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http断点续传简单实现(java)

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/* ~KHVY)@P  
**SiteFileFetch.java &wi e]  
*/ 9`wZz~hL"  
package NetFox; <nE>XAI_7  
import java.io.*; `q?8A3A  
import java.net.*; BZ:H`M`n  
-- PtZ]Z  
A$<.a'&T!  
public class SiteFileFetch extends Thread { @AG n{q  
X59: C3c  
0":ib0=  
SiteInfoBean siteInfoBean = null; //文件信息Bean T29Dt  
long[] nStartPos; //开始位置 YX=a#%vrl  
long[] nEndPos; //结束位置 kv3E4,<9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3_txg>P"  
long nFileLength; //文件长度 4~y(`\0?4  
boolean bFirst = true; //是否第一次取文件 tro7Di2Q  
boolean bStop = false; //停止标志 +Fuqch jq  
File tmpFile; //文件下载的临时信息 M%Ji0v38  
DataOutputStream output; //输出到文件的输出流 G]D+Sl4<7i  
[f)cL6AeF  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \!>3SKs(e  
public SiteFileFetch(SiteInfoBean bean) throws IOException *#E F sUw  
{ cU;iUf  
siteInfoBean = bean; }M1`di4e  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '3_]Gu-D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ge2q%  
if(tmpFile.exists ()) *-MM<|Qt  
{ O/,aJCe  
bFirst = false; Xa CX!Lr,  
read_nPos(); 61. Brp.eP  
} J!0DR4=Xi  
else !6BW@GeF]  
{ :ZTc7 }  
nStartPos = new long[bean.getNSplitter()]; :axRoRg  
nEndPos = new long[bean.getNSplitter()]; xGu r  
} PfreAEv,  
5i> $]*o  
b@rVo;  
}'""(,2  
} ,-i zEr  
D&/kCi=R  
k,'L}SK  
public void run() ' qWALu  
{ m5L-67[sB  
//获得文件长度 +g` 'J$  
//分割文件 BbW^Wxd3  
//实例FileSplitterFetch @{YS}&Q/  
//启动FileSplitterFetch线程 `4(e  
//等待子线程返回 #,7e NM"  
try{ g}f`,r9  
if(bFirst) C 'v+f=  
{ \Z]UA&v_  
nFileLength = getFileSize(); eAXc:222  
if(nFileLength == -1) v\!Be[ ?  
{ Y]NSN-t  
System.err.println("File Length is not known!"); \]&#%6|V  
} qDv93  
else if(nFileLength == -2) )>.&N[v  
{ sArhZ[H  
System.err.println("File is not access!"); Y<mej][  
} {XNREjhm  
else hJn%mdx~w|  
{ R<[qGt|L  
for(int i=0;i<nStartPos.length;i++) :A1{d?B  
{ Qy.w=80kf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "5-^l.CKH  
} V^JV4 `o  
for(int i=0;i<nEndPos.length-1;i++) N F2/B#q  
{ S'A>2>  
nEndPos = nStartPos[i+1]; (5R?#vj  
} +s,Qmmb7)  
nEndPos[nEndPos.length-1] = nFileLength; g6Q!8  
} 7N-w eX  
} Fz1_w$^  
f#?fxUH~  
h!&prYx  
//启动子线程 {U!8|(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; .z 6fv  
for(int i=0;i<nStartPos.length;i++) GqWB{$J;"  
{ 2W/?q!t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \]=7!RQ\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kB/D!1 "  
nStartPos,nEndPos,i); ,=tD8@a<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |p><'Q% *  
fileSplitterFetch.start(); dik:4;  
} 4"{ooy^Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2ggdWg7z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0o+6Q8q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", y9_K, g  
nEndPos = " + nFileLength); A3|Dz&@:  
// fileSplitterFetch[nPos.length-1].start(); D$bIo "  
F_;vO%}  
%%NlTE8*  
//等待子线程结束 -sw  .  
