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http断点续传简单实现(java)

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/* 6Cut[*lj^  
**SiteFileFetch.java y 1fl=i  
*/ zV {[0s  
package NetFox; &UG7 g  
import java.io.*; rvRtR/*?j  
import java.net.*; 372ewh3'  
jyPY]r  
(S+tQ2bt  
public class SiteFileFetch extends Thread { { #CyO b4  
K /h9x9^  
jp2AU,Cl  
SiteInfoBean siteInfoBean = null; //文件信息Bean AF5.gk=  
long[] nStartPos; //开始位置 /+ G&N{)k  
long[] nEndPos; //结束位置 Au'[|Pr r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Sk@~}  
long nFileLength; //文件长度 _N~h#(  
boolean bFirst = true; //是否第一次取文件 UO}Kk*  
boolean bStop = false; //停止标志 *ms?UFV[r  
File tmpFile; //文件下载的临时信息 H".~@,-}  
DataOutputStream output; //输出到文件的输出流 28M! G~|  
w/s{{X<bF  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Qz;2RELz  
public SiteFileFetch(SiteInfoBean bean) throws IOException >lqWni  
{ v/f&rK*>  
siteInfoBean = bean; d [z+/L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T"-HBwl  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @W|}|V5  
if(tmpFile.exists ()) HUurDgRi]  
{ M?5[#0"&V  
bFirst = false; c$ Kn.<a  
read_nPos(); Qh-k[w0  
} 9I/o;Js  
else +` B m  
{ KLlo^1.<  
nStartPos = new long[bean.getNSplitter()]; _$"qC[.  
nEndPos = new long[bean.getNSplitter()]; 6Gjr8  
} NS "hdyA  
0V*L",9M  
zw^jIg$  
^1U2&S  
} /EhojODMF  
<'QH e4  
Dm6WSp1|b  
public void run() Bsw5A7,-  
{ !8ub3oj)  
//获得文件长度 =!r9;L,?  
//分割文件 $@q)IK%FDL  
//实例FileSplitterFetch +\9Y;N y  
//启动FileSplitterFetch线程 5B| iBS l  
//等待子线程返回 uYiM~^ 0  
try{ Mq]~Ka3q7  
if(bFirst) nK Rx_D$d  
{ =x}27f%-Mg  
nFileLength = getFileSize(); oQ@X}6B%S  
if(nFileLength == -1) q%#dx4z&  
{ S|Wv1H>  
System.err.println("File Length is not known!"); z (rQ6  
} YD$fN"}-  
else if(nFileLength == -2) ;7&RmIXKh'  
{ |_HH[s*U  
System.err.println("File is not access!"); lKEdpF<  
} 9 8bmia&H  
else v#:#w.]-Y  
{ YS k,kU  
for(int i=0;i<nStartPos.length;i++) <T:u&Ic  
{ OUn,URI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); R@t?!`f!+  
} UO8#8  
for(int i=0;i<nEndPos.length-1;i++) Z2`(UbG}  
{ e4Ol:V  
nEndPos = nStartPos[i+1]; u*Eb4  
} /r Zj=  
nEndPos[nEndPos.length-1] = nFileLength; "YHqls}c  
} 31k.{dnm  
} h9LA&!  
%v:9_nwO)  
| "DQ^)3Pi  
//启动子线程 Q u2W  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 21M@z(q*  
for(int i=0;i<nStartPos.length;i++) /og2+!  
{ l,HMm|oU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ra[{K@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), em<(wJ-Y  
nStartPos,nEndPos,i); HS]|s':  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "zR+}  
fileSplitterFetch.start(); f$9V_j-K+  
} ?%(8RQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q/r9r*>z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); He. gl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "CBe$b4  
nEndPos = " + nFileLength); Z.<OtsQN  
// fileSplitterFetch[nPos.length-1].start(); t.c XrX`k  
zS18Kl  
j*<H18^G  
//等待子线程结束 v7T05  
//int count = 0; #rqLuqw  
//是否结束while循环 E"&fT!yi  
boolean breakWhile = false; !6\{q M  
 #-1 ;  
N|?"=4Z?  
while(!bStop) B@G'6 ?  
