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http断点续传简单实现(java)

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/* oMh$:jR$  
**SiteFileFetch.java Sj9fq*  
*/ jr6_|(0 i6  
package NetFox; )vp0X\3q`  
import java.io.*; v+c>iI  
import java.net.*; d2k-MZuT6  
K/Q"Z*  
_( W@FS  
public class SiteFileFetch extends Thread { dG\ wW@}J  
Q8p6n  
.Y)[c. ,j  
SiteInfoBean siteInfoBean = null; //文件信息Bean !Ok(mgV$/  
long[] nStartPos; //开始位置 -YRIe<}E -  
long[] nEndPos; //结束位置 1+l8%G=hB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Up9{aX  
long nFileLength; //文件长度 s#2t\}/  
boolean bFirst = true; //是否第一次取文件 %fS9F^AK  
boolean bStop = false; //停止标志 Oy6fl'FIt  
File tmpFile; //文件下载的临时信息 n3^(y"q  
DataOutputStream output; //输出到文件的输出流 ho]:)!|VY  
ui8 Q2{z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Y\|#Lu>B  
public SiteFileFetch(SiteInfoBean bean) throws IOException &C 9hT  
{ 3h@]cWp  
siteInfoBean = bean; FDHW' OP4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^t >mdxuq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;KeU f(tH  
if(tmpFile.exists ()) ]hl*6  
{ 12$0-@U  
bFirst = false; >)><u4}  
read_nPos(); _)A|JC!jId  
} 8tY>%A~^z  
else 7& M-^Ev  
{ {#,<)wFV\  
nStartPos = new long[bean.getNSplitter()]; }^"6:;,  
nEndPos = new long[bean.getNSplitter()]; .;#T<S "  
} -m@o\9Ic  
h`[$ Bp  
,75)  
L/3A g* ]  
} .RD<]BxJ  
"wUIsuG/p  
pYr"3BwG  
public void run() J<) qw  
{ tbrU>KCBD  
//获得文件长度 tgRj8 @  
//分割文件 o)`PS w=  
//实例FileSplitterFetch } ueFy<F  
//启动FileSplitterFetch线程 aDlp>p^E>  
//等待子线程返回 Fs+ tcr/\[  
try{ O zAIz+`  
if(bFirst) 4kOO3[r  
{ #-{<d% qk  
nFileLength = getFileSize(); U,P_bz*)  
if(nFileLength == -1) k.J%rRneN  
{ [4)Oi-_Y>  
System.err.println("File Length is not known!"); b3(* /KgK  
} 9A .RD`fg  
else if(nFileLength == -2) m5Bf<E,c  
{ b R\7j+*&  
System.err.println("File is not access!"); XS<>0YM  
} $vn6%M[  
else 3JazQU  
{ #3uv^m LGa  
for(int i=0;i<nStartPos.length;i++) (vXr2Z<l  
{ Sp `l>BL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FO{=^I5YA  
} 1 ZdB6U0  
for(int i=0;i<nEndPos.length-1;i++) %6K7uvTq  
{ t)SZ2G1r  
nEndPos = nStartPos[i+1]; |IxHtg3>6{  
} OL'Ito  
nEndPos[nEndPos.length-1] = nFileLength; P.~UU S  
} Vk5Z[w a  
} C@M-_Ud>Q  
8%rD/b6`  
WM bkKC.{J  
//启动子线程 ChBf:`e  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,H7X_KbFD4  
for(int i=0;i<nStartPos.length;i++) Ee>VA_ss  
{ dQ:,pe7A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z]7 WC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), r>mBe;[TX  
nStartPos,nEndPos,i); u6iW1,#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _3IT3mb2n  
fileSplitterFetch.start(); "be\%W+<  
} 'nmGHorp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4.A^5J'W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q^X7x_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w,|@e_|J  
nEndPos = " + nFileLength); ns[/M~_r  
// fileSplitterFetch[nPos.length-1].start(); 5eAZfe%H  
UmKE]1Yw4r  
I}$`gUXX8x  
//等待子线程结束 '|yxB')  
//int count = 0; (P>nA3:UXB  
//是否结束while循环 *,u3Wm|7  
boolean breakWhile = false; 2=cx`"a$  
+LHU}'|  
*CN *G"  
while(!bStop) d3%qYL_+a  
{ f-U zFlU  
write_nPos(); kBUkE-~  
Utility.sleep(500); D?Oe";"/  
breakWhile = true; ]4~Yi1]  
+IZ=E >a  
VZ]iep  
for(int i=0;i<nStartPos.length;i++) "&(/bdah?&  
{ H4M=&"ll}  
if(!fileSplitterFetch.bDownOver) V 6}5^W  
{ 6@]o,O  
breakWhile = false; $q!A1Fgk0  
break; (Tx_`rO4VY  
} 0aT:Gy;  
} m:BzIcW<\  
if(breakWhile) ]2zM~  
break; Jv~R/qaaD  
+%5L2/n7  
<H64L*,5'7  
//count++; :8S;34Y;  
//if(count>4) 74e=zW?  
