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http断点续传简单实现(java)

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/* Yj/S(4(h?  
**SiteFileFetch.java 7zVaj"N(  
*/ p<`q^D  
package NetFox; K;_p>bI5  
import java.io.*; _z)G!_7.>\  
import java.net.*; 4NQS'*%D  
5(%+8<2  
b@Ik c<  
public class SiteFileFetch extends Thread { OlRBv foh8  
EW0H"YIC  
`{N0+n  
SiteInfoBean siteInfoBean = null; //文件信息Bean |Ag~k? QC  
long[] nStartPos; //开始位置 E6NkuBQ((  
long[] nEndPos; //结束位置 aa.EtKl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PX(.bP2^Lq  
long nFileLength; //文件长度 nDkyo>t .  
boolean bFirst = true; //是否第一次取文件 Dsm_T1X  
boolean bStop = false; //停止标志 9&g//JlD  
File tmpFile; //文件下载的临时信息 >9Fs)R]P  
DataOutputStream output; //输出到文件的输出流 &tj0Z:  
}7IS:"tu  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7cK#fh"hvg  
public SiteFileFetch(SiteInfoBean bean) throws IOException I6M 7xn  
{ ?M;2H {KG:  
siteInfoBean = bean; FdKp@&O+1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bkceR>h%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DCPK1ql  
if(tmpFile.exists ()) LU?X|{z  
{ z/.x*A=  
bFirst = false; P cnr  
read_nPos(); %?<C ?.  
} ' 6Ybf  
else R KFz6t  
{ ^IjKT  
nStartPos = new long[bean.getNSplitter()]; [~W"$sT  
nEndPos = new long[bean.getNSplitter()]; 1 C{n!l  
} (WVN*OR?  
drBWo|/  
up=4B  
dFjB &#Tl  
} T@U_;v|rf  
sw[1T_S>  
\wCj$- ;Jt  
public void run() u&I?LZ-=,  
{ 3=o3VGZP  
//获得文件长度 jJQ6]ucwa  
//分割文件 -w1U /o.  
//实例FileSplitterFetch }W#Gf.$6C  
//启动FileSplitterFetch线程 pD9*WKEf*  
//等待子线程返回 nC$f0r"z  
try{ 9.m_3"s  
if(bFirst) SZpBbX$  
{ Uq<c+4)5  
nFileLength = getFileSize(); /1zi(z   
if(nFileLength == -1) &$lz@Z  
{ H1yl88K  
System.err.println("File Length is not known!"); "diF$Lj  
} Y#V`i K  
else if(nFileLength == -2) :7K cD\fCj  
{ u> XCE|D*  
System.err.println("File is not access!"); n[|&nv6x  
} M/x49qO#  
else x~j>Lvw L  
{ 3V?JX5X\  
for(int i=0;i<nStartPos.length;i++) G#t!{Q}8  
{ mDEO$:A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (TM1(<j  
} @] uvpI!h  
for(int i=0;i<nEndPos.length-1;i++) v#q7hw=  
{ 4:.yE|@h[  
nEndPos = nStartPos[i+1]; \L>3E#R-Q  
} wb~#=6Y  
nEndPos[nEndPos.length-1] = nFileLength; u27K 0}  
} eU&[^  
} 2a'b}<|[(  
g VX  
9_)*b  
//启动子线程 m X{_B!j^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (S$ziV  
for(int i=0;i<nStartPos.length;i++) M>nplHq   
{ I(y:Td  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `qnSq(tNq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^&F8NEb=2>  
nStartPos,nEndPos,i); \=Rw/[lR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T}d% XMXq  
fileSplitterFetch.start(); -7,xjn  
} %"B+;{y(5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bHZXMUewC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I!>pHF4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D@A@5pvS  
nEndPos = " + nFileLength); `1k0wT(  
// fileSplitterFetch[nPos.length-1].start(); i,|2F9YH  
$L%gQkz_  
z/Z 0cM#  
//等待子线程结束 }TE4)vXs  
//int count = 0; ZmU7tK  
//是否结束while循环 WX<),u2@  
boolean breakWhile = false; uU_lC5A|  
}8tD|t[  
v d A 3  
while(!bStop) s[6y|{&ze  
{ f/+UD-@%m  
write_nPos(); is`O,Met  
Utility.sleep(500); )vWI{Q]r  
breakWhile = true; [C_Dv-d  
d0ZbusHHb  
fP 4  
for(int i=0;i<nStartPos.length;i++) N;N,5rxV  
{ c*R?eLt/  
if(!fileSplitterFetch.bDownOver) C.su<B?  
