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http断点续传简单实现(java)

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/* )"7hyW5  
**SiteFileFetch.java JL~QE-pvD  
*/ UA4Q9<>~  
package NetFox; } g  WSV  
import java.io.*;  & y1' J  
import java.net.*; ?p{xt$<p  
\jn[kQ+pJ  
&fBLPF%6  
public class SiteFileFetch extends Thread { %gd=d0vm  
% '>S9Ja3  
!O$*/7  
SiteInfoBean siteInfoBean = null; //文件信息Bean a!"81*&4#  
long[] nStartPos; //开始位置 66\0JsT?3  
long[] nEndPos; //结束位置 {8M=[4_`l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7e&R6j  
long nFileLength; //文件长度 { .KCK_ d  
boolean bFirst = true; //是否第一次取文件 TQ&%SMCn  
boolean bStop = false; //停止标志 oRM EC7!A0  
File tmpFile; //文件下载的临时信息 od>DSn3T  
DataOutputStream output; //输出到文件的输出流 fFXG;Q8&  
=YX/]g|9K  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) bw#zMU^E  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4QWDuLu  
{ Kb0OauW  
siteInfoBean = bean; ~CRr)(M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %h U8ycI*h  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7BCCQsz<  
if(tmpFile.exists ()) /'1UfjW>  
{ qF6YH  
bFirst = false; D={|&:`L e  
read_nPos(); y(|6`  
} Gy[;yLnX  
else <!:,(V>F(C  
{ iV#JJ-OBq  
nStartPos = new long[bean.getNSplitter()]; *IzcW6 [9  
nEndPos = new long[bean.getNSplitter()]; uF>I0J#z?  
} ]I"oS?  
p#.B Fy  
|0(Z)s,  
b:7;zOtF  
} [!{*)4$6  
64}Oa+*s  
M;W{A)0i1  
public void run() Kp"mV=RG2T  
{ zMX7 #,  
//获得文件长度 oaI7j=Gp  
//分割文件 7\^b+*  
//实例FileSplitterFetch  ,[ +  
//启动FileSplitterFetch线程 !U#kUj:4I  
//等待子线程返回 `"[VkQFB/  
try{ } oJ+2OepN  
if(bFirst) wP1dPl_j:0  
{ ~fsAPIQ  
nFileLength = getFileSize(); MxxYMR  
if(nFileLength == -1) r&"}zyL  
{ </<_e0  
System.err.println("File Length is not known!"); wd*i~A3+?  
}  ;9c3IK@  
else if(nFileLength == -2) oUZwZ_yKW  
{ 7"=  
System.err.println("File is not access!"); ,oDZ:";  
} g'Ft5fQ"o/  
else }Evyfc#D  
{ fl~k')s  
for(int i=0;i<nStartPos.length;i++) n4)G g~PE  
{ #e&j]Q$Eh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N`y!Km  
} \~xsBPX+x  
for(int i=0;i<nEndPos.length-1;i++) wpY%"x#-+=  
{ H's67E/>*  
nEndPos = nStartPos[i+1]; -]5dD VSO  
} ksY^w+>(!  
nEndPos[nEndPos.length-1] = nFileLength; %-]j;'6}cX  
} !'ajpK  
} IGql^,b  
U*/  
a#!Vi93  
//启动子线程 <PW*vo9v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; | x{:GWq  
for(int i=0;i<nStartPos.length;i++) 3z: rUhA  
{ qYIBP?`g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EBw}/y{Kt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), VYf$0oo\4  
nStartPos,nEndPos,i); U_!"&O5lr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?TE#4}p|  
fileSplitterFetch.start(); H1|X0 a(j  
} X =S;8=N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gq[}/E0e  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2DTH|Yv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yt  C{,g>  
nEndPos = " + nFileLength); bEbO){Fe  
// fileSplitterFetch[nPos.length-1].start(); - J!F((jt  
]*juF[r(  
B/E1nBobC  
//等待子线程结束 D8h ?s  
//int count = 0; }<FBcc(n  
//是否结束while循环 S7wZCQe  
boolean breakWhile = false; D.qbzJz  
{_3ZKD(\  
uVDB; 6  
while(!bStop) 30FYq?  