// siteStop(); b42%^E  
} ;@+ |]I  
FgdnX2s J  
cXXZ'y>FP  
System.err.println("文件下载结束!"); -"-.Z&#  
} ,fjY|ip  
catch(Exception e){e.printStackTrace ();} Qt u;_  
} rrIyZ@_d9  
A}fm).Wp@  
hs6pp/h>  
//获得文件长度 M+"6VtZH  
public long getFileSize() #p+iwW-  
{ HDm]njF%qQ  
int nFileLength = -1; 2gWR2 H@  
try{ wd:Yy  
URL url = new URL(siteInfoBean.getSSiteURL());  9q X$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y S3~sA  
httpConnection.setRequestProperty("User-Agent","NetFox"); WZa6*pF  
-TD\?Q  
}L0 [ Jo:  
int responseCode=httpConnection.getResponseCode(); (bm^R-SbB  
if(responseCode>=400) MqJTRBs%  
{ Zo UeLU  
processErrorCode(responseCode); B*/!s7c.  
return -2; //-2 represent access is error DG&'x;K"$  
} 8Qi)E 1n  
 }$oS /bo  
c[ 2t,+O  
String sHeader; 3ynkf77cn  
|bk9< i ?  
~[=<O s  
for(int i=1;;i++) S1|5+PPs  
{ $f@YQN=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?N4FB*x  
//Utility.log(in.readLine()); .!q_jl%U  
sHeader=httpConnection.getHeaderFieldKey(i); k26C=tlkv"  
if(sHeader!=null) RvG=GJJ9  
{ ,#;hI{E  
if(sHeader.equals("Content-Length")) MkW=sD_  
{ V7,dx@J-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cvcZ\y  
break; &mX_\w /%  
} 8K4^05*S   
} *+v*VH  
else I<}% L V  
break; lIyMNw  
} 9L$OSy|  
} tR51Pw  
catch(IOException e){e.printStackTrace ();} GR|\OJ<2  
catch(Exception e){e.printStackTrace ();} P!-RZEt$  
b5MBzFw  
bo<P%$(D  
Utility.log(nFileLength); HMVP71  
*iB&tWv  
eb7UA=[Z  
return nFileLength; 3cHYe  
}  hh4R  
Cab-:2L]  
1$RJzHS  
//保存下载信息(文件指针位置) J0V m&TY  
private void write_nPos() ILr=< j  
{ 1;[KBYUH  
try{ +cfcr*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8SpG/gl"  
output.writeInt(nStartPos.length); { <Gyjq  
for(int i=0;i<nStartPos.length;i++) ;PaU"z+Je~  
{ NU=2*gM  
// output.writeLong(nPos); rp\`uj*D  
output.writeLong(fileSplitterFetch.nStartPos); 0n:cmML )D  
output.writeLong(fileSplitterFetch.nEndPos); `M~R4lr  
} :G>w MMv&z  
output.close(); I^EZs6~  
} =r+K2]z,L  
catch(IOException e){e.printStackTrace ();} x8aOXN#w}  
catch(Exception e){e.printStackTrace ();} LZ wCe$1  
} yF\yxdUX#  
 Gd A!8  
WVD48}HF-  
//读取保存的下载信息(文件指针位置) yKhI&  
private void read_nPos() z~2{`pET  
{ W=HvMD  
try{ XaCvBQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jyD~ER}J  
int nCount = input.readInt(); CHTK.%AQH!  
