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http断点续传简单实现(java)

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/* ~:>AR` 9G  
**SiteFileFetch.java keLR1qf  
*/ *Jvxs R'a1  
package NetFox; t;8\fIW5  
import java.io.*;  nbI= r+  
import java.net.*; LY]nl3{E  
d2rL 8jW  
Hm%g_Mt  
public class SiteFileFetch extends Thread { gmh5 %2M  
9!9> ?Z  
ugYw <  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^P`NMSw  
long[] nStartPos; //开始位置 Q%ruQ#  
long[] nEndPos; //结束位置 c juZB Fl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q|5Q?t:,r  
long nFileLength; //文件长度 *>jjMyn  
boolean bFirst = true; //是否第一次取文件 Dv&>*0B  
boolean bStop = false; //停止标志 25:Z;J>  
File tmpFile; //文件下载的临时信息 3bC+Mco  
DataOutputStream output; //输出到文件的输出流 LVnHt}  
NYBe"/}GS  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) h#i\iK&A  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3{"byfO#%  
{ Nl@k*^  
siteInfoBean = bean; /aZE,IeEz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); CSL#s^4T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !z"Nv1!~|  
if(tmpFile.exists ()) ;DuXS y!g  
{ y&"!m }  
bFirst = false; 7+}JgUh  
read_nPos(); hd B |#t  
} j{"z4Y4  
else "O*x' XhN  
{ 8pXKO"u],  
nStartPos = new long[bean.getNSplitter()]; lWWP03er!  
nEndPos = new long[bean.getNSplitter()]; Z%}4bJ  
} n`(~O O  
8eluO ?p  
-v+&pG?m  
@%1IkvJV  
} ebC)H  
r}_lxr  
W|MWXs5'1*  
public void run() %r%So_^  
{ .2.qR,"j  
//获得文件长度 pMR,#[U<  
//分割文件 ~6`iY@)  
//实例FileSplitterFetch 5RF4]$zT  
//启动FileSplitterFetch线程 ExVDkt0  
//等待子线程返回 h[kU<mU"T  
try{ qP3q  
if(bFirst) F";.6%;AC  
{ gl{B=NN  
nFileLength = getFileSize(); hmpr%(c`  
if(nFileLength == -1) d"E^SBO&  
{ +m)q%I>  
System.err.println("File Length is not known!"); p[9s<lEh  
} Y9Z]i$qS&k  
else if(nFileLength == -2) ve Tx, \6@  
{ >oGiIYq  
System.err.println("File is not access!"); fE]XWA4U  
} LlHa5]E@6  
else ;),"M{"v  
{ uo2'"@[e  
for(int i=0;i<nStartPos.length;i++) 8|@9{  
{ zF`3 gl.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ml6u1+v5  
} m&*JMA;^  
for(int i=0;i<nEndPos.length-1;i++) d$t40+v  
{ pTJX""C  
nEndPos = nStartPos[i+1]; ",yc0 2<  
} *bd[S0l  
nEndPos[nEndPos.length-1] = nFileLength; X6\ sF"E  
} oDn|2Sdqd  
} Qkcjr]#^$  
aC%&U4OS  
.iG&Lw\,  
//启动子线程 z//VlB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; -0Cnp/Yj@  
for(int i=0;i<nStartPos.length;i++) 5T@aCC@$h  
{ Qm4o7x{q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [P~hjmJ(y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), C0jj(ku&  
nStartPos,nEndPos,i); @-HG`c ct  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _oG&OJ@  
fileSplitterFetch.start(); v&a4^s  
} x3 >  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =WIJ>#Go<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tM4 Cx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Hnk:K9u.B:  
nEndPos = " + nFileLength); CVNj- &vj  
// fileSplitterFetch[nPos.length-1].start(); vi.w8 >CE  
;&V s4  
ntFT>g{B  
//等待子线程结束 Ep9W-n?}  
//int count = 0; `h:34RC;  
//是否结束while循环 >-8cU_m7s  
boolean breakWhile = false; ",6M)3{|c  
.*g0w`H5pU  
JN+_|`  
while(!bStop) 21hv%CF\9  
{ Q7Iw[=;\  
write_nPos(); 0:w"M<80  
Utility.sleep(500); ,#MCn  
breakWhile = true; #$1Z  
'R-3fO???  
