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http断点续传简单实现(java)

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/* :qxd s>Xm  
**SiteFileFetch.java tRzo}_+N  
*/ nH(H k%~  
package NetFox; fudLm  
import java.io.*; fS- 31<?  
import java.net.*; h@D</2>  
.ta*M{t  
xyaU!E*  
public class SiteFileFetch extends Thread { SO}en[()O  
m9li%p  
Nbm=;FHB`  
SiteInfoBean siteInfoBean = null; //文件信息Bean c[E>2P2-_  
long[] nStartPos; //开始位置 F<^93a9  
long[] nEndPos; //结束位置 % ovk}}%;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h| ]BA}D  
long nFileLength; //文件长度 c69M   
boolean bFirst = true; //是否第一次取文件 VsR`y]"g  
boolean bStop = false; //停止标志 K$Yc!4M  
File tmpFile; //文件下载的临时信息 *l\vqgv.Z  
DataOutputStream output; //输出到文件的输出流 zP;1mN  
u9^R ?y  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _.ELN/$-  
public SiteFileFetch(SiteInfoBean bean) throws IOException }hX"A!0  
{ G8ksm2}  
siteInfoBean = bean; "Qxn}$6-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :O{oVR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `Ef &h V  
if(tmpFile.exists ()) i4*!t.eI  
{ 4j h4XdH  
bFirst = false; m8ydX6~max  
read_nPos(); lITZ|u  
} ?$\y0lHw/7  
else (!&g (l;  
{ uH?lj&  
nStartPos = new long[bean.getNSplitter()]; 4,g3 c  
nEndPos = new long[bean.getNSplitter()]; x1ID6kI[{*  
} ky5gU[  
DozC>  
uyDYS  
M"$TXXe  
} ;r XhK$  
dk9nhS+faJ  
Ch9A6?=Hj8  
public void run() t?j2Rw3f`I  
{ hhvP*a_J  
//获得文件长度 /,Sd  
//分割文件 !saKAb}d7H  
//实例FileSplitterFetch k&>l#oH  
//启动FileSplitterFetch线程 JI}p{ yI  
//等待子线程返回 hT<:)MG)+K  
try{ C JNz J(  
if(bFirst) 3tTz$$-#  
{ QU{\ClW/?  
nFileLength = getFileSize(); Pf]O'G&F  
if(nFileLength == -1) 4MOA}FZ~  
{ ~IE5j,SC  
System.err.println("File Length is not known!"); (B zf~#]~  
}  YErn50L  
else if(nFileLength == -2) 5bzYTK&-  
{ WsCzC_'j.  
System.err.println("File is not access!"); ^2PQ75V@.  
} +6* .lRA  
else AH(O"v`  
{ N#`aVW'{v2  
for(int i=0;i<nStartPos.length;i++) .iL_3:6f  
{ 7" wn0 24  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); WxS=Aip'  
} 'k9hzk(*  
for(int i=0;i<nEndPos.length-1;i++) S-:7P.#Q  
{ {@u}-6:wAT  
nEndPos = nStartPos[i+1]; m 5NF)eL  
} x6x6N&f?  
nEndPos[nEndPos.length-1] = nFileLength; s!E-+Gw  
} ^Y:Q%?uB/  
} zA/W+j$:  
pPG@_9qf  
`|^<y.-6  
//启动子线程 E4'D4@\W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; '#.:%4  
for(int i=0;i<nStartPos.length;i++) B&m?3w  
{ 6YZ&>` a^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wzMWuA4vX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Y e}y_W  
nStartPos,nEndPos,i); VrokEK*qbY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }m<)$.x|P  
fileSplitterFetch.start(); dMwVgc:  
} XjwTjgL<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `<>8tZS9"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A{E0 a:v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y4Z?`TL  
nEndPos = " + nFileLength); Xklp6{VH9  
// fileSplitterFetch[nPos.length-1].start(); NwG&uc+Q  
[VPqI~u5)  
ZtEHP`Iin  
//等待子线程结束 HC8{);  
//int count = 0; V_(?mC  
//是否结束while循环 !+M H?A  
boolean breakWhile = false; 6iFd[<.*j  
#V8='qD  
,9#G/nF  
while(!bStop) ANCgch\  
{ {Pg7IYjH  
write_nPos(); V]PTAhc  
Utility.sleep(500); M{7EFTy!y  
breakWhile = true; _pNUI {De  
`z3?ET  
kx1-.~)p(z  
for(int i=0;i<nStartPos.length;i++) Y#6@0Nn[G  
{ ^D B0C  
if(!fileSplitterFetch.bDownOver) T"Q4vk,3*J  
{ l{Hi5x'H  
breakWhile = false; .@APxeU  
break; "MXd!  
