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http断点续传简单实现(java)

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/* Ko4)0&  
**SiteFileFetch.java ?U}sQ;c$  
*/ GA(OK-WUd  
package NetFox; %N7gT*B:  
import java.io.*; @;g`+:=  
import java.net.*; /4(Z`e;0  
7Y%!,ff  
qwL 0~I  
public class SiteFileFetch extends Thread { CQj/e+eE4  
l#tS.+B7  
\)uy"+ Z`  
SiteInfoBean siteInfoBean = null; //文件信息Bean *iPs4Es-  
long[] nStartPos; //开始位置 W]} #\\$z  
long[] nEndPos; //结束位置 LQ~LB'L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XCW+ pUX  
long nFileLength; //文件长度 Xs{/}wc.q;  
boolean bFirst = true; //是否第一次取文件 N-]\oMc2  
boolean bStop = false; //停止标志 MP6 \r  
File tmpFile; //文件下载的临时信息  =|^X$H  
DataOutputStream output; //输出到文件的输出流 Q~x*bMb.  
czXI?]gg,  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) (r.$%[,.<  
public SiteFileFetch(SiteInfoBean bean) throws IOException &*X3c h  
{ ;%v%K+}r  
siteInfoBean = bean; nrxjN(9V%+  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dVasm<lZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OJnPP>  
if(tmpFile.exists ()) Vww@eK%5Q  
{ ;5&k/CB1  
bFirst = false; _JfJ%YXy  
read_nPos(); HR/k{"8W4Q  
} U;x99Go:  
else PpX{+^z-%  
{ ;m-6.AV  
nStartPos = new long[bean.getNSplitter()]; \W3+VG2cA  
nEndPos = new long[bean.getNSplitter()]; ?q+8 /2  
} trID#DT~  
'?&B5C  
s4\SX,  
6|Ba  
} v1`bDS?*Q  
[V!^\g\6  
u.ULS3`C/X  
public void run() FE$M[^1_  
{ AlPL;^Y_l  
//获得文件长度 f 3nnXE"  
//分割文件 9+WY@du+  
//实例FileSplitterFetch fY| @{]rx  
//启动FileSplitterFetch线程 V Z4nAG  
//等待子线程返回 K8yWg\K  
try{ 5Ws:Ei{R  
if(bFirst) B`'}&6jr.  
{ f~n' Ki+'  
nFileLength = getFileSize(); z/ c'Z#w%  
if(nFileLength == -1) v.~Nv@+kR  
{ |THkS@Br  
System.err.println("File Length is not known!"); OF<[Nh\.  
} ~m,mvRS  
else if(nFileLength == -2) cOj +}Hz58  
{ pn ~/!y  
System.err.println("File is not access!"); brp N >\  
} MSxU>FX0  
else fzPgX  
{ BMtYM{S6  
for(int i=0;i<nStartPos.length;i++) @E&X &F%  
{ m%BMd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +#i,87  
} ( S C7m /  
for(int i=0;i<nEndPos.length-1;i++) Aw_R $  
{ DI2S %N l  
nEndPos = nStartPos[i+1]; 9I^H)~S  
} \k$]GK-  
nEndPos[nEndPos.length-1] = nFileLength; v]d?6g  
} $AL|d[[T[  
} p!rG PyGC  
;1(qGy4  
  t`&s  
//启动子线程 5BGv^Qb_2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; BhhK| U/  
for(int i=0;i<nStartPos.length;i++) 7\Yq]:;O  
{ 37za^n?SG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e-T9HM&%P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p lz=G}Y  
nStartPos,nEndPos,i); :u|UVp5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G41$oalQ1  
fileSplitterFetch.start(); B=nx8s  
} l*V72!Mv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ' m# Ymp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z;@S_0M,Z  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a7 '\*  
nEndPos = " + nFileLength); YRT}fd>R&  
// fileSplitterFetch[nPos.length-1].start(); (HP={MrV  
a}+ _Yo(Q  
:;gwdZ  
//等待子线程结束 s$=B~l  
//int count = 0; >=RHE@  
//是否结束while循环 ;tIIEc  
boolean breakWhile = false; {3 yws 4  
&<; nl^  
[+[fD  
while(!bStop) y5opdIaT  
{ nh_xbo5L[  
write_nPos(); F\$}8,9  
Utility.sleep(500); )-6[ Bw  
breakWhile = true; s13 d*  
3ks|  
,\">ovV33  
for(int i=0;i<nStartPos.length;i++) tZ6v@W  
{ }Q,C;!'"  