Guz"wY  
for(int i=0;i<nStartPos.length;i++) W-NDBP:  
{ Gx`Lks  
if(!fileSplitterFetch.bDownOver) wO?{?+I`q  
{ (aOv#Vor]%  
breakWhile = false; '5&s=M_  
break; .7K7h^*F  
} .X# `k  
} Z}$TKO*u  
if(breakWhile) [sB 9gY(  
break; VD_$$Gn*q  
|$?bc3  
]a5 f2lE  
//count++; lXcx@#~  
//if(count>4) AGLscf.  
// siteStop(); '!/<P"5t  
} J8mdoVt  
yKO`rtP  
`BlI@6th  
System.err.println("文件下载结束!"); !pD*p)`s  
} BNL;Biy t7  
catch(Exception e){e.printStackTrace ();} w!fE;H8w6  
} ZYC<Wb)I  
8F._9U-EN  
IiG6<|d8H  
//获得文件长度 #O+),,WS  
public long getFileSize() EK4d_L]I  
{ r-:Uz\gM  
int nFileLength = -1; \[y`'OD~  
try{ N;\'N ne  
URL url = new URL(siteInfoBean.getSSiteURL()); hEp(A8g)bQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'FDef#P<  
httpConnection.setRequestProperty("User-Agent","NetFox"); G K7![p  
_H5o'>=  
S:O O0<W  
int responseCode=httpConnection.getResponseCode(); cXKjrL[b  
if(responseCode>=400) /Njd[= B  
{ 3.*8)NW  
processErrorCode(responseCode); p>4-s, W  
return -2; //-2 represent access is error ; #&yn=^  
} INJEsz  
~{jcH  
G|!on<l&  
String sHeader; n CdR EXw  
8|\8O@  
g\&g N  
for(int i=1;;i++) ]GW]dM  
{ 5fd]v<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jcrw#l8|C  
//Utility.log(in.readLine()); L6|oyf  
sHeader=httpConnection.getHeaderFieldKey(i); :gWu9Y|{  
if(sHeader!=null) toBHkiuD  
{ NgP&.39U  
if(sHeader.equals("Content-Length")) ~ v|>xqWV  
{ %5"9</a&G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \D*KGd]M0  
break; H _zo1AW  
} 6\q]rfQ  
} mc? Vq  
else J;8IY=  
break; lww!-(<ww  
} 3 :<WY&9  
} #."-#"0  
catch(IOException e){e.printStackTrace ();} $Avjnm  
catch(Exception e){e.printStackTrace ();} s;01u_  
/rnu<Q#iH  
{Tq_7,8  
Utility.log(nFileLength); YUtC.TR1  
C26>BU<  
K;?m';z0  
return nFileLength; pZqq]mHK  
} [\v}Ul  
Whm,F^  
+0nJ  
//保存下载信息(文件指针位置) 3TeY%5iVt  
private void write_nPos() 4;yKOQD|  
{ <lx+/o  
try{ $_"'&zQ'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )rn*iJ.e8  
output.writeInt(nStartPos.length); 7&jTtKLj  
for(int i=0;i<nStartPos.length;i++) cPyE 6\lN  
{ a|t$l=|DD  
// output.writeLong(nPos); sBvzAVBL  
output.writeLong(fileSplitterFetch.nStartPos); `yrB->|vG  
output.writeLong(fileSplitterFetch.nEndPos); I9_RlAd  
} g+vva"  
output.close(); gY/"cq  
} SJb&m-  
catch(IOException e){e.printStackTrace ();} PUp6Q;AdQ  
catch(Exception e){e.printStackTrace ();} J\twZ>w~0  
} n' n/Tu   
%*A0# F  
x<tb  
//读取保存的下载信息(文件指针位置) IA8f*]?  