//int count = 0; /wP@2ADB  
//是否结束while循环 L%Ow#.[C2  
boolean breakWhile = false; W.dt:_  
Rn{iaM2Y<  
: y5<go8e  
while(!bStop) kBYNf =  
{ Hj:r[/  
write_nPos(); ;k7xMZs  
Utility.sleep(500); L1i eaKw  
breakWhile = true; lmfi  
I3,= 0z  
@r#v[I  
for(int i=0;i<nStartPos.length;i++) .Jt[(;  
{ ;\lW5ZX  
if(!fileSplitterFetch.bDownOver) lD"(MQV@0  
{ sYjpU  
breakWhile = false; O>^C4c!  
break; P5 K' p5}#  
} *tgnYa[l  
} | \'rP_I>  
if(breakWhile) W6"v)Jc>_  
break; 3 |hHR  
VwOW=4`6  
Svc|0Ad&  
//count++; SILQ  
//if(count>4) J]&y$?C  
// siteStop(); O9EKRt  
} I9:Cb)hbU]  
l~6?kFy9h  
o'W5|Gy  
System.err.println("文件下载结束!"); uoHNn7W  
} %,D<O,N  
catch(Exception e){e.printStackTrace ();} &jsVw)Ue  
} 7PANtCFb&  
4g : >[q  
5e$~)fL  
//获得文件长度 F8;dKyT?q  
public long getFileSize() dl ~%MWAVb  
{ ?gJy3@D  
int nFileLength = -1; 6`]$qSTS  
try{ A8pIs  
URL url = new URL(siteInfoBean.getSSiteURL()); D9FJ 1~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vgUb{D  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5m9*85Ib  
{@tv>!WW  
4?-.Z UT-1  
int responseCode=httpConnection.getResponseCode(); qEpi]=|  
if(responseCode>=400) iMs5zf <M  
{ hRty [  
processErrorCode(responseCode); WHjUR0NZ  
return -2; //-2 represent access is error R}lsnX<  
} SE),":aY  
w9, iq@  
2 !At2P2  
String sHeader; VUhbD  
SQqD:{#g"  
L{(QpgHZ  
for(int i=1;;i++) #B:hPZM1  
{ O2BW6Wc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 91$]Qg,lB  
//Utility.log(in.readLine()); %,Ap7X3:QT  
sHeader=httpConnection.getHeaderFieldKey(i); :{oZ~<  
if(sHeader!=null) ~-PjW#J%  
{ :cGt#d6  
if(sHeader.equals("Content-Length")) {K9/H qH  
{ _>9.v%5cs(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ti'}MC+0  
break; -u? S=h}  
} ,(;lIP  
} 3:8{"md@2  
else #Sa27$&.>  
break; OtGb<v<_H  
} ^NX"sM0g  
} .!G94b  
catch(IOException e){e.printStackTrace ();} xA9:*>+>  
catch(Exception e){e.printStackTrace ();}  >lBD<;T  
(HSgEs1d  
g_G6~-.9I  
Utility.log(nFileLength); e_V O3"  
%-<'QYYP  
#/I[Jqf  
return nFileLength; ]|sAK%/  
}  nv0]05.4  
t`+'r}=d  
h}]fn A  
//保存下载信息(文件指针位置) ~M\I;8ne  
private void write_nPos() J,zO2572u  
{ 4"xPr[=iG  
try{ cCa|YW^j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NcP.;u;`  
output.writeInt(nStartPos.length); {; .T7dL  
for(int i=0;i<nStartPos.length;i++) 2D:fJ~|-[  
{ S-YM%8A[  
// output.writeLong(nPos); |]aE<`D  
output.writeLong(fileSplitterFetch.nStartPos); KyzFnVH3)  
output.writeLong(fileSplitterFetch.nEndPos); ~_s{0g]B  
} HW7; {QMg  
output.close(); *X4PM\ck  
} !}4MN:r  
catch(IOException e){e.printStackTrace ();} ,:`ND28V7  
catch(Exception e){e.printStackTrace ();} JB>b`W9   
} A0fFv+RN3  
(sQr X{~  
I(9R~q  
//读取保存的下载信息(文件指针位置) "h|'}7p  
private void read_nPos() 9Ffp2NW`;  
{ _z54Ycr4H  
try{ C#H:-Q&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !vk|<P1  
int nCount = input.readInt(); >5j<4ShW  
nStartPos = new long[nCount]; zcva-ze:;  
nEndPos = new long[nCount]; '&sE=.  