nStartPos = new long[nCount]; n*"r!&Dg  
nEndPos = new long[nCount]; 1\}XL=BE  
for(int i=0;i<nStartPos.length;i++) Z,"4f*2  
{ .Wt3|?\=nd  
nStartPos = input.readLong(); %%ouf06.|  
nEndPos = input.readLong(); (Yz[SK=U}  
} a0hBF4+6  
input.close(); [.4{s  
} e1g3a1tnWl  
catch(IOException e){e.printStackTrace ();} /4O))}TX  
catch(Exception e){e.printStackTrace ();} WowT!0$  
} $y6 <2w%b  
U;/2\Ii  
QM8Ic,QFvo  
private void processErrorCode(int nErrorCode) R*vQvO%)h  
{ ,c"J[$i$  
System.err.println("Error Code : " + nErrorCode); |Uics:cQC  
} {C&U q#V  
1UK= t  
"dP-e  
//停止文件下载 ,c:NdY(,)  
public void siteStop() zg3kU65PJE  
{ uD@ ZM  
bStop = true; FD[*Q2fU  
for(int i=0;i<nStartPos.length;i++) O*v&C Hd3  
fileSplitterFetch.splitterStop(); vyDxX  
_yg;5#3  
Lfn$Q3}O`$  
} :!MEBqcU  
} {U2AAQSa  
//负责部分文件的抓取 HL&HY)W1gf  
**FileSplitterFetch.java 0)SRLHTY%  
*/ dV[G-p  
package NetFox; WP*}X7IS  
tx7 zG.,  
2*Qi4%s#  
import java.io.*; $ (;:4  
import java.net.*; |'-aR@xJ  
!#pc@(rE  
;@=3 @v  
public class FileSplitterFetch extends Thread { ;[;WEA  
t@R[:n;+  
wxqX42v  
String sURL; //File URL mDK*LL5]W  
long nStartPos; //File Snippet Start Position -&D=4,#  
long nEndPos; //File Snippet End Position K@*+;6y@  
int nThreadID; //Thread's ID I'*,<BPG  
boolean bDownOver = false; //Downing is over @Dfg6<0  
boolean bStop = false; //Stop identical rX)&U4#[m  
FileAccessI fileAccessI = null; //File Access interface v4hrS\M  
3N$@K"qM#  
"LlQl3"=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &(,\~  
{ 4/~x+tdc  
this.sURL = sURL; Jy/< {7j  
this.nStartPos = nStart; lv=q( &  
this.nEndPos = nEnd; b5H}0<  
nThreadID = id; {Z k^J  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7YD+zd:  
} FWJ**J  
4_5f4%S  
HSysME1X:/  
public void run() tkZUjQIX  
{ s8&q8r7%  
while(nStartPos < nEndPos && !bStop) Z@1kx3Wx$  
{ d7](fw@c  
[L2+k? *  
OGg\VV'  
try{ F/ZFO5C%  
URL url = new URL(sURL); |P]W#~Y-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }O7sP^  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Xg5=zn$  
String sProperty = "bytes="+nStartPos+"-"; UH-873AK  
httpConnection.setRequestProperty("RANGE",sProperty); rmzzbLTu  
Utility.log(sProperty); Fc@R,9  
YA,~qT|  
lND2Kb  
InputStream input = httpConnection.getInputStream(); OC*28)  
//logResponseHead(httpConnection); IrQ.[?C  
4 9N.P;b  
nrMW5>&-`  
byte[] b = new byte[1024]; > )< ?  
int nRead; }P?e31@:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1W'Ai"DLw  
{ SbGdcCB  
nStartPos += fileAccessI.write(b,0,nRead);  7qy PI  
//if(nThreadID == 1) z*h:Nt%.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2j8GJU/L  
} te( H6c#0  
uCr& `  
BJwuN  
Utility.log("Thread " + nThreadID + " is over!"); F8Ety^9>9  
bDownOver = true; #?w07/~L  
//nPos = fileAccessI.write (b,0,nRead); LH2B*8=^2  
} =_#b .8K  
catch(Exception e){e.printStackTrace ();} sR1_L/.  