private void read_nPos() Gp?a(-K5  
{ ?+@n3]`0  
try{ _S<3\%(0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kCWV r  
int nCount = input.readInt(); ]b2pG'  
nStartPos = new long[nCount]; +h|`/ &,  
nEndPos = new long[nCount]; \)#kquH/l  
for(int i=0;i<nStartPos.length;i++) nv*FT  
{ ry`Ho8N  
nStartPos = input.readLong(); s4X>.ToMC  
nEndPos = input.readLong(); 5d Eh7XL  
} ]sf7{lVT  
input.close(); eenH0Ovv  
} KKj a/p  
catch(IOException e){e.printStackTrace ();} (y=C_wvqZ  
catch(Exception e){e.printStackTrace ();} =upeRY@u5  
} '}ptj@,  
h5*JkRm  
^me-[ 5  
private void processErrorCode(int nErrorCode) ugdQAg  
{ ;#g"(  
System.err.println("Error Code : " + nErrorCode); + [iQLM?zo  
} B3pCy~*5  
~ (|5/ p7t  
.F4>p=r  
//停止文件下载 [A+ >^ {  
public void siteStop() [L3=x;U  
{ xK *b1CB  
bStop = true; 9&-dTayIz  
for(int i=0;i<nStartPos.length;i++) sXLq*b?  
fileSplitterFetch.splitterStop(); |HiE@  
BRw .]&/  
}MJy +Z8&  
} 5kc/Y/4o  
} }^ApJS(FQ  
//负责部分文件的抓取 ],@rS9K  
**FileSplitterFetch.java ($q-_m  
*/ 0.`/X66;V  
package NetFox; i?p$H0b n  
m|SUV  
Z^bQ^zk-  
import java.io.*; &jS>UsGh  
import java.net.*; m~iXl,r  
pj\u9 L_  
v> LIvi|]  
public class FileSplitterFetch extends Thread { G?L HmTHg  
pR*VdC _mY  
O*hDbM2QQw  
String sURL; //File URL ak7bJ~)X=  
long nStartPos; //File Snippet Start Position lEH65;Nh*  
long nEndPos; //File Snippet End Position rMdt:`  
int nThreadID; //Thread's ID $njUXSQ;  
boolean bDownOver = false; //Downing is over z6KCv(zvB  
boolean bStop = false; //Stop identical QmQ=q7  
FileAccessI fileAccessI = null; //File Access interface ^=GC3%  J  
5dx$HE&b)  
E(*0jAvO[z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QE^$=\l0  
{ 2~Kgv|09  
this.sURL = sURL; cVXLKO  
this.nStartPos = nStart; {j{u6i  
this.nEndPos = nEnd; 8v:T.o;<  
nThreadID = id; `LrHKb aP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L ^r#o-H<  
} +Zb;Vn4  
LD+{o4i  
!44/sr'  
public void run() j b!x:  
{  |tKsgj  
while(nStartPos < nEndPos && !bStop) 57'*w]4f  
{ {0L1X6eg  
[@&m4 7  
i[O& )N,c  
try{ g?c xp +  
URL url = new URL(sURL); aHV;N#Lx3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vHgi <@u  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;0Q4<F  
String sProperty = "bytes="+nStartPos+"-"; 1XrO~W\=  
httpConnection.setRequestProperty("RANGE",sProperty); `"Jj1O@  
Utility.log(sProperty); JYMiLph<  
J! AgBF N4  
TtJH7  
InputStream input = httpConnection.getInputStream(); TYy?KG>:'  
//logResponseHead(httpConnection); +vw\y  
j5(Z_dm'  
|hKDvH  
byte[] b = new byte[1024]; "SNn^p59k  
int nRead; [meO[otb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r7RIRg_  
{ 8^kGS-+^  
nStartPos += fileAccessI.write(b,0,nRead); /,BD#|  
//if(nThreadID == 1) L 8c0lx}Nn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mu\6z_e  