for(int i=0;i<nStartPos.length;i++) (XXheC  
{ P9S2?Q  
nStartPos = input.readLong(); hAm`NJMSO  
nEndPos = input.readLong(); > ]8a3x  
} 9 JWa$iBH@  
input.close(); OQ,NOiNkap  
} ua OKv.%  
catch(IOException e){e.printStackTrace ();} NHl|x4Zpw  
catch(Exception e){e.printStackTrace ();} +n7?S~R$  
} ~u.T-0F  
UThB7(O,  
) /v6l  
private void processErrorCode(int nErrorCode) rvyr xw%[  
{ /"?HZ% W  
System.err.println("Error Code : " + nErrorCode); z.6$W^  
} (?H0+zws^  
Q43|U4a  
4]/7 )x?R  
//停止文件下载 ^::EikpF%  
public void siteStop() >+mD$:L  
{ 8&Myva  
bStop = true; T2D<UhP  
for(int i=0;i<nStartPos.length;i++) 5P .qXA"D  
fileSplitterFetch.splitterStop(); qiZO _=0  
8`b`QtGf  
*c)uGz'cD  
} @m?QR(LJ  
} } %'bullT  
//负责部分文件的抓取 Pub0IIs  
**FileSplitterFetch.java ;r /;m\V  
*/ 'SYo_!  
package NetFox; S2>c#BQ  
kqb0>rYa   
8_&CT :u>  
import java.io.*; BI:k#jO!  
import java.net.*; TM8 =U-A  
&vovA} F  
{T'GQz+R"  
public class FileSplitterFetch extends Thread { zd]D(qeX  
+f0~D(d!_  
t |W)   
String sURL; //File URL f1PN |  
long nStartPos; //File Snippet Start Position \ j.x0/;  
long nEndPos; //File Snippet End Position fZKt%m  
int nThreadID; //Thread's ID 4gSH(*}  
boolean bDownOver = false; //Downing is over jEz+1Nl)  
boolean bStop = false; //Stop identical nJ?^?M'F%  
FileAccessI fileAccessI = null; //File Access interface `O^G5 0  
_28<m JfG  
OquAql:   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 39 Y(!q  
{ I =Wc&1g  
this.sURL = sURL; YHV-|UNF  
this.nStartPos = nStart; q EUT90  
this.nEndPos = nEnd; QHBtWQgS  
nThreadID = id; fWGOP~0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^")F7`PF  
} d {2  
~^)^q8  
2eQdQwX  
public void run() JM.XH7k  
{ RE3Z%;'  
while(nStartPos < nEndPos && !bStop) ?R Fg$Z'^  
{  6qo^2  
uk`8X`'  
iF+RnWX\  
try{ $mA5@O~C5\  
URL url = new URL(sURL); :Zw @yt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }iBC@`mg(  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zt3}Z4d  
String sProperty = "bytes="+nStartPos+"-"; K,xW6DiH  
httpConnection.setRequestProperty("RANGE",sProperty); pL1s@KR  
Utility.log(sProperty); %bb~Y"  
qBk``!|s]  
ts9pM~_~  
InputStream input = httpConnection.getInputStream(); ;SKh   
//logResponseHead(httpConnection); #6S75{rnW"  
(9fdljl],:  
3mt%!}S  
byte[] b = new byte[1024]; )E7 FA|  
int nRead; \ SCy$,m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) N1--~e  
{ @fn6<3  
nStartPos += fileAccessI.write(b,0,nRead); ? S=W&  
//if(nThreadID == 1)  h=RD O  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _EYB 8e  
} &b C}3D  
0??Yr  
R 4EEelSZu  
Utility.log("Thread " + nThreadID + " is over!"); hY \{|  
bDownOver = true; J0<p4%Cf  
//nPos = fileAccessI.write (b,0,nRead); CSn<]%GL  
} ddpl Pzm#  
catch(Exception e){e.printStackTrace ();} 7$T8&Mh  
} )q?$p9  
} ML!9:vz  
7|D|4!i2Y  
$@[)nvV\  
//打印回应的头信息 KXBL eR&^  
public void logResponseHead(HttpURLConnection con) s^C;>  
{ !QC<n/  
for(int i=1;;i++) /#q")4Mf  
{ NtZ6$o<Y  
String header=con.getHeaderFieldKey(i); J1 tDO?  