{ %S>lPt  
write_nPos(); ,k{{ZP P  
Utility.sleep(500); 2K, 1wqf'  
breakWhile = true; [ $.oyjd  
MnKEZ: 2  
jY>KF'y  
for(int i=0;i<nStartPos.length;i++) ErB6fl  
{ {>QrI4*A  
if(!fileSplitterFetch.bDownOver) /RmLV  
{ fLc<}DF  
breakWhile = false; nT|fDD|  
break; JS&l h  
} S?hM  
} G7%Nwe~Y  
if(breakWhile) 0g]ABzTn  
break; p`{<q -  
Fxv~;o#  
jc;&g)Rv  
//count++; !Si ZA"  
//if(count>4) ; {I{X}b  
// siteStop(); rVQ:7\=Z  
} JEY%(UR8  
sF_.9G)S0  
_}jj>+zA`  
System.err.println("文件下载结束!"); X@x: F|/P  
} plfz)x3  
catch(Exception e){e.printStackTrace ();} q7 Uu 8JXF  
} ?Dd2k%o  
'y-IE#!5  
H W.S~eLw*  
//获得文件长度 34JkB+#a  
public long getFileSize() c)@M7UK[  
{ 4CX*  
int nFileLength = -1; 5I T'u3V  
try{ B HZGQm  
URL url = new URL(siteInfoBean.getSSiteURL()); }qV4]*+{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o>U%3-+T^J  
httpConnection.setRequestProperty("User-Agent","NetFox"); w^R5/#F_r  
=*Wl;PI'  
XZp(Po:H  
int responseCode=httpConnection.getResponseCode(); q#sMew\{  
if(responseCode>=400) UfcM2OmbK  
{ * +A!12s@  
processErrorCode(responseCode); &??(EA3  
return -2; //-2 represent access is error 5Odi\SJ&  
} oH6(Lq'q  
n6Q 3X  
lt,x(2  
String sHeader; s)/i_Oe$\  
&lI.N~Ao  
n )`*{uv$  
for(int i=1;;i++) +/Y )s5@<  
{ zb9d{e   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h3@mN\=h'  
//Utility.log(in.readLine()); n=rPFp RLF  
sHeader=httpConnection.getHeaderFieldKey(i); *%Gy-5hM  
if(sHeader!=null) /"iYEr%_  
{ )E6m}?H5  
if(sHeader.equals("Content-Length")) MlRgdVX  
{ Mqw&%dz'_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \8Blq5n-O*  
break; LfgR[!  
} dhm ;  
} Q.\+ XR_|  
else xu+wi>Y^  
break; / d6mlQS  
} i7 p#%2  
} zac>tXU;  
catch(IOException e){e.printStackTrace ();} i9.5 2  
catch(Exception e){e.printStackTrace ();} Pq7YJ"Z?:  
LgUaX  
!\|&E>Gy  
Utility.log(nFileLength); XHpoaHyx  
Fzu"&&>0$  
#+Vvf  
return nFileLength; JvHJ*E   
} l[\[)X3$  
0dIJgKanGP  
p[Q   
//保存下载信息(文件指针位置) 1q\U (^  
private void write_nPos() %gw0^^A  
{ NRoi` IIj  
try{ {'d?vm!r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .P,\69g~A  
output.writeInt(nStartPos.length); W4>8  
for(int i=0;i<nStartPos.length;i++) GVEjB;  
{ I[[rVts  
// output.writeLong(nPos); ,T&B.'cq  
output.writeLong(fileSplitterFetch.nStartPos); ?]3`WJOj  
output.writeLong(fileSplitterFetch.nEndPos); \n<N>j@3  
} gvy%`SSW  
output.close(); I9>1WT<Yy  
} 5[/ *UtB  
catch(IOException e){e.printStackTrace ();} &lGp /m:  
catch(Exception e){e.printStackTrace ();} ZB ~D_S  
} eKStt|M'  
5vP*oD  
L}:u9$w  
//读取保存的下载信息(文件指针位置) 6x[gg !;85  
private void read_nPos() H3a}`3}U  
{ { Ja#pt  
try{ aNXu"US+Sp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %X[|7D-  
int nCount = input.readInt(); _Dk;U*2  
nStartPos = new long[nCount]; =BX<;vU  
nEndPos = new long[nCount]; xhqIE3gd  
for(int i=0;i<nStartPos.length;i++) 7J>n;8{%?  
