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http断点续传简单实现(java)

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/* f({-j% m  
**SiteFileFetch.java ) Q  
*/ g d}TTe  
package NetFox; |8U7C\S[  
import java.io.*; Hv7D+ j8M  
import java.net.*; }Keon.N?   
>RqT7n8h  
y:[VRLo  
public class SiteFileFetch extends Thread { I^\bS  
bb :|1D  
m6Cd^'J9^  
SiteInfoBean siteInfoBean = null; //文件信息Bean E~@HC5.M  
long[] nStartPos; //开始位置 #z^1)7  
long[] nEndPos; //结束位置 xE-`Bb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6k=Wt7C  
long nFileLength; //文件长度 ;Y XrG  
boolean bFirst = true; //是否第一次取文件 {6y.%ysU  
boolean bStop = false; //停止标志 Q.E^9giC  
File tmpFile; //文件下载的临时信息 =jv$ 1  
DataOutputStream output; //输出到文件的输出流 sd@gEp)L  
FQ~ead36C  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) iN/!k.ybW}  
public SiteFileFetch(SiteInfoBean bean) throws IOException [BR}4(7  
{ RJs G]`  
siteInfoBean = bean; `"=L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); aU8Ti8A>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s1vYZ  
if(tmpFile.exists ()) NG W{Z~l  
{ "JLhOTPaHf  
bFirst = false; |VR5Q(d  
read_nPos(); E?h2e~ ,]  
} GGQ(|?w  
else 'W2$wN+P  
{ TNT"2FoBd  
nStartPos = new long[bean.getNSplitter()]; GKx,6E#JM  
nEndPos = new long[bean.getNSplitter()]; @P5@ &G  
} Ft8h=  
f5qHBQ  
D& 6Qk&>  
I 3,e)Z  
} CU^3L|f2N  
@C [|'[xQ  
,~?A. 5  
public void run() iK:qPrk-  
{ {,C8}8 a W  
//获得文件长度 % ih7Jt  
//分割文件 #`)-$vUv^f  
//实例FileSplitterFetch ^8*SCM_A  
//启动FileSplitterFetch线程 s!fY^3  
//等待子线程返回 /z?7ic0  
try{ JEF7hJz~  
if(bFirst) Qg$Nj=Cw  
{ yy.:0:ema  
nFileLength = getFileSize(); 4bi\$   
if(nFileLength == -1) } 9s  
{  glX2L ~  
System.err.println("File Length is not known!"); ;Y&?ixx  
} XaS_3d  
else if(nFileLength == -2) ^PR,TR.  
{ @ZPTf>J}  
System.err.println("File is not access!"); 18tQWI$  
} A;`U{7IST  
else JG4*B|3  
{ 8+cpNX  
for(int i=0;i<nStartPos.length;i++) ` +UMZc  
{ -2ij;pkIW$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (BQ3M-  
} s /q5o@b{  
for(int i=0;i<nEndPos.length-1;i++) TdIFZ[<7  
{ v oS"X  
nEndPos = nStartPos[i+1]; GJ_)Cl+5E  
} ~@?-|xLqQ  
nEndPos[nEndPos.length-1] = nFileLength; n)!_HNc9  
} mXM>6>;y  
} >MY.Fr#.m  
17]31  
qFChZ+3>  
//启动子线程 % j{pz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; EI+/%.,  
for(int i=0;i<nStartPos.length;i++) zd4y5/aoS  
{ Z?aR9OTP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w*P4_= :%Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yBh"qnOT  
nStartPos,nEndPos,i); sq|@9GS0T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9<c4y4#y  
fileSplitterFetch.start(); 'J0s%m|j  
} Ngc+<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w$:)wyR-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =usDI<3r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NKhR%H  
nEndPos = " + nFileLength); #$B,8LFz,$  
// fileSplitterFetch[nPos.length-1].start(); yzR=:0J  
U`_vF~el~  
)&!@O$RS8(  
//等待子线程结束 E!l1a5qB  
//int count = 0; 5GL+j%7  
//是否结束while循环 G-?9;w'@  
boolean breakWhile = false; !:[n3.vm   
NRF%Qd8I/2  
wggHUr(g,  
while(!bStop) ?s} E<Kr  
{ <@!kR$Rd  
write_nPos(); `0sk2fn  
Utility.sleep(500); nJH%pBc  
breakWhile = true; (jFE{M$-  
% peb{i  
m1i$>9,  
for(int i=0;i<nStartPos.length;i++) c} ET#2,  
{ cNc _ n<M  
if(!fileSplitterFetch.bDownOver) )K3 vzX  
{ tg3JU\  
breakWhile = false; IqKXFORiNI  
break; pv SFp-:_  
} o`! :Q!+  
} Fe< t@W  
if(breakWhile) JlGD.!`  
break; Q&Ahr  
rL3Vogw'e  
(gB=!1/|G  
//count++; bx e97]  
//if(count>4) lD#1"$Coz  
// siteStop(); i3j jPN!  
