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http断点续传简单实现(java)

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/* -1]8f  
**SiteFileFetch.java b./MVz  
*/ $HFimU,V=0  
package NetFox; [CG*o>n&|  
import java.io.*; Z$Vd8U;  
import java.net.*; Uc]sWcR  
9Cq"Szs  
lXu6=r  
public class SiteFileFetch extends Thread { tS3{y*yi  
7[YulC-pH  
Xm~N Bt  
SiteInfoBean siteInfoBean = null; //文件信息Bean U^9#uK6GM  
long[] nStartPos; //开始位置 H>|*D~RdT  
long[] nEndPos; //结束位置 RhSoD.Da  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4cJka~  
long nFileLength; //文件长度 d0G d5%  
boolean bFirst = true; //是否第一次取文件 bA(-7l?  
boolean bStop = false; //停止标志 ~x g#6%<=  
File tmpFile; //文件下载的临时信息 je5GZFQw  
DataOutputStream output; //输出到文件的输出流 n4DKLAl  
7;Vqr$9)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) C{FE*@U.  
public SiteFileFetch(SiteInfoBean bean) throws IOException _K<Z  
{ Og9:MFI  
siteInfoBean = bean; "Rr650w[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nb #)$l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W=!di3IA  
if(tmpFile.exists ()) K&TO8   
{ !)LVZfQ0  
bFirst = false; 9wpV} .(  
read_nPos(); ?m:,hI  
} t4r%EP|Zt  
else 7uxUqM  
{ |HA1.Y=  
nStartPos = new long[bean.getNSplitter()]; 05Y4=7,!  
nEndPos = new long[bean.getNSplitter()]; ,O 1/|Y  
} K7}]pk,AG  
xA]}/*  
H{VJ S Jc{  
0E/,l``p  
} j5bp)U  
[^ eQGv[S  
d9.~W5^fC  
public void run() 2rG$.cGN"  
{ ja+PVf  
//获得文件长度 xw~3x*{  
//分割文件 N 2$uw@s  
//实例FileSplitterFetch @$!rgLyL[  
//启动FileSplitterFetch线程 zL/r V<  
//等待子线程返回 UA(&_-C\  
try{ 3D2i32Y@!  
if(bFirst) P|QM0GI  
{ :L5k#E "u  
nFileLength = getFileSize(); ((mR' A|`  
if(nFileLength == -1) Ula h!s  
{ bSj-xxB]e  
System.err.println("File Length is not known!"); _tR?WmNH=  
} X}_Gk5q*  
else if(nFileLength == -2) n+SHkrW  
{ Fu[<zA^  
System.err.println("File is not access!"); /SD(g@G,  
} 9|qzFmE#  
else >h{)7Hv  
{ :'X:cL  
for(int i=0;i<nStartPos.length;i++) b&2 N7%  
{ cN%@ nW0i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0rCQz3gh1  
} %abc -q  
for(int i=0;i<nEndPos.length-1;i++) \"1%>O*  
{ hkl9 EVO)  
nEndPos = nStartPos[i+1]; /|>?!;   
} DAf0bh"  
nEndPos[nEndPos.length-1] = nFileLength; =+w!fy  
} PpezWo)9  
} &.[I}KH|B  
WYd9p;k  
7[ZoUWx  
//启动子线程 t_w2J=2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k c /"  
for(int i=0;i<nStartPos.length;i++) V)A7q9Bum  
{ i$lp8Y2ih  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U88gJ[$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K@tELYb  
nStartPos,nEndPos,i); 9xaieR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !p!^[/9"c  
fileSplitterFetch.start(); `wKd##v'@  
} ti!kJ"q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $V,ZH* g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W#kd[Wi  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~- eB  
nEndPos = " + nFileLength); oaG;i51!  
