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http断点续传简单实现(java)

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/* v+7*R)/  
**SiteFileFetch.java :D^Y?  
*/ MyM+C}  
package NetFox; 7n<#y;wo  
import java.io.*; }RDb1~6C  
import java.net.*; Z3I L8  
xK=J.>h3  
IKtiR8  
public class SiteFileFetch extends Thread { ~e+0c'n\  
IF$^ 0q  
q'fPNQg  
SiteInfoBean siteInfoBean = null; //文件信息Bean Kd TE{].d  
long[] nStartPos; //开始位置 ][ rTQt m  
long[] nEndPos; //结束位置 Cl-S=q@>V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 tbRE/L<  
long nFileLength; //文件长度 SDJ;*s-  
boolean bFirst = true; //是否第一次取文件 eTT^KqE>&  
boolean bStop = false; //停止标志 $ #t|(\  
File tmpFile; //文件下载的临时信息 XzN-slu!  
DataOutputStream output; //输出到文件的输出流 s.bT[0Vl  
@qpYDnJ:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) JYl\<Z' {  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1wU=WE(kKZ  
{ B5 tx f.  
siteInfoBean = bean; ^,~N7`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T:dX4=z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); qYDj*wqf  
if(tmpFile.exists ()) <XY;fhnB  
{ Iy6p>z|  
bFirst = false; T&mbXMN  
read_nPos(); e%'z=%(  
} vx PDC~3;  
else q!9^#c  
{ @OBHAoz%/  
nStartPos = new long[bean.getNSplitter()]; J]$er0`LY  
nEndPos = new long[bean.getNSplitter()]; {rtM%%l  
} x$*E\/zi<!  
K:Mujx:  
91U^o8y  
/kAwe *)  
} ^#}dPGm  
[U% .Gi  
rO5u~"v]  
public void run() !~ BZHi6\  
{ 2Ti" s-  
//获得文件长度 3"f)*w7d  
//分割文件 <!$dp9y.  
//实例FileSplitterFetch 'MSEki67  
//启动FileSplitterFetch线程 ze*&*csO  
//等待子线程返回 /0Rt+`  
try{ d?Ia#K9 3G  
if(bFirst) s+(l7xH$  
{ &S9f#Ui  
nFileLength = getFileSize(); 0zlM.rjEZ  
if(nFileLength == -1) r.Y*{!t  
{ e~tr^$/(  
System.err.println("File Length is not known!"); iLjuE)6-$  
} d3\OHkM0^  
else if(nFileLength == -2) t5I^1u6  
{ ]u\  `  
System.err.println("File is not access!"); C+X)">/+L  
} 7=$+k]U8  
else 4!NfQk>X  
{ Y] D7i?3N  
for(int i=0;i<nStartPos.length;i++) 3D]2$a_d  
{ i#CaKS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jc${.?m  
} ._8xY$l$  
for(int i=0;i<nEndPos.length-1;i++) dM$N1DB{U+  
{ bbfDt^  
nEndPos = nStartPos[i+1]; N |OMj%Uk  
} 7KvXTrN!9  
nEndPos[nEndPos.length-1] = nFileLength; CsJ)Z%4_  
} -d$8WSI 8  
} MLkL.1eGSb  
>cGh|_9  
P-/XYZ]`  
//启动子线程 Z?!JV_K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {m?K2]](  
for(int i=0;i<nStartPos.length;i++) K> c8r8!  