if(!fileSplitterFetch.bDownOver) Zp P6Q  
{ (j\UoKLRt  
breakWhile = false; {~ vPq  
break; Vt 5XC~jK  
} "nS{ ;:  
} r'}k`A 5>  
if(breakWhile) pz z`4VS:  
break; [O =)FiY-  
;Q%19f3,6  
,@j& q  
//count++; :Y&W)V-  
//if(count>4) < oG\)!O  
// siteStop(); MDXQj5s^  
} &qj&WfrB,  
1F%*k &R  
;@$," P  
System.err.println("文件下载结束!"); >Sl:Z ,g;  
} Xv;ZAa  
catch(Exception e){e.printStackTrace ();} u K&_IE}  
} @ F"ShT0  
7*W$GCd8  
<Ucfd G&Lp  
//获得文件长度 e2H'uMy;&  
public long getFileSize() nT6iS}h  
{ G7#~=W 2M  
int nFileLength = -1; EwJn1Mvq  
try{ l<:)rg^,  
URL url = new URL(siteInfoBean.getSSiteURL()); t@mw f3,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +]2~@=<@  
httpConnection.setRequestProperty("User-Agent","NetFox"); uTF EI.N  
6O?Sr,  
9U%}"uE  
int responseCode=httpConnection.getResponseCode(); jF2GHyB  
if(responseCode>=400) >@\?\!Go  
{ {.[,ee-)9  
processErrorCode(responseCode); WN?`Od:y  
return -2; //-2 represent access is error nWg)zj:  
} [UrS%]OSR  
s%re>)=|  
|0Ug~jKU  
String sHeader; X_yU"U  
]uXsl0'`V  
Yl3PZ*#@ Q  
for(int i=1;;i++) @g` ,'r  
{ eyp\h8!u_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [_B&7#3>7  
//Utility.log(in.readLine()); H s 3*OhK\  
sHeader=httpConnection.getHeaderFieldKey(i); x" =q+sA  
if(sHeader!=null) m.X+sP-e  
{ 3S21DC@Y  
if(sHeader.equals("Content-Length")) LPgI"6cP  
{ y^fU_L?p  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [~0q )  
break; tUnVdh6L.B  
} e;Z`&  
} =C}<0<"iF  
else @_Oe`j^  
break; Z-V%lRQ=b  
}  ~&jCz4M  
} *g}&&$b0  
catch(IOException e){e.printStackTrace ();} r\D8_S_  
catch(Exception e){e.printStackTrace ();} T`G"2|ISS  
S}I=i>QB  
Y3&ecEE  
Utility.log(nFileLength); <08V-   
-L3RzX  
BGjTa.&  
return nFileLength; (pg9cM]NA  
} n[-!Jp[  
HK.J/Zr  
p-Btbhv  
//保存下载信息(文件指针位置) fL:Fn"Nv  
private void write_nPos() \mG M#E  
{ X"GQ^]$O  
try{ h}_q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); k,(_R=  
output.writeInt(nStartPos.length); Mb!^_cS(  
for(int i=0;i<nStartPos.length;i++) K>6p5*&  
{ U]$3NIe  
// output.writeLong(nPos); %tLq&tyeY  
output.writeLong(fileSplitterFetch.nStartPos); C_)>VPD  
output.writeLong(fileSplitterFetch.nEndPos); R:p,Hav<q  
} #+\G- =-  
output.close(); r/f;\w7  
}  (La  
catch(IOException e){e.printStackTrace ();} '_Oprx  
catch(Exception e){e.printStackTrace ();} B/}>UHM  
} {D#`+uw  
h#nQd=H<g#  
tTt~W5lo  
//读取保存的下载信息(文件指针位置) W@=ilW3RD  
private void read_nPos() * vD<6qf  
{ .|-y+9IP  
try{ vS#]RW&j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); yL-L2  
int nCount = input.readInt(); t"fD"Xpj  
nStartPos = new long[nCount]; ],|B4\b;  
nEndPos = new long[nCount]; e+TNG &_  
for(int i=0;i<nStartPos.length;i++) (#qVtN`t  
{ 9~yuyv4$  
nStartPos = input.readLong(); ZxQP,Ys_Y  
nEndPos = input.readLong(); g~b'}^J  
} t,_[nu(~8%  
input.close(); 5JXLfYTUI  
} u!W00;`L  
catch(IOException e){e.printStackTrace ();} D.?gV_  
catch(Exception e){e.printStackTrace ();} 5"U7I{\  
} \\JXY*DA:+  
4NIfQYC.  