// fileSplitterFetch[nPos.length-1].start(); L [&|<<c  
yb!/DaCd  
B["jndyr  
//等待子线程结束 epgAfx-_OH  
//int count = 0; *yYeqm  
//是否结束while循环 Vp&"[rC_z  
boolean breakWhile = false; [@Mo3]#\  
g[ N3jt@  
eI98J"h%?  
while(!bStop) B*:W`}G]_c  
{ ( 'Ha$O72  
write_nPos(); iLQ;`/j  
Utility.sleep(500); zMh`Uqid  
breakWhile = true; NZz^*Ela  
z}F^HQ 1  
)M* Sg?L  
for(int i=0;i<nStartPos.length;i++) o:`^1  
{ B]I*ymc#  
if(!fileSplitterFetch.bDownOver) Mavid kS  
{ >Se-5QtLcf  
breakWhile = false; ;gLOd5*0  
break; wRg[Mu,Q5  
} /9o6R:B  
} d2fiPI7lg  
if(breakWhile) .|@2Uf  
break; <Ok7 -:OxA  
jT`u!CwdT  
Tnas$=J  
//count++; NfZC}  
//if(count>4) ~( :$c3\  
// siteStop(); 4kR;K !@k  
} Zt}b}Bz  
1n[wk'}qf4  
,(f({l[J}  
System.err.println("文件下载结束!"); G 2uM6  
} f8-~&N/_R  
catch(Exception e){e.printStackTrace ();} XB a^ A  
} {vk%&{D0)  
:s1.TQ;Y(  
)5fly%-r)  
//获得文件长度 "n{JH9sA:  
public long getFileSize() y5XFJj  
{ U+aiH U9  
int nFileLength = -1; Jl|^^?  
try{ _ Td#C1g3  
URL url = new URL(siteInfoBean.getSSiteURL()); c *i,z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T8^l}Y B  
httpConnection.setRequestProperty("User-Agent","NetFox"); js!C`]1  
}?MbU6"  
HY;kV6g{P  
int responseCode=httpConnection.getResponseCode(); FGeKhA 8jT  
if(responseCode>=400) ru|*xNXKgC  
{ ;zd.KaS  
processErrorCode(responseCode); zjSHa'9*  
return -2; //-2 represent access is error UzW]kY[A<  
} ]W5p\(1g  
!_oR/)  
*;Cpz[N  
String sHeader; ?!.J 0q  
_C19eW'  
uo ;m  
for(int i=1;;i++)  x$FcF8  
{ nWh f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QZ[S, c^  
//Utility.log(in.readLine()); `fl$ o6S/  
sHeader=httpConnection.getHeaderFieldKey(i); X~/-,oV=A  
if(sHeader!=null) 9W-1P}e,  
{ /%)(Uz  
if(sHeader.equals("Content-Length")) G<]@nP{P  
{ Sggl*V/q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;P$ _:-C  
break; _xBhMu2f  
} [+="I &  
} C0 /G1\  
else ux,eY  
break; JIqg[Mao  
} <9T,J"y  
} %a:T9v  
catch(IOException e){e.printStackTrace ();} 87m`K Str7  
catch(Exception e){e.printStackTrace ();} JY,oXA6O  
qE VpkvEq  
w,_LC)9  
Utility.log(nFileLength); :_`Yrx5  
sbFIKq]  
`cIeqp  
return nFileLength; "z= ~7g  
} *SlWA)9 Y  
B\l0kiNT  
^(@]5$^Z  
//保存下载信息(文件指针位置) MXjN ./  
private void write_nPos() i6y=3k  
{ A PrrUo  
try{ l.Z+.<@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); qT&zg@m  
output.writeInt(nStartPos.length); C~'.3Q6  
for(int i=0;i<nStartPos.length;i++) P"Z1K5>2L  
{ 8dJ+Ei~M  
// output.writeLong(nPos); c?aOX/C'  
output.writeLong(fileSplitterFetch.nStartPos); f9+6gY  
output.writeLong(fileSplitterFetch.nEndPos); f zL5C2d  
} r=p^~tuyxr  
output.close(); sP~xe(  
} NRspi_&4J  
catch(IOException e){e.printStackTrace ();} /zr)9LQY0  
catch(Exception e){e.printStackTrace ();} +}:2DXy@  
} I|;C} lfp  
JNP6qM  
@X9T"  
//读取保存的下载信息(文件指针位置) DJqJ6z:'  
