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http断点续传简单实现(java)

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/* TF%Xb>jy[  
**SiteFileFetch.java l>MDCqV  
*/ \ )=WA!  
package NetFox; n>?D-)g  
import java.io.*; 4EHrd;|   
import java.net.*; zs~Tu  
M+0PEf.  
\n t~K}a  
public class SiteFileFetch extends Thread { )q[P&f(h  
{9yf0n  
BY.k.]/  
SiteInfoBean siteInfoBean = null; //文件信息Bean V ^+p:nP  
long[] nStartPos; //开始位置 J*[@M*R;&  
long[] nEndPos; //结束位置 4Wp5[(bg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 'L7qf'RV  
long nFileLength; //文件长度 SIV !8mz  
boolean bFirst = true; //是否第一次取文件 h~m,0nGO  
boolean bStop = false; //停止标志 .07`nIs"  
File tmpFile; //文件下载的临时信息 ~N/r;omVc  
DataOutputStream output; //输出到文件的输出流 mUbm3JIjJ  
X%+lgm+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) R!%nzL@e&`  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0_eqO'"  
{ mwo:+^v(  
siteInfoBean = bean; !( rAI  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); QXZyiJX}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @uH!n~QV  
if(tmpFile.exists ()) qx'0(q2Ii(  
{ c7jmzo  
bFirst = false; >;^/B R=  
read_nPos(); (Kwqa"Hk4{  
} ~g\~x  
else rNR7}o~qo  
{ Rh ^(91d  
nStartPos = new long[bean.getNSplitter()]; F)(^c  
nEndPos = new long[bean.getNSplitter()]; gLB(A\yG  
} |ZL?Pqki  
{2h *NFp  
b!P,+!<  
CtXbAcN2B  
} V6X )L>!xx  
'< U&8?S  
-BH/)$-$  
public void run() O|V0WiY<  
{ !,$#i  
//获得文件长度 7ocUFY0"  
//分割文件 ZQ]qJDk  
//实例FileSplitterFetch mUa#sTm  
//启动FileSplitterFetch线程 Ifn|wrx;g  
//等待子线程返回  d 2d-Mk  
try{ 393c |8M  
if(bFirst) Zp> v  
{ Y {^*y  
nFileLength = getFileSize(); tL$,]I$1+  
if(nFileLength == -1) Z0fa;%:  
{ AP=h*1udk  
System.err.println("File Length is not known!"); =P]Z"Ok  
} *O :JECKU  
else if(nFileLength == -2) .;]WcC<3  
{ p L"{Uqi  
System.err.println("File is not access!"); x ;|HT  
} TKR#YJQ?K  
else oFj_o  
{ ^e8xg=8(  
for(int i=0;i<nStartPos.length;i++) !+%gJiu:  
{ . vb##D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -N*[f9EJB  
} $6a9<&LP_  
for(int i=0;i<nEndPos.length-1;i++) Gr\ ]6  
{ A?H#bRAs  
nEndPos = nStartPos[i+1]; Hu"$ )V  
} 509T?\r  
nEndPos[nEndPos.length-1] = nFileLength; ]SCHni_  
} "[N2qJ}p  
} +})QTFV  
?4bYb]8Z  
2g= 6 s  
//启动子线程 rGP;0KtQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G*I    
for(int i=0;i<nStartPos.length;i++) s<zN`&t  
{ lxyTh'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "V' r}>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &DWSf`:Hx  
nStartPos,nEndPos,i); +]eG=. u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M-nRhso  
fileSplitterFetch.start(); i1cd9  
} 0vqVE]C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J\y^T3Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); mD'nF1o Ly  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $|=| "/  
nEndPos = " + nFileLength); ]lwf6'  
// fileSplitterFetch[nPos.length-1].start(); +MX~1RU+  
zR<{z  
,`bW (V  
//等待子线程结束 },8|9z#pyB  
//int count = 0; NftnbsTmy  
//是否结束while循环 "z{/*uM2<  
boolean breakWhile = false; @P7'MiP]K  
(%X *b.n=  
1kvX#h&V  
while(!bStop) FBXktSg  
{ )/jDt dI  
write_nPos(); gy}3ZA*F  
Utility.sleep(500); cy8>M))c  
breakWhile = true; dHDtY$/_  
3gUY13C}:p  
V *@q< rQ  
for(int i=0;i<nStartPos.length;i++) ^*}D*=>\  
{ 7Mh'x:p  
if(!fileSplitterFetch.bDownOver) 28"1ONs 3  
{ VZi1b0k1.  
breakWhile = false;  p& _Z}Wv  
break; JTKS5 r7?  
