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http断点续传简单实现(java)

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/* h*Y);mc$#  
**SiteFileFetch.java ( {H5k''  
*/ :sBg+MS  
package NetFox; n@xDFa  
import java.io.*; +]Y&las  
import java.net.*; +t R6[%  
{7)D/WY5  
Ogf myYMtc  
public class SiteFileFetch extends Thread { vb}; _/ #?  
sSi1;9^o  
MX?K3=j @>  
SiteInfoBean siteInfoBean = null; //文件信息Bean "}]1OL SV  
long[] nStartPos; //开始位置 pCNihZ~  
long[] nEndPos; //结束位置 M ,8r{[2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D!~-53f@  
long nFileLength; //文件长度 x(z[S$6Y\  
boolean bFirst = true; //是否第一次取文件 ~3.1. 'A  
boolean bStop = false; //停止标志 I#kK! m1Q  
File tmpFile; //文件下载的临时信息 *Ri?mEv hF  
DataOutputStream output; //输出到文件的输出流 .foM>UOY  
' @M  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) >yn%.Uoh@  
public SiteFileFetch(SiteInfoBean bean) throws IOException d9[*&[2J|  
{ elZ?>5P$}  
siteInfoBean = bean; F+_4Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PqIGc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H>[1D H#b  
if(tmpFile.exists ()) QtQku1{  
{ +n]U3b  
bFirst = false; 8| zR8L  
read_nPos(); ;5A&[]@^^@  
} a2*WZc`  
else {hX. R  
{ dx@#6Fhy  
nStartPos = new long[bean.getNSplitter()]; R v6{ '\:  
nEndPos = new long[bean.getNSplitter()]; !Ljs9 =UF  
} #:Di1I9<O7  
|$":7)e H!  
AU}P`fT!  
Ay!=Yk ^~  
} d+%1q  
hNXPm~OK\  
YZf<S:  
public void run() 1<^"OjQ  
{ /J8AnA1  
//获得文件长度 86~HkHliv  
//分割文件 /!UuGm   
//实例FileSplitterFetch phUno2fH  
//启动FileSplitterFetch线程 0yXUVKq3  
//等待子线程返回 Z bxd,|<|  
try{ -Xkdu?6Eh  
if(bFirst) 28-6(oG  
{ *~fZ9EkD  
nFileLength = getFileSize(); |^Z1 D TAw  
if(nFileLength == -1) <oPo?r|oM|  
{ VY@uQ#&A  
System.err.println("File Length is not known!"); /g712\?M4  
} rSB"0 W7  
else if(nFileLength == -2) Ywt_h;:  
{ 8UoMOeI3  
System.err.println("File is not access!"); cn=~}T@~Z  
} l2=.;7 IV  
else 3~BL!e,  
{ }#q9>gx  
for(int i=0;i<nStartPos.length;i++) *8U+2zgfC  
{ b/'fC%o,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t/_w}  
} -c%GlpZw  
for(int i=0;i<nEndPos.length-1;i++) 52tIe|KwL  
{ R 3 Eh47  
nEndPos = nStartPos[i+1]; =V_} z3b  
} $ # @G!  
nEndPos[nEndPos.length-1] = nFileLength; N- ?U2V  
} 3`J?as@^8  
} Xcicqywe?  