{ bcC ;i~9  
write_nPos(); `gfh]7T  
Utility.sleep(500); #, W7N_mt  
breakWhile = true; 0Pu$1Fp  
3D[IZ^%VtM  
`omZ'n)  
for(int i=0;i<nStartPos.length;i++) 8v\BW^z3  
{ xR q|W4ay  
if(!fileSplitterFetch.bDownOver) `] ;*k2  
{ N^xnx<  
breakWhile = false; ])egke\!  
break; o X )r4H?  
} ?@6N EfQf  
} QNJ )HNLp  
if(breakWhile) _C DUUr  
break; ]6Kx0mW  
+rfw)c'  
a,x-akZWf  
//count++; F]@vmzr  
//if(count>4) :w:hqe|_  
// siteStop(); w4<1*u@${  
} j8WnXp_  
\I1+J9Gl  
(e S4$$g  
System.err.println("文件下载结束!"); 3|8\,fO?  
} Z\D!'FX  
catch(Exception e){e.printStackTrace ();} LJ`*&J   
} R2yiExw<  
CEq0ZL-W  
Tn< <i  
//获得文件长度 uV`r_P  
public long getFileSize() m!SxX&m"G  
{ v#{Sx>lO  
int nFileLength = -1; C:xg M'~+  
try{ lt`(R*B%  
URL url = new URL(siteInfoBean.getSSiteURL()); ({i}EC7{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QI'ule  
httpConnection.setRequestProperty("User-Agent","NetFox"); t J N;WK.6  
/]=Ih  
aFGEHZJQ  
int responseCode=httpConnection.getResponseCode(); s'qd%JxD  
if(responseCode>=400) zs:O HEZw  
{ :{bvCos<)  
processErrorCode(responseCode); #mLF6 "A  
return -2; //-2 represent access is error u6Fm qK]Dj  
} Pky/fF7e  
b^_#f:_j  
A^nB!veh  
String sHeader; SB0Cq  
=7wI/5iN  
CtJ*:wF  
for(int i=1;;i++) F=!p7msRB  
{ luRtuXn[8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0+%{1JkJq  
//Utility.log(in.readLine()); q">lP (t  
sHeader=httpConnection.getHeaderFieldKey(i); *UhYX)J  
if(sHeader!=null) F9p'|-   
{ s9+Rq*Qd  
if(sHeader.equals("Content-Length")) 4<[,"<G~3  
{ ?-%Q[W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L|pMq!@J  
break; 5&Al  
} N^z4I,GV(  
} kN_ i0~y@-  
else 8Yc'4v#}  
break; z)p( l!  
} ui%B|b&&  
} rT7W_[&P  
catch(IOException e){e.printStackTrace ();} WyciIO1  
catch(Exception e){e.printStackTrace ();} IA I!a1e!  
`,a6su (?  
U27YH1OK  
Utility.log(nFileLength); KtTv0[66  
&0cfTb)dG  
;]!QLO.bs^  
return nFileLength; Ro3C(aRx  
} l\g>@b  
G(gJt l  
m_YXTwwx  
//保存下载信息(文件指针位置) ~SUrbRaY>  
private void write_nPos() z#9Tg"8]  
{ }zC9;R(E  
try{ d1]CN6 7{G  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3+vbA;R  
output.writeInt(nStartPos.length); N$]B$vv  
for(int i=0;i<nStartPos.length;i++) ,yc_r= _  
{ eA q/[(  
// output.writeLong(nPos); xe?!UCUb@  
output.writeLong(fileSplitterFetch.nStartPos); Rr#Zcs!G  
output.writeLong(fileSplitterFetch.nEndPos); ZD!?mR+-  
} q_iPWmf p*  
output.close(); <8;SSdoKi  
} !2L?8oP-z  
catch(IOException e){e.printStackTrace ();} N~NUBEKcp  