} 05 6K)E  
} =`3r'c  
if(breakWhile) l ms^|?  
break; i{fw?))+  
=MqEbQn{C3  
D`p2aeI  
//count++; RnkV)ed(  
//if(count>4) nX!%9x$3  
// siteStop(); hl:Ba2_E +  
} 4mDHAR%D  
`j{3|C=  
16 AlmegDk  
System.err.println("文件下载结束!"); > SZ95@Oh  
} ;5/Se"Nd  
catch(Exception e){e.printStackTrace ();} mfj{_fR3  
} SD^::bH  
c,r6+oX  
nOPB*{r|  
//获得文件长度 =78y* `L  
public long getFileSize() .4a|^ vT  
{ QT%`=b  
int nFileLength = -1; Z?eTjkNS#  
try{ NOTG|\{  
URL url = new URL(siteInfoBean.getSSiteURL()); -U2Su|:\N8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (]q ([e  
httpConnection.setRequestProperty("User-Agent","NetFox"); <#:iltO  
oO tjG3B({  
&E]) sJ0  
int responseCode=httpConnection.getResponseCode(); ;-1KPDIp`  
if(responseCode>=400) dzIBdth  
{ s]m]b#1!r  
processErrorCode(responseCode); %72# tY  
return -2; //-2 represent access is error (Iv@SiZf(  
} ~aotV1"D  
#X)DFAtb  
()|e xWW  
String sHeader; pss')YP.  
UT@Qo}:  
F[c oa5  
for(int i=1;;i++) 4M"'B A<  
{ 7oE:]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j/Kul}Ml\*  
//Utility.log(in.readLine()); #sU>L=  
sHeader=httpConnection.getHeaderFieldKey(i); w?D=  
if(sHeader!=null) A@3'I  ;  
{ 'cCM[P+  
if(sHeader.equals("Content-Length")) ar@,SKU'K  
{ Z84w9y7O<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MTwzL<@$  
break; b|87=1^m[  
} 9+(b7L   
} %{ U (y#  
else ]fY:+Ru  
break; :LuA6  
} &v]xYb)+<  
} 6<z#*`U1  
catch(IOException e){e.printStackTrace ();} jXx~ 5  
catch(Exception e){e.printStackTrace ();} /\fR6|tJ  
sB0]lj-[Un  
fbI5!i#lz  
Utility.log(nFileLength); iw.F8[})  
"U9e)a0v  
~e|E5[-i  
return nFileLength; <YCjo[(~  
} h/5V~ :)  
ZXhNn<  
vmxS^_I  
//保存下载信息(文件指针位置) ^E, #}cW  
private void write_nPos() l )r^|9{  
{ 0]ai*\,W7~  
try{ sfVzVS[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `_&vvJPn@!  
output.writeInt(nStartPos.length); 1&h\\&ic  
for(int i=0;i<nStartPos.length;i++) nVpDjUpN  
{ wI7.M Gt  
// output.writeLong(nPos); yTc&C)Jba  
output.writeLong(fileSplitterFetch.nStartPos); HZ(giAyjq  
output.writeLong(fileSplitterFetch.nEndPos); a"cw%L  
} {dh@|BzsbH  
output.close(); Wu,=jL3?$A  
} 8I*yS#  
catch(IOException e){e.printStackTrace ();} W G3 _(mM  
catch(Exception e){e.printStackTrace ();} [g==#[  
} :EPe,v RT  
pl}W|kW}  
BD$Lf,_  
//读取保存的下载信息(文件指针位置) DW,Z})9  
private void read_nPos() s&%r?  