{ lZ_i~;u4@v  
nStartPos = input.readLong(); bcj7.rh]'h  
nEndPos = input.readLong(); 9.%{M#j  
} oz[E>%  
input.close(); Keof{>V=CA  
} v5<Ext rV  
catch(IOException e){e.printStackTrace ();} vhhsOga  
catch(Exception e){e.printStackTrace ();} uOW9FAW  
} `+* Mr  
pOS.`rSK  
O'idS`   
private void processErrorCode(int nErrorCode) YtIJJH  
{ <cepRjDn  
System.err.println("Error Code : " + nErrorCode); iY*Xm,#  
} !T @|9PCp  
:5CwRg  
M>T#MDK\(  
//停止文件下载 %W`pTvF  
public void siteStop() >_&+gn${  
{ ,"}'NH@  
bStop = true; roRZE[ya  
for(int i=0;i<nStartPos.length;i++) }A2@1TTPX  
fileSplitterFetch.splitterStop(); g7d)YUc  
$>#PhOC  
/- kMzL  
} X8*q[@$  
} L:B&`,E  
//负责部分文件的抓取 fNB*o={r|  
**FileSplitterFetch.java k`TEA?RfQ  
*/ y l3iU:+V  
package NetFox; PU-;Q@< E  
U15Hq*8Z  
yY,.GzIjCj  
import java.io.*; Ye1P5+W(  
import java.net.*; [_H9l)  
M(/%w"R  
B>~E6j7[Mp  
public class FileSplitterFetch extends Thread { S!g&&RDx  
<y`yKXzBUV  
ulVHsWg  
String sURL; //File URL n}?kQOg0/  
long nStartPos; //File Snippet Start Position Ui1K66{  
long nEndPos; //File Snippet End Position 'VF9j\a  
int nThreadID; //Thread's ID \8F$85g  
boolean bDownOver = false; //Downing is over ikm4Y`c  
boolean bStop = false; //Stop identical ]`:Fj|>  
FileAccessI fileAccessI = null; //File Access interface O`Z>Oon?  
$wX5`d 1  
^s24f?3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l}<s~ip  
{ 9prG@  
this.sURL = sURL; F /t;y\)  
this.nStartPos = nStart;  i4Fw+Z  
this.nEndPos = nEnd; ,Xb:f/lB  
nThreadID = id; rU'&o) a^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #UGbSOoCtn  
} oA42?I ^  
, :kCt=4%  
[& hdyLt  
public void run() TJO|{Lxm  
{ Gzm[4|nO^  
while(nStartPos < nEndPos && !bStop) v8w N2[fC  
{ d5WE^H)E.  
sY1*Wo lA  
=#>P !  