} 5?;<^J  
} 7tlK'j'  
k5E2{&wZ  
3bWGWI  
//打印回应的头信息 _Z]l=5d  
public void logResponseHead(HttpURLConnection con) 'wEQvCS  
{ <z\SKR[  
for(int i=1;;i++) |Jn|GnM  
{ Is4,QnY_[  
String header=con.getHeaderFieldKey(i); g0j)k6<6(Y  
if(header!=null) `;Tf_6c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ywJ [WfCY  
Utility.log(header+" : "+con.getHeaderField(header)); #epbc K  
else g6%]uCFB  
break; 4+q,[m-$(  
} :41Y  
} L0"|4=  
0\XWdTj{  
eZOR{|z  
public void splitterStop() .4^+q9M  
{ _aevaWtEx  
bStop = true; \85%d0@3  
} }y6@YfV${  
nDdY~f.B  
~'lT8 n_  
} syB pF:`-W  
1<'z)r4  
D/Ki^E  
/* /al56n  
**FileAccess.java FTCIfW  
*//文件访问(定位,写) <VhmtT%7  
package NetFox; THhxj)  
import java.io.*; _y[C52,  
R 9` [C  
QIMd`c  
public class FileAccessI implements Serializable{ S'34](9n6  
Y"bm4&'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B-N//ef}  
RandomAccessFile oSavedFile; 8c.>6 Hy  
long nPos; sPi  
IrL7%?  
bK%F_v3'  
public FileAccessI() throws IOException P}8hK   
{ %>Gb]dv?  
this("",0); :4V5p =v-  
} UCcr>  
@>O7/d?O  
[T r7SU#x  
public FileAccessI(String sName,long nPos) throws IOException Dst;sLr[,  
{ ^WB[uFt-  
oSavedFile = new RandomAccessFile(sName,"rw"); 9f0`HvHC  
this.nPos = nPos; y[$UeE"0  
oSavedFile.seek(nPos); Bbs1U  
} 0]7jb_n1  
6Sd:5eTEQ  
M,JwoKyg  
public synchronized int write(byte[] b,int nStart,int nLen) }PK4 KRn  
{ k*;U?C!  
int n = -1; 5%2~/ "  
try{ HD KF>S_S  
oSavedFile.write(b,nStart,nLen); f]pHJVgFV  
n = nLen; qix$ }(P  
} G?M<B~}  
catch(IOException e) k~0#Iy_{M  
{ r*q  
e.printStackTrace (); cv{icz,%w  
} 3u 'VPF2  
JRw<v4pZ  
Ao )\/AR'  
return n; ybC0Ee@  
} Aaw]=8 OI  
~hZr1hT6L  
exZgk2[0  
} 2jVvK"C  
'^n,)oA/G  
.Ei#mG-=}&  
/* QO/nUl0E  
**SiteInfoBean.java !.G knDT  
*/ A'tv[T d8,  
package NetFox; I!?)}d  
q90 ~)n?  
e**<et.  