catch(Exception e){e.printStackTrace ();} 9#(Nd, m})  
} *{WhUHZF  
SFqY*:svOw  
8R|!$P  
//读取保存的下载信息(文件指针位置) @cYb37)q=  
private void read_nPos() W D8  
{ j=|cx+nb  
try{ MX Qua:&HW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wNc.z*+O"H  
int nCount = input.readInt(); xs#g  
nStartPos = new long[nCount]; >,%or cN  
nEndPos = new long[nCount]; #<h//<  
for(int i=0;i<nStartPos.length;i++) +}3l$L'bY  
{ u7||]|2  
nStartPos = input.readLong(); PY81MTv0;  
nEndPos = input.readLong(); (|O9L s7N  
} %M)LC>c  
input.close(); rnAQwm-8O%  
} RW"QUT  
catch(IOException e){e.printStackTrace ();} vq?Lej  
catch(Exception e){e.printStackTrace ();} 4# +i\H`  
} WSEw:pln  
hK]mnA[Y  
)?`G"( y  
private void processErrorCode(int nErrorCode) Y#e,NN  
{ LH}]& >F  
System.err.println("Error Code : " + nErrorCode); :/A7Z<u,  
} W*2d!/;7>  
#hMS?F|  
6LRvl6ik  
//停止文件下载 SG$V%z"e  
public void siteStop() m3T=x =  
{ _c!$K#Yl{  
bStop = true; xP{)+$n  
for(int i=0;i<nStartPos.length;i++) t;HM  
fileSplitterFetch.splitterStop(); sdp3geBYo  
#jj+/>ZOi  
`;j@v8n$*  
} HQkK8'\LP  
} nh XVc((  
//负责部分文件的抓取 7q%xF#mK=  
**FileSplitterFetch.java ^sVr#T  
*/ 52,[dP,g  
package NetFox; Am ~P$dN  
B,S~Idr}  
gwGw  
import java.io.*; &9Kni/  
import java.net.*; -UB XWl  
;cEoc(<?  
;F_pF+&q  
public class FileSplitterFetch extends Thread { =\`iC6xP}  
%6.WGuO  
Z ".Xroq~  
String sURL; //File URL U9"(jl/o  
long nStartPos; //File Snippet Start Position v<3KxP'a  
long nEndPos; //File Snippet End Position Y_zMj`HE  
int nThreadID; //Thread's ID xovsh\s  
boolean bDownOver = false; //Downing is over c/DK31K  
boolean bStop = false; //Stop identical O!G!Gq&  
FileAccessI fileAccessI = null; //File Access interface zm!M'|~@7  
4`e[gvh  
q6'Q-e)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException lrjVD(R=g  
{ :%-w/QwTR  
this.sURL = sURL; ~pT1,1  
this.nStartPos = nStart; }el7@Gv  
this.nEndPos = nEnd; Xj9\:M-  
nThreadID = id; a[_IG-l|i4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X5pb9zRq  
} uG$*DeZti  
4mHk,Dd9,  
$ \+x7"pI  
public void run() +70x0z2  
{ h+R26lI1x  
while(nStartPos < nEndPos && !bStop) b4qMTRnv  
{ YP Qix  
a]/KJn /B(  
1}_4C0h\'  
try{ YK\pV'&+  
URL url = new URL(sURL); j1rR3)oP  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q|{z9V<  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,!40\"A  
String sProperty = "bytes="+nStartPos+"-"; Z;<:=#  
httpConnection.setRequestProperty("RANGE",sProperty); KKq%'y)u^  
Utility.log(sProperty); $cW t^B'  
%*NED zy  
-7KoR}Ck!  
