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http断点续传简单实现(java)

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/* )b (X  
**SiteFileFetch.java x=3I)}J(kn  
*/ <W|1<=z(  
package NetFox; Q}z{AZ  
import java.io.*; 0(vdkC4\A  
import java.net.*; 7h1"^}M&  
M;@Ex`+?i  
| W?[,|e  
public class SiteFileFetch extends Thread { i-V0Lm/  
-t b;igv  
tD^a5qPh  
SiteInfoBean siteInfoBean = null; //文件信息Bean *C/KM;&  
long[] nStartPos; //开始位置 / T#o<D  
long[] nEndPos; //结束位置 gDc]^K4>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #]5)]LF1q  
long nFileLength; //文件长度 S W-0h4  
boolean bFirst = true; //是否第一次取文件 ;Yu>82o.:  
boolean bStop = false; //停止标志 -~0'a  
File tmpFile; //文件下载的临时信息 GsRt5?X/*  
DataOutputStream output; //输出到文件的输出流 a?\ `  
\"bLE0~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }JJ::*W2n  
public SiteFileFetch(SiteInfoBean bean) throws IOException Dzm qR0)  
{ 9>zDJx  
siteInfoBean = bean; 8"pA9Mr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "{6KZ!+0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +TWJNI  
if(tmpFile.exists ()) +ks$UvtY  
{ xx}'l:}2 ]  
bFirst = false; 'T{pdEn8u  
read_nPos(); 6fQ*X~| p  
} PJ6$);9}6  
else k#-[ M.i  
{ p|;o5j{  
nStartPos = new long[bean.getNSplitter()]; SOYDp;j  
nEndPos = new long[bean.getNSplitter()]; Vg) ^|  
} 6<Be#Y]b  
h?3f5G*&H  
t.u{.P\Md\  
T)O]:v  
} 9Iy[E,j  
X~#@rg!"  
`;T? 9n  
public void run() td`wNy\  
{ cG5$lB  
//获得文件长度 ] : Wb1  
//分割文件 R =QM;  
//实例FileSplitterFetch 0YHYxn  
//启动FileSplitterFetch线程 3 dY6;/s  
//等待子线程返回 p\)h",RkA  
try{ @nW'(x(  
if(bFirst) L7[X|zmy*x  
{ E'fX&[  
nFileLength = getFileSize(); r}Q@VS% %  
if(nFileLength == -1) dfXV1B5  
{ Z^C!RSQ  
System.err.println("File Length is not known!"); 1gL8$.B?  
} vatx+)  
else if(nFileLength == -2) lTd+{TF.  
{ t>=GVu^  
System.err.println("File is not access!"); a#>t+.dd  
} o^N%;d1%E  
else ~ 6TfW~V  
{ xDNw /'  
for(int i=0;i<nStartPos.length;i++) 6pS Rum  
{ s@R3#"I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F 'fM?!(  
} yFa&GxSq  
for(int i=0;i<nEndPos.length-1;i++) ;Ce 2d+K  
{ _6| /P7"  
nEndPos = nStartPos[i+1]; s-y'<(ll  
}  z, :+Oc  
nEndPos[nEndPos.length-1] = nFileLength; $d5&~I  
} ]q@rGD85K  
} 7?)m(CFy  
H74NU_   
N7%=K9  
//启动子线程 &Qz"nCvJ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 48W:4B'l9  
for(int i=0;i<nStartPos.length;i++) _zAc 5rS  
{ Uia)5zz8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t^dakL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &fh.w]\  
nStartPos,nEndPos,i); K1CMLX]m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); sz){uOI  
fileSplitterFetch.start(); q|m#IVc  
} 0R.Gjz*Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z2$F Yn Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zkw0jX~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tVK?VNW  
nEndPos = " + nFileLength); !hpTyO+%  
// fileSplitterFetch[nPos.length-1].start(); _AA`R`p;  
2-/YYe;C  
0^_)OsFA  
//等待子线程结束 m  mw)C"  
//int count = 0; t(Cq(.u`:  
//是否结束while循环 \v B9fA:*  
boolean breakWhile = false; \["1N-q b  
fte!Ll'  
\L&qfMjW"Z  
while(!bStop) ZfF`kD\  
{ rl_1),J\qG  
write_nPos(); +X4ttv  
Utility.sleep(500); #0#V$AA>  
breakWhile = true; .oB'ttF1  
y$"~^8"z  
C:TuC5Sr  
for(int i=0;i<nStartPos.length;i++) jp\JwE  
{ oQKcGUZ  
if(!fileSplitterFetch.bDownOver) [ 7CH(o1a&  
{ j.e`ip  
breakWhile = false; s7X~OF(#  
break; K[Ws/yc^a  
} oc,U4+T  
} (W{rv6cq  
if(breakWhile) j8F~j?%!  
