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http断点续传简单实现(java)

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/* BqG7E t  
**SiteFileFetch.java #P/}'rdt  
*/ (V:)`A_-  
package NetFox; +h?Rb3=S  
import java.io.*; 8;+dlWp  
import java.net.*; _WB*ArR  
CWx_9b zk  
0m>?-/uDx  
public class SiteFileFetch extends Thread { 1_MaaA;ow"  
ps&p|  
*;!p#qL  
SiteInfoBean siteInfoBean = null; //文件信息Bean c[zaYcbl  
long[] nStartPos; //开始位置 &$<7]a\dM  
long[] nEndPos; //结束位置 rd hM#?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K=Y{iHn  
long nFileLength; //文件长度 ~H\1dCW  
boolean bFirst = true; //是否第一次取文件 #Ab,h#f*7  
boolean bStop = false; //停止标志  &C&?kS(  
File tmpFile; //文件下载的临时信息 &|#z" E^-  
DataOutputStream output; //输出到文件的输出流 34s>hm=0.  
hutdw>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) hY}.2  
public SiteFileFetch(SiteInfoBean bean) throws IOException a&)4Dv0  
{ _a&Mk  
siteInfoBean = bean; <v+M~"%V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O tD!@GQ6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F0 ^kUyF|  
if(tmpFile.exists ()) cjyb:gAO  
{ $?Z-BD1  
bFirst = false; ,Jqk0cW2  
read_nPos(); E*]%@6tH  
} i8 fUzg)  
else +~l`rJ  
{ @(I)]Ca%O  
nStartPos = new long[bean.getNSplitter()]; snti*e4"V  
nEndPos = new long[bean.getNSplitter()]; Rf0F`D k  
} }&qr"z4  
0OF]|hH  
nA 5-P}  
LAcK%  
} Y>a2w zr  
MB3 0.V/\  
,?(IRiq%  
public void run() Wt $q{g{C  
{ .p?kAf`  
//获得文件长度 )uxXG `,h  
//分割文件 8Ssk>M*  
//实例FileSplitterFetch @$] CC1Y  
//启动FileSplitterFetch线程 r}~|,O3bc'  
//等待子线程返回 "Qfw)!#  
try{ $,DX^I%!  
if(bFirst) 0{zA6Xu  
{ ,W:Bh$%  
nFileLength = getFileSize(); K.I  \E  
if(nFileLength == -1) hJasnY7  
{ ` 8OA:4).  
System.err.println("File Length is not known!"); t}A n:  
} ppXt8G3% x  
else if(nFileLength == -2) w?Nx ^)xX  
{ q@8j[15  
System.err.println("File is not access!"); Yt#e[CYnu  
} 81&5g'  
else r5(-c]E7  
{ +t`QHvxv  
for(int i=0;i<nStartPos.length;i++) W y%'<f  
{ 1 6G/'Hb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9<Kc9Z  
} lL]8~3b  
for(int i=0;i<nEndPos.length-1;i++) &bw ``e&c  
{ 9G)q U  
nEndPos = nStartPos[i+1]; `|d&ta[{  
} ?> SH`\  
nEndPos[nEndPos.length-1] = nFileLength; .X(*mmH  
} Ii4lwZnz  
} mIUpAOC`"Z  
&] euL:C  
\5=fC9*G  
//启动子线程 -4!i(^w[m/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q[T='!Z\  
for(int i=0;i<nStartPos.length;i++) `Q~`Eq?@  
{ y*fU_Il|!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `Z!NOC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "i3Q)$"S  
nStartPos,nEndPos,i); FdVWj 5 $a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +5C*i@v  
fileSplitterFetch.start(); )Og,VXEB  
} KtY_m`DY4R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ecl$z6'c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IsjD-t  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \/ 8 V|E  
nEndPos = " + nFileLength); DGllJ_/Z  
// fileSplitterFetch[nPos.length-1].start(); w+Cs=!  