X_|8CD-@6  
P@p(Y2&~g  
//启动子线程 1#Dpj.cO#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _$0<]O$  
for(int i=0;i<nStartPos.length;i++) jwTb09  
{ D*`|MzlQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;or(:Yoc-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `Te n2(D  
nStartPos,nEndPos,i); Wk'KN o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k _hiGg  
fileSplitterFetch.start(); 18Pc4~ >0  
} =XJ SE+ 7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q0!gTV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J:'cj5@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WO)rJr!C  
nEndPos = " + nFileLength); 6t TLyI$+  
// fileSplitterFetch[nPos.length-1].start(); r`i<XGPJ%  
-Duy: C6W  
F^IYx~:  
//等待子线程结束 &m`1lxT  
//int count = 0; vML01SAi  
//是否结束while循环 ,2[laJ  
boolean breakWhile = false; u1ggLH!U  
 e1S |&W8  
/lm;.7_J+  
while(!bStop) K-)_1  
{ q>%KIBh(  
write_nPos(); wtetB')yD  
Utility.sleep(500); B=7bQli}  
breakWhile = true; q+3Z3v  
,!|/|4vh  
gT'c`3Gkz  
for(int i=0;i<nStartPos.length;i++) f3|ttUX  
{ L"1UUOKy  
if(!fileSplitterFetch.bDownOver) m7^aa@^m  
{ z;GnQfYG  
breakWhile = false; $=4T# W=m  
break; nu}$wLM  
} PNd]Xmv)  
} O!lZ%j@%  
if(breakWhile) R?Ki~'k=  
break; B+iVK(j'[v  
 1SP )`Q  
+e`f|OQ  
//count++; J8J~$DU\Gv  
//if(count>4) i RS )Z )  
// siteStop(); ?zQ\u{]=  
} c\-5vw||b  
syA*!Up  
CVo@zr$  
System.err.println("文件下载结束!"); K\nN2y  
} d47b&.v8e  
catch(Exception e){e.printStackTrace ();} 5.]+K<:h"A  
} vJ7I [Z  
LgjL+w19  
IwKhun  
//获得文件长度 ^L+*}4Dr  
public long getFileSize() b>hNkVI  
{ =;7gxV3;  
int nFileLength = -1; H`njKKdR  
try{ 7UejK r  
URL url = new URL(siteInfoBean.getSSiteURL()); m(s(2wq"f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G`8gI)$u  
httpConnection.setRequestProperty("User-Agent","NetFox"); iP~5=  
LpGplD lB  
&&xBq?  
int responseCode=httpConnection.getResponseCode(); '~VKH}b  
if(responseCode>=400) %UI.E=`n  
{ Lz2wOB1Zc+  
processErrorCode(responseCode); *j?tcxq  
return -2; //-2 represent access is error ?!U=S=8  
} }BKEz[G(  
2S&e!d-  
m beM/  
String sHeader; 4{(uw  
X,IjM&o"Y  
sHyhR:  
for(int i=1;;i++) ^rfY9qMJr8  
{ [!]a' T#x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L$cNxz0$  
//Utility.log(in.readLine()); #M$[C d I$  
sHeader=httpConnection.getHeaderFieldKey(i); Jor >YB`X  
if(sHeader!=null) -ZlBg~E  
{ zIi|z}WJ  
if(sHeader.equals("Content-Length")) TUIj-HSe  
{ bTHKMaGWC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c$rkbbf~V  
break; 0Jm6 r4s?  
} KiT>W~  
} ,a eQXI#@  
else 8;ke,x  
break; S(.AE@U  
} ~YA* RCe  
} \{t#V ~  
catch(IOException e){e.printStackTrace ();} a*$to/^r  
catch(Exception e){e.printStackTrace ();} mv O!Y  
}=z_3JfO  
Y;8Ys&/t  
Utility.log(nFileLength); _7'9omq@  
8*!<,k="9  
mTz %;+|L  
return nFileLength; 0; 2i"mzS\  
} :'91qA%Wr  
D*6v.`]X  
mcy\nAf5%  
//保存下载信息(文件指针位置) L3JFQc/oh~  
private void write_nPos() Yz=(zj  
{ OXe+=Lp<  
try{ |!E>I  
output = new DataOutputStream(new FileOutputStream(tmpFile));  H;s  
output.writeInt(nStartPos.length); n$ $^(-g@)  
for(int i=0;i<nStartPos.length;i++) lqn7$  
{ B8UtD  
// output.writeLong(nPos); veAg?N<c p  
output.writeLong(fileSplitterFetch.nStartPos); RbzSQr>a\  
output.writeLong(fileSplitterFetch.nEndPos); /:3:Ky3  
} HS XS%v/Y  
output.close(); f]`#BE)V  
}  n0F.Um  
catch(IOException e){e.printStackTrace ();} FRd!UqMXY  
catch(Exception e){e.printStackTrace ();} (+6 8s9XS7  
} C93BK)$}  
Xf!@uS6<X  
NUbw]Y90~  
//读取保存的下载信息(文件指针位置) u~[HC)4(0  
private void read_nPos() fuSfBtLPR#  
{ ^e:C{]S=  
try{ +%Q:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,A`d!{]5  
int nCount = input.readInt(); 0{^vqh.La  
nStartPos = new long[nCount]; 1 rKKph  
nEndPos = new long[nCount]; u\wdb^8ds  
for(int i=0;i<nStartPos.length;i++) T]Z|Wq`bot  
{ s:3 altv  
nStartPos = input.readLong(); #"-?+F=rk  
nEndPos = input.readLong(); 5Ds/^fA  
} l*>t@:2J  
input.close(); 'KB\K)cD=3  
} 6zh<PETa03  
catch(IOException e){e.printStackTrace ();} lffp\v{w  
catch(Exception e){e.printStackTrace ();} Hy ^E m  
} ;*1bTdB5a  
uPKq<hBI  
<_$]!Z6UR  
private void processErrorCode(int nErrorCode) ?j;e/r.  