*VB*/^6A  
private void processErrorCode(int nErrorCode) jC%I]#!n  
{ |Oe6OCPf  
System.err.println("Error Code : " + nErrorCode); dQ]j r.  
} RU=%yk-gM  
;f Gi5=-  
`u-Y 5mY  
//停止文件下载 >B0S5:S$W  
public void siteStop() `Ec+i  
{ H'2 =yhtVh  
bStop = true; {YFru6$  
for(int i=0;i<nStartPos.length;i++) al/~  
fileSplitterFetch.splitterStop(); U' Cp3>  
&n|gPp77$  
;<\*(rUe  
} d<o  
} 5|Qr"c$p  
//负责部分文件的抓取 aF:LL>H  
**FileSplitterFetch.java H@zpw1fH+  
*/ -84Z8?_  
package NetFox; Tb^9J7]  
y06 2/$*$  
f+ &yc'[  
import java.io.*; JLhp25{x  
import java.net.*; sdLFBiR  
 f$3  
B}W^s;h  
public class FileSplitterFetch extends Thread { F3q5!1  
8Bhng;jX  
A.[T#ZB.4  
String sURL; //File URL dn Xc- <  
long nStartPos; //File Snippet Start Position 4?Io@[7A)  
long nEndPos; //File Snippet End Position vd~O:=)4  
int nThreadID; //Thread's ID <FP -]R)  
boolean bDownOver = false; //Downing is over wZ^/-  
boolean bStop = false; //Stop identical ^P[*yf  
FileAccessI fileAccessI = null; //File Access interface ;(V=disU/  
f5N~K>  
MmX42;Pw  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aD4ln]sFxG  
{ XP'KgTF  
this.sURL = sURL; -&c@c@dC  
this.nStartPos = nStart; *G9;d0  
this.nEndPos = nEnd; xsfq[}eH<  
nThreadID = id; z# y<QH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 HBt?cA '  
} thh, V   
G 5)?!  
pH4i6B*5  
public void run() KT3[{lr  
{ ?}W:DGudZ  
while(nStartPos < nEndPos && !bStop) w:qwU\U>x  
{ 2]@U$E='s  
h.67] U7m  
{vaq,2_w  
try{ F*a+&% Q  
URL url = new URL(sURL); DU;]Q:r{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zR e0z2  
httpConnection.setRequestProperty("User-Agent","NetFox"); =/zQJzN  
String sProperty = "bytes="+nStartPos+"-"; NWKD:{  
httpConnection.setRequestProperty("RANGE",sProperty); 5vS'Qhc  
Utility.log(sProperty); QPBf++|  
=~R 0U  
77)C`]0(  
InputStream input = httpConnection.getInputStream(); aUd6 33  
//logResponseHead(httpConnection); 3c6<JW  
n.XT-X^  
3iY`kf  
byte[] b = new byte[1024]; 5^%FEZ&Sp  
int nRead; -`rz[";n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AR&u9Y)I  
{ HIF.;ImG^  
nStartPos += fileAccessI.write(b,0,nRead); |`,%%p|T%  
//if(nThreadID == 1) A6-JV8^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uHy^ Bq  
} c: _l+CgeH  
p`Ax)L\f  
,KZ_#9[>  
Utility.log("Thread " + nThreadID + " is over!"); :c c#e&BO  
bDownOver = true; ni9/7  
//nPos = fileAccessI.write (b,0,nRead); ujHqw Rh  
} 94H 6`  
catch(Exception e){e.printStackTrace ();} 1XwbsKQ}  
} uQrD}%GI  
} N{f RZN  
I:[3x2H  
R\)pW9)  
//打印回应的头信息 =p$1v{L8  
public void logResponseHead(HttpURLConnection con) @ 3FTf"#Y  
{ c_+}`  
for(int i=1;;i++) 5_{C \S`T  
{ LC/6'4}_  
String header=con.getHeaderFieldKey(i); K`D>G<  
if(header!=null) :4/RB%)"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a*! wiTGf  
Utility.log(header+" : "+con.getHeaderField(header)); "\Z.YZUa\  
else (m25ZhW  
break; Y0 Ta&TYZ0  
} 3 `$-  
} +,f|Y6L<  
g&) XaF[!  
