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http断点续传简单实现(java)

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/* Qv0>Pf  
**SiteFileFetch.java G'?f!fz;  
*/ .cT$h?+jyl  
package NetFox; *CY6 a  
import java.io.*; CDwIq>0j  
import java.net.*; aQ&8fteFR  
lDPRn~[#\  
hW !@$Ph  
public class SiteFileFetch extends Thread { #D LT-G0  
h[je_^5  
g1 Wtu*K3  
SiteInfoBean siteInfoBean = null; //文件信息Bean yp2'KES>  
long[] nStartPos; //开始位置 TQ\wHJ  
long[] nEndPos; //结束位置 fFZ` rPb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,gL)~6!A  
long nFileLength; //文件长度 N 1f~K.e\  
boolean bFirst = true; //是否第一次取文件 .H (}[eG_  
boolean bStop = false; //停止标志 oF b mz*  
File tmpFile; //文件下载的临时信息 7{+Io  
DataOutputStream output; //输出到文件的输出流 `b#nC[b6|v  
X:SzkkVl7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 18p3  
public SiteFileFetch(SiteInfoBean bean) throws IOException U??f<  
{ 4`!  
siteInfoBean = bean; ]i,Mq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9HNh*Gc=  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); fyg~KF}  
if(tmpFile.exists ()) &pMlt7  
{ ??zABV  
bFirst = false; )-9w3W1r  
read_nPos(); Pvg  
} Ro'4/{}+  
else ^I'Lw  
{ )>/j&>%  
nStartPos = new long[bean.getNSplitter()]; ^tg6JB;s  
nEndPos = new long[bean.getNSplitter()]; !: EW21m  
} tU)r[2H2  
+NLQYuN  
^{fi^lL=  
4-d99|mv  
} zN)|g  
dW{o+9nw  
76IALJ00V  
public void run() yNqm]H3<MP  
{ # McK46B z  
//获得文件长度 (ju aDn)  
//分割文件 q]iKz%|Z/  
//实例FileSplitterFetch %KJhtd"q  
//启动FileSplitterFetch线程 @q{:Oc^  
//等待子线程返回 3vRL g b  
try{ rtYb"-&  
if(bFirst) 9#s95R O  
{ >Oi2gPA  
nFileLength = getFileSize(); x<{;1F,k3  
if(nFileLength == -1) &w;^m/zP3  
{ > G4HZE  
System.err.println("File Length is not known!"); 5}X<(q(  
} anz9lGG#  
else if(nFileLength == -2) N.5KPAvg%  
{ 7>t$<J  
System.err.println("File is not access!"); e}?1T7NPG]  
} s`Be#v  
else vh. Wm?qQ  
{ *,pZ fc  
for(int i=0;i<nStartPos.length;i++) `b^#quz  
{ oA!5dpNhU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); - 5o<Q'(  
} k}I5x1>&  
for(int i=0;i<nEndPos.length-1;i++) mI?* Z%>g  
{ 7}#*3*]  
nEndPos = nStartPos[i+1]; y?*[}S  
} W>q*.9}Y"  
nEndPos[nEndPos.length-1] = nFileLength; 5I)~4.U|,m  
} U+9- li  
} j1;_w  
?O<`h~'$+  
cYq']$]  
//启动子线程 vR%j#v|s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]5o0  
for(int i=0;i<nStartPos.length;i++) _A;vSp.`  
{ eN<>#: `  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7,W]zKH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;<bj{#mMv  
nStartPos,nEndPos,i); "o^bN 9=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nl)_`8=  
fileSplitterFetch.start(); "q9~ C  
} WIEx '{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a%MzNH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @O}IrC!bf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $tDCS  
nEndPos = " + nFileLength); vDK:v$g  
// fileSplitterFetch[nPos.length-1].start(); ;Ch+X$m9  
=2.tu*!C  
zJnL<Q  
//等待子线程结束 )d770Xg+  
//int count = 0; 1EC-e|M.  
