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http断点续传简单实现(java)

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/* v={{ $=/t  
**SiteFileFetch.java ur\6~'l4  
*/ PnA{@n\  
package NetFox; JRo/ HY+  
import java.io.*; v/q-{ 1   
import java.net.*; ,;6V=ok  
/oHCV0!0  
[jzsB:;XB&  
public class SiteFileFetch extends Thread { O*~z@"\  
;na%*G`  
< ,*\t  
SiteInfoBean siteInfoBean = null; //文件信息Bean {g<D:"Q  
long[] nStartPos; //开始位置 $TXxhd 6  
long[] nEndPos; //结束位置 ovTL'j!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p> `rTaeZg  
long nFileLength; //文件长度 fUkqhqe  
boolean bFirst = true; //是否第一次取文件 0X5cn 0L^  
boolean bStop = false; //停止标志 <.QaOLD  
File tmpFile; //文件下载的临时信息  7;fC%Fq  
DataOutputStream output; //输出到文件的输出流 eZa*WI=  
3- Kgz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) w}>%E6UY  
public SiteFileFetch(SiteInfoBean bean) throws IOException gmRc4o  
{ OL>>/T  
siteInfoBean = bean; *x|%Nua"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )}`z<)3jP  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FOsd{Fw  
if(tmpFile.exists ()) U`ttT5;  
{ !H\o Qv-I  
bFirst = false; sv% X8  
read_nPos(); N|DI k  
} qY#*LqV  
else UhDQl%&He  
{ FBNLszT{L  
nStartPos = new long[bean.getNSplitter()]; 9{jMO  
nEndPos = new long[bean.getNSplitter()]; +Y sGH~jX  
} #&}- q RA  
9:USxFM  
G<$:[ +w  
@-!P1]V|  
} #:gd9os :  
)=[\YfK  
T(D6'm:X  
public void run() x|rc[e%k  
{ lmzHE8MUNu  
//获得文件长度 Q"XDxa'7"  
//分割文件 gu(:'5cX  
//实例FileSplitterFetch w*VN =  
//启动FileSplitterFetch线程 _YF>Y=D-  
//等待子线程返回 i-OD"5a`  
try{ c,~uurVi  
if(bFirst) bkV<ZUW|;  
{ >zW2w2O3  
nFileLength = getFileSize(); [Km{6L&  
if(nFileLength == -1) Dt: Q$  
{  pux IJ  
System.err.println("File Length is not known!"); rFg$7  
} o72r `2  
else if(nFileLength == -2) -qIi.]/f"9  
{ f CU]  
System.err.println("File is not access!"); (u@:PiU/eP  
} aj&L ZDD6  
else oRWje#4O  
{ fs 'SCwx  
for(int i=0;i<nStartPos.length;i++) kXwAw]ogN  
{ c4tw)O-X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9Y:I)^ek  
} 3x+lf4"  
for(int i=0;i<nEndPos.length-1;i++) 0Qt!w(  
{ E)_n?>Ar  
nEndPos = nStartPos[i+1]; } {1IB  
} 6Rn?pe^  
nEndPos[nEndPos.length-1] = nFileLength; 4E^ ?}_$  
} H0afu)$,  
} gXdMGO>  
0~qc,-)3  
/mex{+p>tO  
//启动子线程 F06o-xH=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #DUfEZ  
for(int i=0;i<nStartPos.length;i++) eP-|3$  
{ |UXSUP @s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +F8{4^w1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z{rV|vQ  
nStartPos,nEndPos,i); -#|;qFD]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l )%PvLbL  
fileSplitterFetch.start(); DhyR  
} Z3S+")^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >O-KJZ'GV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'C'mgEl%L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zXY8:+f  
nEndPos = " + nFileLength); ZyGoOk  
// fileSplitterFetch[nPos.length-1].start(); [:y:_ECs6  
T8o](:B~  
B)JMughq_  
//等待子线程结束 JQ03om--(  
//int count = 0; :wC\IwG~CE  
//是否结束while循环 :0J`4  
boolean breakWhile = false;  >(Y CZ  
;qWu8\T+  
su%(!XJQpg  
while(!bStop) Z2g'&,uc#  
{ |.N[NY  
write_nPos(); Bh3F4k2bg7  
Utility.sleep(500); }>@\I^Xm,  
breakWhile = true; !Km[Qw k-  
eYUb>M)  
V]zc-gYI  
for(int i=0;i<nStartPos.length;i++) dCd~]CI  
{ <\&9Odqc  
if(!fileSplitterFetch.bDownOver) TR DQ+Z  
{ *S,~zOYN  
breakWhile = false; lfgJQzi G  
break; lz,M$HG<[  
} xi5"?*&Sb  
} <V&0GAZ  
if(breakWhile) +{:uPY#1  
break; {kpF etXt?  
