http断点续传简单实现（java)

/* <EE)d@%>v  
**SiteFileFetch.java (j'[t  
*/ ?&Lb6(}e  
package NetFox; b[/-lNrc  
import java.io.*; Pp}j=$&j\  
import java.net.*; k:c)|2  
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public class SiteFileFetch extends Thread { xL mo?Y*  
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#t;@x_2yD\  
SiteInfoBean siteInfoBean = null; //文件信息Bean :imp~~L;  
long[] nStartPos; //开始位置 fSSDOH!U,  
long[] nEndPos; //结束位置 N5g!,
3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .aNy)Yu8  
long nFileLength; //文件长度 !"_\5$5i<X  
boolean bFirst = true; //是否第一次取文件 pwm]2}+  
boolean bStop = false; //停止标志 xvb5-tK -  
File tmpFile; //文件下载的临时信息 oas}8A)  
DataOutputStream output; //输出到文件的输出流 f 1]1ZOb  
}VyDX14j  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xFgY#F  
public SiteFileFetch(SiteInfoBean bean) throws IOException h_H$+!Nzb  
{ ^f@EDG8  
siteInfoBean = bean; +Ge-!&.;A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); :dB6/@fW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ZXp=QH+f  
if(tmpFile.exists ()) V,lz}&3L  
{ F(mm0:lT  
bFirst = false; )/Ul"QF  
read_nPos(); c\7~_w2  
} ,
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biL  
else bKiV<&Z5d  
{ g&&5F>mF  
nStartPos = new long[bean.getNSplitter()]; {8'I+-  
nEndPos = new long[bean.getNSplitter()]; iFpJ/L  
} .]P@{T||Y  
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rtC.!].;%  
iE>T5XV8$B  
} TTu<~GH  
!@5B:n*  
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public void run() ]Z6==+mCP  
{
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//获得文件长度 usX aT(K  
//分割文件 F~4oPB K<  
//实例FileSplitterFetch BlMc<k  
//启动FileSplitterFetch线程 k\I+T~~xD  
//等待子线程返回 S}mqK|!
 
try{  {|a=  
if(bFirst) .r$d 8J  
{ &E0P`F,GQA  
nFileLength = getFileSize(); yKgA"NaM  
if(nFileLength == -1) |cUTP!iy  
{ N"@aisi)  
System.err.println("File Length is not known!"); yMB*/vs  
} xXQDHc-Ba  
else if(nFileLength == -2) )BmK'H+l  
{ +<7`Gn(n3  
System.err.println("File is not access!"); |]*]k`o<)  
} v?vm-e  
else DavpjwSn  
{ :[A>O(  
for(int i=0;i<nStartPos.length;i++) }y;s(4  
{ %9C_p]P*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .Xqe]cax%  
} F=bX\T7  
for(int i=0;i<nEndPos.length-1;i++) *;5P65:u$>  
{ 1#/>[B  
nEndPos = nStartPos[i+1]; #+
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} cA m>f[  
nEndPos[nEndPos.length-1] = nFileLength; rzsAnLxo  
} *#\da]"{  
} o)GLh^g_I'  
R,>LUa*u  
RutRA  
//启动子线程 ^Cs?FF@P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; C5"=%v[gQv  
for(int i=0;i<nStartPos.length;i++) lpi^<LQ@l  
{ DSf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AU0pJB'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^M
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nStartPos,nEndPos,i); A0~uv4MC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u?,M`w0'  
fileSplitterFetch.start(); 2SVBuV/R  
} HtFc+%=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wA$ JDf)Vg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jJc:%h$|2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |soDt<y+L  
nEndPos = " + nFileLength); N/CL?Z>c  
// fileSplitterFetch[nPos.length-1].start(); X2\1OWR0  
j%%& G$Tfu  
I5Vp%mCY  
//等待子线程结束 T8'm{[C  
//int count = 0; WOkAma-  
//是否结束while循环 Pk)>@F<  
boolean breakWhile = false; QPr29  
v{tw;Z#  
~*NG~Kn"s  
while(!bStop) #s%_ L  
{ &pCa{p  
write_nPos(); ;@/^hk{A  
Utility.sleep(500); 9+S$,|9
 