break; u/K)y:ZZ  
ueS[sN!  
cviN$oL  
//count++; '{1W)X  
//if(count>4) gGceK^#  
// siteStop(); 1yY'hb,0  
} QB oZCLv  
d60Fi#3d  
a93d'ZE-X  
System.err.println("文件下载结束!"); 0VWCm( f-  
} C=pPI  
catch(Exception e){e.printStackTrace ();} ^.B `Z{Jb  
} ()rx>?x5  
r A&#>R`  
n[S41809<  
//获得文件长度 ^y;OHo  
public long getFileSize() z;Gbqr?{{  
{ 7m@^=w  
int nFileLength = -1; Z"PDOwj5  
try{ |M0,%~Kt  
URL url = new URL(siteInfoBean.getSSiteURL()); h)aWerzL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D[FfJcV'$  
httpConnection.setRequestProperty("User-Agent","NetFox"); A,A-5l<h]?  
EIVQu~,H  
Q?I"J$]&L  
int responseCode=httpConnection.getResponseCode(); 8Y;zs7Y  
if(responseCode>=400) QL|:(QM  
{ E|6Z]6[  
processErrorCode(responseCode); kcZ;SYosj  
return -2; //-2 represent access is error -qnXa  
} 71.:p,Z@z  
<o"D/<XnB3  
kAKqW7,q"  
String sHeader; eUUD|U*b   
j)SgB7Q  
au9Wo<mR  
for(int i=1;;i++) D aqy+:  
{ f T+n-B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Wy0a2Ve  
//Utility.log(in.readLine()); 1V?Sj  
sHeader=httpConnection.getHeaderFieldKey(i); 6DiA2'{f  
if(sHeader!=null) D2wgSrY  
{ `'tw5}  
if(sHeader.equals("Content-Length")) D;#Yn M3  
{ R'a5,zEo/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F.* snF  
break; (J) Rs`_  
} ezNE9g  
} xF:poi  
else zI*/u)48  
break; K]=>F  
} wW)&Px n  
} `peJ s~V  
catch(IOException e){e.printStackTrace ();} IUBps0.T\  
catch(Exception e){e.printStackTrace ();} wx?{|  
G5eLs  
v!v0,?b*  
Utility.log(nFileLength); B}xo|:f!zj  
{Z{NH:^  
qh'f,#dI}  
return nFileLength; 7{/:,  
} rF j)5~  
'<E8< bi  
Xrzh*sp  
//保存下载信息(文件指针位置) F|ML$  
private void write_nPos() S:GUR6g8D  
{ C?c-V,  
try{ p?gLW/n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MBTt'6M  
output.writeInt(nStartPos.length); Exo`Z`m`U  
for(int i=0;i<nStartPos.length;i++) =[-- Hf  
{ R`3>0LrC8  
// output.writeLong(nPos); Wg;TXs/  
output.writeLong(fileSplitterFetch.nStartPos); $vicHuX!  