{ a(cZ]`s]*  
breakWhile = false; \ k&(D*u  
break; &\Kp_AR  
} (.D|%P  
} i_<Uk8  
if(breakWhile) |a! y%R=  
break; &.D#OnRh9  
{Ee[rAVGp  
\M(#FS  
//count++; R8"qDj  
//if(count>4) c ow]qe6K  
// siteStop(); #ArMX3^+w7  
} 1uz7E  
%v)m&VUi%  
CEOD$nYc  
System.err.println("文件下载结束!"); LS(J%\hMDm  
} P`ZYm  
catch(Exception e){e.printStackTrace ();} (}^Qo^Vr  
} HzuB.B<  
)wFr%wNe  
;Nfd  
//获得文件长度 e3YdHp  
public long getFileSize() TOUP.,f/!  
{ |~V`Es +j  
int nFileLength = -1; R\VM6>SN'S  
try{ ICbT{Mla  
URL url = new URL(siteInfoBean.getSSiteURL()); /C: rr_4=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c+_F}2)  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z{#;my*X|  
uoX] #<1J  
!X 8<;e}2  
int responseCode=httpConnection.getResponseCode(); C{"uz_Gh  
if(responseCode>=400) +0)zB;~7  
{ }3rWmo8V  
processErrorCode(responseCode); |N^z=g P[  
return -2; //-2 represent access is error gp?|UMA9 .  
} fxR}a,a  
ab5uZ0@  
`;'fCO!  
String sHeader; }'o[6#_*X  
x?|C-v  
L.]mC !  
for(int i=1;;i++) %uVbI'n)  
{ G0u3*.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); GNv5yWQ@  
//Utility.log(in.readLine()); p]7Gj &a  
sHeader=httpConnection.getHeaderFieldKey(i); 1|PmZPKq9n  
if(sHeader!=null) IdvBQ [Gj  
{ ' YONRha  
if(sHeader.equals("Content-Length")) 7+h*&f3>  
{ k*;2QED  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /G>reG,G  
break; qZ39TTQ*p  
} 5xEk 7g.  
} a%wK[yVp  
else v7l4g&  
break; !`VO#_TJ  
} kP6P/F|RcZ  
} >QusXD"L>  
catch(IOException e){e.printStackTrace ();} :EUV#5V.  
catch(Exception e){e.printStackTrace ();} }UzO_&Z#6  
LX %8a^?;  
vd5"phn 3  
Utility.log(nFileLength); [|sKu#yW  
wFW2m  
9u'hCi(  
return nFileLength; p,?8s%  
} LRhq%7p7  
TwZvz[u  
jH*+\:UP-  
//保存下载信息(文件指针位置) h&!k!Su3#  
private void write_nPos() tk^1Ga3  
{ AJ;Y Nb  
try{ -S=Zsr\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]`D(/l'  
output.writeInt(nStartPos.length); 5k`[a93T  
for(int i=0;i<nStartPos.length;i++)  X7sWu{n  
{ k3m|I*_\L  
// output.writeLong(nPos); ;3n0 bKDY  
output.writeLong(fileSplitterFetch.nStartPos); B[ f{Ys  
output.writeLong(fileSplitterFetch.nEndPos); }lgqRg)F9[  
} pGi "*oZD  
output.close(); @1 #$  
} s0Ii;7fA{  
catch(IOException e){e.printStackTrace ();} @j$tpz  
catch(Exception e){e.printStackTrace ();} F}Bc +i#]  
} DytOS}/^9  
+q]  
y(:hN)  
//读取保存的下载信息(文件指针位置) M* W=v  
private void read_nPos() F9e$2J)C  
{ &7 }!U  
try{ Gvt.m&_  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 66=6;77  
int nCount = input.readInt(); `n:IXD5'  
nStartPos = new long[nCount]; ~(B\X?v  
nEndPos = new long[nCount]; v&(X& q  
for(int i=0;i<nStartPos.length;i++) 9`^VuC'  
{ ewgcpV|spn  
nStartPos = input.readLong(); zQ {g~x  
nEndPos = input.readLong(); nJ4h9`[>V  
} 0$,Ag;"^?  
