvp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;lP/hG;`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ? dh  
nEndPos = " + nFileLength); ;k |U2ajFJ  
// fileSplitterFetch[nPos.length-1].start(); D8 BmC  
{3`cSm6c  
RIdh],-  
//等待子线程结束 +=MN_  
//int count = 0; N> jQe  
//是否结束while循环 C116 c"  
boolean breakWhile = false; j@u]( nf  
Ek6z[G` O  
%5$)w;p.$'  
while(!bStop) mJNw<T4!/  
{ E^4}l2m_  
write_nPos(); O;lGh1.  
Utility.sleep(500); WRov7  
breakWhile = true; [jEZ5]%  
iu.v8I ;<  
B? Z_~Bf&  
for(int i=0;i<nStartPos.length;i++) 9T#${NK  
{ %EH{p@nM&-  
if(!fileSplitterFetch.bDownOver) ~YRG9TK  
{ oH='\M%+  
breakWhile = false; zQ~ax!}R  
break; Ms 3Sri  
} u*=8s5Q[  
} 572{DC&T  
if(breakWhile) [nASMKK0  
break; m gE r+  
).3riR  
3 63KU@`  
//count++; e|}B;<  
//if(count>4) B",;z)(%  
// siteStop(); z_8lf_N  
} .+(R,SvN%<  
%k'>bmJ  
<&RpGAk%I  
System.err.println("文件下载结束!"); \2))c@@%  
} \,S4-~(:!  
catch(Exception e){e.printStackTrace ();} /b7]NC%  
} gY&WH9sp?9  
bRD-[)  
)uu(I5St  
//获得文件长度 +L|x^ B3  
public long getFileSize() b/"gUYo  
{ >@)p*y.K  
int nFileLength = -1; $f?GD<}?7r  
try{ w ZfY~  
URL url = new URL(siteInfoBean.getSSiteURL()); |Kb m74Z%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FBxg^g%PB@  
httpConnection.setRequestProperty("User-Agent","NetFox"); MfZamu5+F  
bae;2| w  
Y'<wE2ZL)  
int responseCode=httpConnection.getResponseCode(); 3Fw7q"  
if(responseCode>=400) :cvT/xhO  
{ G=/^]E  
processErrorCode(responseCode); #y-R*4G  
return -2; //-2 represent access is error Du #>y!  
} Cto>~pV  
c] -  
7M)<Sv  
String sHeader; E#R1  
o3$dl`'  
I0*N "07n  
for(int i=1;;i++) X-*LA*xbN  
{ fjCFJ_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d$^ @$E2f  
//Utility.log(in.readLine()); y* :C~  
sHeader=httpConnection.getHeaderFieldKey(i); U@9v(TfV  
if(sHeader!=null) &F:%y(;{Y  
{ WjguM  
if(sHeader.equals("Content-Length")) :T{VCw:*  
{ gBr /Y}I  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1~Z   
break; K@%gvLa\  
} xX|f{)<  
} =QK ucLo  
else 2H1 [ oD[  
break; _(-i46x}  
} R"j<C13;%  
} CG;+Z-"X  
catch(IOException e){e.printStackTrace ();} g:Q:cSg<  
catch(Exception e){e.printStackTrace ();} {n&GZG"f  
Id1de>:;  
orOq5?3  
Utility.log(nFileLength); EU Z7?4o  
 ~)F_FS  
osc A\r  
return nFileLength; fZoQQ[s  
} :k-@w5(  
g/(BV7V  
*eGG6$I  
//保存下载信息(文件指针位置) Zv2]X-  
private void write_nPos() G5%k.IRz  
{ _0BQnzC=  
try{ 2}XxRJ0   
output = new DataOutputStream(new FileOutputStream(tmpFile)); c/^l2CJ0  
output.writeInt(nStartPos.length); 4 |bu= T  
for(int i=0;i<nStartPos.length;i++) Y9I|s{~  
{ h^v#?3.@  
// output.writeLong(nPos); Ii# +JY0k  
output.writeLong(fileSplitterFetch.nStartPos); l$[,V:N  
output.writeLong(fileSplitterFetch.nEndPos); 1]9l SE!E7  
} #0?3RP  
output.close(); y|=KrvMHJ  
} R;pIi/yDRe  
catch(IOException e){e.printStackTrace ();} BNe>Lko  
catch(Exception e){e.printStackTrace ();} ~^'WHuz Py  
} ?gBFfi  
~k%XW$cV  
ayh235>a(  
//读取保存的下载信息(文件指针位置) -BSO$'{7  
private void read_nPos() .K1wp G[4  
{ FY-eoq0O3  
try{ 9kwiG7V1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Nv|0Z'M  