} ;8g#"p*&  
} Vb 4Qt#o  
if(breakWhile) ~pj9_I  
break; US7hKNm.  
(>0d+ KT  
-lMC{~h\(S  
//count++; zPV/{)S  
//if(count>4) G-n`X":$DT  
// siteStop(); z6G^BaT'  
} ~|J6M  
W{;!JI7;z  
r+0)l:{.  
System.err.println("文件下载结束!"); HXdPKS4q  
} O|j5ulO}&"  
catch(Exception e){e.printStackTrace ();} 8XJ%Yuu  
} ^[%~cG  
J7QlGm,=  
/,0t,"&Aqa  
//获得文件长度 z4-AOTo2y  
public long getFileSize() 3<+l.Wly  
{ l}(~q!r  
int nFileLength = -1; V6$v@Zq  
try{ 6g$04C3tHi  
URL url = new URL(siteInfoBean.getSSiteURL()); ~*B1}#;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >/bl r}5 H  
httpConnection.setRequestProperty("User-Agent","NetFox"); lGLZIp  
RFK N,oB  
\0WMb  
int responseCode=httpConnection.getResponseCode(); (I[o;0w  
if(responseCode>=400) t41cl  
{ ?o.G@-  
processErrorCode(responseCode); =,@SZsM*B  
return -2; //-2 represent access is error jQ`"Op 3  
} Op%^dwVG(v  
u khI#:[  
@/0aj  
String sHeader; 6xFZv t  
(tq)64XVz  
9D#PO">|  
for(int i=1;;i++) yl'~H;su  
{ RycEM|51V  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WejY b;KS  
//Utility.log(in.readLine()); W&!Yprr  
sHeader=httpConnection.getHeaderFieldKey(i); 2qr%xK'^B  
if(sHeader!=null) N'`*#UI+  
{ n1ED _9  
if(sHeader.equals("Content-Length")) 6:EO  
{ 7GP?;P  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iqoPD4A  
break; N l@Hx  
} t'Q48QAb?  
} _ _)Z Q  
else XPEjMm'*b3  
break; akqXh 9g  
} `a6;*r y  
} tcX7Ua(I`  
catch(IOException e){e.printStackTrace ();} 95!xTf  
catch(Exception e){e.printStackTrace ();} "Z{^i3 gN  
v;$^1I  
nlmkkTHF8  
Utility.log(nFileLength); I'@ }Yjm|  
@s IZ  
*Cb(4h-  
return nFileLength; q$t& *O_  
} 0Hz3nd?v  
GS{9MGl  
Ti)n(G9$  
//保存下载信息(文件指针位置) 0"QE,pLe4  
private void write_nPos() 7CIje=u.q  
{ g]ihwm~  
try{ ,5\n%J:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gEe}xI  
output.writeInt(nStartPos.length); 2)8lJXM$L  
for(int i=0;i<nStartPos.length;i++) k{b ba=<  
{ q/3}8BJ  
// output.writeLong(nPos); 8EE7mEmLH  
output.writeLong(fileSplitterFetch.nStartPos); 3Q]MT  
output.writeLong(fileSplitterFetch.nEndPos); q@!:<Ra,){  
} b]Y,& 8}[+  
output.close(); & aLR'*]6  
} OKU P  
catch(IOException e){e.printStackTrace ();} SA&wW\Ym]  
catch(Exception e){e.printStackTrace ();} n)=&=Uj`f  
} \D[BRE+  
vB Jva8;Q  
B#DV<%GPl  
//读取保存的下载信息(文件指针位置) 7uDUZdJy  
private void read_nPos() vn_avYwiy  
{ 9qW,I|G  
try{ X%-4x   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); WIGb7}egR  
int nCount = input.readInt(); t!=S[  
nStartPos = new long[nCount]; <7&b|f$CL  
nEndPos = new long[nCount]; k@Tt,.];  
for(int i=0;i<nStartPos.length;i++) cnc$^[c  
{ H{XW?O^@  
nStartPos = input.readLong(); @<PL  
nEndPos = input.readLong(); 4Oy c D  
} _YJwF1e+M  
