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http断点续传简单实现(java)

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/* sT<{SmBF  
**SiteFileFetch.java 1<uwU(  
*/ 'TEyP56  
package NetFox; X}apxSd"  
import java.io.*; *1;23BiH-  
import java.net.*; 4]UT+'RubX  
",Wf uz  
\ j]~>9  
public class SiteFileFetch extends Thread { 11*"d#  
-Uf4v6A  
o5#,\Y[ g  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5X;?I/9  
long[] nStartPos; //开始位置 Cnur"?w@o  
long[] nEndPos; //结束位置 =mJ F_Ri  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 '?R=P  
long nFileLength; //文件长度 zXgkcq)  
boolean bFirst = true; //是否第一次取文件 @+0V& jc  
boolean bStop = false; //停止标志 /s-d?  
File tmpFile; //文件下载的临时信息 ,iOZ |  
DataOutputStream output; //输出到文件的输出流 zMU68vwM  
&V;x 4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Bi_J5 If  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~\bHfiIDy  
{ Y?.gfEXSQo  
siteInfoBean = bean; jmPp-} tS7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #f 9qlM32  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7h1"^}M&  
if(tmpFile.exists ()) Et0&E  
{ q+J0}y{#8)  
bFirst = false; tD^a5qPh  
read_nPos(); 3AP YO  
} "sIN86pCs  
else S W-0h4  
{ n@o  
nStartPos = new long[bean.getNSplitter()]; J<-Fua^  
nEndPos = new long[bean.getNSplitter()]; P59uALi  
} PE7t_iSV  
[R$liN99z;  
I,z"_[^G  
U*xxrt/On/  
} " xxXZGUp  
wJr/FE 7c  
OMxxI6h  
public void run() xF^r`  
{ 'iDu0LX  
//获得文件长度 {!tOI  
//分割文件 '&{(:,!B  
//实例FileSplitterFetch uyvskz\  
//启动FileSplitterFetch线程 `;T? 9n  
//等待子线程返回 @+Pf[J41  
try{ X[Y #+z4  
if(bFirst) H;X~<WN&AW  
{ ?/^VOj4&  
nFileLength = getFileSize(); 1URT2$2p  
if(nFileLength == -1) hXBqz9  
{ OC`QD5  
System.err.println("File Length is not known!"); d OzO/w&  
} w`"W3(  
else if(nFileLength == -2) 'fX er!L}  
{ M!{Rq1M  
System.err.println("File is not access!"); $t%"Tr  
} 8g&uE*7N  
else 6pS Rum  
{ x%ZiE5#  
for(int i=0;i<nStartPos.length;i++) Q&tFv;1w6  
{ _6| /P7"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xU:PhhS  
} l ,ZzB,"  
for(int i=0;i<nEndPos.length-1;i++) 7?)m(CFy  
{ x Xl$Mp7  
nEndPos = nStartPos[i+1]; YL_!#<k@  
} ok8JnQC  
nEndPos[nEndPos.length-1] = nFileLength; I]s:Ev[~  
} !<JG&9ODP  
} t"4Rn<-  
oo"JMD)  
,|=iv  
//启动子线程 s#4))yUR6Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c|8KT  
for(int i=0;i<nStartPos.length;i++) 9p!dQx  
{ 0^_)OsFA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), m^(E:6T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bt. K<Y0  
nStartPos,nEndPos,i); +/1P^U /  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r5<e}t-  
fileSplitterFetch.start(); &ij^FAM  
} #0#V$AA>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xQcMQ{&;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "y3dwSS  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oQKcGUZ  
nEndPos = " + nFileLength); ,(5dQ`hA0  
// fileSplitterFetch[nPos.length-1].start(); Qt)7mf  
H>Iet}/c   
NiU tH  
//等待子线程结束 @vDgpb@TM  
//int count = 0; xf{C 'uF/  
//是否结束while循环 cPa 0n4  
boolean breakWhile = false; >(YPkmH  
d60Fi#3d  
`"1{Sx.  