//是否结束while循环 `uIx/.L  
boolean breakWhile = false; Qfkh0DX B  
(aDb^(]>  
>0Fxyv8  
while(!bStop) |dl0B26x  
{ "t (1tWO1o  
write_nPos(); ! F0rd9  
Utility.sleep(500); _KSfP7VU  
breakWhile = true; A6?qIy  
BB2_J=wA  
njy~   
for(int i=0;i<nStartPos.length;i++) >zPO>.?h7T  
{ K;<NBnH  
if(!fileSplitterFetch.bDownOver) >u9id>+  
{ Ax5mP8S  
breakWhile = false; O3^98n2  
break; N5q}::Odc  
} u"`5  
} {\vI9cni|"  
if(breakWhile) :DOr!PNA  
break; o9KyAP$2  
bc3|;O  
[+hy_Nc$  
//count++; Ij;==f~G  
//if(count>4) x !#Ma  
// siteStop(); ]k[ Q]:q  
} 8BYIxHHz  
.DgoOo%?"  
cPA~eZbX  
System.err.println("文件下载结束!"); 7.wR"1p#  
} wFK:Dp_^  
catch(Exception e){e.printStackTrace ();} Q  `e~MD  
} bn0"M+7)f  
`FZ(#GDF  
i&A{L}eCr:  
//获得文件长度 |Hx%f  
public long getFileSize() K(-G: |  
{ 5xh!f%6  
int nFileLength = -1; 52>[d3I3  
try{ G"G{AS  
URL url = new URL(siteInfoBean.getSSiteURL()); =]=B}L `  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -rE eKt  
httpConnection.setRequestProperty("User-Agent","NetFox"); %iK%$  
R<0Fy=z  
e%PC e9  
int responseCode=httpConnection.getResponseCode(); @PYW|*VS  
if(responseCode>=400) [GtcaX{Zz  
{ #^5a\XJb  
processErrorCode(responseCode); *e(:["v  
return -2; //-2 represent access is error Dl0/-=L  
} NzjMk4t  
 5Waw?1GL  
9k+N3vA  
String sHeader; 8# 6\+R  
' oBo|  
]WTf< W<  
for(int i=1;;i++) ]O6KKz  
{ x7vq?fP0n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); XxmJP5  
//Utility.log(in.readLine()); "nVK< Vd  
sHeader=httpConnection.getHeaderFieldKey(i); K5P Gi#  
if(sHeader!=null) +n@f'a">  
{ JzHqNUn*M  
if(sHeader.equals("Content-Length")) Z1VC5* K  
{ " <<A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7sj<|g<h(_  
break; U5|B9%:&  
} G1kDM.L  
} l<u{6o  
else }16&1@8  
break; l*$WX=h6n  
} ?g5iok {  
} 4BHtR017r  
catch(IOException e){e.printStackTrace ();} a`DWpc~  
catch(Exception e){e.printStackTrace ();} \M+MDT&  
gdOe)il\  
0LS -i%0  
Utility.log(nFileLength); N2ni3M5v  
%,33gZzf  
E|Q{]&$;Z"  
return nFileLength; S  <2}8D  
} AnRlH  
qpoquWZ  
- o4@#p>>  
//保存下载信息(文件指针位置) \^Ep>Pq`]  
private void write_nPos() 9X!ET!  
{ $2Kau 1  
try{ iwvt%7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Vre=%bGw  
output.writeInt(nStartPos.length); dAL0.>|`0  
for(int i=0;i<nStartPos.length;i++) (RExV?:  
{ P=c?QYF  
// output.writeLong(nPos); L {!ihJr  
output.writeLong(fileSplitterFetch.nStartPos); :lNg:r$4  
output.writeLong(fileSplitterFetch.nEndPos); X2i*iW<  
} YdK _.t0Mu  
output.close(); T0;u+$  
} p Z"o@';!  