input.close(); NWpRzh8$u  
} j>T''T f  
catch(IOException e){e.printStackTrace ();} !^7:Rr _  
catch(Exception e){e.printStackTrace ();} [Vf|4xcD  
} m88~+o<G%  
1)R)+`y  
z%KChU  
private void processErrorCode(int nErrorCode) Qh[t##I/  
{ H xlw1(zS  
System.err.println("Error Code : " + nErrorCode); 1,QRfckks  
} Xm4wuX"e=  
QXz!1o+"  
S&Sf}uK  
//停止文件下载 zXD@M{  
public void siteStop() 4[ra  
{ S'O0'5U@  
bStop = true; JU@$(  
for(int i=0;i<nStartPos.length;i++) + ND9###  
fileSplitterFetch.splitterStop(); .3&m:P8zV  
<D^x6{}  
%;5hHRA  
} H5AY6),  
} OS 6 )`  
//负责部分文件的抓取 s7e'9Bx  
**FileSplitterFetch.java hJ<2bgQo  
*/ @CmxH(-i-  
package NetFox; {2x5 V#6  
B<R-|-#  
hmH$_YP}  
import java.io.*; qWFg~s#+  
import java.net.*; cTnbI4S;  
vy#(|[pL{  
f+6l0@K2  
public class FileSplitterFetch extends Thread { GCKl [<9*  
US|vYd}u+  
0o]K6 b  
String sURL; //File URL >+#[O"  
long nStartPos; //File Snippet Start Position f3>/6 C  
long nEndPos; //File Snippet End Position ,2`d3u^CW  
int nThreadID; //Thread's ID  {5udol5?  
boolean bDownOver = false; //Downing is over jveRiW@  
boolean bStop = false; //Stop identical @\y7 9FX  
FileAccessI fileAccessI = null; //File Access interface P1QJ'eC;T  
Kq$Zyf=E  
ie!4z34  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `9+EhP$RS  
{ 3EvA 5K.  
this.sURL = sURL; #+;=ijyF  
this.nStartPos = nStart; taQ[>x7b  
this.nEndPos = nEnd;  T_uuFL  
nThreadID = id; O5Lv :qAa  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ; ]Aa  
} YiTp-@$}  
t}7wR TG  
a{+oN $  
public void run() DR /)hAE  
{  vt N5{C  
while(nStartPos < nEndPos && !bStop) >I?Mi{'a  
{ "{_"Nj H  
^H4i Hjg  
A 5 X+Z  
try{ .y/b$|d,  
URL url = new URL(sURL); $D5U#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2YKM9Ks  
httpConnection.setRequestProperty("User-Agent","NetFox"); SDIeq  
String sProperty = "bytes="+nStartPos+"-"; 4AYc 8Z#'  
httpConnection.setRequestProperty("RANGE",sProperty); Xoy1Gi?  
Utility.log(sProperty); zq.&Mw?  
v+#j>   
dYd~9  
InputStream input = httpConnection.getInputStream(); <.b$ gX  
//logResponseHead(httpConnection); |S{P`)z%f  
\6hL W_q1  
Q /c WV  
byte[] b = new byte[1024]; hD1AK+y  
int nRead; Wts{tb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GZEonCk[&  
{ (J&Xo.<Z-  
nStartPos += fileAccessI.write(b,0,nRead); 4E>(Y98  
//if(nThreadID == 1) _,FoXf7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~8(X@~Tn*  
} dSVu_*y  
k~f+LO  
j9}0jC2Tb  
Utility.log("Thread " + nThreadID + " is over!"); NE3wui1 V  
bDownOver = true; p*,P%tX  
//nPos = fileAccessI.write (b,0,nRead); :XSc#H4  
} 0 '7s  
catch(Exception e){e.printStackTrace ();} wW8 6rB  
} rfRo*u2"  
} N[bN"'U/1  
=h::VB}Lv  
&ZN'Ey?  