private void read_nPos() gA3f@7}d  
{ =}Q|#C  
try{ NS;L FeGD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +8"P*z,  
int nCount = input.readInt(); ]86*k %A  
nStartPos = new long[nCount]; U!E}(9 tb  
nEndPos = new long[nCount]; ][YuJUK8  
for(int i=0;i<nStartPos.length;i++) 2OqEyXh  
{ 7) a f  
nStartPos = input.readLong(); WGyPyG#Fl  
nEndPos = input.readLong(); Lf%}\0:  
} -8d z`o}  
input.close(); pd.unEWwF  
} ZCMH?>  
catch(IOException e){e.printStackTrace ();} 6z:/ma^  
catch(Exception e){e.printStackTrace ();} P8;1,?ou  
} `)MKCw$e  
O`aNNy  
8U7d d[  
private void processErrorCode(int nErrorCode) nwqA\  
{ bf2r8   
System.err.println("Error Code : " + nErrorCode); u g;~dhe~  
} {>XoE %  
1TF S2R n  
Z`zLrXPD)  
//停止文件下载 <:mK&qu f  
public void siteStop() |ZXz&Xor  
{ '$J M2 u  
bStop = true; N[v=;&  
for(int i=0;i<nStartPos.length;i++) mgM"u94-]  
fileSplitterFetch.splitterStop(); 1KR4Wq@  
:_=YH+bZ  
2iO{*cB  
} :uC9 #H"b  
} "CREls,  
//负责部分文件的抓取 VWzuV&;P  
**FileSplitterFetch.java Sq:J'%/z  
*/ */K]sQZa  
package NetFox; pF8+< T3y  
Z)@[N 6\?  
Y]uVA`%"b  
import java.io.*; Z+[W@5q  
import java.net.*; s<aG  
W"CG&.  
f&RjvVP?s  
public class FileSplitterFetch extends Thread { ,e'"SVQc  
W/~q%\M {  
XD_!5+\H1  
String sURL; //File URL  acQHqR  
long nStartPos; //File Snippet Start Position T7O)  
long nEndPos; //File Snippet End Position A4b+:MQ*OX  
int nThreadID; //Thread's ID Dk8@x8  
boolean bDownOver = false; //Downing is over jpoNTl'  
boolean bStop = false; //Stop identical 6K=}n] n  
FileAccessI fileAccessI = null; //File Access interface #uCfXJ-  
>g@@ yR,  
\ Z5160  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,q{~lf -  
{ 6E^9>  
this.sURL = sURL; j#Lj<jX!xR  
this.nStartPos = nStart; { 9\/aXPS  
this.nEndPos = nEnd; =En1?3?  
nThreadID = id; wrK@1F9!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JeA_mtSQ|  
} 2 &_>2"=<@  
raU_Z[  
8LXK3D}?3  
public void run() I9`ZK2S  
{ 9jNh%raG|  
while(nStartPos < nEndPos && !bStop) sb?!U"v.'  
{ ^),t=!;p  
pr,1pqiAf  
2k&Voa  
try{ :C,}DyZy  
URL url = new URL(sURL); r)Ml-r =  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /WK1(B:  
httpConnection.setRequestProperty("User-Agent","NetFox"); )a `kL,  
String sProperty = "bytes="+nStartPos+"-"; %[azMlp<  
httpConnection.setRequestProperty("RANGE",sProperty); KDA2 H>  
Utility.log(sProperty); *Ue#Sade  
NGO?K?  
bMv[.Z@v(  
InputStream input = httpConnection.getInputStream(); Re'3bs:+  
//logResponseHead(httpConnection); S1C#5=  
Z$6B}cz<  
:()K2<E  
byte[] b = new byte[1024]; !:tr\L {  
int nRead; U:[CcN/~3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %afF%y  
{ 7-\wr^ll3  
nStartPos += fileAccessI.write(b,0,nRead); IH5^M74b  
//if(nThreadID == 1) LCq1F(q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =@X?$>'  
} uX&h~qE/  
h,b_8g{!  