{ Z/XM `Cy  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (#f m (@T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r78u=r  
nStartPos,nEndPos,i); }:,o Y<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "R@$Wu53|  
fileSplitterFetch.start(); m_{%tU;N  
} A^}i^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R@)'Bs  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3K=q)|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x.0k%H  
nEndPos = " + nFileLength); B[) [fE  
// fileSplitterFetch[nPos.length-1].start(); VEFwqB1l  
bLU^1S8Z  
FYx `o\  
//等待子线程结束 ~zXG<}n  
//int count = 0; UFzM#  
//是否结束while循环 <3i4NXnL2  
boolean breakWhile = false; LUe>)eqw  
~!a~C~_  
2b 6? 9FX*  
while(!bStop) iBGSBSeL&  
{ 3p?<iVE  
write_nPos(); =j'J !M  
Utility.sleep(500); r`&2-]  
breakWhile = true; h"RP>fZt  
zIAu3  
EI?d(K  
for(int i=0;i<nStartPos.length;i++) X/- W8  
{ fD3jwPL  
if(!fileSplitterFetch.bDownOver) ,ZzB#\  
{ vp )}/&/  
breakWhile = false; AF9[2AH=Y  
break; Mp^OL7p^^  
} pJ 2:` f<;  
} Z1)jRE2dl  
if(breakWhile) v&[X&Hu[  
break; F #!@}K8  
gL[1wM%?  
XEvGhy#  
//count++; ;Sx'O  
//if(count>4) Dr8WV \4@  
// siteStop(); v -|P_O&z  
} %-1BA *J`|  
L5V'Sr  
S|RpA'n  
System.err.println("文件下载结束!"); A4 A6F<  
} ] dm1Qm  
catch(Exception e){e.printStackTrace ();} 5v Uz  
} |1<]o;:  
xzMeKC `  
D^N#E>,  
//获得文件长度 K#JabT  
public long getFileSize() Cu ['&_@  
{ dIBKE0`  
int nFileLength = -1; jE?\Yv3  
try{ p,[XT`q^  
URL url = new URL(siteInfoBean.getSSiteURL()); (^s&M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m p|20`go  
httpConnection.setRequestProperty("User-Agent","NetFox"); /A[oj2un  
*D09P%  
HX /GLnY/X  
int responseCode=httpConnection.getResponseCode(); |&0"N[t  
if(responseCode>=400) .%J?T5D  
{  xnRp/I  
processErrorCode(responseCode); T~wZ  
return -2; //-2 represent access is error Dh!iY0Lz  
} k+7M|t.?4  
R$T[%AGZ.  
Wd^F%)(  
String sHeader; Bah.\ZsYQP  
; $ ?jR c  
oM18aR&  
for(int i=1;;i++) #iR yjD  
{ U&]p!DV&;  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +LI*!(T|lm  
//Utility.log(in.readLine()); 5E\<r /FeJ  
sHeader=httpConnection.getHeaderFieldKey(i); zT4ulXN  
if(sHeader!=null) 9znx1AsN  
{ 8}pcanPg  
if(sHeader.equals("Content-Length")) ?5r2j3mqgv  
{ 9pl_V WrQ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4I:JaRT d  
break; O yH!V&w  
} @F3-Ugm  
} Qa7S'(  
else cyHak u+  
break; WFeMr%Zqh>  
} ].<sAmL^  
} #<tWYE  
catch(IOException e){e.printStackTrace ();} jL7MmR#y5"  
catch(Exception e){e.printStackTrace ();} $!l2=^\3  
eUKl Co  
$)TF,-#x  
Utility.log(nFileLength); ExOB P  
]"7DV3_  
u7Y'3x,`  
return nFileLength; Io4:$w  
} /|u]Y/ *  
}x#P<d(  
?D~SHcBaN  
//保存下载信息(文件指针位置) rlO%%Qn`  
private void write_nPos() 49J+&G?)j  
{ mBpsgm:g^  
try{ 4_m /_Z0x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]|$$:e^U9  
output.writeInt(nStartPos.length); \_I)loPc8  
for(int i=0;i<nStartPos.length;i++) z?t(+^  
{ O[hbu![  
// output.writeLong(nPos); WKrZTPD'm  
output.writeLong(fileSplitterFetch.nStartPos); X%9xuc  
output.writeLong(fileSplitterFetch.nEndPos); M ly z><  
} |jaY[_ .@  
output.close(); n;k97>m${x  
} 9+is?Pj  
catch(IOException e){e.printStackTrace ();} [P&,}o)+E0  
catch(Exception e){e.printStackTrace ();} ~4~Tcn  
} gh #w%g1g  
y~A7pzBZ=  
l-^XW?CfL  
//读取保存的下载信息(文件指针位置) H;t8(-F@'  
private void read_nPos() 't]EkH]BC  
{ da?th  
try{ o4[2`mT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @X6#$ex  
int nCount = input.readInt(); H+#wj|,+\  
nStartPos = new long[nCount]; @aD~YtL"n  
nEndPos = new long[nCount]; a] wcA  
for(int i=0;i<nStartPos.length;i++) \]`(xxt1  
{ Tx!m6B`Y  
nStartPos = input.readLong(); +|"n4iZ!)  