input.close(); d@"eWvnlZ  
} +byw*Kk  
catch(IOException e){e.printStackTrace ();} Z`"UT#^SI  
catch(Exception e){e.printStackTrace ();} Ta!.oC[  
} kTex>1W;  
d\, 4Wet;#  
W.\HfJ74  
private void processErrorCode(int nErrorCode) z$-/yT"M  
{ 6!bA~"N  
System.err.println("Error Code : " + nErrorCode); xn@?CP`-y  
} %>i7A?L  
fB"3R-H?O  
;0xCrE{l"  
//停止文件下载 $t 1]w]}d  
public void siteStop() 5G){7]P+r"  
{ D{.%Dr?  
bStop = true; $Miii`VS9  
for(int i=0;i<nStartPos.length;i++) 6FSw_[)  
fileSplitterFetch.splitterStop(); Oe$cM=Yf  
)dF(5,y)  
N,'JQch},8  
} l$,l3  
} AXPUJ?V  
//负责部分文件的抓取 l(=#c/f  
**FileSplitterFetch.java 9aZ3W<N`M  
*/ lbg6n:@  
package NetFox; h#]}J}si  
/gy;~eB01  
(^a;2j9  
import java.io.*; QJdSNkc6  
import java.net.*; ]N=C%#ki!  
dN |w;|M  
{k?Y :  
public class FileSplitterFetch extends Thread { -&,NM  
nQ$N(2<Fe  
,C&h~uRi#f  
String sURL; //File URL (= !_ 5l  
long nStartPos; //File Snippet Start Position Mh+'f 93  
long nEndPos; //File Snippet End Position Vg \-^$  
int nThreadID; //Thread's ID i6`8yw  
boolean bDownOver = false; //Downing is over @/$mZ]|T  
boolean bStop = false; //Stop identical x ;Gyo  
FileAccessI fileAccessI = null; //File Access interface n"FOCcTIs  
f6|3| +  
o=`9JKB~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uhc0,V;S  
{ Plq [Ml9  
this.sURL = sURL; 29qQ3M?  
this.nStartPos = nStart; e/Q[%y.X  
this.nEndPos = nEnd; (ZEVbAY?i  
nThreadID = id; t91CxZQ^s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *|E@ 81s#  
} cF(9[8c{  
:T{or-  
(B$FX<K3  
public void run() @nc!(P7_  
{ \clWrK  
while(nStartPos < nEndPos && !bStop) epG;=\f}m`  
{ hYWWvJ)S  
^_=0.:QaW  
[ThzLk#m  
try{ WX=+\`NyJ(  
URL url = new URL(sURL); ix#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F Q k;  
httpConnection.setRequestProperty("User-Agent","NetFox"); C,<TAm  
String sProperty = "bytes="+nStartPos+"-"; BuvBSLC~  
httpConnection.setRequestProperty("RANGE",sProperty); <bjy<98LT  
Utility.log(sProperty); A!Yqj~  
CTP%  
n=>Gu9`  
InputStream input = httpConnection.getInputStream(); C {,d4KG  
//logResponseHead(httpConnection); >L;O, {Px-  
<n:?WP~U  
6,h<0j{  
byte[] b = new byte[1024]; /<2_K4(-{4  
int nRead; gU%GM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7, 4x7!  