InputStream input = httpConnection.getInputStream(); .?vHoNvo  
//logResponseHead(httpConnection); 8y']kVg  
9}wI@  
43 vF(<r&f  
byte[] b = new byte[1024]; ..kFn!5(g  
int nRead; +MZI\>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) WG&! VK  
{ 9W0*|!tQ,+  
nStartPos += fileAccessI.write(b,0,nRead); dS8ydG2  
//if(nThreadID == 1) g< xE}[gF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BRy3D\}  
} +%f6{&q$  
b "aF-,M>  
hFo29oN  
Utility.log("Thread " + nThreadID + " is over!"); A`#?Bj   
bDownOver = true; eBH:_Ls_-^  
//nPos = fileAccessI.write (b,0,nRead); dF[|9%)  
} hF{gN3v5  
catch(Exception e){e.printStackTrace ();} Fge ["p?GF  
} :>iN#)S  
} {+m8^-T  
,CI-IR2  
q_6fr$-Qh  
//打印回应的头信息 A%2B3@1'q  
public void logResponseHead(HttpURLConnection con) HC} vO0X4  
{ X}xf_3N "  
for(int i=1;;i++) U9\\8  
{ ohbU~R3{U  
String header=con.getHeaderFieldKey(i); @t a:9wZ  
if(header!=null) :%z#s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zYP6m3 n  
Utility.log(header+" : "+con.getHeaderField(header)); }SC&6B?G  
else YKz#,  
break; 9%Tqk"x?  
} Zs]n0iwM'@  
} {sf ,(.W  
b*Q3j}cZ  
$/lM %yXe  
public void splitterStop() D;s%cL`  
{ `#' j3,\6  
bStop = true; wAw1K2d  
} .'&pw }F  
c:e3hJ  
PZQAlO,  
} Z;V(YK(WO.  
{_-T!yb  
">G*hS  
/* t=X=",)f  
**FileAccess.java HE35QH@/`  
*//文件访问(定位,写) nw\C+1F  
package NetFox; }AA">FF'y4  
import java.io.*; %*szB$ [3  
L}CU"  
8 R%<~fq r  
public class FileAccessI implements Serializable{ HAL\j 5i  
mI5J] hk  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;:_AOb31N  
RandomAccessFile oSavedFile; J;NIa[a  
long nPos; KJV8y"^=Q  
tT!' qL.*  
bZ1*:k2  
public FileAccessI() throws IOException 7)]boW~Q  
{ AmHj\NX$  
this("",0); (~eS$8>.  
} 6lCpf1>6@  
jC_'6sc`  
24nNRTI  
public FileAccessI(String sName,long nPos) throws IOException :{N*Z}]  
{ U#c Gd\b  
oSavedFile = new RandomAccessFile(sName,"rw"); 'iF%mnJ  
this.nPos = nPos; f] #\&"  
oSavedFile.seek(nPos); u178vby;l  
} Ovc9x\N  
JH{/0x#+  
"5L?RkFi\  
public synchronized int write(byte[] b,int nStart,int nLen) >t.Lc.  
{ {?`7D:]`^  
int n = -1; =y-yHRC7  
try{ .SjJG67OyA  
oSavedFile.write(b,nStart,nLen); F \ls]luN  
n = nLen; ]:#=[ CH  
} T 5Zh2Q@  
catch(IOException e) +Eh.PWEe  
{ bS;_xDXd  
e.printStackTrace (); McN[  
} r}&&e BY f  
FJDC^@Ne  
J{^md0l  
return n; Mib .,J~  
} eM_;rMCr}  
[:.wCG5  
|,p"<a!+{w  
} WM`3QJb  
COsmVQ.  
{Y@shf;  
/* ~9 .=t'  
**SiteInfoBean.java 7tXy3-~biz  
*/ 'bJGQ[c  
package NetFox; -'g> i  
w") G:K  
_$96y]Bpi  
public class SiteInfoBean { ed`"xm  
\894 Jqh  
#?Kw y  
private String sSiteURL; //Site's URL 0: a2ER|J  
private String sFilePath; //Saved File's Path $*942. =Q  
private String sFileName; //Saved File's Name pdRM%ug   
private int nSplitter; //Count of Splited Downloading File ?/OF=C#  
~*7$aj  
E+i*u   
public SiteInfoBean() z'm}p  
{//nSplitter的缺省值为5 UP^8Yhdo  
//default value of nSplitter is 5 !{r2`d09n)  
this("","","",5); @Suz-j(H  
} T/g\v?>  
!nSa4U,$w<  
V.&F%(L  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /Ne#{*z)hO  
{ GZ~Tl0U  
sSiteURL= sURL; `=H*4I-"  
sFilePath = sPath; sko7,&  
sFileName = sName; ,)Q-o2(C  
this.nSplitter = nSpiltter; P !i_?M  
p /-du^:2  
fr/EkL1Dl  
} ):'wxIVGI  
86OrJdD8  
U;#KFZ+~  
public String getSSiteURL() VKl,m ;&N  
{ 6 X~><r  
return sSiteURL; 8In\Jo$|q>  
} |-x-CSN  
n"htx|v  
OW@%H;b  
public void setSSiteURL(String value) Jz` jN~  
{ BDI@h%tJb:  
sSiteURL = value; :oZ<[#p"*  
} 6p4BsWPx  
2.aCo, Kb;  
QcL@3QC  
public String getSFilePath() U0_)J1Yp  
{ D_d>A+  
return sFilePath; xRD+!3  
} ;[::&qf  
G`zNCx.  