int nCount = input.readInt(); f|ERZN`uB  
nStartPos = new long[nCount]; \GV'{W+o2  
nEndPos = new long[nCount]; ;O|u`fAqT  
for(int i=0;i<nStartPos.length;i++) Rn`DUYg  
{ 9R">l5u  
nStartPos = input.readLong(); 4 L 5$=V  
nEndPos = input.readLong(); JP(0/?Q  
} | #b/EA9  
input.close(); qQIX:HWDKZ  
} 8)M WC:  
catch(IOException e){e.printStackTrace ();} !@*= b1  
catch(Exception e){e.printStackTrace ();} {6%-/$LX  
} scTt53v^  
4;@L#Pzt  
Z +O< IF%  
private void processErrorCode(int nErrorCode) <EdNF&S-  
{ C9_[ke[1D  
System.err.println("Error Code : " + nErrorCode); xB]^^ NYE=  
} a_]l?t  
CMyz!jZ3  
K"hnGYt?  
//停止文件下载 >^IUS8v  
public void siteStop() ktRGl>J  
{ *yY\d.6(  
bStop = true; GZHJ 4|DK  
for(int i=0;i<nStartPos.length;i++) u%6b|M@P  
fileSplitterFetch.splitterStop(); LM 1Vsh<  
.;S1HOHz4  
d^v.tYM$N  
} k2.k}?w!JO  
} L4ct2|w}ul  
//负责部分文件的抓取 yY*(!^S  
**FileSplitterFetch.java Z$r7Hi  
*/ ur7S K(#  
package NetFox; (Q&O'ng1  
@6%7X7m  
}$sTnea  
import java.io.*; mi7~(V>  
import java.net.*; KfYT  
vT @25  
W`P>vK@=  
public class FileSplitterFetch extends Thread { :."6g)T  
I[?bM-  
sl(go^  
String sURL; //File URL ic4hO>p&  
long nStartPos; //File Snippet Start Position 4@Z!?QzW  
long nEndPos; //File Snippet End Position E$ &bl  
int nThreadID; //Thread's ID +WKN&@  
boolean bDownOver = false; //Downing is over KfPgj  
boolean bStop = false; //Stop identical y&eU\>M  
FileAccessI fileAccessI = null; //File Access interface UR S=1+  
rQ6>*0xL_  
Pp_? z0M  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .>~er?-  
{ U_.}V  
this.sURL = sURL; m8G/;V[x  
this.nStartPos = nStart; fU\;\  
this.nEndPos = nEnd; a,)/D_{1  
nThreadID = id; ksJ 1:_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ImD&~^-_<  
} 'NCx<0*  
VR%*8=  
,rF!o_7  
public void run() 'H4?V  
{ B2KBJ4rI[1  
while(nStartPos < nEndPos && !bStop) FFe{=H,=  
{ J\p-5[E  
B/^o$i  
H0yM`7[y  
try{ e 'F:LMX  
URL url = new URL(sURL); sY?wQ:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); rx@i .+  
httpConnection.setRequestProperty("User-Agent","NetFox"); !, rF(pz  
String sProperty = "bytes="+nStartPos+"-"; D~|q^Ms,%  
httpConnection.setRequestProperty("RANGE",sProperty); 5*Qzw[[=  
Utility.log(sProperty); Y7 K2@257  
iel@"E 4  
9 '(m"c_  
InputStream input = httpConnection.getInputStream(); "DH>4Q] d  
//logResponseHead(httpConnection); U!K#g_}  
QUfF>,[sv  
W7@Vma`  
byte[] b = new byte[1024]; &3x da1H  
int nRead; ?^^TR/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) uq7/G|  
{ -j:yEZ4Oy  
nStartPos += fileAccessI.write(b,0,nRead); GU9p'E  
//if(nThreadID == 1) .2_xTt   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m(EV C}Y  
} :S7[<SwL  
57]La^#  
X?JtEQ~>  
Utility.log("Thread " + nThreadID + " is over!"); p,uM)LD  
bDownOver = true; h?} S|>9  
//nPos = fileAccessI.write (b,0,nRead); T &bB8tQk  
} a<>cbP  
catch(Exception e){e.printStackTrace ();} l<ZHS'-;8  
} 2R^Eea  
} =UWW(^M#[:  
{sj{3Iu  
aGws?<1$  
//打印回应的头信息 'z)cieFKP  
public void logResponseHead(HttpURLConnection con) {yEL$8MC  
{ <X5ge>.  