breakWhile = true; KUD&vqx3  
C^QpVt-T  
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for(int i=0;i<nStartPos.length;i++) wX/0.aZ|  
{ z'"e|)  
if(!fileSplitterFetch.bDownOver) Es]:-TR  
{ EnW}>X
N  
breakWhile = false; ,r_%p<lOFu  
break; ?/3'j(Gk  
} b}<?& @  
} y
VZLZLm  
if(breakWhile) `|&#=hl~  
break; 7F$G.LhMw  
2;2FyKF(  
Iy[TEB  
//count++; UmEc")3  
//if(count>4) 6 rp(<D/_  
// siteStop(); F .hA.E  
} v=8sj{g3,3  
HAKB@h)  
[[FDt[
l4  
System.err.println("文件下载结束！"); FW=`Fm@z%%  
} ?cur}`  
catch(Exception e){e.printStackTrace ();} !a9`]c  
} 4J5 RtK  
?q{HS&k  
%H/V iC  
//获得文件长度 u7(<
YSOs  
public long getFileSize() -}x( MZ  
{ GUDz>(  
int nFileLength = -1; ! mb<z^>5  
try{ ^jYE4gHM  
URL url = new URL(siteInfoBean.getSSiteURL()); Q
 h~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K&'Vd@  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'Bx"i  
}z,f8Yz  
,azBk`$iQr  
int responseCode=httpConnection.getResponseCode(); v{r,Wy3  
if(responseCode>=400) nI_UL  
{ 0+
{CN|0  
processErrorCode(responseCode); yt+d f0l  
return -2; //-2 represent access is error [x[nTIg  
} ;)Fc@OXN>  
W @ ?*~  
Fswr @du  
String sHeader; K3dg.>O  
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_ci8!PP  
for(int i=1;;i++) GtLnh~)  
{ a1dkB"Zp.p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2I$-&c]  
//Utility.log(in.readLine()); O= 84ZP%  
sHeader=httpConnection.getHeaderFieldKey(i); qbx}9pp}g  
if(sHeader!=null) _=YHO.  
{ 2'U+QK@  
if(sHeader.equals("Content-Length")) &zV;p  
{ @V=HY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5c ($~EFr  
break; v{8W+  
} |SX31T9rG  
} RLNto5?  
else Vw";< <0HZ  
break; p>h&SD?b  
} ;%^T*?t  
} Jp 7m$D%  
catch(IOException e){e.printStackTrace ();} $+WMKv@<  
catch(Exception e){e.printStackTrace ();} l1UN.l'p  
~O8Xj6  
b wqd`C  
Utility.log(nFileLength); kO}QOL4  
|%$mN{  
{Rtl<W0  
return nFileLength; Y^2]*e%  
} 9s2N!bx  
`xsU'Wd^<  
*pSD[E>SU  
//保存下载信息（文件指针位置） AQgagE^  
private void write_nPos() z8JdA%YBM  
{  j|owU  
try{ \O=t5yS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }@TtX\7(D  
output.writeInt(nStartPos.length);
>
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for(int i=0;i<nStartPos.length;i++) ? t_$C,A+  
{ :9]"4ktoJ  
// output.writeLong(nPos); 5Y#~+Im=[@  
output.writeLong(fileSplitterFetch.nStartPos); >5MHn@  
output.writeLong(fileSplitterFetch.nEndPos); Oi4y~C_Xd  
} e)#f`wM  
output.close(); NR.YeKsBq  
} q[
5&  
catch(IOException e){e.printStackTrace ();} f9a_:]F   
catch(Exception e){e.printStackTrace ();} ><w=  
} cz;gz4d8  
I?X!v6
 