try{ qLPI^g,  
URL url = new URL(sURL); lkl#AH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,cbP yg  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1lx\Pz@ol  
String sProperty = "bytes="+nStartPos+"-"; _ k>j?j-  
httpConnection.setRequestProperty("RANGE",sProperty); /?by4v73P  
Utility.log(sProperty); 1bvL  
9`vse>,-hg  
Cf%)W:Q9  
InputStream input = httpConnection.getInputStream(); L(X:=) !K0  
//logResponseHead(httpConnection); wV(_=LF  
n}._Nb 5  
(r7~ccy4  
byte[] b = new byte[1024]; V#sANi?mpo  
int nRead; +/UInAM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7GPBn}{W  
{ oTfEX4 t {  
nStartPos += fileAccessI.write(b,0,nRead); %7L'2/Y2x  
//if(nThreadID == 1)   (+Er  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Rhr]ML  
} $Y ]*v)}X  
qnT:x{o  
1M<'^(t3d  
Utility.log("Thread " + nThreadID + " is over!"); @Yt[%tOF+  
bDownOver = true; Lp{l& -uQ  
//nPos = fileAccessI.write (b,0,nRead); j[=f;&1  
} q 2= ^l  
catch(Exception e){e.printStackTrace ();} LWIU7dw  
} ]aaHb  
} Lqz}h-Ei  
;Hm\?n)a  
8BWLi5R[  
//打印回应的头信息 7AtJ6  
public void logResponseHead(HttpURLConnection con) p%,JWZ[  
{ Ak4iG2  
for(int i=1;;i++) tp0^%!*9  
{ cL`l1:j\}  
String header=con.getHeaderFieldKey(i); \)LY_D:  
if(header!=null) N-vr_4{g  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #>!!#e!*  
Utility.log(header+" : "+con.getHeaderField(header)); EV~_-YC   
else WlG/7$  
break; Le_?x  
} n1!u aUC  
} Yz{UP)TC  
mEE/Olh W  
y+X%qTB  
public void splitterStop() AMtFOXx%I  
{ " $m3xO  
bStop = true; {L.0jAwB  
} HW{+THNj  
 BeP0lZ  
=(@J+Ou  
} GKm)wOb(*S  
*a\1*Jk  
)%UO@4  
/* V_Y SYG9f  
**FileAccess.java !QC->  
*//文件访问(定位,写) N!HiQ  
package NetFox; 03{e[#6   
import java.io.*; <tFq6|  
A "w 1GBx  
4UG7{[!+  
public class FileAccessI implements Serializable{ o3%+FWrVTS  
Fet>KacTht  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o2Z# 5-  
RandomAccessFile oSavedFile; i) :Q{[D  
long nPos; +}*]9nG  
6``!DMDt/P  
YZ'gd10T  
public FileAccessI() throws IOException P^.L0T5g  
{ G?YKm1:w   
this("",0); h5B'w  
} z^=9%tLJ  
yPuT%H&i  
3<?(1kSo>>  
public FileAccessI(String sName,long nPos) throws IOException 3O$Q>.0w/  
{ l$.C40v  
oSavedFile = new RandomAccessFile(sName,"rw"); )<jj O  
this.nPos = nPos; Ue~M .LZb  
oSavedFile.seek(nPos); |?{Zx&yUw  
} }0qgvw  
N{oD1%  
P>jlFm  
public synchronized int write(byte[] b,int nStart,int nLen) "TG}aS  
{ ar>S_VW*  
int n = -1; g6 r3V.X'  
try{ / 1E6U6  
oSavedFile.write(b,nStart,nLen); S,qsCnz  
n = nLen; uiO8F*,!&r  
} qI KVu_  
catch(IOException e) 8CwgV  
{ m<TKy_C`  
e.printStackTrace (); x!gu&AA<*  
} _f2(vWCW;J  
Smg,1,=  
q=g;TAXZl  
return n; /R@eOl}D  
} 9?@M Zh  
-:>Mi5/ s  
*7DQ#bD  
} 0FHN  
.gx*gX1<  
p \F*Y,4  
/* :/d#U:I  
**SiteInfoBean.java #L[Atx  
*/ ZShRE"`  
package NetFox; t"JfqD E  
yj"+!g  
8@Y]dz gjj  
public class SiteInfoBean { jD'\\jAUdm  
2Vt iL^;5  
rS8/_'  
private String sSiteURL; //Site's URL H8rDG/>^  
private String sFilePath; //Saved File's Path 8T7[/"hi\  
private String sFileName; //Saved File's Name dk-Y!RfNx  
private int nSplitter; //Count of Splited Downloading File &F)P3=  
oTT/;~I  
- =QA{n  
public SiteInfoBean() oB#KR1 >%7  
{//nSplitter的缺省值为5 ^Jsx^?  