{ k-4z2qB  
try{ Yi-,Pb?   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 87pu\(,'  
int nCount = input.readInt(); p*jH5h cy  
nStartPos = new long[nCount]; C\[:{d  
nEndPos = new long[nCount]; #.FhN x  
for(int i=0;i<nStartPos.length;i++) (R s;+S  
{ &/Gf@[  
nStartPos = input.readLong(); 9r:|u:i7m  
nEndPos = input.readLong(); \1u^?cBd  
} RSe av  
input.close(); W T @XHwt  
} 4U$M0 =  
catch(IOException e){e.printStackTrace ();} a U<+ `  
catch(Exception e){e.printStackTrace ();} h5vetci/  
} 9qq6P!  
ra ,.vJuT  
jJ RaY3  
private void processErrorCode(int nErrorCode) B&(/,.  
{ 6EY 0Fjsi  
System.err.println("Error Code : " + nErrorCode); nBd(p Oe  
} 'K23oQwDB  
k/U rz*O  
B0g?!.#23  
//停止文件下载 2Z9ck|L>  
public void siteStop() U[pR `u  
{ HKC&grp  
bStop = true; Wa!C2nB  
for(int i=0;i<nStartPos.length;i++) `OZiN;*|  
fileSplitterFetch.splitterStop(); ( s+}l?  
fDXTedrG/  
e ?Jgk$"  
} d_[ zt)  
} &?j\=%  
//负责部分文件的抓取 M?m@o1\;W  
**FileSplitterFetch.java oB<!U%BN  
*/ &`'@}o>2  
package NetFox;  u7&5t  
7 /" Z/^  
-23sm~`  
import java.io.*; dM -<aq  
import java.net.*; eS%8WmCV9<  
&j"_hFhv  
##" Hui  
public class FileSplitterFetch extends Thread { p CeCR  
I,/E.cRV<  
R<r,&X?m  
String sURL; //File URL y?iW^>|?L=  
long nStartPos; //File Snippet Start Position fndH]Yp  
long nEndPos; //File Snippet End Position Rd@?2)Xm  
int nThreadID; //Thread's ID p8iKZI]g  
boolean bDownOver = false; //Downing is over JGYJ;j{E]  
boolean bStop = false; //Stop identical ayg^js2,  
FileAccessI fileAccessI = null; //File Access interface V>4v6)N  
8y4t9V  
5p7i9"tgn  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KO))2GET  
{ ]~pM;6Pu0  
this.sURL = sURL; 5IRUG)Icr  
this.nStartPos = nStart; DnCIfda2g  
this.nEndPos = nEnd; ;|,*zD  
nThreadID = id; !W b Q9o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6anH#=(  
} y=}o|/5"  
_Q*,~ z~  
MdnapxuS  
public void run() FW4#/H  
{ rj29$d?Y9  
while(nStartPos < nEndPos && !bStop) rLp0)Go  
{ ~kI$8oAry  
K;R!>p}t  
YCG $GD  
try{ cU "uKR  
URL url = new URL(sURL); 5hDm[*83  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bW GMgC  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rf!$n7& \  
String sProperty = "bytes="+nStartPos+"-"; mW3 IR3 b  
httpConnection.setRequestProperty("RANGE",sProperty); =)! ~t/  
Utility.log(sProperty); !^aJS'aq  
cmp@Ow"c  
Vzh\ 1cF  
InputStream input = httpConnection.getInputStream(); Ki[&DvW:  
//logResponseHead(httpConnection); b~!Q3o'W  
@ n$/2y_.  
2t3)$\ylQp  
byte[] b = new byte[1024]; AD7&-=p&w  
int nRead; 0>3Sn\gZ(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F ^)( 7}ph  
{ -{p~sRc&  
nStartPos += fileAccessI.write(b,0,nRead); 5[`f(;  
//if(nThreadID == 1) *n9=Q9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e'3y^Vg  
} K{iC'^wP  
%\1W0%w  
O~5*X f  
Utility.log("Thread " + nThreadID + " is over!"); MVDy|i4  
bDownOver = true; \ Ju7.3.  