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//读取保存的下载信息（文件指针位置） T{
4Ru6[  
private void read_nPos() ay>u``$R  
{ ,}23  
try{ XK,l9 {*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;@s'JSPt  
int nCount = input.readInt(); &BE'~G  
nStartPos = new long[nCount]; IRK(y*6  
nEndPos = new long[nCount]; }0 b[/ZwQ  
for(int i=0;i<nStartPos.length;i++) ;oivG)hJl  
{ V1 O]L66  
nStartPos = input.readLong(); U}:e-
 
nEndPos = input.readLong(); LWIPq"  
} hZ~\Z S7  
input.close(); |.{[%OJP  
} ~9JLqN"  
catch(IOException e){e.printStackTrace ();} HOb0\X  
catch(Exception e){e.printStackTrace ();} dU.H9\p  
}
v~KgCLo  
}gtkO&  
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private void processErrorCode(int nErrorCode) Ja%(kq[v  
{ c=u'#|/eb  
System.err.println("Error Code : " + nErrorCode); q%hxU.h  
} !_pryNcb  
V)3S.*]  
]vUTb9>{?  
//停止文件下载 cwBf((~  
public void siteStop() M2rgB%W)m  
{ 2>h.K/pC  
bStop = true; n+H);Dg<8  
for(int i=0;i<nStartPos.length;i++) DcX,o*ec!  
fileSplitterFetch.splitterStop(); B`/p

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,#hx%$f}d  
BiI`oCX  
} {N`<THPP  
} c5AEn -Q  
//负责部分文件的抓取 a[A*9%a  
**FileSplitterFetch.java X%]m^[6  
*/ We:b1sZR  
package NetFox; -=VGXd  
I1fUV72  
e>Q_&6L  
import java.io.*; b^C2<'  
import java.net.*; 'G8.)eTA'  
[.LbX`K:  
n81z0lnr  
public class FileSplitterFetch extends Thread { [O\[,E"K  
#7"*Pxb#A  
65AG#O5R  
String sURL; //File URL D9-D%R,
 
long nStartPos; //File Snippet Start Position D/TEx2.=J3  
long nEndPos; //File Snippet End Position G;yh$n<"  
int nThreadID; //Thread's ID +/Qgl  
boolean bDownOver = false; //Downing is over Jwe9L^gL  
boolean bStop = false; //Stop identical B<6Ye9zuG  
FileAccessI fileAccessI = null; //File Access interface \zv?r:1t  
d!#qBn$*[  
Gb_y"rx?0  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hl b%/&  
{ $|n#L6k  
this.sURL = sURL; +9[s(E?SY  
this.nStartPos = nStart; k/mO(i%qi  
this.nEndPos = nEnd; Hribk[99  
nThreadID = id; s2;
b-0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _S3qPPo3l]  
} =.yKl*WV{  
%2z]2@  
q8[I` V{  
public void run() (vb8Mk
  