public class SiteInfoBean { *g*~+B :  
\y(ZeNs  
XtZeT~/7RT  
private String sSiteURL; //Site's URL zv-9z  
private String sFilePath; //Saved File's Path R?3N><oh*  
private String sFileName; //Saved File's Name <Fi*wV  
private int nSplitter; //Count of Splited Downloading File 34 '[O  
z"D0Th`S6  
#ZC9=  
public SiteInfoBean() * lJkk  
{//nSplitter的缺省值为5 { v  [  
//default value of nSplitter is 5 Al3*? H&  
this("","","",5); s$JO3-)  
} {/|tVc63  
DO 0  
hAV@/oQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dw-o71(1d  
{ cGSG}m@B`  
sSiteURL= sURL; ${5E  
sFilePath = sPath; G@3Jw[t  
sFileName = sName; ?{;7\1 [4  
this.nSplitter = nSpiltter; IkuE|  
NI:3hfs  
<^w4+5sT/  
} C"0vMUZ  
K8JshF Ie  
5^97#;Q;J"  
public String getSSiteURL() ,_UTeW6M  
{ 1{<r~  
return sSiteURL; +w2 `  
} l*z+<c6$_  
KJ7-Vl>  
`)tIXMn  
public void setSSiteURL(String value)  \62!{  
{ rhDiIO_  
sSiteURL = value; 4 'DEdx,&f  
} gle<{ `   
r+ usMF<'  
iOtf7.@  
public String getSFilePath() h-]c   
{ R:`)*=rL%  
return sFilePath; +xuj]J  
} $=5kn>[_Z%  
=u`tlN5pOT  
@Hl+]arUh  
public void setSFilePath(String value) G+t=+T2m  
{ oL7F^34;  
sFilePath = value; h2 y<vO  
} FY)US>  
X4JSI%E  
3$9V4v@2  
public String getSFileName() 2v<O}   
{ )S`=y-L$  
return sFileName; 7$v_#ZE.H  
} bs'hA@r  
Js&.p9S2  
5 FE&  
public void setSFileName(String value) f#\Nz>tOhE  
{ A*{CT>  
sFileName = value; +`ug?`_  
} hGcu(kAC,  
9TZ6c  
@V Sr'?7-  
public int getNSplitter() :_h#A }8Xd  
{ Ek60[a  
return nSplitter; q<K/q"0-l  
} NFPWh3),f  
lMgPwvs'  
v\+`n^=  
public void setNSplitter(int nCount) r)Ja\ ;  
{ Y(Y#H$w  
nSplitter = nCount; ]QQeUxi  
} FzAzAl 5  
} ,Fn-SrB:  
?aguAqG$  
;?y~ h$  
/* #itZ~tol  
**Utility.java =imJ0V~RW  
*/ /i{V21(%  
package NetFox; ^mouWw)a_  
TPYh<p#  
?KWo1  
public class Utility { @p@b6iLpO  
$$XeCPs 0  
"8L v  
public Utility() rN,T}M= 2  
{ L^=G(op*  
<`u_O!h  
i]Bu7Fuu  
} -@XOe&q  
AwZz}J+  
//线程睡眠 Ph)>;jU  
public static void sleep(int nSecond) 7~SnY\B|  
{ o+Mc%O Z  
try{ et/v/Hvw1  
Thread.sleep(nSecond); 8~F?%!X  
} >uYU_/y$2  
catch(Exception e) x.sC015Id  
{ oPVt qQ  
e.printStackTrace (); r^ {Bw1+  
} B=%x#em  
} 7nsovWp  
UjMWSPEBy  
//日志 ZSr!L@S  
public static void log(String sMsg) ?g:sAR'  
{ W\<HUd  
System.err.println(sMsg); bq9/ d4  
} )iJv?Y\]  
D^}2ilk!  
<`?%Cz AO  
public static void log(int sMsg) z0%tBgqY(  
{ hVl@7B~  
System.err.println(sMsg); vpC?JXz=H  
} VB`% u=  
} fYW9Zbov-  
n:f&4uKoG<  
=G !]_d0  
/* ^9><qKbO  
**TestMethod.java |7Qe{  
*/ \Yn0|j>  
package NetFox; 5~d=,;yE  
p K ^$^*#  
zRgAmX/g  
public class TestMethod { < FY%QB)h  
[,{Nu EI  
";/ogFi  
public TestMethod() )i_:[ l6  
{ ///xx/weblogic60b2_win.exe de;CEm<n  
try{ !N!AO(Z  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5#y_EpL"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); oArXP\#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j6j4M,UI43  
fileFetch.start(); #. 71O#!  
} BO8?{~i  
catch(Exception e){e.printStackTrace ();} 4$81ilBcL  
<8YvsJ  
ah,"c9YX  
} wk{]eD%  
LB[?kpy  
`xZ,*G7(*  
public static void main(String[] args) |9p0"#4u  
{ C Sz+cS  
new TestMethod(); :F9Oj1lM%  
} bkz/V/Y  
} +(W7hK4ip  
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