//打印回应的头信息 0:'jU  
public void logResponseHead(HttpURLConnection con) >iH).:j  
{ yZp:hs#  
for(int i=1;;i++) VaSNFl1_M  
{ wLSZL  
String header=con.getHeaderFieldKey(i); x{>Y$t]  
if(header!=null) jF{gDK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &&1Y"dFs  
Utility.log(header+" : "+con.getHeaderField(header)); $|(|Qzi%  
else S7ehk*`  
break; xzl4v=7  
} I ~L Q1 _  
} F/*fQAa"  
} Tr83B|  
x7Rq|NQ  
public void splitterStop() s2?,'es  
{ :.o=F`W  
bStop = true; =jIT"rk  
} V`,[=u?c  
R}wwC[{  
d Zz^9:C+  
} p@8krOo`  
qM>OE8c#/  
{Okik}Oh  
/* o+-Ge J  
**FileAccess.java >|/ ? Up  
*//文件访问(定位,写) on;sq8;  
package NetFox; fsJTwSI["  
import java.io.*; #)mkD4  
A Ok7G?Y  
V87ee,  
public class FileAccessI implements Serializable{ 9`C iE  
$qtU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /-{O\7-D  
RandomAccessFile oSavedFile; wGzXp5 dl  
long nPos; e0N=2i?I#z  
#4_O;]{'  
7tl)4A6  
public FileAccessI() throws IOException k]$E8[.t  
{ M-Z6TL  
this("",0); $sc8)d\B  
} y:|.m@ j1  
?Y0$X>nm  
! jX+ox  
public FileAccessI(String sName,long nPos) throws IOException nhP~jJn  
{ I "Q9W|J_&  
oSavedFile = new RandomAccessFile(sName,"rw"); ;/";d]j  
this.nPos = nPos; e,#+Xx0M  
oSavedFile.seek(nPos); 9S H<d)^  
} %<=vbL9  
9(^X2L&Z  
_N,KHxsG8B  
public synchronized int write(byte[] b,int nStart,int nLen) O5TK&j  
{ 1x\W52 1  
int n = -1; &Qq/Xi,bZ  
try{ Eo { 1y  
oSavedFile.write(b,nStart,nLen); }U?gKlLg  
n = nLen; p21=$?k!;  
} krr-ZiK  
catch(IOException e) D2TXOPH  
{ SJ@8[n.x  
e.printStackTrace (); yToT7 X7F7  
} e1`)3-f  
+%e%UF@  
4('0f:9z+  
return n; GwMUIevO_  
} .}$`+h8W T  
Y1yXB).AH8  
\}u7T[R=`  
} Owh*KY:  
igRDt{}  
^i`3cCFB<  
/* xyS2_Q  
**SiteInfoBean.java 8V=HyF#  
*/ v E3{H  
package NetFox; !X\sQNp  
C NzSBm  
} Jdh^t.  