_SBbd9  
Z1HH0{q-A  
//count++; 4IeCb?  
//if(count>4) l f>/  
// siteStop(); k =! Q  
} {MgRi 7  
xKUL}>8  
2%%\jlT_  
System.err.println("文件下载结束!"); =]7o+L4  
} p!UR;xHI\  
catch(Exception e){e.printStackTrace ();} rwP#Yj[BK+  
} I"Zp^j  
K<>kT4  
e5' I W__  
//获得文件长度 h4;kjr}h}  
public long getFileSize() jK w 96  
{ G2` z?);1b  
int nFileLength = -1; ~5KcbGD~  
try{ `c  
URL url = new URL(siteInfoBean.getSSiteURL()); y!FO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k\f _\pj6  
httpConnection.setRequestProperty("User-Agent","NetFox"); meX2Y;  
J2z/XHS  
%qc_kQ5%  
int responseCode=httpConnection.getResponseCode(); 6 s=VU\  
if(responseCode>=400) 9!( 8o  
{ n5}]C{s'  
processErrorCode(responseCode); OC=&!<  
return -2; //-2 represent access is error d(q1 ?{zr4  
} p@tg pFt  
*[si!e%  
p'jc=bL E  
String sHeader; =5|7S&{  
p<fCGU  
TLwxP"  
for(int i=1;;i++) RjW wsC~B  
{ Q %o@s3~O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tsb[=W!Ar8  
//Utility.log(in.readLine()); :iE b^F}  
sHeader=httpConnection.getHeaderFieldKey(i); `ASDUgx Mq  
if(sHeader!=null) JK/{Ik F  
{ :;{M0  
if(sHeader.equals("Content-Length")) As,`($=  
{ 6v)TCj/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SQN?[v  
break; rpow@@ad<  
} xw#CwMbbi  
} ?ko#N?hgI  
else H*W>v[>  
break; 2zC4nF)>O  
} Ta?J;&<u]/  
} (?4%Xtul1  
catch(IOException e){e.printStackTrace ();} m{q'RAw  
catch(Exception e){e.printStackTrace ();} (:l6R9'=  
5JzvT JMx  
n>'(d*[e&  
Utility.log(nFileLength); eRMN=qP.q  
^j}C]cq{Xg  
F-m%d@P&X  
return nFileLength; !r njmc  
} F6\{gQ<E  
d( v"{N}  
Q|_F P:  
//保存下载信息(文件指针位置) ~]KdsT(=_  
private void write_nPos() k|;a"56F  
{ JxVGzb`8  
try{  Vl_6nY;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gFaZ ._  
output.writeInt(nStartPos.length); D$ds[if$U,  
for(int i=0;i<nStartPos.length;i++) 7H Har'=T  
{ u BEw YQB  
// output.writeLong(nPos); qDdO-fPev  
output.writeLong(fileSplitterFetch.nStartPos); F- ,gj{s  
output.writeLong(fileSplitterFetch.nEndPos); khy'Y&\F;  
} NW\CEJV  
output.close(); 5H3o?x   
} w'@gzK  
catch(IOException e){e.printStackTrace ();} Nv5^2^Sc=  
catch(Exception e){e.printStackTrace ();}  ~~>m  
} !5*VBE\  
p4VARAqi  
I*rUe#$  
//读取保存的下载信息(文件指针位置) kvbZx{s  
private void read_nPos() !JCs'?A  
{ 7By7F:[b  
try{ ^Om}9rXw1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L( 6b2{"  
int nCount = input.readInt(); !f~a3 {;j  
nStartPos = new long[nCount]; R~g|w4a@sC  
nEndPos = new long[nCount]; !gX xM,R  
for(int i=0;i<nStartPos.length;i++) Q>1BOH1by  
{ h#0n2o#  
nStartPos = input.readLong(); j97+'AKX  
nEndPos = input.readLong(); hUMG}<  
} %1#\LRA(  
input.close(); '{d _q6,%  
} ,3:f4e\<  
catch(IOException e){e.printStackTrace ();} SdH=1zBc  
catch(Exception e){e.printStackTrace ();} s$fM,l:!  