*#w+*ywVZH  
public void splitterStop() w>J|416  
{ .9PPWY;H  
bStop = true; `~F=  
} EE=!Y NP]  
]^$3S  
=E,^ +`M  
} 1!~=8FTv  
Qk *`9  
ssUWr=mD  
/* k|'{$/ n  
**FileAccess.java gDa}8!+i  
*//文件访问(定位,写) HM /2/ /  
package NetFox; vlY83mU.  
import java.io.*; |VQ17*4ff1  
Y/?V%X  
6w|s1!B l  
public class FileAccessI implements Serializable{ _o`+c wc  
Bf1,(^3XH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z9,-FO{#3-  
RandomAccessFile oSavedFile; ^}fc]ovV  
long nPos; B+:/!_  
V{+'(<SV  
LVP2jTz  
public FileAccessI() throws IOException <[Oe.0SGu  
{ 6}4?, r  
this("",0); GCm(3%{V%(  
} BJC$KmGk  
"NWILZwEV  
kCRfO}wt3  
public FileAccessI(String sName,long nPos) throws IOException cuzU*QW"g  
{ tqbYrF)  
oSavedFile = new RandomAccessFile(sName,"rw"); :+#$=4  
this.nPos = nPos; i7D[5!  
oSavedFile.seek(nPos); F#Y9 @E  
} d^h`gu~3  
2[} O:  
c[VVCN8dA  
public synchronized int write(byte[] b,int nStart,int nLen) I[nSf]Vm>  
{ XNbeYj  
int n = -1; !r^fX=X>'  
try{ 8_$[SV$q  
oSavedFile.write(b,nStart,nLen); %[S-"k  
n = nLen; 'aV])(Wm>  
} Uzh#z eZ`<  
catch(IOException e) Ln+;HorZ]  
{ ' _ZiZ4O  
e.printStackTrace (); xB4}9zN s  
} !#&`1cYX  
 GY`mF1b  
;*(i}'  
return n; 2`dKnaF|  
} _p*a`,tK  
i8w/a  
S$N!Dj@e;  
} M:M"7>:  
f/PqkHF  
E4N/or  
/* ,tTq25~H\  
**SiteInfoBean.java 1R.|j_HYy  
*/ /6 y9 u}  
package NetFox; _.%U}U  
{k}$L|w  
I3qTSX-  
public class SiteInfoBean { +lplQh@RB  
c/lT S  
3d`u!i?/  
private String sSiteURL; //Site's URL N&yr?b'!-*  
private String sFilePath; //Saved File's Path HT:V;?"  