//nPos = fileAccessI.write (b,0,nRead); PSU}fo  
} Bf$` Hf6  
catch(Exception e){e.printStackTrace ();} wd2z=^S~  
} T=[ /x=  
} u y13SkW  
b%xG^jUXsX  
,a ":/ /[  
//打印回应的头信息 D1wONss  
public void logResponseHead(HttpURLConnection con) To,*H OP  
{ Lr*\LP6jx3  
for(int i=1;;i++) +6(\7?  
{ w u0q.]  
String header=con.getHeaderFieldKey(i); Bh65qHQO  
if(header!=null) zCmx1Djz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O&@CT])8  
Utility.log(header+" : "+con.getHeaderField(header)); ^(Wu$\SA  
else O_v*,L!  
break; PeJIa %iE  
} #1p\\Av  
} yg82a7D  
]3L/8]:  
ZQ_AqzT3D  
public void splitterStop() QVkrhwp  
{ $-paYQ4  
bStop = true; h*\u0yD)  
} V}Ce3wgvA  
"-Wb[*U;  
^`bMFsP  
} %m-U:H.Vp  
k\-h-0[|  
\%&eDE0  
/* aAgQ^LY  
**FileAccess.java -[[( Zx  
*//文件访问(定位,写) l\ Vr D2j8  
package NetFox; v4F+^0?  
import java.io.*; P[tYu:  
LHSbc!Y'.  
9^@)R ED  
public class FileAccessI implements Serializable{ (QQkXlJ  
-s]@8VJA"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9T0g%&  
RandomAccessFile oSavedFile; ,( NN)Oj  
long nPos; 0B: v0 R  
- B?c F9  
N! I$Qtr,  
public FileAccessI() throws IOException R[OXYHu  
{ MfO: BX@$  
this("",0); B lqISyrY  
} %^[D+1ULb  
/O~Np|~v  
B:Hr{%O  
public FileAccessI(String sName,long nPos) throws IOException c:""&>Z  
{ m~uT8R#$  
oSavedFile = new RandomAccessFile(sName,"rw"); &^l(RBp]0  
this.nPos = nPos; 13+. >  
oSavedFile.seek(nPos); ^!gq_x  
} fElFyOo+  
1x%B`d  
UqNUX?(  
public synchronized int write(byte[] b,int nStart,int nLen) n}c~+ 0`un  
{ bAwKmk9C  
int n = -1; egVKAR-  
try{ (%mV,2|:20  
oSavedFile.write(b,nStart,nLen); o7@C$R_#  
n = nLen; zjOOEvi  
} cQm4q19  
catch(IOException e)  K~B  
{ Y=5P=wE  
e.printStackTrace (); 3 FV -&Y  
} u08QE,  
h J0U-m  
$tej~xZK  
return n; %r8;i  
} g/VV2^,  
<y?=;54a  
Ej1 <T,w_  
} T"<)B^8f  
7Gy:T47T\@  
'u~0rMe4})  
/* |gIE$rt-~W  
**SiteInfoBean.java hCS}  
*/ 3#Bb4\_v  
package NetFox; -:E~Z_J`  
3R0ioi 7  
eze%RjO}  
public class SiteInfoBean { 2=/-,kOL_  
zTc*1(^  
Qj*.Z4ue  
private String sSiteURL; //Site's URL xF@&wg  
private String sFilePath; //Saved File's Path I Zw  
private String sFileName; //Saved File's Name :q?#$?  
private int nSplitter; //Count of Splited Downloading File e .~11bx  
ncMzHw  
&} { #g  
public SiteInfoBean() um}q@BU  
{//nSplitter的缺省值为5 &BRa5`  
//default value of nSplitter is 5 |Wjpnz  
this("","","",5); cnI5 G!  
