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http断点续传简单实现(java)

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/* dy]ZS<Hz8G  
**SiteFileFetch.java {a0yHy$H  
*/ IXpn(vX  
package NetFox; Zp/$:ny  
import java.io.*; 3z% W5[E)  
import java.net.*; ) uTFId  
O=}d:yZb!  
Sq]QRI/  
public class SiteFileFetch extends Thread { L&0aS:  
YySo%\d  
*uoO#4g~  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6&o?#l;|  
long[] nStartPos; //开始位置 *p0Kw>  
long[] nEndPos; //结束位置 uyvjo)T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 o(yyj'=(  
long nFileLength; //文件长度 0UhJ I  
boolean bFirst = true; //是否第一次取文件 %D3Asw/5a  
boolean bStop = false; //停止标志 N(%(B  
File tmpFile; //文件下载的临时信息 ZF@$3   
DataOutputStream output; //输出到文件的输出流 Of>2m<  
Hu+GN3`sx^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) O9rA3qv B  
public SiteFileFetch(SiteInfoBean bean) throws IOException sGx3O i   
{ !oYNJE Y7  
siteInfoBean = bean;  9XhcA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3_"tds <L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); o,RiAtdk  
if(tmpFile.exists ()) w+$~ ds  
{ W3jwc{lj  
bFirst = false; c7D{^$L9 v  
read_nPos(); 7^<6|>j4  
} 3mhjwgP<nn  
else i,wZNX  
{ "c+$GS  
nStartPos = new long[bean.getNSplitter()]; }#S1!TU  
nEndPos = new long[bean.getNSplitter()]; "s}Oeu[  
} /[!<rhY  
g(i8HU*{q  
$LVzhQlD  
w?P ex]i{  
}  uU=!e&3  
mbns%%GJU  
Tj+U:#!!~  
public void run() S]NT+XM  
{ CSY-{  
//获得文件长度 R6TT1Ka3c  
//分割文件 L tUvFe  
//实例FileSplitterFetch W#2} EX  
//启动FileSplitterFetch线程 "R"{xOQl  
//等待子线程返回 aYM~Ub:x{  
try{ )iid9K<HB  
if(bFirst) /D964VR1M\  
{ 3taGb>15  
nFileLength = getFileSize(); ^6J*:(eM  
if(nFileLength == -1) ^^F 8M0k3  
{ 0rvBjlFT  
System.err.println("File Length is not known!"); F` &W5[  
} WF:4p]0~)  
else if(nFileLength == -2) V9jxmu F,  
{ [^D>xD3B2  
System.err.println("File is not access!"); L1f=90  
} bu -6}T+  
else {< EPm&q  
{ O[\mPFu5  
for(int i=0;i<nStartPos.length;i++) R{ udV  
{ Tv6y +l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GWLdz0`2_  
} =~5N/!  
for(int i=0;i<nEndPos.length-1;i++) 5H 1N]v+  
{ \01 kK)  
nEndPos = nStartPos[i+1]; ?Qx4Z3n  
} 'Va<GHr>+  
nEndPos[nEndPos.length-1] = nFileLength; t+K1ArQc  
} _Tm]tlV  
} UA(4mbz+  
@v3)N[|d  
3D^cPkX  
//启动子线程 qHT73_R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }=Xlac_U  
for(int i=0;i<nStartPos.length;i++) )5n:UD{f[#  
{ Q @[gj:w  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O<#8R\v  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p5% %k-  