5Kk}sxol  
Utility.log("Thread " + nThreadID + " is over!"); (|3?wX'2U  
bDownOver = true; F5M|QX@-  
//nPos = fileAccessI.write (b,0,nRead); Ub4)x  
} r/HG{XH`  
catch(Exception e){e.printStackTrace ();} %/hokyx  
} lEb H4 g  
} J{L d)Q,^  
N.SV*G @  
C+mPl+}w  
//打印回应的头信息 G(t&(t`[  
public void logResponseHead(HttpURLConnection con) |It{L0=U  
{ .G"T;w 6d  
for(int i=1;;i++) `R lWhdE  
{ -B-HZ_  
String header=con.getHeaderFieldKey(i); 0}T 56aD=!  
if(header!=null) uv{*f)j/d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); s!Iinc^p  
Utility.log(header+" : "+con.getHeaderField(header)); dwiLu&]u  
else 9C5F#(uY  
break; _p9 _Pg8  
} sAZL,w  
} 0TiDQ4}i[  
C/ ]Bx  
JxM32?Rm*w  
public void splitterStop() RtDTcaW/  
{ (dV7N  
bStop = true; 0$U\H>r  
} A v;NQt8ut  
!9j6l 0  
y'JJ#7O=  
} !!Yf>0u#  
4e?cW&  
i=fhK~Jd  
/* G,(Xz"`,  
**FileAccess.java ?3v-ppw%  
*//文件访问(定位,写) "ZmxHMf  
package NetFox; x$S~>H<a  
import java.io.*; M[_Ptqjb  
yC!>7@m  
yV&]i-ey  
public class FileAccessI implements Serializable{ 4(,X. GVY/  
a^VI)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 bPl'?3  
RandomAccessFile oSavedFile; XqcNFSo)  
long nPos; u=(.}  
SF[Z]|0gs  
90H/Txq  
public FileAccessI() throws IOException '6T  *b  
{ $u)#-X;x  
this("",0); 'sk M$jr  
} T%YN(f  
5?E;Yy A  
oL9ELtb ]s  
public FileAccessI(String sName,long nPos) throws IOException \PmM856=ms  
{ c&`]O\D-c  
oSavedFile = new RandomAccessFile(sName,"rw"); t Q>/1  
this.nPos = nPos; gM6o~ E  
oSavedFile.seek(nPos); mt-t8~A  
} LM!@LQAMY  
7~H$p X  
,JJ1sf2A  
public synchronized int write(byte[] b,int nStart,int nLen) 3BB/u%N}  
{ ^j?"0|  
int n = -1; F}5skD=  
try{ 2W63/kRbU  
oSavedFile.write(b,nStart,nLen); o;pJjC]  
n = nLen; ORfMp'uP=  
} ~jC$C2A0  
catch(IOException e) }jNVR#D:  
{ *uF Iw}C/  
e.printStackTrace (); . B6mvb\  
} ^3Z~RK\}  
c>#3{}X|x%  
_wZr`E)  
return n; <mQ9YO#  
} ' KNg;  
s 8lfW6  
$rQi$w/  
} _+&/P&  
>i2WYT  
v=YI%{tx)  
/* 7t6TB*H  
**SiteInfoBean.java 3+I"Dm,  
*/ I"WmDC`1  
package NetFox; NF_[q(k'  
vVbS 4_  
0}$R4<"{Y>  
public class SiteInfoBean { j|y"Lcq  
FF30 VlJ  
<T$rvS  
private String sSiteURL; //Site's URL f5#VU7=1F2  
private String sFilePath; //Saved File's Path ER<Z!*2  
private String sFileName; //Saved File's Name stOD5yi  
private int nSplitter; //Count of Splited Downloading File F^7qr  
q&: t$tSS  
C)ebZ3  
public SiteInfoBean() XC[bEp$  
{//nSplitter的缺省值为5 D(">bR)1  
//default value of nSplitter is 5 G2FD'Sf  
this("","","",5); ;QQ/bM&I  
} EA<x$O  
bHmn0fZ9  
OJ)XJL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) cb_nlG!  