if(header!=null) ,?b78_,2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6Dzs?P  
Utility.log(header+" : "+con.getHeaderField(header)); xUj2 ]Q>R+  
else r\mPIr|  
break; kV^?p  
} =:5<{J OG  
} {rGYRn,  
$pu3Ig$^  
V/H@vKN2  
public void splitterStop() I6w/0,azC  
{ M/w{&&  
bStop = true; Y+|PY? ~  
} (|0b7 |'T  
#S?c ;3-  
'O "kt T  
} ONWO`XD  
ZlM_ m >,o  
wznn #j  
/* t,Q'S`eTU  
**FileAccess.java Jk*QcEE=  
*//文件访问(定位,写) n0FYfqH  
package NetFox; /+P5)q TKL  
import java.io.*; cdp{W  
4<yK7x  
BGpk&.J  
public class FileAccessI implements Serializable{ *R!]47Y d  
bA+[{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pX]21&F  
RandomAccessFile oSavedFile; >Fh#DmQ  
long nPos; [D9:A  
KL~AzLI  
Qg{WMlyOP  
public FileAccessI() throws IOException @ay|]w  
{ y{;u@o?T  
this("",0); yjv&4pIc1  
} (olLB  
1w) fu  
Q %y,;N"ro  
public FileAccessI(String sName,long nPos) throws IOException L`pY27 |  
{ yjR)Z9t  
oSavedFile = new RandomAccessFile(sName,"rw"); |P~q/Wff  
this.nPos = nPos; m|`VJ 0  
oSavedFile.seek(nPos); 2moIgJ   
} ` Rsl] GB  
BWohMT  
i)8gCDc  
public synchronized int write(byte[] b,int nStart,int nLen) ;6zPiaDQ  
{ ?0m?7{  
int n = -1; n8Q* _?Z/  
try{ _4Ii5CNNU  
oSavedFile.write(b,nStart,nLen); b+_hI)T  
n = nLen; DUQ9AT#3  
} CJ:uYXJJ:z  
catch(IOException e) h%/ssB  
{ dGa@<hg  
e.printStackTrace (); .2/,XwIr  
} %L28$c3p  
K^8@'#S  
#[Z<=i~C  
return n; HmFNE$k  
} vD_u[j]  
y3Y2 QC(  
T4vogoy  
} (26Bs':M~  
eC.w?(RB  
W.z$a.<(rF  
/* F@Pem  
**SiteInfoBean.java a4:`2  
*/ iY}QgB< M  
package NetFox; 9A(n _Rs7?  
/#@LRN<oCq  
2$iw/ r  
public class SiteInfoBean { f>|9 l  
rtcJ=`)0`  
i_|h{JK)  
private String sSiteURL; //Site's URL <xXiJU+  
private String sFilePath; //Saved File's Path sw[<VsxjR  
private String sFileName; //Saved File's Name bGhhh/n  
private int nSplitter; //Count of Splited Downloading File 8rla0d@  
P Q6T| >  
hT\p)w  
public SiteInfoBean() q$ bHO  
{//nSplitter的缺省值为5 Ml'bZLwq  
//default value of nSplitter is 5 ="/R5fp  
this("","","",5); Dr4?Ow  
} |}l@w +N3  
22l|!B%o  
B 9%yd*SJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @>d&5}F_>{  
{ q] 2}UuM|U  
sSiteURL= sURL; K!pxDW}  
sFilePath = sPath; $_4oN(WSz  
sFileName = sName; \Mobq  
this.nSplitter = nSpiltter; F! |TW6)gv  
T3=-UYx]  
iuvtj]/  
} oVKsic?  