while(!bStop) I NFz X  
{ ()rx>?x5  
write_nPos(); +"fM &F]  
Utility.sleep(500);  G> 5=`  
breakWhile = true; 7m@^=w  
N1B$G  
'44nk(hM69  
for(int i=0;i<nStartPos.length;i++) 9# .NPfMF  
{ FK/ro91L  
if(!fileSplitterFetch.bDownOver) "|~B};|MFF  
{ UO7a}Tz<  
breakWhile = false; kcZ;SYosj  
break; fQ?n(  
} [b\lcQ8O  
} eUUD|U*b   
if(breakWhile) ?yd(er<_f  
break; 5)o-]S>  
Wy0a2Ve  
D;T r  
//count++; 8-l)TTP&.  
//if(count>4) O7#}8-@}<u  
// siteStop(); |SXMu_w  
} V HY<(4@  
,:Ix s^-  
C">=2OO  
System.err.println("文件下载结束!"); w[$Wpae  
} :Y)kKq d  
catch(Exception e){e.printStackTrace ();} ![MDmt5Ub^  
} ~IN$hKg^  
Vp0GmZ  
H?r;S 5)c  
//获得文件长度 m3v* ,~  
public long getFileSize() Up2\X#6  
{ T`2fPxM:cZ  
int nFileLength = -1; do?n /<@o  
try{ ?jM7C}  
URL url = new URL(siteInfoBean.getSSiteURL()); 0 ?*I_[Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q)|LiCR,  
httpConnection.setRequestProperty("User-Agent","NetFox"); !NY^(^   
SJuf`  
.$x[!fuuR&  
int responseCode=httpConnection.getResponseCode(); ^OcfM_4pN  
if(responseCode>=400) 6+d"3-R.  
{ $T%<'=u|E  
processErrorCode(responseCode); "5DAGMU  
return -2; //-2 represent access is error KD3To%  
} rL+n$p X-  
hFPRC0ftE  
QNI|h;D  
String sHeader; D/6@bcCSY  
tMk>Bx9[  
HyYQQ  
for(int i=1;;i++) [/,6O  
{ g~sNY|%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); KI QBY!N+  
//Utility.log(in.readLine()); :/[ZgreN6  
sHeader=httpConnection.getHeaderFieldKey(i); JfINAaboi  
if(sHeader!=null) FG36,6N%2j  
{ `1v!sSR0R  
if(sHeader.equals("Content-Length")) *R6eykp  
{ xR6IXF>*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wn#JY p  
break; p. ~jo  
} `A{~}6jw  
} v#2qwd3x  
else ]4~D;mv  
break; Id 7  
} 2EcYO$R!  
} CN>};>WlG  
catch(IOException e){e.printStackTrace ();} ` i^1U O  
catch(Exception e){e.printStackTrace ();} rBPxGBd4  
)g<qEyJR  
KgAX0dM  
Utility.log(nFileLength); WbzL!zLd!  
DL!s)5!M  
 o%4+I>  
return nFileLength; O5*uL{pvT{  
} 7B2Og{P  
5|t&qUV  
5DUPsV  
//保存下载信息(文件指针位置) XdVC>6  
private void write_nPos() = gyK*F(RK  
{ LtIZgOd<  
try{ sb5kexGxkc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4 /vQ=t  
output.writeInt(nStartPos.length); uCr  
for(int i=0;i<nStartPos.length;i++) 'Em($A (  
{ nu -wQr  
// output.writeLong(nPos); > n\ Q [W  
output.writeLong(fileSplitterFetch.nStartPos); %LW~oI.  
output.writeLong(fileSplitterFetch.nEndPos); @V u[Tg}J  
} z<=t3dj  
output.close(); Bv*h ?`Q  
} ]`m5!V_Y  
catch(IOException e){e.printStackTrace ();} I2Q?7p  
catch(Exception e){e.printStackTrace ();} '|r !yAO6  
} j* ?MFvwE  
YI+|6s[  
<O&s 'A[  
//读取保存的下载信息(文件指针位置) % m$Mn x  
private void read_nPos() A 76yz`D  
{ %"V,V3kw4  
try{ o LRio.u*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); i:To8kdO  
int nCount = input.readInt(); }c:0cl  
nStartPos = new long[nCount]; eU*h qy?0  
nEndPos = new long[nCount]; K~G^jAk+  
for(int i=0;i<nStartPos.length;i++) ? ~8V;Qn  
{ dksnW!  
nStartPos = input.readLong(); 2x CGr>X  
nEndPos = input.readLong(); .kV/ 0!q?  