{ ;=F]{w]$+  
while(nStartPos < nEndPos && !bStop) VtzX I2.2  
{ 4pC.mRu 0  
>Z&Y!w'A|u  
*\T ]Z&E"  
try{ FCPiU3  
URL url = new URL(sURL); (|_N2R!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }RN&w]<  
httpConnection.setRequestProperty("User-Agent","NetFox"); #25%17  
String sProperty = "bytes="+nStartPos+"-"; $G.ws  
httpConnection.setRequestProperty("RANGE",sProperty); -$+`v<[r  
Utility.log(sProperty); Avr2MaY{h  
ZINqIfc  
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InputStream input = httpConnection.getInputStream(); iR6w)  
//logResponseHead(httpConnection); cgF?[Z+x  
3|9 U`@  
#0gwN2Nv"L  
byte[] b = new byte[1024]; kSq1Q#Bxq  
int nRead; Sz#dld Mz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J-)9>~[E<  
{ /4lm=ZE/  
nStartPos += fileAccessI.write(b,0,nRead); aEwwK(ny  
//if(nThreadID == 1) kCVA~%d7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); yx&'W_Q@  
} jk-e/C  
CF_pIfbaf  
Kt\#|-{CH-  
Utility.log("Thread " + nThreadID + " is over!"); >nOU 8  
bDownOver = true; LJ+Qe%|  
//nPos = fileAccessI.write (b,0,nRead); mOE%:xq9-  
} Ed+"F{!eQ  
catch(Exception e){e.printStackTrace ();} ^;gwD4(hs  
} M8}t`q[-&  
} f_qW+fN::s  
(S=RFd  
0Z<&M|G  
//打印回应的头信息 y8|?J\eRy  
public void logResponseHead(HttpURLConnection con) N]iu o.  
{ j@4AY}[tX  
for(int i=1;;i++) >4@/x{{  
{ L6E8A?>5rD  
String header=con.getHeaderFieldKey(i); dzn[4  
if(header!=null) C=uYX"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `am]&0g^+(  
Utility.log(header+" : "+con.getHeaderField(header)); s
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else #CYDh8X<i  
break; d]<S/D'i  
} 7GVI={
b  
} Z[pMlg6Z  
/Xo8 kC  
u[;,~eB%w  
public void splitterStop() ERQc1G]3Dd  
{ JLFZy\  
bStop = true; qTD^Vz V  
} ]31UA>/TI  
()+PP}:$A  
'g7eN@Wh.z  
} 1?j['~aE  
@x@*=  
Fo@cz"%  
/* 3sy|pa  
**FileAccess.java Sp>v`{F  
*//文件访问(定位，写) kvo V?<!  
package NetFox; N+M^e`H  
import java.io.*;
MzudCMF  
W{z{AxS  
L/sMAB  
public class FileAccessI implements Serializable{ QqU>V0y"w(  
!0k'fYCa  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +'f+0T\)  
RandomAccessFile oSavedFile; ~qP_1() ?  
long nPos; 5B76D12  
r(Vz(  
MR{JMo=r  
public FileAccessI() throws IOException O<EFm}Ae  
{ Nt5`F@;B  
this("",0); Hz6tk9;w  
} r3_O?b  
!|@hU/  
IVblSiFF  
public FileAccessI(String sName,long nPos) throws IOException -4IHs=`;I  
{ /suW{8A(E  
oSavedFile = new RandomAccessFile(sName,"rw"); 4`M7 3k0  
this.nPos = nPos; *(>,\8OVf  
oSavedFile.seek(nPos); M1 5_  
} ^+'[:rE  
qVDf98  
Ub_!~tb}?  
public synchronized int write(byte[] b,int nStart,int nLen) ].e4a;pt  
{ !/;/ X\d  
int n = -1; &?)? w-$p  
try{ vdt":  
oSavedFile.write(b,nStart,nLen); bB->7.GXu  
n = nLen; 7yM"G$  
} H/?@UJ5m  
catch(IOException e) RL|d-A+;  
{ do$+ Eh  
e.printStackTrace (); v+b#8  
} XHER[8
l  
.nG14i7C  
6J""gyK.  
return n; )5NjwL
s  
} xB<^ar  
q<Sb>M/
\,  
NZW)$c'  
} .%x%b6EI  
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,^K}_z\9f  
/* rTmVHt  
**SiteInfoBean.java  Z,Z4Sp  
*/ $]`rWSYtv`  
package NetFox; n
;+`%;6  
N R0"yJV>  
F
).7%YfY  
public class SiteInfoBean { BGOajYD  
uGW!~qAr*  
49?wEm#  
private String sSiteURL; //Site's URL 0`y*7.Ip  
private String sFilePath; //Saved File's Path FJCLK#-  
private String sFileName; //Saved File's Name \)'5V!B|s  
private int nSplitter; //Count of Splited Downloading File FMNT0  
`$oy4lDKQ  
p`I[3/$3  
public SiteInfoBean() m*f"Y"B.1I  
{//nSplitter的缺省值为5 =euMOs  
//default value of nSplitter is 5 JV`"kk/  
this("","","",5); uG){0%nX  
} qOs'Ljx6l  
~cL)0/j}  
49iqrP'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E3"j7y[S  
{ ][TA7pDPV  
sSiteURL= sURL; + \jn$>E  
sFilePath = sPath; vXLGdv::  
sFileName = sName; o^8Z cN>  
this.nSplitter = nSpiltter; vBLs88  
/Y#Q<=X  
`37%|e3bQ  
} B{hV|2  
4o69t  
qvC2BQ  
public String getSSiteURL() #6F|
}E  
{ 8c3/n   
return sSiteURL; N#<X"&-_#  
} )zv"<>Q 6  
VYw<8AEFY  
/)*si  
public void setSSiteURL(String value) !~_6S*~  
{ HrS-o=  
sSiteURL = value; ym;I(TC+  
} l0K_29^  
9'Cu9nR  