{ (MhC83|?  
System.err.println("Error Code : " + nErrorCode); &IsQgS7R  
} =M'M/vKD  
PLU8:H@X  
+^ a9i5  
//停止文件下载 bP\0S@1YL  
public void siteStop() A'r 3%mC  
{ E9z^#@s  
bStop = true; =y -L'z&r  
for(int i=0;i<nStartPos.length;i++) CF"$&+s9  
fileSplitterFetch.splitterStop(); rCfr&>nn  
<6QG7 i  
uMVM-(g%  
} %|E'cdvkX  
} _Z?{&k  
//负责部分文件的抓取 `q|&;wP.  
**FileSplitterFetch.java mAMi-9  
*/ **_`AM~  
package NetFox; D,q=?~  
g?` g+:nug  
.w2QiJ  
import java.io.*; Go~bQ2*'(/  
import java.net.*; BC*vG=a  
arJ4^  d  
:MeshzWK  
public class FileSplitterFetch extends Thread { D FDC'E  
^,u0kMG5l  
|T?wM/  
String sURL; //File URL sqTBlP  
long nStartPos; //File Snippet Start Position Ay)q %:qx  
long nEndPos; //File Snippet End Position :K.%^ag=j  
int nThreadID; //Thread's ID  R}Pw#*B  
boolean bDownOver = false; //Downing is over [M>Md-pj  
boolean bStop = false; //Stop identical :*bv(~FW  
FileAccessI fileAccessI = null; //File Access interface %x@ D i`;  
>dKK [E/[d  
dv=y,q@W  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %pj 6[x`@  
{ PN9^ sLx=  
this.sURL = sURL; u.;zz'|  
this.nStartPos = nStart; ^kZfE"iE2  
this.nEndPos = nEnd; "<o[X ?u  
nThreadID = id; M S 3?#b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +Go(y S  
} :$k':0 n  
.N2yn`  
HR)Dz~Obw  
public void run() 5\93-e  
{ VD}8ei  
while(nStartPos < nEndPos && !bStop) J)1:jieQ  
{ RtVy^~=G  
r /v'h@  
<;O=h; ~|  
try{ H`u8}{7  
URL url = new URL(sURL); ~RcI+jR)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KHwzQ<Z3  
httpConnection.setRequestProperty("User-Agent","NetFox"); AA][}lU:5  
String sProperty = "bytes="+nStartPos+"-"; z_qy >  
httpConnection.setRequestProperty("RANGE",sProperty); ~\= VSwJ  
Utility.log(sProperty); [A$5~/Q{U1  
&v!=\Fig4  
pR_cI]{=SA  
InputStream input = httpConnection.getInputStream(); FTM(y CN  
//logResponseHead(httpConnection); Jf\lnJTyU8  
hZGoiWC  
d:/8P985  
byte[] b = new byte[1024]; W: Rs 0O  
int nRead; @L^Fz$Sx  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .d< +-w2Mu  
{ <viIpz2jh%  
nStartPos += fileAccessI.write(b,0,nRead); u@|izRk  
//if(nThreadID == 1) aE}1~`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u\YH,  
}  V|=PaO  
B$~oZ'4v  
whb|N2  
Utility.log("Thread " + nThreadID + " is over!"); DLMG<4Cd~  
bDownOver = true; e$F]t *)Xa  
//nPos = fileAccessI.write (b,0,nRead); z;1y7W!v  
} =Y`P}vI]w%  
catch(Exception e){e.printStackTrace ();} Rz}?@zh_8  
} n}==  
} p.KX[I  
9hAS#|vK  
mv@cGdxu  
//打印回应的头信息 KTn,}7vZ  
public void logResponseHead(HttpURLConnection con) 8 vNgePn  
{ ~;St,Fw<<  
for(int i=1;;i++) +EJwWDJ!%  
{ +|.}oL^}G  
String header=con.getHeaderFieldKey(i); RZ)sCR  
if(header!=null) B5J!&suX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QS2J271E}  
Utility.log(header+" : "+con.getHeaderField(header)); [?)=3Pp  
else Gd0-}4S?  