} @bJIN]R  
^3 9lUKL  
,[)l>!0\H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~?FhQd\Q  
{ gn&Zt}@[  
sSiteURL= sURL; imeE&  
sFilePath = sPath; 4QTHBT+2`  
sFileName = sName; 0^sY>N"  
this.nSplitter = nSpiltter; f 9Kt>2IN  
%S'+x[ 4W  
Fj]06~u  
} q=Vh"]0g  
ixSr*+  
CS~_>bn  
public String getSSiteURL() ~$J(it-a  
{ ~UZ3 lN\E  
return sSiteURL; &*%x]fQ@  
} x~vNUyEN)  
RB4 +"QUh  
"RN] @p#m  
public void setSSiteURL(String value) x7U=1y(  
{ ^6z"@+;*  
sSiteURL = value; N2"B\  
} bd~m'cob>  
kS8?N`2}LV  
6(rN(C  
public String getSFilePath() T7^;!;i`X  
{ `Z8k#z'bN  
return sFilePath; <|jh3Hlp  
} }Sbk qd5  
pCA`OP);=  
IEMa/[n/  
public void setSFilePath(String value) -v.\W y~\  
{ &i(Ip'r  
sFilePath = value; 5a$EXV  
} 849,1n^  
:C(/yg  
#[bL9R5NC  
public String getSFileName() }#7rg_O]>  
{ yV )fJ_  
return sFileName; 0hV#]`9`gN  
} {;u,04OVK  
OtmDZ.t;`  
75zU,0"j  
public void setSFileName(String value) V<J1.8H  
{ [I3Nu8  
sFileName = value; 5dI=;L >D  
} J\Pb/9M/  
oDMPYkpTu  
XhHgXVVGG<  
public int getNSplitter() OyF=G^w  
{ R`Z"ey@C  
return nSplitter; nOvR, 6  
} _ERtL5^  
G<n75!  
Q(nTL WW  
public void setNSplitter(int nCount) ]}XDDPbZ}  
{ G rp{ .  
nSplitter = nCount; >kK@tJn  
} ZBK0`7#&EH  
} Nw1*);b[y  
8O9^g4?  
+w^,!gA&  
/* R ~kO5jpW  
**Utility.java in<.0v9w  
*/ XGR2L DR  
package NetFox; s@@Km1w  
A-T-4I  
Ee2P]4_d  
public class Utility { "u!gfG?oH  
dX cbS<  
QQ.?A(U7  
public Utility() <&l$xn  
{ MmN{f~Kq9  
#0aBQ+_8H  
eTvWkpK+  
} ;+E]F8G9r  
'7sf)0\:<p  
//线程睡眠 PJC(:R(j  
public static void sleep(int nSecond) {MUiK 5:  
{ e"%TU  
try{ gHBvQ1g  
Thread.sleep(nSecond); vS>'LX  
} ]O"f%   
catch(Exception e) r6Yd"~ n  
{ ly17FLJ].  
e.printStackTrace (); k8+J7(_c  
} hhy+bA}  
} |VWT4*K  
7sxX?u  
//日志 g2|Myz)  
public static void log(String sMsg) 6MT (k:  
{ 0vm>*M*p  
System.err.println(sMsg); ?n `m  
} 3 y}E*QE  
q5SPyfE[  
*=!e,  
public static void log(int sMsg) noxJr/A]  
{ eut2x7Z(c  
System.err.println(sMsg); iQgg[ )  
} 8@m$(I +  
} eUA]OF @  
>o?v[:u*  
4f[%Bb  
/* 1l$Ei,9  
**TestMethod.java >9&31wA_  
*/ u[b |QR=5  
package NetFox;  p@ ^G)x  
\sAaVdZJH(  
'ztOl`I5V  
public class TestMethod { lI=<lmM0|/  
0hemXvv1  
5[ zN M  
public TestMethod() M,]|L ch  
{ ///xx/weblogic60b2_win.exe k."p&  
try{ \~ D(ww  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WP L@v+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xak)YOLRV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^HC 6v;K  
fileFetch.start(); 6eV#x%z@v'  
} EnM  
catch(Exception e){e.printStackTrace ();} .HS6DOQ  
1D*=ZkA)  
1|MRXK  
} ]y0Y(  
}<04\t?  
'I]XX==_  
public static void main(String[] args) )!"fUz$  
{ |sZqqgZ-  
new TestMethod(); p'K`K\X  
} xqG<R5k>>  
} ~lw9sm*2v2  
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