nEndPos = input.readLong(); DN 8pJa  
} &!YH"{b  
input.close(); eRx[&-c  
} $W_o$'crW  
catch(IOException e){e.printStackTrace ();} )p^jsv.  
catch(Exception e){e.printStackTrace ();} 1uge>o&  
} UWWD8~:  
_g`0td>N  
dzv,)X  
private void processErrorCode(int nErrorCode) ~"r wP=<}  
{ e>zk3\D!  
System.err.println("Error Code : " + nErrorCode); X.AOp  
} q'V{vFfY%  
ot+~|Dl  
*1)NABp6D  
//停止文件下载 [ rQ(ae  
public void siteStop() wIR[2&b  
{ "xc*A&Sg  
bStop = true; gAUQQ  
for(int i=0;i<nStartPos.length;i++) 1707  
fileSplitterFetch.splitterStop(); Z8dN0AqZ  
]>4Qs  
:XQ  
} 'lRHdD}s  
} _TN$c  
//负责部分文件的抓取 +@)$l+kk9  
**FileSplitterFetch.java yzNX2u1  
*/ L{0OMyUA  
package NetFox; S5 nw  
IM5^E#-g7  
a=B0ytNm  
import java.io.*; 5NF&LM;i(  
import java.net.*; \HQb#f,  
*-!ndbf  
WfbNar[  
public class FileSplitterFetch extends Thread { W>|b98NPu  
3Q~&xNf  
l`%} {3r9  
String sURL; //File URL gcCYXPZp  
long nStartPos; //File Snippet Start Position x[>_I1TJ  
long nEndPos; //File Snippet End Position )B&<Bk+  
int nThreadID; //Thread's ID rH:X/i;D  
boolean bDownOver = false; //Downing is over v8k ^=A:  
boolean bStop = false; //Stop identical *4^]?Y\*  
FileAccessI fileAccessI = null; //File Access interface [<fLPa  
0o=)&%G  
Z%9^6kdY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dVt@D&  
{ +95dz?~  
this.sURL = sURL; %y7wF'_Y  
this.nStartPos = nStart; $)7f%II  
this.nEndPos = nEnd; h-rj  
nThreadID = id; s]%!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I2lZ>3X{  
} P~ZV:Of  
h%^kA@3F  
Lpbn@y26<  
public void run() R Mt vEa  
{ )Q j9kJq  
while(nStartPos < nEndPos && !bStop) Q0; gF?  
{ 4$2T zJE  
99>yaW  
coVT+we  
try{ F}.TT =((8  
URL url = new URL(sURL); 2_\|>g|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U`p<lxRgQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); _w/N[E  
String sProperty = "bytes="+nStartPos+"-"; `LU,uz  
httpConnection.setRequestProperty("RANGE",sProperty); l<: E+lU  
Utility.log(sProperty); JI,hy <3l0  
.*f4e3  
kpw4Mq@  
InputStream input = httpConnection.getInputStream(); W!B4< 'Fjc  
//logResponseHead(httpConnection); wP':B AQ4U  
S^VV^O5 ^  
a[cH@7W.#  
byte[] b = new byte[1024]; E=*Q\3G~  
int nRead; X/7_mU>aKT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3M*[a~  
{ *K.7Zf0  
nStartPos += fileAccessI.write(b,0,nRead); [f(^vlK  
//if(nThreadID == 1) ~wg^>!E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BF [?* b  
} vm^# aoDB  
,:4w$!;  
uBkn y;  
Utility.log("Thread " + nThreadID + " is over!"); 7 =*k@9  
bDownOver = true; TXl9c 6  
//nPos = fileAccessI.write (b,0,nRead); c]R![sa  
} 3&Rqz9W  
catch(Exception e){e.printStackTrace ();} B[|/wHMsT}  
} $K fk=@  
} !jq6cND  
3i}B\ {  
|3@Pt>Ikl  
//打印回应的头信息 _-\{kJ  
public void logResponseHead(HttpURLConnection con) &LQab>{*K  
{ TC#B^m`'p  
for(int i=1;;i++) 2U+p@}cQUA  
{ B "zg85 e  
String header=con.getHeaderFieldKey(i); 3 v$4LY  
if(header!=null) #}yFHM?i  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7 ~8Fs@  
Utility.log(header+" : "+con.getHeaderField(header)); u.Yb#?  