} kVuUjP6(c  
%2}-2}[>  
](Xb _xMf  
Utility.log("Thread " + nThreadID + " is over!"); >,v`EIg  
bDownOver = true; pf]xqhL  
//nPos = fileAccessI.write (b,0,nRead); 272q1~&  
} [xK3F+  
catch(Exception e){e.printStackTrace ();} ,bZL C  
} aE Bu *`-j  
} C+* d8_L  
Yc`o5Q\>  
GiJ *Wp  
//打印回应的头信息 nB_?ckj,  
public void logResponseHead(HttpURLConnection con) b}2ED9HG\  
{ J9..P&c\  
for(int i=1;;i++) loEPr5 bL  
{ ~jWn4 \  
String header=con.getHeaderFieldKey(i); H/"-Z;0{  
if(header!=null) uY{|szC^2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !-g{[19\  
Utility.log(header+" : "+con.getHeaderField(header)); ##q2mm:a9P  
else L s G\OG  
break; ww)<E`eGi  
} 'Y?"{HZ  
} ~b(i&DVK  
3(``#7  
QpF;:YX^3  
public void splitterStop() #F:p-nOq  
{ S\^P ha q  
bStop = true; i9rN9Mq?O  
} ]q\b,)4 e  
?#Ge.D~u  
?)/#+[xa  
} LY+@o<>  
m\;R2"H%  
[m- >5H  
/* LmRy1T,act  
**FileAccess.java [RS|gem`  
*//文件访问(定位,写) T!uM+6|Y  
package NetFox; !d'GE`w T  
import java.io.*; R1Pk TZP&  
;[(oaK@+n  
pD(j'[  
public class FileAccessI implements Serializable{ p$O.> [  
} j<)L,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {GvJZ!,RCg  
RandomAccessFile oSavedFile; N>Xo_-QCY  
long nPos; rr/B= O7  
G `+T+  
Ig$(3p  
public FileAccessI() throws IOException |U~<3.:m:  
{ .GbX]?dN  
this("",0); }pDqe;a{  
} 02Y]`CXj  
8<5]\X  
ih)zG  
public FileAccessI(String sName,long nPos) throws IOException ysJQb~2q  
{ #akpXdXs  
oSavedFile = new RandomAccessFile(sName,"rw"); zofa-7'Bn  
this.nPos = nPos; w2Us!<x  
oSavedFile.seek(nPos); EJj.1/]|r  
} 16w|O |^<  
m&xW6!x  
GC<l#3+  
public synchronized int write(byte[] b,int nStart,int nLen) &\#sI9  
{ dW_KU}  
int n = -1; \@Ts+7%  
try{ @#<D ^"  
oSavedFile.write(b,nStart,nLen); Amp#GR1CA  
n = nLen; ]99|KQ<s  
} 9"NF/)_  
catch(IOException e) :Hn6b$Vy8  
{ u&^b~# T  
e.printStackTrace (); }bs+-K  
} ?OId\'q  
6RG)` bu  
VX].3=T8  
return n; N c1"g1JR  
} -] L6=  
LVX[uWEM  
W~6EEyD%  
} WeJl4wF  
O80<Z#%j`  
<x@}01 ~  
/* " f <Z=c  
**SiteInfoBean.java [V^WGW2oY  
*/ ?*2CpM&l  
package NetFox; 4 <9=5q]  
pSoiH<33  
VA WF3  
public class SiteInfoBean { 5BWH-2HsB  
1Y/s%L  
-jW.TT h]  
private String sSiteURL; //Site's URL hwu]Er.gn  
private String sFilePath; //Saved File's Path RdWRWxTn8+  
private String sFileName; //Saved File's Name <_h~w}  
private int nSplitter; //Count of Splited Downloading File O#b6mKPt;t  
N+++4;  
'GB. UKlR  
public SiteInfoBean() 7_%"BVb"  
{//nSplitter的缺省值为5 0x'#_G65y  
//default value of nSplitter is 5 FO=4:   
this("","","",5); ]*v dSr-J  
} t'VV>;-RO=  
T3~k>"W  
Q(@U2a8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z?}dq-Vh&  
{ XJ;D=~  
sSiteURL= sURL; E'G4Y-  
sFilePath = sPath; 4y)P>c  
sFileName = sName; ;L cVr13J/  
this.nSplitter = nSpiltter; A$<.a'&T!  