public class SiteInfoBean { (}*\ {  
F;?TR[4!k  
(EOec5qXU  
private String sSiteURL; //Site's URL ]xJ'oBhy  
private String sFilePath; //Saved File's Path ^Kw&=u  
private String sFileName; //Saved File's Name a8bX"#OR&N  
private int nSplitter; //Count of Splited Downloading File :\1rQT  
2\nBqCxR  
uGP[l`f|FQ  
public SiteInfoBean() X|-v0 f  
{//nSplitter的缺省值为5 (5Z8zNH`3  
//default value of nSplitter is 5 8g# c%eZ  
this("","","",5); c6?c>*z  
} F;d%@E_Bc  
.`p<hA)%[C  
YoV^xl6g  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7 zJrT5   
{ F,L82N6\U  
sSiteURL= sURL; R<y  Nv  
sFilePath = sPath; ,`%k'ecN  
sFileName = sName; @wYQLZ  
this.nSplitter = nSpiltter; P EX26==  
_q$0lqq~u  
%2@ Tj}xa  
} |z!q r}i  
Q QsVIHA  
{UX"Epd);n  
public String getSSiteURL() 5bF9I H  
{ ]689Q%D  
return sSiteURL; H7z>S G0  
} AQnJxIL:  
~J:$gu~`  
{dy` %It  
public void setSSiteURL(String value) a2c x  
{ c]s (u+i  
sSiteURL = value; a!c/5)v(  
} eEWro F  
r%g <h T 8  
E(aX4^]g  
public String getSFilePath() ";-{ ~  
{ 7X9+Qj;  
return sFilePath; $I)Tk`=  
} V!pq,!C$v  
gD,YQ%aq  
vF.?] u  
public void setSFilePath(String value) Vr&el  
{ RR[)UQ  
sFilePath = value; i$`|Y*  
} vKU]80T  
dp"<KcP_  
]97Xu_  
public String getSFileName() ;-3h~k  
{ i63`B+L{  
return sFileName; 9_J!s  
} N<L$gw+)$D  
q;~R:}?@  
bGGeg%7  
public void setSFileName(String value) 4B:\  
{ &57qjA ,8<  
sFileName = value; sow bg<D  
} `!UaScM  
 uD.  
qO:U]\P  
public int getNSplitter() {Ior.(D>Y  
{ zVp[YOS&c  
return nSplitter; jGk7=}nw  
} 92P ,:2`a  
3n.+_jQ>s  
th.M.jas  
public void setNSplitter(int nCount) k1^V?O  
{ S`pF7[%rp  
nSplitter = nCount; !6XvvTs/<  
} +l2e[P+qA  
} /p"U  
g6rv`I $l  
RE ![O  
/* Du)B9s  
**Utility.java T$gkq>!j<E  
*/ KW&nDu t  
package NetFox; vqrBRlZ  
YYTO,4  
"_ nX5J9  
public class Utility { +G5'kYzJ  
4ggVj*{v  
z{Hz;m:*_  
public Utility() $?H]S]#|}.  
{ M?E9N{t8)a  
_Ct}%-,4  
Q;XXgX#l  
} fl!mYCPv  
#[no~&E  
//线程睡眠  C#A@)>  
public static void sleep(int nSecond)  )v${&H  
{ &tlR~?$e*  
try{ fs wZM\@  
Thread.sleep(nSecond); Eem 2qKj  
} M.o?CX'  
catch(Exception e) ,$HHaoo g  
{ ,3G$`  
e.printStackTrace (); Zr\2BOcc.l  
} fdd~e52f  
} "F&Tnhh4  
LTg?5GwD\j  
//日志 \ua9thOG  
public static void log(String sMsg) kFS0i%Sr  
{ &(lMm)  
System.err.println(sMsg); 11i"nR|  
} 8&?^XcJ*x  
^bF}_CSE  
~ wfoK7T}  
public static void log(int sMsg) k%"$$uo  
{ ]MC/t5vCu  
System.err.println(sMsg); 6o$Z0mG  
} iYkRo>3!QX  
} "EJ\]S]$X  
OZ eiH X!  
8r2XGR  
/* Xyb8u})p'  
**TestMethod.java K3La9O)>  
*/ +nU',E  
package NetFox; Xfj)gPt}  
kBrvl^D{5  
`2pO5B50  
public class TestMethod { jeY4yM  
FL59  
l#b:^3  
public TestMethod() 4+)Z k$E  
{ ///xx/weblogic60b2_win.exe 7 2`/d`  
try{ ymHKcQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bAUHUPe  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0rV/qMo;K  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2q+la|1Cr  
fileFetch.start(); DKR<W.!*t  
} [.M  
catch(Exception e){e.printStackTrace ();} ty':`)  
QyTh!QM~`  
h!QjpzQe  
} x]H3Y3  
 }K?F7cD  
)sqaR^  
public static void main(String[] args) 8^i\Y;6  
{ 5@K\c6   
new TestMethod(); bC6X?m=  
} c qv .dC  
} L%f-L.9`u  
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