private String sFileName; //Saved File's Name ;e)`C v  
private int nSplitter; //Count of Splited Downloading File nV:RL|p2jw  
W" Tj.oCUG  
?WP*At0  
public SiteInfoBean() 4iDqd  
{//nSplitter的缺省值为5 e_YTh^wU  
//default value of nSplitter is 5 8kLHQ0pmu  
this("","","",5); oTJ^WePZQ  
} f"z;'  
OF}."a  
vRh)o1u)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7NvnCs  
{ r$:hiE@  
sSiteURL= sURL; dv Vz#  
sFilePath = sPath; x7xMSy  
sFileName = sName; 5?Ukf$)x  
this.nSplitter = nSpiltter; %Yt;)q3U  
Kzx` E>,z'  
x1h&`QUP  
} Zi?:< H}  
"$/1.SX;]  
[<|$If99\  
public String getSSiteURL() 6p9 { z42  
{ hSz_e  
return sSiteURL; Eunmc  
} h1H$3TpP  
;F_P<b 2  
"ql$Rz8  
public void setSSiteURL(String value) OdpHF~(Y/  
{ u#y#(1 =  
sSiteURL = value; Qz89=#W  
} /'/i?9:  
18Vn[}]"  
FJ{/EloF  
public String getSFilePath()  =W&m{F96  
{ +cbF$,M4  
return sFilePath; +|x{?%.O  
} .SLpgYFL{  
A2ufET  
L?Ys(a"k  
public void setSFilePath(String value) `8r$b/6  
{ FUf.3@}  
sFilePath = value; `kE7PXqa  
} puLgc$?  
t(dVd%   
6$0<&')Yb  
public String getSFileName() 6i%6u=um3  
{ IM ncl=1  
return sFileName; Dw.I<fns^B  
} 4l{$dtKbI  
p_ f<@WE  
4"H *hKp  
public void setSFileName(String value) ZyDNtX%  
{ jO/cdLKX(  
sFileName = value; :b*7TJ\grN  
} BU4IN$d0Po  
g$jTP#%b  
4lWqQVx  
public int getNSplitter() mE5{)<N:C  
{ 1Y&W>p  
return nSplitter; z9g ++]rkJ  
} 934j5D  
g1|Py t{  
p"c6d'qe  
public void setNSplitter(int nCount) J5HN*Wd  
{ [qW%H,_  
nSplitter = nCount; J4"A6`O  
} {@iLfBh5  
} tq~4W% p/  
 Igmg&  
< K!r\^  
/* u<uc"KY=  
**Utility.java \Cu=Le^  
*/ #*/nUbsg  
package NetFox; 8b.k*,r>  
Wh..QVv  
ZzNHEV  
public class Utility { |'1.a jxw  
=.;ib6M  
?4U4o<   
public Utility() Ahl&2f\  
{ 0?8>{!I  
fMFkA(Of^  
yQUrHxm  
} H390<`  
]o]`X$n  
//线程睡眠 $)"T9 $>$  
public static void sleep(int nSecond) '%t$m f!nV  
{ v~Dobk/n  
try{ [KYq01cj  
Thread.sleep(nSecond); WN{8gL&y  
} ;Us6:}s  
catch(Exception e) Yg '(  
{ .<>t2,Af  
e.printStackTrace (); -s2)!Iko&  
} Qc-W2%  
} 7F>]zrbK  
72xf| s=  
//日志 9C,gJp}P  
public static void log(String sMsg) *~6]IWN`  
{ Bf00&PE;  
System.err.println(sMsg); 8 A]8yX =  
}  EH2):  
!gLJBp  
.O0eSp|e  
public static void log(int sMsg) uGXvP(Pg'  
{ W`_Wi*z4  
System.err.println(sMsg); rtvLLOIO  
} g~K-'Nw  
} mD +9/O!  
~oSA&v4V  
:%mls Nw  
/* wjX0r7^@  
**TestMethod.java nY1PRX\  
*/ -M]/Xv]  
package NetFox; ^8oN~HLZ  
AX@bM  
;MYK TE>m  
public class TestMethod { x?{l<mc  
E"BW-<_!  
X%*BiI  
public TestMethod() ]OKKR/:  
{ ///xx/weblogic60b2_win.exe epk C '  
try{ 0[ n;ZL~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p |;#frj  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,bzgjw+R5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^|rzqXW  
fileFetch.start(); <4?(|Vh[m]  
} cru&nH*O^  
catch(Exception e){e.printStackTrace ();} dXt@x8E  
}/NL"0j+4  
m7> )p]]  
} 9ys[xOh WM  
**9[e[(X  
=1B;<aZH!  
public static void main(String[] args) K^AIqL8  
{ Sf`?j  
new TestMethod(); i2O$oHd  
} ]tK<[8Y  
}  ,8p-EH  
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