y6LWx:  
!LggIk1  
} lU @]@_<  
o1Ph~|s*8  
4~y(`\0?4  
public String getSSiteURL() `)` n(B  
{ h^?\xm|  
return sSiteURL; yGWxpzmRS  
} ^X0P'l &D2  
3 N.~mR  
~$ng^D  
public void setSSiteURL(String value) I`p+Qt  
{ e91aK  
sSiteURL = value; m=?KZ?U`  
} &f"-d  
L0* nm.1X  
"7!;KHc  
public String getSFilePath() plUZ"Tr  
{ -}=i 04^  
return sFilePath; t\Nq R  
} t0o`-d(  
Z9MdD>uwi  
X*M#FT-  
public void setSFilePath(String value) q;QbUO  
{ !u_Y7i3^  
sFilePath = value; ;gBRCZ  
} i;NUAmx  
f47Od-\-  
qDv93  
public String getSFileName() IOb*GTb  
{ bu |a0h7e  
return sFileName; >=RmGS  
} z8QAo\_I(  
?3%` bY+3;  
?3*l{[@J  
public void setSFileName(String value) {p;zuCF1  
{ lp<g \  
sFileName = value; JQ,1D`?.a  
} 4kG,*3 &2  
qR(\5}  
LA@w:Fg  
public int getNSplitter() wT `a3Ymm  
{ 3D` YZ#M  
return nSplitter;  TR<<+  
} Q?3Gk%T0[  
Yj)#k)x  
@n(Z$)8tR  
public void setNSplitter(int nCount) ?mWw@6G,  
{ y9_K, g  
nSplitter = nCount; ? %`@ub$  
} CPP` qt%f  
} o>/YAX:.!T  
aemc2b*  
c%&: 6QniZ  
/* {P{bOe  
**Utility.java HR ;)|j{!  
*/ ROk5]b.  
package NetFox; _h X]%  
/h*>P:i].  
5D_fXfx_|  
public class Utility { T-5nB>)  
%7"X(Ts7B  
}"=AG  
public Utility() TYJ:!  
{ 0BH_'ZW  
bty/  
eU<]o< \Qo  
} HRiL.DS  
EGZb7:Y?  
//线程睡眠 :cq9f2)  
public static void sleep(int nSecond) (xVsDAp=@  
{ 9T |IvQK8  
try{ 6`v7c!7  
Thread.sleep(nSecond); y($%;l   
} po$ /7  
catch(Exception e) dl ~%MWAVb  
{ EmODBTu+  
e.printStackTrace (); G8r``{C!  
} q{t*34R  
} ~ECD`N<YF  
=0G!f$7^i  
//日志 9G+V;0Q  
public static void log(String sMsg) B x (uRj  
{ KuMF^0V%c  
System.err.println(sMsg); `FsH}UPu b  
} ]3g?hM6  
L{(QpgHZ  
.h9l7 nZt  
public static void log(int sMsg) Sh?4r i@:  
{ o>7ts&rk  
System.err.println(sMsg); i{ \%e  
} JaK}|  
} qUxRM_7U  
co9 .wB@  
9nH?l{As   
/* Nkp)Ax&  
**TestMethod.java e_/b2"{  
*/ xo&]RYG[<  
package NetFox; '1$!jmY  
[o.B  
oiX+l5`pz  
public class TestMethod { ppFe-wY  
xia|+  
t`+'r}=d  
public TestMethod() * 1Od-3  
{ ///xx/weblogic60b2_win.exe ~i21%$  
try{ 8HRmQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L5qwWvbT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qQ0cJIISb\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bks/ `rIA  
fileFetch.start(); }J7zTj~{  
} HW7; {QMg  
catch(Exception e){e.printStackTrace ();} glDh([  
({NAMc*  
Fr%d}g  
} :"l-KQ0  
"h|'}7p  
Qu7T[ <  
public static void main(String[] args) 'w14sr%  
{ me'd6!O9-  
new TestMethod(); v*9<c{a  
} (XXheC  
} h68]=KyK  
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