{ co@8w!W  
nStartPos += fileAccessI.write(b,0,nRead); jCl[!L5/1  
//if(nThreadID == 1) o{hKt?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0x & ^{P~  
} Wm,,OioK  
Tc*PDt0C  
Rq9gtx8,=  
Utility.log("Thread " + nThreadID + " is over!"); =@z"k'Vl`  
bDownOver = true; 5a~1RL  
//nPos = fileAccessI.write (b,0,nRead); 51,m^veO  
} 3OZ}&[3  
catch(Exception e){e.printStackTrace ();} \'KzSkC8  
} `WT7w']NT  
} ;uDFd04w [  
F)IP~BE-k  
Z4!3I@yZ  
//打印回应的头信息 O(d'8`8  
public void logResponseHead(HttpURLConnection con) 4jW{IGW  
{ )?WoL Ejq  
for(int i=1;;i++) x9e 9$ww}  
{ #n"/9%35f`  
String header=con.getHeaderFieldKey(i); 6xe |L  
if(header!=null) l rzW H0Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |H4'*NP"  
Utility.log(header+" : "+con.getHeaderField(header)); 'n no)kQ"  
else m+=!Z|K  
break; 5-*]PAC  
} [ n2udV  
} j$^]WRt  
O2e "TH3  
{V8Pn2mlo  
public void splitterStop() 1dcy+ !>  
{ 1#(1Bs6X  
bStop = true; S(6ZX>wv:  
} z#4g,)ZX  
NP8TF*5V  
7yp*I[1Qf>  
} :m\KQ1sq  
vF&b|V+,  
Tt\w^Gv\d  
/* q1y4B`  
**FileAccess.java g8Z14'Ke  
*//文件访问(定位,写) 4lA+V,#  
package NetFox; .D .Rn/  
import java.io.*; F 4/Uu"J:  
2XHk}M|  
+b+sQ<w?.  
public class FileAccessI implements Serializable{ 2#3R]zIO  
}H=OVbQor  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s /M~RB!w  
RandomAccessFile oSavedFile; O 0#Jl8  
long nPos; `qTY  
]B4mm__  
i1\2lh$  
public FileAccessI() throws IOException 7VcVI? ?  
{ Z<W6Avr  
this("",0); 4Z }{hc\J  
} {M/c!  
.h,xBT`}Ji  
LltguNM$  
public FileAccessI(String sName,long nPos) throws IOException Tm\[q  
{ )/"7$2Aoy  
oSavedFile = new RandomAccessFile(sName,"rw"); 7-I>5 3@  
this.nPos = nPos; K"7;Y#1g  
oSavedFile.seek(nPos); *K'ej4"u  
} Q/)ok$A&  
E]U0CwFtr  
N?0y<S ?!  
public synchronized int write(byte[] b,int nStart,int nLen) S7{.liHf  
{ ~aAJn IO  
int n = -1; ?4e6w  
try{ :)95 b fa.  
oSavedFile.write(b,nStart,nLen); R Sz[6  
n = nLen; yB%)D0  
} '-33iG  
catch(IOException e) h;qy5KS  
{ o!`O i5  
e.printStackTrace (); orH0M!OtS!  
} 2 pa3}6P+  
dqA[|bV  
KTjlWxD  
return n; ;+34g6  
} M5WtGIV  
!]+Z%ed`%  
5;8B!%b  
} wZ8 MhE  
B36puz 0{  
D%UZ'bHN*  
/* l@r wf$-  
**SiteInfoBean.java E8_Le  
*/ ?4[Oh/]R  
package NetFox; kEhm'  
nIQ&gbfO  
Fra>|;do  
public class SiteInfoBean { hr4ye`c j  
U5CPkH1  
MiH}VfI  
private String sSiteURL; //Site's URL 7X{bB  
private String sFilePath; //Saved File's Path Fiu!!M6  
private String sFileName; //Saved File's Name *Ht*)l?  
private int nSplitter; //Count of Splited Downloading File #3K,V8(  
N^ s!!Sbpq  
guOSO@  
public SiteInfoBean() Va@6=U7c  
{//nSplitter的缺省值为5 y (nsyA  
//default value of nSplitter is 5 p/k<wCm6  
this("","","",5);  /MqXwUbO  
}  S2&9# 6  
w^])(  
]oeuIRyQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^0~c 7`k`V  
{ wY3|#P CDV  
sSiteURL= sURL; ,<$YVXe/  
sFilePath = sPath; ]A]Ft!`6z  
sFileName = sName; Z.:<TrN  
this.nSplitter = nSpiltter; kOAY@a  
&{zwM |Q@?  
gX$0[ sIS.  