for(int i=1;;i++) $fT#Wva-\d  
{ ,t9CP  
String header=con.getHeaderFieldKey(i); -mo4`F  
if(header!=null) \%%M>4c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;XlCd[J<  
Utility.log(header+" : "+con.getHeaderField(header)); Ex@}x#3  
else qK~]au:C  
break; +qqCk  
} *P5/S8c  
} Jw^my4  
0dI7{o;<|  
,OP\^  
public void splitterStop() "?W8 o[c+  
{ !x||ObW\H  
bStop = true; )nK+`{;@!  
} i }Zz[b  
r(_Fr#Qn  
* kUb[  
} 5lM 3In@  
d-W*`:Q  
TIaiJvo  
/* gp H@F X  
**FileAccess.java Qv;b$by3  
*//文件访问(定位,写) 0AoWw-H6V  
package NetFox; MBU4Awj  
import java.io.*; No+BS%F5  
&_j<! 3*  
A1z<2.R  
public class FileAccessI implements Serializable{ 6Bexwf<u  
\yLFV9P}EL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7uF @Xh  
RandomAccessFile oSavedFile; w !<-e>  
long nPos; IlI5xkJ(  
Mii&doU  
9y} J|z  
public FileAccessI() throws IOException > %Hw008  
{ 6x/o j`_[  
this("",0); [biz[ fm  
} Zw%:mZN  
+UTBiB R  
S@~ReRew2  
public FileAccessI(String sName,long nPos) throws IOException f}ch1u>  
{ fjuPGg~  
oSavedFile = new RandomAccessFile(sName,"rw"); *#@{&Q(Qh  
this.nPos = nPos; IF<T{/MA  
oSavedFile.seek(nPos); |%3>i"Y@AK  
} 4$ah~E>,t  
A8AeM `  
1-.i^Hal  
public synchronized int write(byte[] b,int nStart,int nLen) 7qWa>fX  
{ /#L4ec-'  
int n = -1; :`<MlX  
try{ T8W^qrx.v  
oSavedFile.write(b,nStart,nLen); qDfhR`1k  
n = nLen; Z*v`kl  
} }>3jHWxLc  
catch(IOException e) at2)%V)  
{ ?nE9@G5Gc  
e.printStackTrace (); pE0@m-p  
} E>2AG3)  
?#nk}=;g8  
~*~aFf5  
return n; [i> D|X  
} Eq8:[o  
E(f|LG[I  
R?}%rP+^e  
} E5*pD*#  
ltkA7dUbu  
1$:O9 {F  
/* ygK,t*T20  
**SiteInfoBean.java W&3,XFnI_  
*/ 1:u~T@;" `  
package NetFox; A,7* 52U  
.hoVy*I  
hVJ}EF 0  
public class SiteInfoBean { +HD2]~{EkL  
U> <$p{ )  
gzlRK^5  
private String sSiteURL; //Site's URL Wrt5eYy  
private String sFilePath; //Saved File's Path KmqgP`Cu  
private String sFileName; //Saved File's Name d*@K5?O.  
private int nSplitter; //Count of Splited Downloading File F+W{R+6  
/L2.7`5  
&k`lb kq  
public SiteInfoBean() EYn9l n_]u  
{//nSplitter的缺省值为5 v`@N R06  
//default value of nSplitter is 5 A-M6MW  
this("","","",5); /IH F  
} c s:E^  
G1 I<B  
};gcM @]]E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]9w TAb  
{ (I{+ %  
sSiteURL= sURL; Le,;)Nd  
sFilePath = sPath; rV*Ri~Vx  
sFileName = sName; `?d` #) Ck  
this.nSplitter = nSpiltter; ?-<>he  
$2Bll5!]  