} n(S-F g  
d'fpaLV  
Q9zpX{JT  
System.err.println("文件下载结束!"); %,D%Q~  
} {5-{f=Rk  
catch(Exception e){e.printStackTrace ();} S*s9 ?  
} tah%jRfT&  
=Fl4tY#X  
wh+ibH}@!  
//获得文件长度 6ng g*kE<  
public long getFileSize() j&GKpt  
{ K): sq{  
int nFileLength = -1; :#jv4N  
try{ .cog9H'  
URL url = new URL(siteInfoBean.getSSiteURL()); &bu`\|V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `.WKU"To  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9GaER+d|  
]%hI-  
vUeel%  
int responseCode=httpConnection.getResponseCode(); Bd[Gsns  
if(responseCode>=400) gg_(%.>  
{ x[6Bc  
processErrorCode(responseCode); v"_#.!V  
return -2; //-2 represent access is error 4FdH:os  
} |JQKxvjT  
RE$-{i  
f L?~1i =  
String sHeader; m uY^Fx  
L$Z_j()2  
nz l,y,  
for(int i=1;;i++) p:%E>K1<  
{ ^ ?9 ~R"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! NE q|Y  
//Utility.log(in.readLine()); @$G K<jl  
sHeader=httpConnection.getHeaderFieldKey(i); imQNfNm  
if(sHeader!=null) '#6DI"vJ  
{ z# B) b5  
if(sHeader.equals("Content-Length")) 1bs95Fh9Q  
{ iO`f{?b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); bYH_U4b  
break; }C#d;JC  
} k"zHrn"$  
} YaNVpLA  
else x#j_}L!V;  
break; O v6=|]cW  
} Big-)7?  
} M!'tD!NWc  
catch(IOException e){e.printStackTrace ();} pl&GFf o  
catch(Exception e){e.printStackTrace ();} kk#d-! $[  
,1L^#?Q~  
/VkJ+%}+j  
Utility.log(nFileLength); o*'3N/D~  
WU_Q 7%+QS  
8+F2 !IM  
return nFileLength; 5]JXXdt  
} DLZ63'  
5w3'yA<vE  
omP 7|  
//保存下载信息(文件指针位置) 8/v_uEG  
private void write_nPos() VZR6oia  
{ :+$_(* Z  
try{ 4R6 .GO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i.&16AY  
output.writeInt(nStartPos.length); j)Gr@F>  
for(int i=0;i<nStartPos.length;i++) ccAEN  
{ )\^OI:E  
// output.writeLong(nPos); 7lu;lAAP  
output.writeLong(fileSplitterFetch.nStartPos); gO36tc:ce  
output.writeLong(fileSplitterFetch.nEndPos); 7\lc aC@  
} :;QLoZh^  
output.close(); [MG:Ym).2`  
} m`aUz}Y>c  
catch(IOException e){e.printStackTrace ();} JG4I-\+H  
catch(Exception e){e.printStackTrace ();} l[Oxf|  
} X3vrD{uNU  
Uz_{jAhW]  
L^}kwu#  
//读取保存的下载信息(文件指针位置) QKxu vW  
private void read_nPos() #a| 5A:g%  
{ 9AaixI  
try{ **"sru;@=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $MHc4FE[  
int nCount = input.readInt(); ww*F}}(  
nStartPos = new long[nCount]; M:N> {_1&  
nEndPos = new long[nCount]; UPsh Y  
for(int i=0;i<nStartPos.length;i++) u#QQCgrs  
{ O^GTPYW  
nStartPos = input.readLong(); X.Kxio $o  
nEndPos = input.readLong(); w*0T"hK  
} h/ic-iH(>  
input.close(); %' Fc%3  
} 1Cthi[ B  
catch(IOException e){e.printStackTrace ();} Gf>T{Q`,is  
catch(Exception e){e.printStackTrace ();} ;x"B ):?\  
} 1L ow[i  
~QXNOtVsN  
HU'}c*d]  
private void processErrorCode(int nErrorCode) XUWza=BR"  
{ #0tM88Wi  
System.err.println("Error Code : " + nErrorCode); MwZ`NH|n3"  
} nr}H;wB  