|e#ea~/b  
a}]zwV&  
//等待子线程结束 $Y Cy,Ew   
//int count = 0; I_/kJ#7vj  
//是否结束while循环 3[E)/~-  
boolean breakWhile = false; //\UthOT  
&:ib>EB03=  
|Lz:i +;  
while(!bStop) \hcb~>=C  
{ ;}=[( eqA  
write_nPos(); Nq3q##Ut:  
Utility.sleep(500); Ikbz3]F^V  
breakWhile = true; C)Ez>~Z  
?[K \X  
USrg,A  
for(int i=0;i<nStartPos.length;i++) QA3q9,C"  
{ 3%$nRP X  
if(!fileSplitterFetch.bDownOver) 0W1=9+c|X  
{ 5lMm8<v  
breakWhile = false; 2rK<UPIq  
break; SKf[&eP,G  
} _Xn[G>1  
} ;v?!Pml2k  
if(breakWhile) Y)=89s&t  
break; E'J| p7  
8}0O @ wq  
jLEwFPz  
//count++; Zg@NMT  
//if(count>4) M6+_Mi.  
// siteStop(); TLk=H Gw  
} u\-f\Z7  
Jc:gNQCsP  
tE: m& ;I  
System.err.println("文件下载结束!"); %TA3o71  
} fEl,jA  
catch(Exception e){e.printStackTrace ();} 4Fr\=TX  
} }FTyRHD|  
`Al5(0Q  
^dzg'6M  
//获得文件长度 K8l|qe  
public long getFileSize() p7A&r:qq#  
{ . d;XLS~  
int nFileLength = -1; \HzI*|*A  
try{ fi2@`37PM  
URL url = new URL(siteInfoBean.getSSiteURL()); n>Rt9   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x@I(G "  
httpConnection.setRequestProperty("User-Agent","NetFox"); U&D"fM8  
_"PT O&E  
}cL9`a9j  
int responseCode=httpConnection.getResponseCode(); L##lXUl  
if(responseCode>=400) .cQ<F4)!tu  
{ l(T CF  
processErrorCode(responseCode); Vc! ;O9dP  
return -2; //-2 represent access is error 'j)xryw  
} 0.~Pzg  
w6fVZY4  
!6pOY*> j  
String sHeader; FX FTf2*T  
xsx @aF  
z~/z>_y$nv  
for(int i=1;;i++)  pv=g)  
{ 8/;q~:v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); OgiElA.  
//Utility.log(in.readLine()); "b!EtlT9  
sHeader=httpConnection.getHeaderFieldKey(i); !`k{Ga  
if(sHeader!=null) T'cahkSw'O  
{ T #&9|  
if(sHeader.equals("Content-Length")) 1A4!zqT;  
{ XF{ g~M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Xz'pZ*Hr$v  
break; ?Mg&e/^  
} () Z!u%j  
} 1}C|Javkn  
else /3! KfG  
break; $T\z  
} c]>s(/}T  
} $#g1Mx{  
catch(IOException e){e.printStackTrace ();} d7y`AS@q6  
catch(Exception e){e.printStackTrace ();} Zu\(XN?62  
X=Q)R1~6v  
:!M/9D*}0  
Utility.log(nFileLength); #ra~Yb-F  
V fJYYR  
vs/.'yD/C  
return nFileLength; )v-sde\  
} +-=w`  
+zQ a"Ep*  
X ?/C9  
//保存下载信息(文件指针位置) h&+dIk\[3  
private void write_nPos() Ji_3*(  
{ 3[E3]]OVa  
try{ bu[v[U4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kzG m D i  
output.writeInt(nStartPos.length); {$,e@nn  
for(int i=0;i<nStartPos.length;i++) :A\8#]3  
{ ~a:0Q{>a  
// output.writeLong(nPos); 8. [TPiUn'  
output.writeLong(fileSplitterFetch.nStartPos); 8,pnm  
output.writeLong(fileSplitterFetch.nEndPos); hBf0kl  
} Fu0 dYN  
output.close(); NKD<VMcqw  
} :?s~,G_*l  
catch(IOException e){e.printStackTrace ();} M-3kF"  
catch(Exception e){e.printStackTrace ();} QCFLi n+r  
}  `Nn=6[]  
Z5re Fok  
NDW6UFd>1  