//default value of nSplitter is 5 jt=mK ,%  
this("","","",5); r1JKTuuo  
} ?neXs-'-p  
*)H?d  
x>Q\j>^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7WKb| /#;  
{ _}{C?611c  
sSiteURL= sURL; .$L'Jt2X  
sFilePath = sPath; p.gi8%f`  
sFileName = sName; i|y8n7c  
this.nSplitter = nSpiltter; rp+&ax}Wh  
68W&qzw.[r  
FE" ksi 9  
} F@)wi0  
M7BJ$fA0E  
Nz\=M|@(#  
public String getSSiteURL() gb( a`  
{ 9}:%CpD^~I  
return sSiteURL; 3g^_Fq'  
} /87?U; |V  
7[.aAGTZ;  
}&bO;o&>  
public void setSSiteURL(String value) Y Dq5%N`  
{ I?EtU/AD  
sSiteURL = value; Pur~Rz\ \  
} OZB(4{vnyC  
)zf&`T  
h/mmV:v  
public String getSFilePath() pa`"f&JO  
{ _.KKh62CN  
return sFilePath; LlrUJ-uC7  
} 2dFC{US'  
48Vmz  
Q+ $+{g-8  
public void setSFilePath(String value) +pkX$yz  
{ B_aLqB]U  
sFilePath = value; dpxP  
} !Z 3iu  
DwMq  
{D={>0  
public String getSFileName() JS1$l+1  
{ ZQlja  
return sFileName; ,Tvfn`;(  
} Mxc0=I'a  
[ ]}E- V  
&-dyg+b3  
public void setSFileName(String value) DZ<q)EpC  
{ & w&JE]$ 5  
sFileName = value; o $7:*jU  
} ifHQ2Ug 9  
xKi: 2  
q@1b{q#C5  
public int getNSplitter() rF'_YYpr>  
{ AvfSR p  
return nSplitter; +fBbW::R^  
} eG55[V<!  
kc Q~}uFB  
|_x U{Pu  
public void setNSplitter(int nCount) p%/Z  
{ LZG?M|(6D  
nSplitter = nCount; _lcx?IV  
} ^`XQ>-wWue  
} 3x@t7B  
VEj-%"\   
b1>zGC^|  
/* *~YU0o  
**Utility.java yU<T_&M  
*/ __dSEOGoe  
package NetFox; ?Imq4I~)  
!VBl/ aU@  
X,DG2HT  
public class Utility { 7jPPN  
#;4<dDVy  
D"UCe7  
public Utility() [CTE"@A  
{ 2#%@j6  
>1q W*  
'M8wjU  
} xn|M]E1)  
"ld4v+o8l  
//线程睡眠 9ozN$:  
public static void sleep(int nSecond) R~TzZ(Ah]  
{ |h}/#qhR  
try{ lKKg n{R  
Thread.sleep(nSecond); "jS @ug  
} %xv }  
catch(Exception e) %P@V7n  
{ *|n-Hr  
e.printStackTrace (); !:"$1kh1("  
} pbc<326X"  
} T rK-XTev  
wyWe2d  
//日志 /&1FgSARK  
public static void log(String sMsg) k;BXt:jDq  
{ Z'=:Bo{  
System.err.println(sMsg); PggjuPPh  
} [[ {L#  
t,H=;U#  
LGu K@^  
public static void log(int sMsg) m ioNMDG  
{ rnX D(  
System.err.println(sMsg); dA4DW  
} p6P .I8g  
} X^Dklqqy  
nSR7$yS_  
9=RfGx  
/* F%|F-6  
**TestMethod.java PiQs Vk  
*/ my|]:(_0d  
package NetFox; DD$YMM  
F{,<6/ayRz  
E^'f'\m  
public class TestMethod { e"g=A=S  
B L^?1x  
5=cS5q@  
public TestMethod() L F<{/c9,  
{ ///xx/weblogic60b2_win.exe vT1StOx<V  
try{ U0X,g(2'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K3g<NC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q)N]*~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~| CWy  
fileFetch.start(); LeP;HP|  
} *m$lAWB5D  
catch(Exception e){e.printStackTrace ();} nLvF^%P8  
I!-"SuBy4J  
4 q-/R  
} yzI`&? P2  
bn*SLWWQ.3  
d-%bRGo/  
public static void main(String[] args) #LU<v  
{ "|k 4<"]  
new TestMethod(); NAg9EaWja{  
} HgY [Q}7s  
} 8_*31Y   
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