nStartPos,nEndPos,i); I1rB,%p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;&'ryYrex  
fileSplitterFetch.start(); .FV^hrJxI;  
} 4LW~  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9hssI ZO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KuW>^mF(I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )FPn_p#3]  
nEndPos = " + nFileLength); 3hxV`rb  
// fileSplitterFetch[nPos.length-1].start(); 6}VFob#h8  
e=aU9v L  
9Ofls9]U  
//等待子线程结束 aqWlX0+  
//int count = 0; Djdd|Z+*{  
//是否结束while循环 v??$z#1F3  
boolean breakWhile = false; Q*M(d\Vs  
f:y1eLl3  
M2c7 |  
while(!bStop) zR <fz  
{ 9gglyoZ%  
write_nPos(); O;i0xWUh  
Utility.sleep(500); W\j)Vg__e  
breakWhile = true; TD%L`Gk  
B?yj U[/R  
l}r9kS  
for(int i=0;i<nStartPos.length;i++) hg#O_4D  
{ 0S9~db  
if(!fileSplitterFetch.bDownOver) fFYoZ/\  
{ 7 \[fjCg\w  
breakWhile = false; 3o0ZS^#eB  
break; xRdx` YYu  
} y. 1F@w|  
} 2i;ox*SfpU  
if(breakWhile) cD=IFOB*GD  
break; QleVW  
z@w}+fYO  
>]&Ow9-  
//count++; u~2]$ /U  
//if(count>4) :Ocw+X3  
// siteStop(); +S[3HX7H  
} Z[ &d2'  
13w(Tf  
4T; <`{]  
System.err.println("文件下载结束!"); $d!Vxm  
} H5&._  
catch(Exception e){e.printStackTrace ();} bM5o-U#^ C  
} (xoYYO  
uubIL +  
17,mqXX>  
//获得文件长度 FvG?%IFM  
public long getFileSize() aWH  
{ ;E[Q/ tr:w  
int nFileLength = -1; XogCq?_m  
try{ v;U5[  
URL url = new URL(siteInfoBean.getSSiteURL()); rGXUV`5Na  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %vm_v.Q4)  
httpConnection.setRequestProperty("User-Agent","NetFox"); X,#~[%h$-=  
(vX< B h  
vC `SD]  
int responseCode=httpConnection.getResponseCode(); iRlpNsN  
if(responseCode>=400) }ijQ*ECdl  
{ IGT9}24  
processErrorCode(responseCode); ,G5[?H;ZN  
return -2; //-2 represent access is error mw}Bl; - O  
} {:#nrD"  
>iRkhA=Vg  
,|}mo+rb-  
String sHeader; V=% ;5/  
9jX_Eoxy  
>KvK'Mus/  
for(int i=1;;i++) ^Y+Lf]zz*  
{ b GI){0A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kP^A~ZO.  
//Utility.log(in.readLine()); XPD1HN!,LT  
sHeader=httpConnection.getHeaderFieldKey(i); ?w'86^_z  
if(sHeader!=null) xy4+ [u  
{ (Nk[ys}%*  
if(sHeader.equals("Content-Length")) v3FdlE  
{ 2<y9xvp  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |#M|"7;2z  
break; *8m['$oyV  
} qk3|fW/-  
}  o kA<  
else %D8.uGsh  
break; I[v`)T'_{  
} W]7/ e  
} .-/IV^lGv  
catch(IOException e){e.printStackTrace ();} c.b| RM0;  
catch(Exception e){e.printStackTrace ();} **kix  
YURMXbj  
,7c Rd}1Y  
Utility.log(nFileLength); .RJMtmp  
X-kOp9/.  