//读取保存的下载信息(文件指针位置) #Jv|zf5Z  
private void read_nPos() 6fhH)]0  
{ 0Zp) DM  
try{ Y]aVa2!Wb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t@[&8j2B>  
int nCount = input.readInt(); D.zEE-cGyb  
nStartPos = new long[nCount]; Vv4 w?K  
nEndPos = new long[nCount]; k/A8 |  
for(int i=0;i<nStartPos.length;i++) 4k5X'&Q  
{ a9C8Q l  
nStartPos = input.readLong(); Ah,X?0+  
nEndPos = input.readLong(); GsG.9nd  
} !rzbm&@  
input.close(); 79|=y7i#  
} dd#=_xe  
catch(IOException e){e.printStackTrace ();} \jDD=ew  
catch(Exception e){e.printStackTrace ();} ufE;rcYE  
} >NWrT^rk  
yrOWC  
M=$ qus  
private void processErrorCode(int nErrorCode) zdFO&YHTw  
{ ?El8:zt?|  
System.err.println("Error Code : " + nErrorCode); VMPBM:k G  
} ?IR]y-r  
,U+y)w]ar  
/EF0~iy  
//停止文件下载 SFVOof#s  
public void siteStop() 4.:2!Q  
{ a>x3UVf_  
bStop = true; u}ULb F  
for(int i=0;i<nStartPos.length;i++) BbEWa  
fileSplitterFetch.splitterStop(); kLa9'c0  
n,hl6[OL7  
sdF;H[  
} T8( \:v  
} YqhZndktX  
//负责部分文件的抓取 ~u-DuOZ8  
**FileSplitterFetch.java f8yE>qJP  
*/ b(JQ>,hX  
package NetFox; DPCB=2E  
r(;sX  
0Q? XU.v  
import java.io.*; d[mmwgSR?I  
import java.net.*; v?e@`;- <  
F?#^wm5TZ  
6-8,qk  
public class FileSplitterFetch extends Thread { p4QQ5O$;  
qdkhfm2(K  
Bw _^"e8X  
String sURL; //File URL 'B dZN  
long nStartPos; //File Snippet Start Position &[u%ZL  
long nEndPos; //File Snippet End Position U$+EUDFi3_  
int nThreadID; //Thread's ID ~d]X@(G&  
boolean bDownOver = false; //Downing is over b&[bfM<  
boolean bStop = false; //Stop identical dU`kJ,=Z  
FileAccessI fileAccessI = null; //File Access interface M0Y#=u.  
+XV7W=  
:.8@ xVH  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Dv~W!T i  
{ 0LEJnl  
this.sURL = sURL; 84g$V}mp  
this.nStartPos = nStart; \)KLm  
this.nEndPos = nEnd; RCM;k;@8V  
nThreadID = id; 'sb&xj`d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O# n<`;W  
} !C13E lf  
ZfMDyS$.  
MIa#\tJj  
public void run() {k BHZ$/  
{ j#:IG/)GL  
while(nStartPos < nEndPos && !bStop) 7A6Qrfw  
{ (QS4<J"  
8t)5b.PS  
.V~z6  
try{ L=g(w$H  
URL url = new URL(sURL); W:5uoO]=<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UnTnc6Bo7W  
httpConnection.setRequestProperty("User-Agent","NetFox"); @ sLb=vb  
String sProperty = "bytes="+nStartPos+"-"; UAleGR`,  
httpConnection.setRequestProperty("RANGE",sProperty); %gBulvg  
Utility.log(sProperty); w[ )97d  
e_U1}{=t  
dsJMhB_41U  
InputStream input = httpConnection.getInputStream(); :g&9v_}&K{  
//logResponseHead(httpConnection); s{g^K#BoFi  
R( 2,1f=d  
vwF#;jj\  
byte[] b = new byte[1024]; O_vCZW a3  
int nRead; KHnq%#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tqo k.h  
{ f/"? (7F  
nStartPos += fileAccessI.write(b,0,nRead); }Pi}? 41!  