catch(IOException e){e.printStackTrace ();} nlaG<L#  
catch(Exception e){e.printStackTrace ();} |Mt&p#y  
} \xF;{}v  
{z=j_;<]  
Ah*wQow  
//读取保存的下载信息(文件指针位置) w %;hl#s  
private void read_nPos() yDzdE;  
{ S)+CTVVE  
try{ tL1P<1j_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vuXS/ d  
int nCount = input.readInt(); HF]EU!OT  
nStartPos = new long[nCount]; p7s@%scp  
nEndPos = new long[nCount]; >o#ERNf  
for(int i=0;i<nStartPos.length;i++) ~xw5\Y^  
{ ,`y yR:F  
nStartPos = input.readLong(); 4b]_ #7Qm  
nEndPos = input.readLong(); Yhe+u\vGs\  
} "2%>M  
input.close(); 6eM6[  
} #^Ys{  
catch(IOException e){e.printStackTrace ();} ^/k ,  
catch(Exception e){e.printStackTrace ();} z9 O~W5-U  
} ,6DD=w0r  
}~rcrm.   
/oFc 03d  
private void processErrorCode(int nErrorCode) vmvFBzLR  
{ `v~!H\q  
System.err.println("Error Code : " + nErrorCode); $Y6 3!*  
} V`by*s  
#XcU{5Qm5  
WK*S4c  
//停止文件下载 R+d< fe  
public void siteStop() w(Gz({l+  
{ kymn)Ea  
bStop = true; aV<^IxE;  
for(int i=0;i<nStartPos.length;i++) xHHV=M2l(s  
fileSplitterFetch.splitterStop(); V`[P4k+b   
`os8;`G  
{8 N=WZ  
} x )3~il5  
} DKTD Z*  
//负责部分文件的抓取 _|X7 n~  
**FileSplitterFetch.java 7lwTZ*rnY  
*/ , |l@j%  
package NetFox; IfMpY;ow=  
x~EKGoz3  
Z["BgEJ  
import java.io.*; Sl"BK0:%7  
import java.net.*; ;T>+,  
0yz~W(tsm  
 &+G; R  
public class FileSplitterFetch extends Thread { 'y.JcS!|  
W^k,Pmopy  
MxTmWsaW  
String sURL; //File URL :Jk33 N4y0  
long nStartPos; //File Snippet Start Position 4%J|DcY2  
long nEndPos; //File Snippet End Position T9?54r  
int nThreadID; //Thread's ID w4,]2Ccn.  
boolean bDownOver = false; //Downing is over L,$3Yj  
boolean bStop = false; //Stop identical Oc~aW3*A(  
FileAccessI fileAccessI = null; //File Access interface NI.`mc6X d  
4-V)_U#8  
W$'0Dc  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _=EZ `!%  
{ M|8 3HTJ  
this.sURL = sURL; + xp*]a  
this.nStartPos = nStart; ! Mo`^ t  
this.nEndPos = nEnd; 8teJ*sz  
nThreadID = id; aMJ;bQD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )7Ixz1I9g  
} ,{8v4b-  
bi$VAYn.^  
Ly>OLI0x_  
public void run() H\#:,s{1  
{ H^ BYd%-  
while(nStartPos < nEndPos && !bStop) OH6n^WKY  
{ NXI[q 'y  
utH%y\NMF|  
,E}$[mHyjz  
try{ "!KpXBc,>  
URL url = new URL(sURL); V!&P(YO:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {/|qjkT&W  
httpConnection.setRequestProperty("User-Agent","NetFox"); eFFc9'o  
String sProperty = "bytes="+nStartPos+"-"; 6Dst;:  
httpConnection.setRequestProperty("RANGE",sProperty); r~>,$[|n})  
Utility.log(sProperty); 'N6 S}w7  
S4bBafj[I  
%4,?kh``D  
InputStream input = httpConnection.getInputStream(); m|F:b}0Hb  
//logResponseHead(httpConnection); w z=z?AZW  
HnU Et/  
,@.EpbB  
byte[] b = new byte[1024]; VLdB_r3lQ  
int nRead; IzUo0D*@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &{z<kmc$6  
{ P^i.La,  
nStartPos += fileAccessI.write(b,0,nRead); ,S!w'0k|n  
//if(nThreadID == 1) Cj^{9'0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hO( RZ '{  
} ;LMWNy4  
;`UecLb#  
rMp9jG@3   
Utility.log("Thread " + nThreadID + " is over!"); |[1D$Qv  
bDownOver = true; Lh ap4:  
//nPos = fileAccessI.write (b,0,nRead); 2"&)W dm  
} Nfn(Xn*J-  
catch(Exception e){e.printStackTrace ();} :2y"3azxk  
} >|*yh~  
} _^\$" nw  
#/ "+  
|W7rr1]~S  
//打印回应的头信息 b$- e\XB!  