+egwZ$5I  
return nFileLength; h~](9e s  
} Rz|@BxB>n  
)RvX}y-  
g#^MO]pY  
//保存下载信息(文件指针位置) m 8b,_1  
private void write_nPos() !khEep}  
{ 1' v!~*af  
try{ 6 h,!;`8O  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3NDddrL9  
output.writeInt(nStartPos.length); Z+J4 q9^$  
for(int i=0;i<nStartPos.length;i++) `&7tADFB  
{ -f mJkI  
// output.writeLong(nPos); jVQ89vf ~  
output.writeLong(fileSplitterFetch.nStartPos); RR ^7/-  
output.writeLong(fileSplitterFetch.nEndPos); DyiJ4m}kh  
} F]UH\1  
output.close(); :S_]!'H  
} 'ScvteQ  
catch(IOException e){e.printStackTrace ();} L 1!V'Hm{  
catch(Exception e){e.printStackTrace ();} )%MC*Z :^  
}  w:QO@  
i2  c|_B  
)"6-7ii7(f  
//读取保存的下载信息(文件指针位置) $HsNV6  
private void read_nPos() QAp]cE1ew  
{ 0]iaNR %  
try{ n+hL/aQ+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \|HNFxT`  
int nCount = input.readInt(); .6azUD4  
nStartPos = new long[nCount]; "O<ETHd0  
nEndPos = new long[nCount]; 2~?E'  
for(int i=0;i<nStartPos.length;i++) PWiUW{7z  
{ L*[3rqER  
nStartPos = input.readLong(); Yg3nT:K_Y&  
nEndPos = input.readLong(); W_JO~P  
} 4fC:8\A  
input.close(); ?SElJ? Z  
} qJrKt=CE  
catch(IOException e){e.printStackTrace ();} $=N?[h&4  
catch(Exception e){e.printStackTrace ();} /B~[,ES@1  
} ?X6}+  
]4en |Aq  
4,c6VCw3+  
private void processErrorCode(int nErrorCode) Z%B6J>;uM  
{ ybE 2N  
System.err.println("Error Code : " + nErrorCode); YnU)f@b#  
} T!KwRxJ23  
CCe>*tdf  
|&rCXfC  
//停止文件下载 ][v]Nk  
public void siteStop() LrbD%2U$j5  
{ -HQbvXAS  
bStop = true; {D Q%fneN4  
for(int i=0;i<nStartPos.length;i++) 8mKp PwG0  
fileSplitterFetch.splitterStop(); %}VH5s9\  
D4[t^G;J  
z77>W}d  
} }0Ns&6)xG  
} aYb97}kI  
//负责部分文件的抓取 ?V^7`3F  
**FileSplitterFetch.java qz>R"pj0g  
*/ /0XMQy  
package NetFox; Tgr,1) T  
()l3X.t,$  
~BmA!BZV`  
import java.io.*; ji1vLu4|t  
import java.net.*; yW= +6@A4  
C$1W+(  
71{jedT  
public class FileSplitterFetch extends Thread { A+0-pF2D  
}QE*-GVv]  
u/u(Z&  
String sURL; //File URL 3^+D,)#D^  
long nStartPos; //File Snippet Start Position U*$xR<8v  
long nEndPos; //File Snippet End Position IUFc_uL@\  
int nThreadID; //Thread's ID @nY]S\if  
boolean bDownOver = false; //Downing is over F9u?+y-xb  
boolean bStop = false; //Stop identical 5MAfuHq^  
FileAccessI fileAccessI = null; //File Access interface ^F+7<$ 2  
" L`)^  
6D`n^uoP  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =,#--1R7g  
{ Ct w<-'  
this.sURL = sURL; UgC65O2  
this.nStartPos = nStart; \}?X5X>  
this.nEndPos = nEnd; w&aZ 97{  
nThreadID = id; 8'8`xu$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wc4BSJa,19  
} ]2wxqglh)  
]$[sfPKA  
ujX; wGje  
public void run() V^5d5Ao  
{ k_=yb^6[U  
while(nStartPos < nEndPos && !bStop) Ptv'.<-  
{ T+F]hv'  
 Qw}1q!89  
TB! I  
try{ !B}9gT  
URL url = new URL(sURL); 7t:RQ`$:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Lz'VQO1U=  
httpConnection.setRequestProperty("User-Agent","NetFox"); *7jz(iX  
String sProperty = "bytes="+nStartPos+"-"; 0B]q /G(  
httpConnection.setRequestProperty("RANGE",sProperty); +y?Ilkk;j  
Utility.log(sProperty); Yg^ &4ZF  
LZRg%3.E  
v\Uk?V5T  
InputStream input = httpConnection.getInputStream(); 4 V')FGB$  
//logResponseHead(httpConnection); Dp ](?Yr  
rR> X<  
 S=(O6+U  
byte[] b = new byte[1024]; o[Jzx2A<  
int nRead; (?na|yd  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }|kFHodo  
{ k||t<&`Ze  
nStartPos += fileAccessI.write(b,0,nRead); -Lh7!d  
//if(nThreadID == 1) 3N2d V6u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;/j2(O^  
} qq| 5[I.?  
ukW&\  
"tzu.V-  
Utility.log("Thread " + nThreadID + " is over!"); N7+L@CC6T  
bDownOver = true; 6QX m] <  
//nPos = fileAccessI.write (b,0,nRead); ixd sz\<  
} 0D s3wNz  
catch(Exception e){e.printStackTrace ();} L=4+rshl!_  
} !mmMAsd,  
} }'$PYAf6  
KhHFJo[8sf  
lT^su'+bk  
//打印回应的头信息  8s0+6{vW  
public void logResponseHead(HttpURLConnection con) MEiP&=gX!  