} m0|Ae@g~3  
6h2x~@  
W(2+z5z  
public String getSSiteURL() @A2/@]HBm  
{ F_nZvv[H?  
return sSiteURL; tE]5@b,R  
} }PI35i1!t  
+ze}0lrEL  
3w/( /|0  
public void setSSiteURL(String value) ?ds f@\  
{ ?7yQ&p  
sSiteURL = value; %2Epgh4?  
} h L]8e>a?  
(Qk&g"I  
As@ihB+(\  
public String getSFilePath() # 0GGc.  
{ :tMre^oP  
return sFilePath; {)B9Z I{+A  
} uxa=KM1H  
)=jT_?9b   
A\".t=+7  
public void setSFilePath(String value) k> b&xM!  
{ rDVgk6  
sFilePath = value; J3;Tm~KJ_  
} )A="eW_>  
Ia=_78MgZ  
ku{XW8  
public String getSFileName() bh6d./  
{ 4~O6$;!|~  
return sFileName; "r8EC  
} =op`fn%  
1"}B]5!  
%_R$K#T^,  
public void setSFileName(String value) $^}[g9]1  
{ 0Tcz[$?  
sFileName = value; ^vpIZjN  
} ~xS@]3n=  
<tFSF%vG=  
(lb6]MtTHY  
public int getNSplitter() R N@^j  
{ ?*[\UC  
return nSplitter; %X;7--S%?g  
} Bc@30KiQ ^  
[s~JceUyX  
k({2yc#RD&  
public void setNSplitter(int nCount) 2\VAmPG.Zs  
{ q]px(  
nSplitter = nCount; QU.0Elw  
} 7i8eg*Gl  
} Va7c#P?  
czI{qi5N  
n@ 4@,  
/* 5G#$c'A{4  
**Utility.java SB TPTb  
*/ 6 }!Z"  
package NetFox; wepwX y"  
u FZ~  
-0$:|p?@^  
public class Utility { QBoFpxh=  
b6"}"bG  
o~#f1$|Xn  
public Utility() qe$33f*  
{ 86%%n?"}  
%:3'4;jh%  
l-}KmZ]  
} .n`( X#,*l  
~.Cv DJy  
//线程睡眠 o'Wz*oY))\  
public static void sleep(int nSecond) ?`"n3!>bS  
{ BFWi(58q  
try{ Q(Gyq:L=>  
Thread.sleep(nSecond); BC! 6O/kr  
} =A@>I0(7  
catch(Exception e) @QdnjXII*  
{ {~N3D4n^  
e.printStackTrace (); S/4r\6  
} NQX>Qh 2  
} >;4!O%F  
LL(|$}yW  
//日志 R>2IRvY(  
public static void log(String sMsg) ?mx\eX{  
{ {6*#3m Kk  
System.err.println(sMsg); 2q PhLCe Z  
} 0{+.H_f`  
nPFwPk8=M  
`G!M>h@  
public static void log(int sMsg) icgJ;Q 5  
{ hJ*Ihwn|  
System.err.println(sMsg); 1J{fXh  
} 5\ hd4  
} |=6_ xRyr  
W .I\J<=V  
tY+$$GSQj  
/* PFrfd_s{>\  
**TestMethod.java ?9mkRd}c  
*/ mwC=o5O  
package NetFox; $,fy$ Qk,S  
$t}<85YCQ  
ZmEEj-*7s  
public class TestMethod { y(W|eBe  
i47j lyH  
S`!-Cal`n  
public TestMethod() 0 1V^L}  
{ ///xx/weblogic60b2_win.exe $}GTG'*.  
try{ g}x(hF  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YXW%]Uy+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "V& I^YSc>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !w39FfU{  
fileFetch.start(); m GjN_  
} @-&MA)SN  
catch(Exception e){e.printStackTrace ();} CGbwmPx  
wkUlrL/~  
V  ~@^`Gd  
} #,d I$gY  
CW&.NT  
O%8EZyu  
public static void main(String[] args) TZR)C P5  
{ 5=|hC3h  
new TestMethod(); ml`8HXK0  
} aj^wRzJ}zA  
} t. ='/`!N  
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3+5=?,请输入中文答案:八 正确答案:八