Mpojabsh  
public void setSFilePath(String value) p qz~9y~  
{ Uw("+[5O0  
sFilePath = value; zbxW U]<S?  
} _=~u\$  
p[C"K0>:_F  
G1 "QX  
public String getSFileName() k`m7j[A]l  
{ +r3)\L{U  
return sFileName; oIE 1j?  
} :EV.nD7  
eL SzGbKf  
Ma|4nLC}  
public void setSFileName(String value) t,7%| {  
{ ekhv.;N~  
sFileName = value; 3:x(2 A  
} A0Mjk  
X(ph$,[  
X} k;(rb  
public int getNSplitter() V O:4wC"7  
{ R'v~:wNTNs  
return nSplitter; ~A=zjkm  
} pJ] Ix *M  
0(7 IsG=t  
>}V?GK36  
public void setNSplitter(int nCount) tVRN3fJH  
{ `3F#k[IR  
nSplitter = nCount; BX?DI-o^h  
} _iJ~O1qx,w  
} 8z1z<\  
h9Far8}  
"r&,#$6W6  
/* P$obID  
**Utility.java `DY yK?R  
*/ ,s~l; Gkj  
package NetFox; 5?-HQoT)G  
"ioO_  
wmr?ANk  
public class Utility { ^Gk`n  
zTg\\z;  
XZIapT  
public Utility() '|IcL1c=I  
{ +yP!7]  
uxf,95<g)  
$.jG O!  
} X+;[Gc}(W  
?Zb+xNKJ(  
//线程睡眠 3NpB1lgh&:  
public static void sleep(int nSecond) q}P@}TE  
{ %l7[eZ{Y  
try{ 63W;N7@  
Thread.sleep(nSecond); j*DPW)RkKX  
} LlX)xJ  
catch(Exception e) zgAU5cw  
{ IIR+qJ__|  
e.printStackTrace (); +Y 7M7  
} KYpS4&Xh  
} AY/.vyS  
w jkh*Y  
//日志 << >+z5D+  
public static void log(String sMsg) aRMlE*yW  
{ ~n]5iGz  
System.err.println(sMsg); h]oUY.Pf  
} E'LI0fr  
9z#8K zXg  
qi,) l*?f  
public static void log(int sMsg) '3l TI  
{ B#V""[Y9  
System.err.println(sMsg); *cb|9elF^  
} E`fG9:6l]  
} )7 p" -  
=?OU^ u`C  
OXQ*Xpc  
/* ?Y~t{5NJR  
**TestMethod.java DhM=q  
*/ $@z77td3  
package NetFox; U?0|2hR~  
H+[?{+"#@l  
1 (<n^\J(  
public class TestMethod { cI2Ps3~"Q  
D^[l~K  
z0}j7ns]  
public TestMethod() <Q|\mUS6  
{ ///xx/weblogic60b2_win.exe wp?:@XM  
try{ kd'b_D[$H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xk,Uf,,>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); x4q}xwH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v}$Q   
fileFetch.start(); layxtECP(  
} q}@L"a`  
catch(Exception e){e.printStackTrace ();} hZ45i?%  
N1'`^ay$  
egq,)6>  
} w 0BphK[  
eft=k}  
pQa51nc  
public static void main(String[] args) O\=Z;}<N  
{ F1yn@a "=J  
new TestMethod(); )  ;0  
} p'h'Cz  
} 8T3,56 >  
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