{ Xo34~V@(  
for(int i=1;;i++) |`5 IP8Z  
{ ]dpL PR  
String header=con.getHeaderFieldKey(i); vwU1}H  
if(header!=null) >.iF,[.[F<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f~`=I NrU  
Utility.log(header+" : "+con.getHeaderField(header)); Q5+1'mzAB  
else 'dLw8&T+W  
break; J?QS7#!%  
} -b(DPte  
} { qNPhi  
m+TAaK  
1UP=(8j/  
public void splitterStop() tJ\ $%  
{ a#YK1n[!  
bStop = true; $ F2Uv\7=  
} dZU#lg  
iVXt@[  
lK0ny>RB  
} [0 F~e  
$.SBW=^V  
\#{PV\x:Nn  
/* *; Jb=  
**FileAccess.java fjh|V9H  
*//文件访问(定位,写) C$OVN$lL`8  
package NetFox; 2%W;#oi?  
import java.io.*; ,QY$:f<  
+1ICX  
m\L`$=eO8  
public class FileAccessI implements Serializable{ b2m={q(s  
Zse&{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j[G`p^ul  
RandomAccessFile oSavedFile; }aZuCe_  
long nPos; >HP `B2Q H  
 Aqy w  
u\]EG{w(  
public FileAccessI() throws IOException ! _S#8"  
{ ~||0lj.D  
this("",0); 6hxZ5&;(*  
} kA:mB;:  
v/+ <YU  
Re$h6sh  
public FileAccessI(String sName,long nPos) throws IOException G;Li!H  
{ Nd~B$venh  
oSavedFile = new RandomAccessFile(sName,"rw"); s2; ~FK#/  
this.nPos = nPos; uoS:-v}/Y~  
oSavedFile.seek(nPos); G{U#9   
} IiU> VLa  
XB)D".\  
$|N6I  
public synchronized int write(byte[] b,int nStart,int nLen) M.W X&;>  
{ T ozx0??)  
int n = -1; (bsx|8[  
try{ |&; ^?M  
oSavedFile.write(b,nStart,nLen); QL?_FwZL  
n = nLen; z 6:Wh  
} 0HzqU31%l@  
catch(IOException e) AkhG~L  
{ 77P\:xc  
e.printStackTrace (); <J/ =$u/  
} ma.84~m  
i?x gV_q;  
"tJ+v*E  
return n; I |Oco?Q"  
} }Q\%tZC#T  
q~ H>rC(\  
x/*lNG/  
} oz) [ -  
"H-s_Y#  
dljE.peL  
/* c4Ebre-Oa  
**SiteInfoBean.java <DF3!r  
*/ qE[S>/R"  
package NetFox; 3JnpI,By  
l2D*b93  
bJ ~H  
public class SiteInfoBean { DB'v7 Ij0  
st-{xC#N#  
8Q'Emw |  
private String sSiteURL; //Site's URL 3SVGx< ,2  
private String sFilePath; //Saved File's Path l/.{F;3F  
private String sFileName; //Saved File's Name EL 5+pt  
private int nSplitter; //Count of Splited Downloading File J<$@X JLS  
ARH~dN*C  
akj<*,  
public SiteInfoBean() a=z] tTs4  
{//nSplitter的缺省值为5 M(%H  
//default value of nSplitter is 5 e &6%  
this("","","",5); TZn 15-O  
} E/;t6& 6  
;tOs A #  
^_2c\mw_I  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H>~CL  
{ |xO*!NR  
sSiteURL= sURL; %yRXOt2(  
sFilePath = sPath; "Xq_N4  
sFileName = sName; Qb536RpcTY  
this.nSplitter = nSpiltter; E&M(QX5  
c;l!i-  
XiUq#84Q  
} MmF&jd-=  
w#A)B<Y/"  
[!'+}  
public String getSSiteURL() 6Yu:v  
{ &f*o rM:  
return sSiteURL; 1"h"(dA  
} b8mH.g&l  
q m3\) 9C  
b1&tk~D  
public void setSSiteURL(String value) fvu{(Tb  
{ ]Q^)9uE\D  
sSiteURL = value; Cf% qap#  
} 7=^{~5#  
U3(+8}Q  
=[B\50]  
public String getSFilePath() I/E9:  
{ 7^L  
return sFilePath; ) .~ "  
} Kk3+ ]W<  
p3s i\Fm!  