{ qmbhx9V   
sSiteURL= sURL; (.9H1aO46|  
sFilePath = sPath; TiSV`V q  
sFileName = sName; zR }vw{  
this.nSplitter = nSpiltter; Y r 1k\q  
bU_P@GKB  
V(6Ql j7  
} A55F* d  
^e1mK4`  
}j|YX&`p  
public String getSSiteURL() Zex`n:Wl?j  
{ u!I=|1s  
return sSiteURL; jxDA+7  
} wRQMuFGY  
ZgL]ex  
=~{W;VZt'  
public void setSSiteURL(String value) b@)nB  
{ -! :h]  
sSiteURL = value; MF4B 2d  
} :.W</o~\s  
jg=}l1M"  
}wV/)Oy[  
public String getSFilePath() fBct%M 3  
{ hE}y/A[  
return sFilePath; "$N 4S9U  
} P<IZ%eS3B  
EL1*@  
0tP{K  
public void setSFilePath(String value) j9$kaEf  
{ 420yaw/":  
sFilePath = value; ^h"F\vIpV  
} ^uWj#  
{#}?-X  
/7yd&6`I  
public String getSFileName() 1Et{lrgh f  
{ ]gB:ht  
return sFileName; YC d  
} ? ]hS^&  
km9@*@)  
NIxtT>[+3  
public void setSFileName(String value) 8Z(\iZ5Rgj  
{ Ky6 d{|H  
sFileName = value; iGsD!2  
} qre(3,VE5  
Yjp*T:6  
"!_,N@\t  
public int getNSplitter() t{Gc,S!]5  
{ 6gJc?+  
return nSplitter; m[6c{$A/w  
} </)QCl'd  
PW GN UNc  
Z6_E/S  
public void setNSplitter(int nCount) cg'z:_l  
{ +"Mlj$O  
nSplitter = nCount; be:=-B7!  
} 2+qU9[kd|  
} lxXIu8  
glgXSOj  
cK~VNzsz  
/* 5WU ? Km  
**Utility.java f&L8<AS Fo  
*/ IltU6=]"l  
package NetFox; x$/: %"E  
_cD-E.E%  
\4roM1&[  
public class Utility { LQ.0"6oj  
/^9yncG;>  
R:t  
public Utility() ~ U`|+ 5  
{ 73>Hzpv0  
D|E,9|=v  
&xMQ  
} %][6TZ}  
"|W``&pM  
//线程睡眠 [gxH,=Pb  
public static void sleep(int nSecond) EK<ly"S.  
{ ` beU2N  
try{ |FxTP&8~  
Thread.sleep(nSecond); oiNt'HQ2/  
} [-'LJG Wb<  
catch(Exception e) f,QBj{M,  
{ YKG}4{T  
e.printStackTrace (); 40R7@Vaf  
} V[baGNe  
} V { yk  
GMQKR,6VM  
//日志 I18<brZJ  
public static void log(String sMsg) UZb!tO2  
{ d+158qQOh]  
System.err.println(sMsg); l F*x\AT  
} El4SL'E@  
_&|<(m&."  
U((mOm6  
public static void log(int sMsg) 8$C?j\J|*  
{ fs6 % M]u  
System.err.println(sMsg); ;P!x/Ct  
} NG?-dkD  
} ooIA#u  
W:*  {7qJ  
l"app]uVZ  
/* !J-oGs\ u  
**TestMethod.java qjI.Sr70  
*/ ]q CCCI`  
package NetFox; uhO-0H  
]iE) 8X  
l~c# X3E  
public class TestMethod { ^b@&O-&s  
rw]7Lr_>  
{&d )O  
public TestMethod() ~fR-cXj"  
{ ///xx/weblogic60b2_win.exe a?P$8NLr  
try{ .U9A \$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p{S#>JTr  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); n06Jg+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [|{m/`8C  
fileFetch.start(); o=ULo &9  
} [[gfR'79{  
catch(Exception e){e.printStackTrace ();} #8;#)q_[u  
MMS#Ci=Lj  
.BjnV%l7Id  
} T }^2IJ]  
bc(b1u?  
I4%25=0?  
public static void main(String[] args) z)0%gd|  
{ z;+LU6V  
new TestMethod(); [y(AdZ0*  
} jhkNi`E7  
} )3A%Un#B  
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