aqlYB7  
mz''-1YY$  
//停止文件下载 ?*g]27f11  
public void siteStop() 2C>PxA6l  
{ $xqphhBg  
bStop = true; F-t-d1w6  
for(int i=0;i<nStartPos.length;i++) ~ lS3+H  
fileSplitterFetch.splitterStop(); Z(FAQ\7  
>r3Wo%F'  
3ul  
} {^v50d  
} (fl2?d5+C  
//负责部分文件的抓取 rmhB!Lo  
**FileSplitterFetch.java Sc(2c.HO*  
*/ u:k#1Nn!  
package NetFox; 59LIK&w  
iJAW| dw}  
h$3Y,-4  
import java.io.*; @/~41\=e  
import java.net.*; qe0@tKim  
,}<v:!  
/#HY-b  
public class FileSplitterFetch extends Thread { 2w%1\TcB$  
HV>Wf"1  
&p*N8S8  
String sURL; //File URL MTQdyTDHl  
long nStartPos; //File Snippet Start Position p 7sYgz  
long nEndPos; //File Snippet End Position r\yj$Gu>(  
int nThreadID; //Thread's ID (jXgJ" m  
boolean bDownOver = false; //Downing is over ?tOzhrv  
boolean bStop = false; //Stop identical &*0V!+#6  
FileAccessI fileAccessI = null; //File Access interface WWY9U  
_ ge3R3  
phTZUm i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rv^j&X+EH  
{ *fx<>aK  
this.sURL = sURL; dW91nTQ:  
this.nStartPos = nStart; [KJm&\evp  
this.nEndPos = nEnd; JprZ6 >  
nThreadID = id; jtA Yp3M-$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 St?vd+(>  
} h/X),aK3  
aJ2-BRn  
}[1I_)  
public void run() Z0x N9S  
{ 7oUYRqd  
while(nStartPos < nEndPos && !bStop) *l|CrUa  
{ BPW:W }  
Ts^IA67&<  
H|Eu,eq-E  
try{ _3`{wzMA  
URL url = new URL(sURL); b2z~C{l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ";Lpf]<  
httpConnection.setRequestProperty("User-Agent","NetFox"); <yeG0`}t  
String sProperty = "bytes="+nStartPos+"-"; :R _(+EK1  
httpConnection.setRequestProperty("RANGE",sProperty); pNDL:vMWP  
Utility.log(sProperty); 3ZC[H'|  
7;Wj ^#  
Hkpn/,D5  
InputStream input = httpConnection.getInputStream(); U,/>p=s  
//logResponseHead(httpConnection); q4VOK 'N  
LJT+tb?K  
' e-FJ')|  
byte[] b = new byte[1024]; QkA79%;j  
int nRead; o zv><e#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Lq yY??\@  
{ XI pXP,Yy  
nStartPos += fileAccessI.write(b,0,nRead); ;i1H {hB  
//if(nThreadID == 1) iNha<iS+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <^M`U>   
} 1Azigd0%  
xl s_g/Q  
R# gip  
Utility.log("Thread " + nThreadID + " is over!"); nF05p2Mh  
bDownOver = true; {>Zc#U'  
//nPos = fileAccessI.write (b,0,nRead);  IF uz'  
} Z$T1nm%lo:  
catch(Exception e){e.printStackTrace ();} ;]|Z8#s  
} RTSg=    
} G<$UcXg  
JGJQ5zt  
@>JO &,od  
//打印回应的头信息 H!,#Z7s  
public void logResponseHead(HttpURLConnection con) m"`&FA  
{ <s  $~h  
for(int i=1;;i++) d!8`}L:=M  
{ ]XU?Wg  
String header=con.getHeaderFieldKey(i); Cdc6<8  
if(header!=null) 1}9@aKM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D guAeK  
Utility.log(header+" : "+con.getHeaderField(header)); eEXer>Rm   
else Q[S""P.Z|  
break; 9"oc.ue.2D  
} Wl}d6ZTm  
} ~c+0SuJ  
 &+u$96  
x# 0(CcKK  
public void splitterStop() GV* B$  
{ 59IxY ?  