public void logResponseHead(HttpURLConnection con)  &`Ck  
{ yI)~]K r  
for(int i=1;;i++) Xy7Z38G  
{ o6L9UdT   
String header=con.getHeaderFieldKey(i); >/^#Drwb!i  
if(header!=null) IIz0m3';+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9[Qd)%MO  
Utility.log(header+" : "+con.getHeaderField(header)); %*W<vu>H  
else ^gYD*K!*  
break; ^p=L\SJ  
} @i%YNI5*  
} c`G&KCw)d  
Q@QFV~  
uk7'K 0j  
public void splitterStop() '&yeQ   
{ sl|_=oXT  
bStop = true; glUo7^ay7  
} ,)fkr]`<  
,k0r  
!GK$[9  
} .$rC0<G[K  
vqNsZ 8|`  
~;#MpG;e  
/* |$+5@+Zz  
**FileAccess.java Re= WfG  
*//文件访问(定位,写) *"{& FEV  
package NetFox; K_BPZ5w  
import java.io.*; .tXtcf/  
7^:4A'  
Nt-<W+,  
public class FileAccessI implements Serializable{ , c;eN  
SUtf[6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6Y384  
RandomAccessFile oSavedFile; lWZuXb,G  
long nPos; fI|[Z+"  
5g ;ac~g  
wts:65~  
public FileAccessI() throws IOException ;%!m<S|%k  
{ _|{aC1Y!V  
this("",0); e [0w5)X   
} LM l~yqM  
,LYFEq_  
2WBq  
public FileAccessI(String sName,long nPos) throws IOException @R2at  
{ M8;lLcgu.  
oSavedFile = new RandomAccessFile(sName,"rw"); =U-r*sGLN  
this.nPos = nPos; UWXm?v2j  
oSavedFile.seek(nPos); ,"?A2n-qO  
} 9IZu$-  
w YNloU  
^4$ 'KIq  
public synchronized int write(byte[] b,int nStart,int nLen) n&XGBwgW  
{ =hH.zrI6e  
int n = -1; {padD p  
try{ +|RB0}hFS-  
oSavedFile.write(b,nStart,nLen);  u\e\'\  
n = nLen; 1cJsj  
} -V<t-}h.  
catch(IOException e) fP-|+Ty O  
{ ' [0AHM  
e.printStackTrace (); +V(5w`qx  
} )9j06(<A  
peVq+(=.  
K`KLC.j  
return n; x^=M6;:  
} '3(l-nPiG^  
Jobiq]|>  
Z@rN_WXx  
} f"5g>[ 1  
*TdnB'Gd  
ra7uU*  
/* j ) vlM+  
**SiteInfoBean.java N=1JhjVk"  
*/ rXi uwz\  
package NetFox; A2H4k|8  
O9h+Q\0\W  
9h,u6e  
public class SiteInfoBean { Xh+ia#K  
J{"kw1Lu  
sKaE-sbJY  
private String sSiteURL; //Site's URL u=+q$Q]  
private String sFilePath; //Saved File's Path keAcKhj  
private String sFileName; //Saved File's Name ] gb=  
private int nSplitter; //Count of Splited Downloading File f<jb=\}x  
q 2? X"!  
vR7HF*8  
public SiteInfoBean() m>&HuHf  
{//nSplitter的缺省值为5 kAzd8nJ'  
//default value of nSplitter is 5 j8,n7!G  
this("","","",5); `(4pu6uT  
} F1azZ (  
7Hw<ojkt  
-#&kYK#Ph  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p#d+>7  
{ xBnbF[  
sSiteURL= sURL; 5ua?I9fY  
sFilePath = sPath; 'C+;r?1!h  
sFileName = sName; {==pZpyyh  
this.nSplitter = nSpiltter; !UBO_X%dz  
8Z#j7)G  
nY?  