*ORa@x  
public String getSFilePath() lKBI3oYn  
{ q5G`N>"V  
return sFilePath; Y1-=H)G  
} E0*62OI~O  
U:q4OtiP  
aHkt K/  
public void setSFilePath(String value) -,qGEJ  
{ b`fWT:?=  
sFilePath = value; ys- w0H  
} ">v-CSHY  
|<2<`3  
J;S Z"I'  
public String getSFileName() t3<HE_B|  
{ kk$D:UQX
 
return sFileName; ?Ll1B3f  
} 95.s,'0  
eHc.#OA&  
Im"8+756  
public void setSFileName(String value) Fgw$;W  
{ #:E^($v  
sFileName = value; x }.&?m  
} Ch'e'EmI  
]vjMfT%]W  
Zjn![  
public int getNSplitter() MUi#3o\f  
{ 9/PX~j9O?  
return nSplitter; 30{+gYA  
} S;}/ql y  
BmFtRbR  
^0(`:*  
public void setNSplitter(int nCount) q rF:=?`E  
{ xgJyG.?  
nSplitter = nCount; p?#xd!tc2N  
} /xb37,   
} gJg%3K~,  
FPkig`(3  
`{&l _  
/* I#-T/
1N  
**Utility.java B*^8kc:)L  
*/ e/Y&d9` I  
package NetFox; JpZ3T~Wrf  
0IxHB|^$  
l'RuzBQr  
public class Utility { g>n1mK|  
:1gcLsF  
>K 7]G?+7E  
public Utility() 2#Y5*r's\  
{ *n`8 -=  
CA3`Ee+rD  
6#Bg99c  
} uiq;{!dop  
?jn";:  
//线程睡眠 N6h.zl&04  
public static void sleep(int nSecond) *lyRy/POB  
{ y<^hM6S?Z  
try{ i)[~]D.EH8  
Thread.sleep(nSecond); S~\u]j^%y  
} :o_6  
catch(Exception e) ~-BIUZ;  
{ r1zuc:W1  
e.printStackTrace (); x?2y^3<5  
} (P 9$Ei0fv  
} TB#oauJm,  
p;rT#R&6>  
//日志 H1e^/JD)  
public static void log(String sMsg) k-8$43  
{ WO+_|*&  
System.err.println(sMsg); V3[>^ZCA  
} Jm3iYR+,  
y2@8?  
Ombvp;  
public static void log(int sMsg) h"(HDnq  
{ 9m}c2:p  
System.err.println(sMsg); 'cf8VD  
} '+iqbcUd,  
} qdwjg8fo4Z  
cB4p.iO   
e2Df@8>  
/* O^4Ko}  
**TestMethod.java ''wF%q  
*/ ;op
8r u  
package NetFox; gro@+^DmT  

$-lP"m@}  
/@9-D 4  
public class TestMethod { (\ Gs7  
^vr`t9EE  
-MItZ  
public TestMethod() ~MW_=6U  
{ ///xx/weblogic60b2_win.exe Jtl[9qe#]  
try{ 8\rHSsP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6Ej@;]^^-  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); psAdYEGk!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); av}pT)]\  
fileFetch.start(); oWdvpvO  
} r^!P=BS{  
catch(Exception e){e.printStackTrace ();} ZH=oQV)6  
28d=-s=[  
r?wE;gH  
} -,}ppTG  
a[Oi  
roE*8:Y  
public static void main(String[] args) uNG?`>4>  
{ 16n8[U!  
new TestMethod(); Zn"1qLPF  
} \!,qXfTMB  
} |k=L&vs  
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