} !).d c.P  
input.close(); iLei-\w6y  
} Jr zU-g  
catch(IOException e){e.printStackTrace ();} mmti3Y  
catch(Exception e){e.printStackTrace ();} @m4d4K@  
} 5@\<:Zmi  
+q!6zGs.  
oizoKwp%  
private void processErrorCode(int nErrorCode) cA,xf@itp  
{ 4`B:Mq&j  
System.err.println("Error Code : " + nErrorCode); ygG9ht  
} F u)7J4Z  
~$<@:z{*  
DzMkeX  
//停止文件下载 qm_\#r  
public void siteStop() YjT #^AH  
{ ,KWeW^z'7  
bStop = true; TDFv\y}yc  
for(int i=0;i<nStartPos.length;i++) ~j_H2+!  
fileSplitterFetch.splitterStop(); F);C?SW"  
-\vq-n  
'=5N?)  
} u Wtp2]A  
} hsh W5j  
//负责部分文件的抓取 %"tf`,d~3  
**FileSplitterFetch.java #i? TCO  
*/ V=U%P[S  
package NetFox; &yuerNK  
S<44{ oH  
pc #^ {-  
import java.io.*; `|4{|X*U.  
import java.net.*; - >2ej4C  
^gy(~u  
BFY~::<b  
public class FileSplitterFetch extends Thread { K)n(U9#  
X~0P+E#  
mcvTz, ; =  
String sURL; //File URL DWDe5$^{  
long nStartPos; //File Snippet Start Position rW6LMkt72  
long nEndPos; //File Snippet End Position m@~HHwj  
int nThreadID; //Thread's ID d-4u*>  
boolean bDownOver = false; //Downing is over !Lo{zTDW  
boolean bStop = false; //Stop identical jU=)4nx  
FileAccessI fileAccessI = null; //File Access interface D:f#  
0kDT:3  
Jv5G:M5+~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9P]TIV.  
{ $iV3>>;eh  
this.sURL = sURL; W[b/.u5z:  
this.nStartPos = nStart; `g#\ Ws  
this.nEndPos = nEnd; Z]aSo07  
nThreadID = id; i^=an?}/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U+W8)7bc  
} zMDR1/|D  
79&Mc,69  
=%bc;ZUu  
public void run() W1#3+  
{ P9c1NX\-  
while(nStartPos < nEndPos && !bStop) /(Y\ <  
{ T_r[#j  
n4"xVDL  
RJN LcIm  
try{ ,s@S`KS0  
URL url = new URL(sURL); Hb^ovc0   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s <$*A;t  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,d=Dicaz  
String sProperty = "bytes="+nStartPos+"-"; jt9@aN.mJN  
httpConnection.setRequestProperty("RANGE",sProperty); q^@*k,HG  
Utility.log(sProperty); *s2 C+@ef  
{gDoktC@M  
[{ A5BE -  
InputStream input = httpConnection.getInputStream(); sP8_Y,  
//logResponseHead(httpConnection); g J$m'kC;  
_.,"`U; H  
!#WJ(zSq  
byte[] b = new byte[1024]; gvP.\,U  
int nRead; -#AO4xpI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o 7&q  
{ R_:-Z .  