} x<(b|2qf  
\&xl{64  
[pOg'  
public String getSSiteURL() /L=(^k=a.;  
{ 5t:8.%<UK  
return sSiteURL; !%L,* '  
} v@ C,RP9  
]n1dp2aH  
jh ez  
public void setSSiteURL(String value) Y#V8(DTyH  
{ CX/(o]  
sSiteURL = value; pR o s{Uq"  
} #~ v4caNx  
`d]Z)*9  
#} ,x @]p  
public String getSFilePath() X~T/qFS   
{ _cqy`p@"  
return sFilePath; &vUq}r%P  
} ,i}|5ozj4  
|cbd6e{!  
H -t|i  
public void setSFilePath(String value) ~9o6 W",  
{ ('k<XOi  
sFilePath = value; E$\~lcq  
} f_mhD dq  
R'K/t|MC  
w_-+o^  
public String getSFileName() >wON\N0V_  
{ uGtV}-t:  
return sFileName; L&2u[ml  
} C*~aSl7  
_kraMQ>  
\{|ImCH  
public void setSFileName(String value) TRvZ  
{ d.F)9h]XHO  
sFileName = value; dbGgD=}o  
} $^%N U  
v"6 \=@  
|Fln8wB  
public int getNSplitter() #;r]/)>  
{ v|t{1[C  
return nSplitter; eD#XDK  
} 70gg4BS  
i?}>.$j  
dSK 0h(8  
public void setNSplitter(int nCount) H[&@}v,L  
{ QJ X/7RA  
nSplitter = nCount; S3 \jcgrS  
} F 1W+o?B  
} e<+<lj "  
:h5J r8  
h[Tk; h  
/* 5G*II_j  
**Utility.java 5~VosUp e7  
*/ a5c'V   
package NetFox; K b(9)Re  
|ng%PQq)  
'1+.t$"/tU  
public class Utility { Bq}x9C&<  
=Viy^ieN$  
EA0iYzV  
public Utility() wK5_t[[  
{  &"S/Lt  
zQfkMa.  
Ol+Kp!ocY  
} 4<gJ2a3  
Z7#7N wy4  
//线程睡眠 *g7DPN$aQ  
public static void sleep(int nSecond) vOT*iax0  
{ Da,Tav%b  
try{ >;lKLGJrd>  
Thread.sleep(nSecond); _/x& <,3  
} bx;f`8SN  
catch(Exception e) GW m4~]0E  
{ 3 N%{B  
e.printStackTrace (); qo;)X0 N  
} Ye |G44z  
} aqL<v94wX  
"'{OIP  
//日志 &HF]\`RNr  
public static void log(String sMsg) L|67f4  
{ gxM[V>[  
System.err.println(sMsg); OlGR<X  
} $ KQ,}I  
kK?zVH-!  
H@W0gK(cS;  
public static void log(int sMsg) |5ONFd e"0  
{ D rS?=C@  
System.err.println(sMsg); *zQOJsg"e  
} In(NF#  
} CA^.?&CH^O  
`]>on`n?  
# "r kuDO  
/* P9yw&A  
**TestMethod.java -1mvhR~  
*/ <%?uYCD  
package NetFox; !R{em48D  
HD00J]y_   
;,`]O!G:P  
public class TestMethod { 6Ct0hk4  
{PmzkT}LF  
ZR mPP  
public TestMethod() ?`i|" y #  
{ ///xx/weblogic60b2_win.exe B1,?{Ur  
try{ fLM.k CD?u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g RU-g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s01$fFJgO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 88YC0!Ni  
fileFetch.start(); m)k-uWc$C  
}  8bGD  
catch(Exception e){e.printStackTrace ();} sH@  &*  
.b~OMTHuvM  
l#ygb|=x  
} Xj;2h{#s  
?\d5;%YSr  
P2QRvn6v  
public static void main(String[] args) "c EvFY  
{ w3d\0ub  
new TestMethod(); X&,N}9>B  
} 8E-Ip>{>  
} Vy r] x  
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