else X*"O'XCA  
break; bd*(]S9d  
} O~OWRJ@p  
} l>?vjy65  
DkKD~  
 /?xn  
public void splitterStop() 9cj-v}5j  
{ HKw:fGt/o^  
bStop = true; F|Ihq^q  
} HZ=yfJs nc  
g|_*(=Q  
*bSG48W("  
} ~At.V+  
'oL[rO~j  
Li^!OHro.  
/* c6)zx b  
**FileAccess.java o:\a  
*//文件访问(定位,写) O^% ace1  
package NetFox; /k"P4\P`+Q  
import java.io.*; K!gFD  
s7} )4.vO  
{~h\;>  
public class FileAccessI implements Serializable{ g(H3arb&  
vJUB;hD  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 NmF2E+'  
RandomAccessFile oSavedFile; Z+4Oa f!  
long nPos; FCJ(D!  
t O>qd#I  
Lpf=VyqC  
public FileAccessI() throws IOException ?EAqv]  
{ (Z +C  
this("",0); ,SwaDWNO  
} <);u]0  
Ec 7M'~1  
)yZE>>3-  
public FileAccessI(String sName,long nPos) throws IOException QjU"|$  
{ }>U03aa!  
oSavedFile = new RandomAccessFile(sName,"rw"); "iGc'?/+  
this.nPos = nPos; ;gV8f{X{Z  
oSavedFile.seek(nPos); 9E?>B3t^  
} \ y",Qq?  
oP 0j>i,"&  
)~(_[='  
public synchronized int write(byte[] b,int nStart,int nLen) yqI|BF`  
{ ~A4WuA  
int n = -1; 0eP~F2<bC  
try{ uu.Nq*3  
oSavedFile.write(b,nStart,nLen); B ;$8<  
n = nLen; &,7(Wab  
} m 0PF"(  
catch(IOException e) oX ,M;;Yq  
{ ^umAfk5r?H  
e.printStackTrace (); rnE'gH(V'  
} B=|sLs`I  
'WCTjTob/  
{!h[@f4  
return n; >,vuC4v-  
} .R5z>:A  
j(JI$  
Y,~]ecI  
} <~w#sIh  
X ii#Qtd.  