break; gLv|Hu7  
} `abQlBb*  
} g*b 4N _  
9tZ)#@\  
9 x WC<i  
public void splitterStop() KDwz!:ye  
{ htc& !m  
bStop = true; d_9Fc" C~  
} Hj ]$  
PoMkFG6  
ps0wN%tA  
} f`<j(.{9F  
_3$@s{k-TI  
gr %8 O-n  
/* I( BG%CO9  
**FileAccess.java tq=1C=h  
*//文件访问(定位,写) dDH+`;$.  
package NetFox; F\1nc"K/(  
import java.io.*;  f])?Gw  
1lyJ;6i6L  
#1R_* Uh  
public class FileAccessI implements Serializable{ }aYm86C]  
9@AGx<S1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @k~?h=o\b  
RandomAccessFile oSavedFile;  ToNi<~  
long nPos; 8?] :>  
<B6@q4Q  
${'gyD  
public FileAccessI() throws IOException D^Dm, -  
{ <'A>7M~h?*  
this("",0); ?7-#iC`  
} pM~Xh ]/  
A2'   
 t K;E&:  
public FileAccessI(String sName,long nPos) throws IOException 7SzY0})<U  
{ K#M h  
oSavedFile = new RandomAccessFile(sName,"rw"); g!n1]- 1  
this.nPos = nPos; ,oe e'  
oSavedFile.seek(nPos); )gdv!  
} || ?B1  
5A1oZ+C#  
Rs B o\#`  
public synchronized int write(byte[] b,int nStart,int nLen) EQPZV K/  
{ Sp)KtMV  
int n = -1; SCeZt [  
try{ RAKQ+Y"nl  
oSavedFile.write(b,nStart,nLen); aKs!*uo0H  
n = nLen; FtN1ZZ"<*  
} ~\dpD  
catch(IOException e) >_M}l @1  
{ >V(>2eD'S  
e.printStackTrace (); .jMm-vox}  
} mFayU w  
vy/U""w`  
kF'^!Hp  
return n; #1Mk9sxo  
} EZ #UdK_  
Y0BvN`E  
hM E|=\  
} :b>Z|7g?  
K-wjQ|*1  
1=#r$H  
/* $oE 4q6b  
**SiteInfoBean.java dgssX9g37  
*/ L*tXy>&b.  
package NetFox; kN9S;o@)  
X@+:O-$  
&n<jpMB  
public class SiteInfoBean { |Ix6D  
x$CpUy{6  
oT 8  
private String sSiteURL; //Site's URL ,r5<v_  
private String sFilePath; //Saved File's Path r0G#BPgdR  
private String sFileName; //Saved File's Name d_J?i]AP|'  
private int nSplitter; //Count of Splited Downloading File iMx+y5O  
Y=X"YH|  
MSeO#X  
public SiteInfoBean() ;t%L (J  
{//nSplitter的缺省值为5 |PH]0.m5  
//default value of nSplitter is 5 !~UI~-i'  
this("","","",5); OfTcF_%  
} xmKa8']x  
yG&kP:k<  
S "oUE_>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B2d$!Any  
{ >0 !J]gK  
sSiteURL= sURL; 4\pA^%73  
sFilePath = sPath; d1e'!y}R5  
sFileName = sName; &o"Hb=k<  
this.nSplitter = nSpiltter; }=A6Jv(j  
zq!2);,  
$Fz/&;KX!  