v'mJ~tz  
CD XB&%Sr  
public String getSSiteURL() K8e4ax  
{ 6$xo# }8  
return sSiteURL; :< KSf#O  
} UXcH";*9b  
,U} 5  
<z~2d  
public void setSSiteURL(String value) @g@ fL%  
{ CDwFVR'_Af  
sSiteURL = value; j]cXLY  
} Z<$E.##  
6KBzlj0T+  
yg-L^`t+B5  
public String getSFilePath() vTe$77n  
{ +=,4@I%  
return sFilePath; \ N-| iq  
} hi4h0\L!}  
q.u[g0h;  
b7>,-O  
public void setSFilePath(String value) [~Z'xY y  
{ 7Y_fF1-wY  
sFilePath = value; ~%8Q75tn.  
} $9 &Q.Kpq>  
~|0F?~eR7  
FBwncG$]F*  
public String getSFileName() jx5[bUp4u  
{ E<98ahZ?l  
return sFileName; Tvksf!ba  
} F'Y 2f6B  
6S&=OK^  
U||w6:W5  
public void setSFileName(String value) Zh fD`@>&  
{ N.Wdi  
sFileName = value; I[cV"BDa  
} 9wYtOQ{g  
"JQt#[9l  
zw%n!wc_\  
public int getNSplitter() ;ow~vO,x  
{ )68fm\t(  
return nSplitter; DESViQM  
} !=h|&Vta  
~QEXB*X-g'  
P9tQS"Rs  
public void setNSplitter(int nCount) M~{P',l*  
{ ]zwqGA  
nSplitter = nCount; w;SH>Ax:  
} ?3"D| cS1  
} k vgs $  
cf[u%{ 6Y  
v<J;S9u=  
/* vX0I^ 8.  
**Utility.java s eZ<52f2  
*/ 3}#XA+Z  
package NetFox; vo( j@+dz  
b-(UsY:  
kFIB lPV  
public class Utility { ?#EXG  
q V UUuyF  
<Ec)m69P  
public Utility() t{S{!SF4  
{ |gRgQGeB  
=Z>V}`n  
Y7t{4P  
} R,5$ 0_]|+  
61rh\<bn  
//线程睡眠 k]/6/s\  
public static void sleep(int nSecond) M+R)P +  
{ On.x~ t  
try{ `w=H'"Zv  
Thread.sleep(nSecond); LI|HET_  
} -^jLU FC  
catch(Exception e) zI:5I@ X  
{ ^.1VhTB  
e.printStackTrace (); >'TD?@sr  
} hYUV9k:  
} eW*ae;-  
^RyTK|SQ  
//日志 %FWfiFV|<  
public static void log(String sMsg) A{Htpm~  
{ aLk2#1$g  
System.err.println(sMsg); L%O8vn^3  
} j _9<=Vu  
4Z~Dxo  
W]}V<S$  
public static void log(int sMsg) a={qA4N  
{ No&[ \;  
System.err.println(sMsg); sAN:C{  
} ;q&D,4r]  
} YB3=ij!K  
rHBjR_L.2  
Bpo68%dx89  
/* kBT}Siw  
**TestMethod.java u&_U CJCf  
*/ UR2)e{RXg  
package NetFox; 5"~^;O  
yj+b/9My   
"3oU (RA  
public class TestMethod { :QL p`s  
&FF. Ddt{  
`h3}"js  
public TestMethod() XK-x*|  
{ ///xx/weblogic60b2_win.exe "}+/ 0$F  
try{ GFa/9Bi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Tn-]0hWkP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >D4Ez  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tRBK1h  
fileFetch.start(); z ;Nk& <?  
} hBE>ea  
catch(Exception e){e.printStackTrace ();} TPFmSDq  
^tcBxDC"]  
emPm^M5/K  
} s;WCz  
iX6jvnJ:/  
xF|*N<9(</  
public static void main(String[] args) Z?' |9FM  
{ 1W<_5 j_  
new TestMethod(); M F: Eu  
} x.Ml~W[  
} #zs\Z]3#  
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