output.writeLong(fileSplitterFetch.nEndPos); PQI,vr'R  
} +cOI`4`$  
output.close(); eVK<%r=  
} <OO/Tn'a  
catch(IOException e){e.printStackTrace ();} oG_'<5Bv>  
catch(Exception e){e.printStackTrace ();} $@f3=NJ4k  
} rp[oH=&  
UDi3dH=  
rM?Dp2  
//读取保存的下载信息(文件指针位置) ,/?V+3l  
private void read_nPos() aFm]?75  
{ d4eCBqx  
try{ rL+n$p X-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7 V1k$S(  
int nCount = input.readInt(); Vv"wf;#  
nStartPos = new long[nCount]; I4p= ?Ds  
nEndPos = new long[nCount]; _e@qv;*  
for(int i=0;i<nStartPos.length;i++) F'_8pD7  
{ <rI$"=7  
nStartPos = input.readLong(); %T*+t"\)  
nEndPos = input.readLong(); pvdZ>D-IU  
} HG 6{`i  
input.close(); [/,6O  
} Rw^YTv  
catch(IOException e){e.printStackTrace ();} jN[6JY1  
catch(Exception e){e.printStackTrace ();} g~["O!K3  
} 9@EnmtR  
:/[ZgreN6  
J?ZVzKTb>}  
private void processErrorCode(int nErrorCode) Pds*M?&F  
{ 4qXUk:C@m  
System.err.println("Error Code : " + nErrorCode); 8ch~UBq/  
} `1v!sSR0R  
$aI MQ[(  
\gQ+@O&+  
//停止文件下载 S<9d^= a  
public void siteStop() fQA)r  
{ umrI4.1c  
bStop = true; 2o5< nGn  
for(int i=0;i<nStartPos.length;i++) ?4?jG3p  
fileSplitterFetch.splitterStop(); PC7.+;1  
B148wh#r  
BW\5RIWwE5  
} .W.U:C1  
} 67:<X(u+!  
//负责部分文件的抓取 !Jp.3,\?~  
**FileSplitterFetch.java #UN{ J6{  
*/ 2EcYO$R!  
package NetFox; +VCo=oA  
D>^ix[:J  
Sqt"G6<  
import java.io.*; 3E@&wpj  
import java.net.*; 3Qr!?=nf  
&rWJg6/  
EUS]Se2  
public class FileSplitterFetch extends Thread { l"!;Vkg.5  
<RsKV$Je I  
3n)iTSU3  
String sURL; //File URL E1v<-UPbA  
long nStartPos; //File Snippet Start Position =w?cp}HW  
long nEndPos; //File Snippet End Position g]Ny?61  
int nThreadID; //Thread's ID H)fo4N4ii  
boolean bDownOver = false; //Downing is over )_.H #|r  
boolean bStop = false; //Stop identical O5*uL{pvT{  
FileAccessI fileAccessI = null; //File Access interface =YsTF T  
HON[{Oq  
54j $A  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6oBt<r?CJ  
{ <aD+Ki6  
this.sURL = sURL; `7n,(  
this.nStartPos = nStart; u"|nu!p`  
this.nEndPos = nEnd; `8bp6}OD,  
nThreadID = id; xEWa<P#.u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /7)G"qG~F~  
} 7+-}8&s yu  
Rp9iX~A`e  
S60`'!y  
public void run() sgsMlZ3/  
{ <W^~Y31:0  
while(nStartPos < nEndPos && !bStop) K ePHn:c  
{ 0].5[Jo  
'Em($A (  
Di=6.gm[<  
try{ O]!DNN  
URL url = new URL(sURL); DcDGrRuh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gukq}ZQd  
httpConnection.setRequestProperty("User-Agent","NetFox"); %LW~oI.  