} ([|5(Omd\  
+^YV>;  
_if&a'  
public String getSSiteURL() ?y<n^`  
{ XeDU ,  
return sSiteURL; 3+A 0O%0*  
} t)XV'J  
O RQGay  
iN<5[ztd  
public void setSSiteURL(String value) 6?*iIA$b  
{ dMGu9k~u  
sSiteURL = value; 3\=8tg p  
} HKOJkbVZ2^  
u MzefRN  
yfTnj:Fz  
public String getSFilePath() n_Um)GI>  
{ u;J=g  
return sFilePath; \(T; @r  
} :#TJ-l:#  
,_NO[+5U  
9Z*`{  
public void setSFilePath(String value) R5]R pW=G  
{ %h|z)  
sFilePath = value; #PXl*~PrQ/  
} |D]jdd@!a2  
q 4 Ye  
|<y[gj4`T/  
public String getSFileName() KH pxWq  
{ { w!}:8p  
return sFileName; b@YSrjJ  
} rA=F:N 2  
jv2l_  
@2$PU{dH  
public void setSFileName(String value) [-6j4D  
{ qgZ(o@\  
sFileName = value; !YJdi~q  
} d,<ctd  
!LIWoa[ F.  
asQ" |]m  
public int getNSplitter() w-/bLg[L?$  
{ 2gt08\  
return nSplitter; Fg#*rzA  
} }d.R=A9L  
SF_kap%JM  
; UrwK  
public void setNSplitter(int nCount) D VSYH{U4  
{ S NK+U"Q  
nSplitter = nCount; AZl=w`;/O%  
} Q|5wz]!5Y(  
} (|U+(~PJ  
&OI=r vDmo  
.\U+`>4av  
/* _"WQi}Mm  
**Utility.java `n^jU92  
*/ qk_ s"}sS  
package NetFox; bO2$0!=I  
?WAlW,H>  
$%1[<}<  
public class Utility { Q8:u1$}  
U +mx@C_  
' J-(v  
public Utility() 8: s3Q`O  
{ Z]SCIU @+  
Nm,v E7M  
<[~x]-  
} Hlz4f+#I  
$wN'mY  
//线程睡眠 m k -" U7;  
public static void sleep(int nSecond) v0$6@K;M4G  
{ f2{4Y)  
try{ }WCz*v1Wq  
Thread.sleep(nSecond); 2o\\qEYg  
} up:e0di{  
catch(Exception e) o.Cj+`0}5  
{ .mok.f<G_m  
e.printStackTrace (); m%Ef]({I  
} 2&tGJq-E  
} u|QfCwQ  
6eS#L21*  
//日志 :=i0$k<E/  
public static void log(String sMsg) /au\OBUge  
{ q1?2 U<  
System.err.println(sMsg); x7NxHTL  
} RIJBHOa  
q!AS}rV  
|xf%1(Rl@  
public static void log(int sMsg) tS!~> X  
{ gcv,]v 8  
System.err.println(sMsg); N}dJ)<(2~  
} pg>P]a{  
} -9aht}Z  
'm2,7]  
x&9 I2"  
/* <c\aZ9+V  
**TestMethod.java B]Zsn`n  
*/ LG,RF:  
package NetFox; e,4!/|H:  
D6ck1pxkx  
x65e,'  
public class TestMethod { N`zHe*=[~  
g:2/!tujL  
mB1)!  
public TestMethod() Zy!\=-dSm  
{ ///xx/weblogic60b2_win.exe ~Yr.0i.W  
try{ (> 8fcQUBb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T.(SBP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xE)pj|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o<g (%ncr  
fileFetch.start(); )E4COw+  
} <=7p~ i5  
catch(Exception e){e.printStackTrace ();} IvO3*{k ,  
,]cd%w9  
2#E;5UYu  
} *uv\V@0  
;ib~c,  
KK] >0QAY  
public static void main(String[] args) d9^=#ot  
{ pixI&iQ  
new TestMethod(); ' l!QGKz  
} fe0 Y^vW  
} &c\8` # 6  
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