nStartPos += fileAccessI.write(b,0,nRead); 4&`d$K  
//if(nThreadID == 1) *NI hYg6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e#tWQM3  
} 6" . v6  
P$`k* v  
7{=+Va5  
Utility.log("Thread " + nThreadID + " is over!"); r`:dUCFE  
bDownOver = true; H<`7){iG  
//nPos = fileAccessI.write (b,0,nRead); ` B+Pl6l)F  
} >9Y0t^Fl  
catch(Exception e){e.printStackTrace ();} piPV&ytI  
} ]=]`Mnuxb  
} S'AS,'EnY  
YzAGhAyw  
v,c:cKj  
//打印回应的头信息 X,+N/ nku  
public void logResponseHead(HttpURLConnection con) 1 swqs7rR|  
{ yrrP#F  
for(int i=1;;i++) <d3N2  
{ l`AA<Rj*O-  
String header=con.getHeaderFieldKey(i); v;R+{K87  
if(header!=null) ]B-3Lh  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "& q])3h=  
Utility.log(header+" : "+con.getHeaderField(header)); xgB-m[Xi  
else jR,3 -JQ  
break; +}!FP3KgT  
} >zcp(M98  
} [~IFg~*,  
~^"s.Lsb  
!tv+,l&L  
public void splitterStop() >U[YSsFt6  
{ JztSP?  
bStop = true; UL\gcZ Zkl  
} $PKUcT0N9  
(C8r^m|A  
.&c!k1kH  
} KH76Vts  
~px)Jd  
uze5u\  
/* $t42?Z=N&z  
**FileAccess.java "Bbd[ZI8  
*//文件访问(定位,写) 5JRj'G0I  
package NetFox; }h_= n>  
import java.io.*; ,zH\&D$>u  
bjGQ04da  
W&Gt^5  
public class FileAccessI implements Serializable{ 3r,^is  
c9N5c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RiM!LX  
RandomAccessFile oSavedFile; N"o+;yR  
long nPos;  8&KqrA86  
>qjV(_?F-  
*Wz\FixP0  
public FileAccessI() throws IOException ? ;)F_aHp  
{ qz/d6-0"  
this("",0); wZ =*ejo  
} rpO>l  
:yC|Q)  
xSoXf0zq:  
public FileAccessI(String sName,long nPos) throws IOException @jevY81)  
{ 04cNi~@m  
oSavedFile = new RandomAccessFile(sName,"rw");  #mcU);s  
this.nPos = nPos; 0I@Cx {$  
oSavedFile.seek(nPos); +zn207 .`  
} tM;S )S(=  
G@;I^_gN  
;Q} H'Wg,  
public synchronized int write(byte[] b,int nStart,int nLen) f.y~Sew  
{ CHRO9  
int n = -1; o|0QstSCl  
try{ /*yPy?  
oSavedFile.write(b,nStart,nLen); 0al8%z9e@  
n = nLen; Pb-Ft =  
} trC+Etc   
catch(IOException e) l]o)KM<  
{ ;BMm47<  
e.printStackTrace (); &k2nt  
} S0<m><|kl  
_z3YB  
d~b#dcv$"  
return n;  kwd)5J  
} $"&U%3  
@)YQiE$  
cWA$O*A  
} t846:Z%[  
Ut xe  
.4NQ2k1io  
/* MjHjL~Tg  
**SiteInfoBean.java axW4 cS ?  
*/ Qb;5:U/x  
package NetFox; `b{.K,  
=_L  
G$D6#/rR  
public class SiteInfoBean { nBVknyMFNF  
!B3lsXLSY  
j>0~"A  
private String sSiteURL; //Site's URL S-Y(Vn4  
private String sFilePath; //Saved File's Path Xkv+"F=-  
private String sFileName; //Saved File's Name '0xJp|[xVP  
private int nSplitter; //Count of Splited Downloading File RO"*&o'K'  
H?=D,  
j8G>0f)  
public SiteInfoBean() !I? J^0T  
{//nSplitter的缺省值为5 D=fB&7%@  
//default value of nSplitter is 5 dIo|i,-  
this("","","",5); DvuL1Me Ko  
} M]>JI'8  
,QpDz{8  
qKL_1 ~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 3o'SY@'W  
{ h,@x5q>g  
sSiteURL= sURL; \4SFD 3$&  
sFilePath = sPath; IpxFME%!  