String sProperty = "bytes="+nStartPos+"-"; ? D'-{/<4  
httpConnection.setRequestProperty("RANGE",sProperty); V-u\TiL  
Utility.log(sProperty); 4f-C]N=  
@"2-tn@q_  
9 9-\cQv  
InputStream input = httpConnection.getInputStream(); 9K(b Z {  
//logResponseHead(httpConnection); Q :|E  
emO!6]0gJ  
H9[.#+ln  
byte[] b = new byte[1024]; _{);n$`  
int nRead; P=z':4,M}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j* ?MFvwE  
{ [_Z3v,vt,  
nStartPos += fileAccessI.write(b,0,nRead); <[~M|OL9q,  
//if(nThreadID == 1) IrM3Uh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kS!*kk*a  
} % m$Mn x  
PrxXL/6  
0CYI,V  
Utility.log("Thread " + nThreadID + " is over!"); $OuA<-  
bDownOver = true; O-YE6u  
//nPos = fileAccessI.write (b,0,nRead); @#">~P|Hp  
} XA%?35v~  
catch(Exception e){e.printStackTrace ();} !4fL|0  
} YJ`>&AJ  
} ?-i&6i6Y  
pqX=l%{4ES  
p]HtJt|]  
//打印回应的头信息 7n.J.<+9  
public void logResponseHead(HttpURLConnection con) <C(2(3  
{ ,)8Hl[y  
for(int i=1;;i++) >MLqOUr#  
{ ~Q\[b%>J  
String header=con.getHeaderFieldKey(i); Hqv(X=6E0  
if(header!=null) Pr'py  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 35et+9  
Utility.log(header+" : "+con.getHeaderField(header)); =*N(8j>y  
else <#i'3TUR  
break; F"I@=R-n  
} W X9BS$}0  
} SY.V_O$l }  
5O*$#C;c  
6A<aelE*i  
public void splitterStop() Zs)9O Ju  
{ +q!6zGs.  
bStop = true; B{<6 &bQ  
} K+H82$ #  
`. Z".  
lC{m;V2  
} Wit1WI;18  
Pc-HQU  
A,@"(3  
/* /);6 j,x  
**FileAccess.java x8t1g,QA  
*//文件访问(定位,写) ,;;~dfHm  
package NetFox; &kGSxYDk%  
import java.io.*; Px`yD3  
4l:+>U@KU  
w@R-@ G  
public class FileAccessI implements Serializable{ W%x#ps5%  
O4{&B@!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O1PdM52  
RandomAccessFile oSavedFile; "wc $'7M  
long nPos; Z]dc%>  
pVM;xxJ  
[iz  
public FileAccessI() throws IOException  E2l.  
{ 08Gr  
this("",0); ?Z"}RMM)8  
} wlJ_, wA  
1Y_fX  
AkF3F^  
public FileAccessI(String sName,long nPos) throws IOException *niQ*A  
{ 5 ,HNb  
oSavedFile = new RandomAccessFile(sName,"rw"); YN^8s  
this.nPos = nPos; j"]%6RwM]  
oSavedFile.seek(nPos); V=U%P[S  
} Aka`L:k  
/TdTo@  
#frhO;6  
public synchronized int write(byte[] b,int nStart,int nLen) Wp ]u0w  
{ UA^E^$f:  
int n = -1; 7G(X:!   
try{ +!rK4[W'  
oSavedFile.write(b,nStart,nLen); Nz8iU@!a  
n = nLen; se-}d.PwL  
} 6%>0g^`)9Y  
catch(IOException e) }[|"db  
{ B dSTB"  
e.printStackTrace (); p<YO3@B+  
} tSjK=1"}  
3N-(`[m{E  
6 J#C  
return n; yq2Bz7P  
} Nt)9- \T  
D6D*RTi4  
%(i(ZW "  
} Adh CC13B  
IkupW|}rc  
x&sF_<[  
/* ({)_[dJ'  
**SiteInfoBean.java q /#O :Q  
*/ $O[ut.   
package NetFox; ( %bfNs|  
1BF+sT3  
0kDT:3  
public class SiteInfoBean { S5;q)qz2J  
db`<E <  
 mJ-@:5  
private String sSiteURL; //Site's URL {Su]P {oJ  
private String sFilePath; //Saved File's Path $iV3>>;eh  
private String sFileName; //Saved File's Name ;^;5"n h  
private int nSplitter; //Count of Splited Downloading File Zhw _L  
d(&vIjy  
T]+*} C  
public SiteInfoBean() 6;VlX,,j  
{//nSplitter的缺省值为5 :=* -x  
//default value of nSplitter is 5 V[% r5!83H  
this("","","",5); 0pu'K)Rb  
} :]x)lP(3E  
dX<UruPA  
^b4o 0me  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;@sxE}`?g  
{ Wd[XQZ<  
sSiteURL= sURL; CN zK-,  
sFilePath = sPath; #SL/Jr DZ  
sFileName = sName; 4;_.|!LN  
this.nSplitter = nSpiltter; Q)v8hNyUmA  
] O 2_&cs  
2)G ZU  
} X;-,3dy  
Z:'2pu U+?  