bStop = true; J'|qFS  
} 5|";L&`  
EG2NE,,r  
eQNo'cz  
} rm<(6zY  
g6+}'MN:5  
GRS[r@W[1  
/* Zn|vT&:Hg  
**FileAccess.java <T{PuS1<o  
*//文件访问(定位,写) "^yTH/m  
package NetFox; g*TAaUs|n  
import java.io.*; 6;k#|-GU&  
$s$z"<  
* 3WK`9q  
public class FileAccessI implements Serializable{ \5cAOBja  
._Wm%'uX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z25^+)uf*U  
RandomAccessFile oSavedFile; pS;jrq I#  
long nPos; j-ZKEA{:1  
I HgYgn  
5Jlz$]f  
public FileAccessI() throws IOException tUH#%  
{ ~Qeyh^wo  
this("",0); kT t;3Ia  
} q3#07o_dV  
ORD@+ {  
F_$eu-y  
public FileAccessI(String sName,long nPos) throws IOException XOAZ  
{ ]^uO3!+  
oSavedFile = new RandomAccessFile(sName,"rw"); LSS3(l[,:  
this.nPos = nPos; R&PQU/t)  
oSavedFile.seek(nPos); 4Bsx[~ u&  
} 8xW_N"P.>  
Tl6%z9rY@  
FhVi|V a  
public synchronized int write(byte[] b,int nStart,int nLen) )<nr;n  
{ !c(B c^  
int n = -1; 3V>2N)3`A  
try{ 1-!u=]JDE  
oSavedFile.write(b,nStart,nLen); :''^a  
n = nLen; ~m2tWi@  
} "9:1>Gr{G  
catch(IOException e) # XE`8$  
{ E=+v1\t)]  
e.printStackTrace (); a=>PGriL  
} Ew~piuj  
3iMh)YH5b  
sg RY`U.C  
return n; ZnVi.s ~1V  
} pj4M|'F7  
5B)Z@-x2  
I@76ABu^  
} zc%#7"FM  
,#@B3~giC  
: z*OAl"  
/* 3R>U^ Y  
**SiteInfoBean.java }D-h=,];  
*/ pHSq,XP-  
package NetFox; ()i8 Qepo}  
R/&Bze  
,{!~rSq-l  
public class SiteInfoBean { Z<T%:F  
Ke@zS9  
Ju4={^#  
private String sSiteURL; //Site's URL Lwm2:_\_b  
private String sFilePath; //Saved File's Path cPZD#";f  
private String sFileName; //Saved File's Name Rrm k\7/  
private int nSplitter; //Count of Splited Downloading File :yO.Te F  
u^&2T(xG i  
P]hS0,sE<(  
public SiteInfoBean() h)2W}p{a4=  
{//nSplitter的缺省值为5 dP}=cZ~  
//default value of nSplitter is 5 KAH9?zI)M  
this("","","",5); 2A'!kd$2  
} U`Bw2Vdk]S  
oju)8H1o#  
Yz4)Q1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MM8@0t'E  
{ R%B"Gtl)  
sSiteURL= sURL; A82Bn|J  
sFilePath = sPath; hqOy*!8'@  
sFileName = sName; w],+lN;  
this.nSplitter = nSpiltter; Y?G\@ 6  
$J}d6%   
@y?<Kv}s  
}  &0! f_  
4Rj;lAlwB  
s}yJkQb  
public String getSSiteURL() #~<cp)!3  
{ %6rMS}  
return sSiteURL; ,[fn? s r  
} Nb;xJSlox  
l,5<g-r V  
l+g\xUP  
public void setSSiteURL(String value) ?`T< sk8c  
{ :KY920/,  
sSiteURL = value; )*< =:  
} $h"Ht2/ J  
CGmObN8~'F  
U,Py+c6  
public String getSFilePath() Teq1VK3Hr  
{ CFdR4vuEI  
return sFilePath; a![x^@nF  
} =xz Dpn>f  
z/09~Hc  
DL0jA/f  
public void setSFilePath(String value) )9LlM2+y  
{ hwgLJY?  