sFileName = sName; iDO~G($C  
this.nSplitter = nSpiltter; _e_]$G/TM  
7#,+Q(2  
c3lfmTT6^  
} Ej1 [ry  
>NwrJSx  
RU `TzD  
public String getSSiteURL() X/1Z9 a+W  
{ @T1 >%oi  
return sSiteURL; 'ce9v@(0  
} ^;YD3EZw  
H[x9 7r  
9w Kz p  
public void setSSiteURL(String value) e7L;{+XI  
{ U hCd,  
sSiteURL = value; a~ REFy  
} B>47Ic  
CSU>nIE0  
Qb# S)[6s+  
public String getSFilePath() @F7QQs3  
{ 3iWLo Qm  
return sFilePath; 1'_OM h*;  
} of& vQ  
d(a6vEL4  
kd\yHI9A  
public void setSFilePath(String value) Fr%KO)s2  
{ "<O?KO 3K  
sFilePath = value; !9)*.9[8  
} N7#GK]n%/}  
\iVYhl  
5. l&nt'  
public String getSFileName() |E7]69=P  
{ hV8A<VT  
return sFileName; .Yu,&HR  
} *`jEg=)  
'ZDa*9nkF  
9)YG)A~<  
public void setSFileName(String value) rWvJ{-%  
{ /|DQ_<*  
sFileName = value; E_yh9lk  
} #-V Kk  
N]=.I   
=C:0 ='a  
public int getNSplitter() Sdt @"6  
{ xjX5PQu  
return nSplitter; LQQhn{[D  
} (?3( =+t  
<n`|zQ  
-zTeIvcy5  
public void setNSplitter(int nCount) p{U8z\  
{ 1IsR}uLh  
nSplitter = nCount; [,e_2<   
} O0I/^  
} 2Vi[qS^  
l:[=M:#p  
P~*fZ)\}F@  
/* 7)]G"m{  
**Utility.java {oZ]1Qf_  
*/ d8K^`k+x  
package NetFox; 2-CK:)n/#  
qy]-YJZ  
]Lh\[@#1f  
public class Utility { K4tX4U[Z  
&vn9l#\(  
qjFgy)qV  
public Utility() 0jyokER  
{ <*\J 6:^n  
Ea !j-Lbo  
])JJ`Z8Bk  
} I F@M  
*Zvw&y*  
//线程睡眠 K XGs'D  
public static void sleep(int nSecond) v 7R&9kU{  
{ D'&L wU,o  
try{ nZ*P:K t:  
Thread.sleep(nSecond); /IC' R"V a  
} F, "x~C  
catch(Exception e) wfdFGoy(  
{ 8+ u8piG  
e.printStackTrace (); y{N9.H2  
} a !IH-XJ2  
} x\%eg w  
>&VL2xLy  
//日志 !2Orklzd1  
public static void log(String sMsg) 1 W0;YcT]  
{ ~JXHBX  
System.err.println(sMsg); >W;i2%T  
} )~/U+,  
&0g,Xkr  
_(hwU>.  
public static void log(int sMsg) d}ZH Y[  
{ ff#-USK^R  
System.err.println(sMsg); c&++[  
} 4(R2V]  
} &Yg/ 08*  
;i9CQ0e ?  
,:`6x[ +  
/* asg>TO W  
**TestMethod.java }]I?vyQ#V  
*/ 'm|m +K83  
package NetFox; ! Cl/=0$[L  
R%%`wmG)"  
GHy#D]Z  
public class TestMethod { c #kV+n<  
}kj6hnQ  
2An`{')  
public TestMethod() 8|({ _Z  
{ ///xx/weblogic60b2_win.exe %U GlAyj  
try{ >|?T|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eEQ[^i  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C~qhwwh  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .jp]S4~  
fileFetch.start(); 0Mg8{  
} ~8*oGG~s  
catch(Exception e){e.printStackTrace ();} PoJ$%_a}  
<^U(ya  
$VWzv4^:  
} s3{s.55{m  
Yys~p2  
~7pjk  
public static void main(String[] args) +ZKhmb!  
{ au|^V^m  
new TestMethod(); X:lPWz!7{  
} Z~c'h  
} wkD:i2E7  
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