//if(nThreadID == 1) M N-j$-y}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sq<ds}o'8l  
} ;og[ q  
c+dmA(JC  
Z+p'3  
Utility.log("Thread " + nThreadID + " is over!"); {X r|L  
bDownOver = true; "XKcbdr8-  
//nPos = fileAccessI.write (b,0,nRead); $TU:iv1Fm  
} Dx1f< A1  
catch(Exception e){e.printStackTrace ();} =74yhPAW  
} V LXU  
} K/T4T\  
dZ6\2ok+  
py-5 :g}d  
//打印回应的头信息 n1Ic[cM}  
public void logResponseHead(HttpURLConnection con) #_(t46  
{ @%"+;D  
for(int i=1;;i++) 3lh^maQ]  
{ L0^rw|Z%'  
String header=con.getHeaderFieldKey(i); Nw3K@ Ge  
if(header!=null) [hhPkJf|f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ve3-GWT{C  
Utility.log(header+" : "+con.getHeaderField(header)); tBB\^xq:  
else `8x.Mv  
break; D MzDV_  
} 2)-V\:;js  
} V1l9T_;f  
K>a@AXC  
bM@8[&t a  
public void splitterStop() Ca]V%g(  
{ Aq]*$s2\G  
bStop = true; @Z+(J:Grm5  
} mMt~4(5  
Q[6<Y,}(pd  
PR+L6DT_  
} zWA~0l.2  
l|jb}9(J  
i3dV2^O  
/* v)c[-:"z  
**FileAccess.java ]y kMh  
*//文件访问(定位,写) =w,cdU*  
package NetFox; }LA7ku  
import java.io.*; +$CO  
#Y_v0.N  
-|cB7 P  
public class FileAccessI implements Serializable{ <&CzM"\Em  
 26[.te9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h.t2;O,b  
RandomAccessFile oSavedFile; 35}]U=  
long nPos; ZHN}:W/p  
-~+Y0\%E  
`mp3ORR;$  
public FileAccessI() throws IOException Y I?4e7Z+  
{ dN)@/R^E;  
this("",0); :c/](M  
} o0B3G  
b%_[\((  
+Rq7m]  
public FileAccessI(String sName,long nPos) throws IOException <#ZDA/G(  
{ \L5h&  
oSavedFile = new RandomAccessFile(sName,"rw"); yv+DM`0  
this.nPos = nPos; u.!<)VIJx  
oSavedFile.seek(nPos); <8sy*A?0z  
} 7nl  
z$]HZ#aRE  
6>e YG <y{  
public synchronized int write(byte[] b,int nStart,int nLen) y&(R1Y75  
{ JQO%-=t  
int n = -1; s9 .nU  
try{ w=}R'O;k  
oSavedFile.write(b,nStart,nLen); TM*<hC  
n = nLen; yS"; q  
} S!{Kn ;@  
catch(IOException e) ptCAtEO72  
{ rvwfQ'14  
e.printStackTrace (); ;sZHE &+  
} _ ATIV  
KOP*\\1 J  
bA*T1Db,t>  
return n; !vwx0  
} ZnXq+^ Z4  
RxrUnMF  
R3!3TJ  
} %>)&QZig/  
9xZ?}S:d  
1 z5\>F  
/* bR&<vrMmrA  
**SiteInfoBean.java AOVoOd+6  
*/ TkjPa};R  
package NetFox; K26x,m]p  
$"`9QD~  
vo3[)BDbT  
public class SiteInfoBean { >x 6$F*:W}  
-mPrmapb3  
iT}L9\  
private String sSiteURL; //Site's URL $KGpcl  
private String sFilePath; //Saved File's Path V9r58hbVT  
private String sFileName; //Saved File's Name  l6uU S  
private int nSplitter; //Count of Splited Downloading File J`@#yHL  
u, Rhm-`  
 ~hxo_&  
public SiteInfoBean() M!E#T-)  
{//nSplitter的缺省值为5 }5qjGD  
//default value of nSplitter is 5 %G>|u/:U  
this("","","",5); c-, 6k  
} xB&6f")  
A1u|L^  
{cF >, T  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c(y~,hN&p  