f ULt4  
public void setSFilePath(String value) <c+.%ka  
{ 1`cH EAa  
sFilePath = value; 2t= = <x  
} Ge^`f<f  
1I Xtu   
)Z7Vm2a  
public String getSFileName() X\^V{v^-  
{  wJp<ZL  
return sFileName; hnj\|6L  
} u]p21)m$x  
d:kB Zrq  
?UnQ?F(+G<  
public void setSFileName(String value) Jf YgZ\#  
{ Kz HYh  
sFileName = value; lC<;Q*Y  
} ' zyw-1  
}(EH5jZ'  
e3I""D{)[=  
public int getNSplitter() /jv/qk3i  
{ 5.rAxdP  
return nSplitter; $dC`keQM>9  
} GppCrQ%Ra|  
=L W!$p  
 N' hT  
public void setNSplitter(int nCount) lY%I("2=  
{ N>mW64_H)  
nSplitter = nCount; 'uL4ezTtA  
} (x=$b(I  
} 7KC>?F  
HuhQ|~C+~  
\Y P,}_ ~  
/* b8WtNVd  
**Utility.java cu!%aM,/<-  
*/ jn(x-fj6R  
package NetFox; c 1YDln  
"@Vyc6L  
*22Vc2[i;  
public class Utility { xyL"U*  
Z.VKG1e}  
tv#oEM9esl  
public Utility() kK &w5'  
{ WzIUHNn'I  
IJ^~,+  
'a#lBzu\b  
} BP/nK.  
p2vN=[g9)  
//线程睡眠 J%"BCbxW~B  
public static void sleep(int nSecond) 0|&@)`  
{ @MSmg3 &  
try{ lQ 8hY$  
Thread.sleep(nSecond); g'.OzD  
} br I;}m  
catch(Exception e) rA~f68h|  
{ Z?)g'n  
e.printStackTrace (); 7;jD>wp 9D  
} "O34 E?ql.  
} \|=6<ZY:  
oe<i\uX8z  
//日志 u\\t~<8  
public static void log(String sMsg) Hw \of  
{ (W}F\P  
System.err.println(sMsg); WZQ2Mi<&1'  
} c'oiW)8;A  
$ XjijD9R  
\n<! ld  
public static void log(int sMsg) VLuHuih  
{ erH,EE^-x<  
System.err.println(sMsg); b RAD_  
} 4'QX1p  
} uw;Sfx,s  
VF`!ks  
fyQOF ItM  
/* (b25g!  
**TestMethod.java {&5lZ<nu8A  
*/ m8sd2&4  
package NetFox; .}==p&(  
f-%M~:  
QjTSbHtH  
public class TestMethod { /U;j-m&   
]az(w&vqg2  
IkCuw./  
public TestMethod() "6B@V=d  
{ ///xx/weblogic60b2_win.exe T^v763%  
try{ .a4,Lr#q.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o[Ffa# sE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); |A&;m}(Mt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8$IKQNS  
fileFetch.start(); H/o_?qK  
} K43%9=sM  
catch(Exception e){e.printStackTrace ();} $DHE%IN`  
q5;dQ8Y ?  
VZ9 p "  
} N/tcW  
E)-;sFz  
7zu\tCWb  
public static void main(String[] args) ]8A*uyi  
{ |  0  
new TestMethod(); X4%uY  
} ]?6wU-a  
} 8iIp[9~=  
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