v9#F\F/  
} RS2uk 7MB  
bY~V?yNgKM  
I y5)SZ'  
public String getSSiteURL() "wxyY^"  
{ H5CL0#I  
return sSiteURL; H#T&7X_<  
} WP^wNi ~>  
v[jg|s&6"  
3wPUP+)c7  
public void setSSiteURL(String value) >3I|5kZ6  
{ ^t`0ul]c  
sSiteURL = value; 3aJYl3:0B  
} }5Km \OI  
@jZ1WHS_a  
f'Oj01[  
public String getSFilePath() 9j 0o)]  
{ <uo@k'   
return sFilePath; jm'^>p,9G  
} -"x@V7X  
\J-D@b;  
/U0,%  
public void setSFilePath(String value) FvD/z ;N  
{ FU)=+m  
sFilePath = value; :8]y*j  
} I(z16wQ  
*-E'$  
@S&QxE^  
public String getSFileName() &WS'Me  
{ ;RMevVw|  
return sFileName; "cvhx/\1#  
} o;OEb  
p]7IoO -@  
|!CAxE0d$B  
public void setSFileName(String value) :xY9eq=  
{ 0aJcX)  
sFileName = value; f7;<jj;w7  
} .F/s (  
%kP=VUXj  
F><ficT  
public int getNSplitter() CbOCL~ "  
{ x X.{(er  
return nSplitter; s'BlFB n  
} 7s Gf_`Z  
P]2V~I/X  
&#!1 Y[e^  
public void setNSplitter(int nCount) a/[)A _-  
{ l;B  
nSplitter = nCount; `(E$-m-~jH  
} '*<I<? z;  
} _s}`ohKvD  
.d?LRf  
O0eM*~zI  
/* }:!X@C~  
**Utility.java drbim8 !q~  
*/ oFsV0 {x%)  
package NetFox; ju1B._48  
|w5,%#AeO$  
{T DZDH  
public class Utility { ((=T E  
dq0!.gBT2  
/<"ok;Pu7  
public Utility() K{ntl-D&y  
{ /. >%IcK  
Z,V<&9a;  
K87yQOjPv  
} F?qg?1v B|  
s(r4m/  
//线程睡眠 Q(x/&]7=V  
public static void sleep(int nSecond) 0g#xQzE  
{ Y+5aT(6O  
try{ bGxHzzU}  
Thread.sleep(nSecond); D&qJ@PR  
} oqzWL~  
catch(Exception e) bV+2U  
{ aj<r=  
e.printStackTrace (); PZI6{KOis  
} m>*~ tP  
} }i^$ li@  
`Q[NrOqe"  
//日志 +zEyCx=8H  
public static void log(String sMsg) hS&.-5v  
{ )_6W@s  
System.err.println(sMsg); 7}`FXB  
} %AmyT  
DVDzYR**4  
$)d34JM  
public static void log(int sMsg) Mh {>#Gs  
{ Eqh*"hE7  
System.err.println(sMsg); T wzpq1  
} ;s-@m<  
} tq51;L  
LjIkZ'HuF  
D0>Pc9  
/* #$F*.vQSs+  
**TestMethod.java kdaq_O:s  
*/ M`E}1WNQ?]  
package NetFox; 1MmEP  
Qj$w7*U  
wJ"]H!r0  
public class TestMethod { 4um^7Ns)7  
unKgOvtj  
UD9JE S,  
public TestMethod() L\V`ou  
{ ///xx/weblogic60b2_win.exe - FJLM  
try{ 9SJSUv:@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rinTB|5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WQbjq}RfI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \[]?9Z=n  
fileFetch.start(); G,<l}(tEG  
} Z*-a=u%gl'  
catch(Exception e){e.printStackTrace ();} T6."j_  
#T@k(Bz{L  
2\;/mQI2A  
} z;_vl  
|dDKO  
ZT8LMPC  
public static void main(String[] args) T|0d2aa  
{ f>|<5zm#<  
new TestMethod(); _ {6l}  
} LF#[$ so{i  
} B#cN'1c  
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