{ af WEt -  
sSiteURL= sURL; FeM,$&G:  
sFilePath = sPath; 3ZKaqwK  
sFileName = sName; FII>6c  
this.nSplitter = nSpiltter; 0XNj! ^&  
e2xqK G  
I$7TnMug  
} =*u:@T=d5  
x# &ZGFr~  
>&kb|)  
public String getSSiteURL() LpJ_HU7@lk  
{ |UO&18Y7-  
return sSiteURL; }M I9?\"q  
} s3LR6Z7;i  
vs )1Rm  
}813.U  
public void setSSiteURL(String value) D(]])4  
{ N>A*N,+  
sSiteURL = value; A -dL_3  
} H#joc0?P  
FS vtiNW<  
I@f">&^  
public String getSFilePath() Cl+TjmOV\`  
{ #VwA?$4g`  
return sFilePath; ?+bDFM}  
} [-bT_X  
vKX $Nf  
wPl!}HNf  
public void setSFilePath(String value) o5N];Nj  
{ 8;YN`S!o  
sFilePath = value; vkXdKL(q  
} Va1 eG]jQ  
&dV|~xA6N  
FB0y  
public String getSFileName() I2!0,1Q  
{ Yz?1]<X  
return sFileName; 1/bu}?a  
} mYudUn4Wo  
k_=~ObA$g  
BlV k?n  
public void setSFileName(String value) g]g2`ab |  
{ (zFUC]  
sFileName = value; V+()`>44  
} oj7X9~ nd  
_`JY A  
<h/\)bPB  
public int getNSplitter() oK GFDl]3  
{ p,=:Ff}~  
return nSplitter; "}bk *2  
} $o"PQ!z  
C_[V[k0(  
lxRzyx  
public void setNSplitter(int nCount) FRicHs n  
{ fWR]L47n  
nSplitter = nCount; #_+T@|r  
} R0y@#}JH  
} 0 mWfR8h0  
] =jnt  
3:rH1vG.m  
/* j/bebR}X  
**Utility.java 1:%m >4U  
*/ c 25wm\\  
package NetFox; X,/@#pSOz  
xw5E!]~D  
&Z+a (  
public class Utility { )>ed6A1  
[|2uu."$  
E( M\U5o:  
public Utility() [H#I:d-+\  
{ xa#:oKF3  
5hE8b  {V  
U/M(4H3>H  
} x7J|  
rbnu:+!  
//线程睡眠 UcMe("U  
public static void sleep(int nSecond) C"/]X  
{ N1I1!!$K;%  
try{ HnVUG4yZTD  
Thread.sleep(nSecond); EjB<`yT  
} n%Xw6qV:  
catch(Exception e) =VlO53Hy{  
{ 4];Qpln  
e.printStackTrace (); x#e(&OjN7  
} Nh41o0  
} #3$U&|`  
E~zLhJTUL'  
//日志 IPcAE!h6zN  
public static void log(String sMsg) k 6~k  
{ :&`Yz   
System.err.println(sMsg); c3|;'s  
} yov:JnWo  
~Gc+naE>  
fPHv|_XM>  
public static void log(int sMsg) sm}v0V.Js  
{ M6!kn~  
System.err.println(sMsg); ~aH*ZA*f  
} 5/mW:G,&  
} "HVwm>qEi  
DRi!WWivn  
muo7KUT  
/* 1uv"5`%s  
**TestMethod.java hE!3kaS  
*/ doXd6q4H  
package NetFox; "Q+'lA[}  
2s EdN$O  
Xt'R@"H<V9  
public class TestMethod { L]#J?lE&  
Ydmz!CEu  
oC U8;z  
public TestMethod() w"-bO ~5h  
{ ///xx/weblogic60b2_win.exe V/|Ln*rm  
try{ t9m: E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )G ,LG0"-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z8k O*LYv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `R8~H7{I6  
fileFetch.start(); ~MO'%'@  
} 9XS+W w7  
catch(Exception e){e.printStackTrace ();} vsoj] R$C  
[_qBp:_j?s  
I~"-  
} \,JRNL&   
/Os)4yH\  
s Xl7  
public static void main(String[] args) 8pDJz_F!{  
{ .Rc&EO  
new TestMethod(); [O [ N_z  
} d[rxmEXht  
} nH% /  
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