 d(k`Yk8  
public String getSSiteURL() i+2J\.~U#G  
{ m^`X|xK-  
return sSiteURL; b*,R9  
} Ros5]5=dP  
:yv!  x  
1r@v \#P  
public void setSSiteURL(String value) }3@`'i7  
{ 0<e7!M=U1  
sSiteURL = value; [QeKT8  
} "5{\0CfS  
4((Z8@iX/  
9~N7hLT  
public String getSFilePath() %e _WO,R  
{ ImgKqp0Z  
return sFilePath; (|Xf=q,Le  
} &%^[2^H8"  
z8A`BVqI  
l.C {Ar  
public void setSFilePath(String value) Yd]f}5F  
{ -5.>9+W8I  
sFilePath = value; `9@!"p f  
} Q&wBX%@^L  
18a6i^7  
Xa-]+_?Q  
public String getSFileName() u6I# D _  
{ YV0e)bf  
return sFileName; _oR6^#5#  
} jk)U~KGcg  
(RGl, x:  
wjpkh~ qo  
public void setSFileName(String value) LM0 TSB?  
{ i^j{l_-JE  
sFileName = value; d@`yRueWiV  
} =_=jXWOQv  
F*} b),  
!1|f,9C  
public int getNSplitter() AX[/S8|6  
{  c,x2   
return nSplitter; \}Hk`n)Aq  
} @@}A\wA-  
gm4-w 9M[p  
YAsvw\iseK  
public void setNSplitter(int nCount) J0^p\mG  
{ D,]m7 yFT  
nSplitter = nCount; 2N`Vx3  
} -0lpsF  
} 3vDV   
=T;%R^@  
,X+071.(  
/* OpYq qBf_  
**Utility.java )6Z)z;n]aW  
*/ >KC*xa"  
package NetFox; ("wPkm^  
E/Y.f  
ePB=aCZ  
public class Utility { ;v#~ o*  
lAV6z%MmM  
0G;RMR':5  
public Utility() R>#T {<<L  
{ +n1}({7m  
%5jxq9:K  
,odjL6u  
} w ~Es,@  
N(/DC)DJg  
//线程睡眠 QfRt3\^`  
public static void sleep(int nSecond) oQFpIX;\m  
{ UP%X`  
try{ '^}l|(  
Thread.sleep(nSecond); dAohj QH:  
} '0z@Jevd?  
catch(Exception e) 2~~Q NWN  
{ 866n{lyL  
e.printStackTrace (); Z6 (;~"Em  
} kQwBrb 4  
} L)4TW6IUk  
T<?JL.8g_  
//日志 qzsS"=5  
public static void log(String sMsg) "P'W@  
{ EivZI<<a  
System.err.println(sMsg); tb^3-ZUb  
} A1>R8Zuhy  
_D[vMr[  
Sh}AGNE'  
public static void log(int sMsg) cPkN)+K  
{ !~"q$T>@  
System.err.println(sMsg); $yHlkd`Y  
} 2U)H2 %  
} "PLZZL$+  
R/A40i  
gfFP-J3cN  
/* 7YkxIzE  
**TestMethod.java 6*{N{]`WZ)  
*/ N@)tU;U3O  
package NetFox; V<?t( _Y  
_Z@- q  
r8}GiP0|  
public class TestMethod { RWz^ MV5K  
*GTCVxu  
[D^KM|I%+  
public TestMethod() (KK9/k  
{ ///xx/weblogic60b2_win.exe 7P.C~,+D%P  
try{ YSs9BF:a  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iK s/8n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V2V^*9(wu@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); XW%!#S&;X  
fileFetch.start(); cc Z A  
} t%/Y^N;  
catch(Exception e){e.printStackTrace ();} G<Z|NT  
`$fwLC3j  
<pK72  
} Ti=~ycwi  
KaZ$!JfT  
m("! M~1  
public static void main(String[] args) d/j$_NQ&!  
{ Yq $(Ex  
new TestMethod(); .UU BAyjm  
} F]q pDv  
} ezY _7  
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