MsQS{ok+  
/* LJ3UB  
**SiteInfoBean.java WpZ^R;eK  
*/ DlI|~  
package NetFox; kw'D2692  
iSlVe~ef  
b\Ub<pE  
public class SiteInfoBean { C:{'0m*jKs  
c3dZ1v  
+i =78  
private String sSiteURL; //Site's URL m(Ynl=c  
private String sFilePath; //Saved File's Path [4yQ-L)]e  
private String sFileName; //Saved File's Name a\E]ueVD2j  
private int nSplitter; //Count of Splited Downloading File _A r ,]v  
H#E0S>Jw|  
Nl _Jp:8s  
public SiteInfoBean() lc7]=,qyF  
{//nSplitter的缺省值为5 |0-L08DW  
//default value of nSplitter is 5 $49tV?q5  
this("","","",5); } _z~:{Y  
} !ZW0yCwLQ  
nE84W$\  
[bXZPIz;j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >2/zL.O  
{ mgWtjV 8  
sSiteURL= sURL; jXf-+ ;ZQ  
sFilePath = sPath; 9nE%r\H  
sFileName = sName; 5hMiCod  
this.nSplitter = nSpiltter; Q23y.^W%c  
.O^|MhBJu  
iy9]Y5b   
} +qec>ALAg  
x;Q2/YZ#  
uItKsu  
public String getSSiteURL() hlZjk0ez  
{ Tw5BvB1  
return sSiteURL; H@:@zD!G[  
} ;21JM2JI8  
\Wk$>?+#@  
JV>OmUAk  
public void setSSiteURL(String value) Pt+_0OsR  
{ kn.z8%^(  
sSiteURL = value;  M > <   
} V*~5*OwB  
tG-MC&;=  
2RCnk&u  
public String getSFilePath() S0`*  
{ MNzq}(p  
return sFilePath; ",m5}mk:4  
} xT/&'$@{)  
W+E2({  
&AVi4zV  
public void setSFilePath(String value) qz&)|~,\C  
{ 3^Y-P8.zdB  
sFilePath = value; $B2@mC([S  
} RZZB?vx  
P}jr 8Z  
|Th{*IJ <,  
public String getSFileName() gnGw7V  
{ ~08v]j q  
return sFileName; `*a,8M%  
} i]v!o$7  
.uP$M(?j  
o&zV8DE_v  
public void setSFileName(String value) jX%Q  
{ .+<K-'&=  
sFileName = value; {`LV{ !  
} f8lww)^,v  
EA\~m*k  
79v&6Io  
public int getNSplitter() K5$ y  
{ !FO)||'[  
return nSplitter; sIpK@BQ'  
} !ktr|9Bl  
~>n<b1}W  
=6$(m}(74  
public void setNSplitter(int nCount) bQ%^l#H_n'  
{ `W9_LROD  
nSplitter = nCount; `6/7},"9t  
} fCKcv |  
} &V"&SV>}  
n!p&.Mt  
?S_S.Bd  
/* R~i<*  
**Utility.java <+a\'Xc  
*/ e/6oC~#]  
package NetFox; 3-05y!vbcE  
+vP1DXtj(  
w%ForDB>P  
public class Utility { epnDvz\   
O  tr@jgw  
]q j%6tz  
public Utility() L`\ILJz  
{ . XmD[=  
~4M]SX1z  
&e(de$}xt  
} _heQ|'(  
Wq4?`{  
//线程睡眠 jHd~yCq  
public static void sleep(int nSecond) pr2d}~q4{  
{ AXyuXB  
try{ SG~R!kN}Q  
Thread.sleep(nSecond); fKfi   
} ,O2F}5|;  
catch(Exception e) C}!|K0t?  
{ [8"nRlXH  
e.printStackTrace (); V;m3=k0U  
} ^^Ius ]  
} +m1edPA[  
O@[q./VV,  
//日志 z|9 ^T@)  
public static void log(String sMsg) T<OLfuV  
{  >4Lb+]  
System.err.println(sMsg); V{npK(  
} ?$ 3=m)s  
b7$?'neH/.  
lBCM; #P  
public static void log(int sMsg) &(K*TB|Om  
{ f /jN$p  
System.err.println(sMsg); Gqs8$[o  
} SbB5J> >7J  
} Z'EZPuZ!'  
rg`"m  
R\<^A~(Gl  
/* k: {$M yK  
**TestMethod.java M! s&<Bi  
*/ =$m|M m[a  
package NetFox; I=1tf;Bsi  
 6} 9A0  
O:#to  
public class TestMethod { m,pDjf  
$oNkE  
!v^D j']  
public TestMethod() K1Tzy=Z9j  
{ ///xx/weblogic60b2_win.exe os>|LPv4  
try{ 9TF[uC)-2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QoqdPk#1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); htaB! Q?V  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k,r\^1h  
fileFetch.start(); MW p^.  
} M?_VYK  
catch(Exception e){e.printStackTrace ();} 03MB,  
ZXco5,1  
k -SUp8}g  
} Dr;@)  
xT@\FwPr  
4Ld0AApncy  
public static void main(String[] args) 5L4~7/kj  
{ 6rRPqO j  
new TestMethod(); jtZ@`io  
} 4 0Du*5M  
} oV*3Mec  
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