sFilePath = value; ~a@O1MB  
} 1 ?X(q  
S ykblP37  
6;"^Id  
public String getSFileName() ;\~{79c  
{ TTB1}j+V6  
return sFileName; 8/lv,m#  
} "]*16t%Z%x  
2E]SKpJ  
EAiE@r>4  
public void setSFileName(String value) sbnNk(XINQ  
{ }2dz];bR  
sFileName = value; Bc1[^{`bq^  
} bMWL^*I  
Gd^K,3:. T  
LvP{"K;   
public int getNSplitter() |KSd@   
{ Fh  t$7V  
return nSplitter; Z#H] yG  
} q:2Vw`g'  
9v[cy`\  
 cTpmklq  
public void setNSplitter(int nCount) /B>p.%M[&  
{ 8$Igo$U-  
nSplitter = nCount; FCO5SX#-g  
} 7+^9"k7  
} F<SCW+>z2a  
ma4Pmk  
[Y@?l]&  
/* +%yVW f  
**Utility.java !YUMAp/  
*/ ] Tc!=SV  
package NetFox; H"v3?g`S%  
/>1Ndj  
7)Zk:53]  
public class Utility { 43_;Z| T  
q:Lw!'Z h  
N^i<A2'6S;  
public Utility() }~gBnq_DDU  
{ S0X %IG  
s"1:#.u  
"r@f&Ssxb  
} G55-{y9Q  
 B _;W!  
//线程睡眠 B I9~% dm  
public static void sleep(int nSecond) 77y_?di^I  
{ SCbN(OBN!  
try{ z=ItKoM*<  
Thread.sleep(nSecond); MF+J3)  
} ~lB im$o  
catch(Exception e) Yt^<^l77D  
{ ym*,X@Qg^  
e.printStackTrace (); (#zSVtZ  
} Rx';P/F0C  
} R7'a/  
Vp3r  
//日志 |Ld/{&Qr  
public static void log(String sMsg) vfb~S~|U6g  
{ B(}u:[ b^S  
System.err.println(sMsg); i1ph{;C  
} &V. ps1  
F_8 < tA6  
.}KY*y  
public static void log(int sMsg) 8J60+2Wa  
{ #ma#oWqF}  
System.err.println(sMsg); +h!OdWD9  
} jVh I`F{n  
} {/f\lS.5g  
FmU>q)  
8u+FWbOl]  
/* B o@B9/ABv  
**TestMethod.java y\}39Z(]  
*/ REd"}zDI  
package NetFox; ?QzA;8H  
Z#8O)GK  
Y yI4T/0s_  
public class TestMethod { b"`Vn,  
:mwNkT2et  
qw]:oh&G  
public TestMethod() lWYZAF>?Ym  
{ ///xx/weblogic60b2_win.exe &[]0yNG  
try{ Fi8'3/q-^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `Qzga}`"]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3Q-i%7l  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hdFIriE3  
fileFetch.start(); 6>I{Ik@>  
} ] i;xeo,  
catch(Exception e){e.printStackTrace ();} .(!> *ka|  
U p1&(  
y  @&Cn  
} rh;@|/<l  
u&Ze$z  
fX)C8J^=G  
public static void main(String[] args) [K2\e N~g  
{ k0;ND  
new TestMethod(); } Qjp,(ye  
} 76i)m!  
} Nr.maucny  
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