} 1Yb&E7j  
NpVL;6?7T  
k{*EoV[.$  
private void processErrorCode(int nErrorCode) d@3DsE.{i  
{ l,@>J9}Se  
System.err.println("Error Code : " + nErrorCode); uaIAVBRcS  
} 0,hs %x>v  
U%vTmdOY  
.tRm1&Qi  
//停止文件下载 /?8 1Ypt  
public void siteStop() ;.h /D4  
{ |V34;}\4  
bStop = true; n.+*_c8k  
for(int i=0;i<nStartPos.length;i++) @<W` w  
fileSplitterFetch.splitterStop(); Iy)1(upM  
Jh+;+"  
24wDnDyh  
} pm O9mWq   
} Bl\:YYd  
//负责部分文件的抓取 vQ< ~-E  
**FileSplitterFetch.java 7C|AiSH  
*/ l!p`g>$&f  
package NetFox; 7-S?RU]g  
dDS{XR  
Xqf\}p n  
import java.io.*; ANm@$xO*  
import java.net.*; eU"yF >6'  
?+}Su'pv}  
9a_P 9s3w  
public class FileSplitterFetch extends Thread { Yc#Uu8f-  
4X=VNORlU0  
5*z>ez2YQ7  
String sURL; //File URL Luao?;|U  
long nStartPos; //File Snippet Start Position :hICe+2ca  
long nEndPos; //File Snippet End Position "kApGNB  
int nThreadID; //Thread's ID 8u*<GbKGI  
boolean bDownOver = false; //Downing is over z83v J*.  
boolean bStop = false; //Stop identical a?gF;AYk  
FileAccessI fileAccessI = null; //File Access interface ~gX1n9_n  
uyX % &r  
?8 }pZ_j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aR2N,<Cp5  
{ ~W @dF~r  
this.sURL = sURL; OP!R>|  
this.nStartPos = nStart; (aYu[ML  
this.nEndPos = nEnd; ?e9tnk3  
nThreadID = id; cyNE}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y1cL dQn  
} $#V'm{Hh  
z$&B7?  
|5flvkid  
public void run() s8 WB!x{t  
{ Y%i<~"k  
while(nStartPos < nEndPos && !bStop) 56C8)?  
{ !$Uo$?gC  
| V(sCF  
M8H hjoo  
try{ ]I*RuDv}  
URL url = new URL(sURL); ]*NYuEgc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i&DbZ=n2  
httpConnection.setRequestProperty("User-Agent","NetFox"); /3)\^Pof  
String sProperty = "bytes="+nStartPos+"-"; FH}?QebSR  
httpConnection.setRequestProperty("RANGE",sProperty); n1\$|[^6  
Utility.log(sProperty); "I56l2dxd  
>FE8CH!W&  
") 8l'^Mq2  
InputStream input = httpConnection.getInputStream(); |-JG _i  
//logResponseHead(httpConnection); )B]"""J  
wXQu%F3  
|ts0j/A]Pi  
byte[] b = new byte[1024]; ]{=y8]7  
int nRead; bB4FjC':  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2>jk@~Z1:u  
{ 6zM:p/  
nStartPos += fileAccessI.write(b,0,nRead); :[@rA;L  
//if(nThreadID == 1) /J^dz vH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]2u   
} tE0{ae  
@*rMMy 4  
 Ht.P670  
Utility.log("Thread " + nThreadID + " is over!"); B-g uz  
bDownOver = true; fDYTupKXH  
//nPos = fileAccessI.write (b,0,nRead); ]D nAW'm  
} O#.YTTj  
catch(Exception e){e.printStackTrace ();} =?|$}vDO[  
} pbKmFweq  
} v,n 8$,  
:G6CWE  
38sLyoG=i  
//打印回应的头信息 =b66H]h?  
public void logResponseHead(HttpURLConnection con) XrUI [ryE  
{ .?:#<=1  
for(int i=1;;i++) Q>L(=j2t  
{ [%^0L~:  
String header=con.getHeaderFieldKey(i); hV $Zr4'  
if(header!=null) ";dS~(~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); \asn^V@"zz  
Utility.log(header+" : "+con.getHeaderField(header)); XR]bd  
else ;):;H?WS|A  
break; `Ku:%~$/  
} NtGJpT4YX  
} KxErWP%  
hXFT(J=  
p7AsNqEp  
public void splitterStop() vcW(?4e  
{ In4VS:dD  
bStop = true; 7zzFM  
} %KF I~Qk  
b7hICO-w  
pIR_2Eq  
} 2r2:  
n-K/d I  
!>'A2V~F  
/* 8nZ_.  
**FileAccess.java <LZ#A@]71  
*//文件访问(定位,写) "~ =O`5V  
package NetFox; S? Cd,WxT  
import java.io.*; m>Z3p7!N}  
O-.G("  
<:AA R2=  
public class FileAccessI implements Serializable{ w3i74C&0  
h>>~Bi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .Ao _c x  
RandomAccessFile oSavedFile; ?6"U('y>n  
long nPos; '-(Z.e~e  
E4=D$hfq`  
("(wap~<nD  
public FileAccessI() throws IOException '=G6$O2  
{ L_ T+KaQCH  
this("",0); |;:Kn*0/]  
} :CqR1_n%  
E<D^j^T  
N[-$*F,:_  
public FileAccessI(String sName,long nPos) throws IOException uo?R;fX26  
{ KCpq<A%  
oSavedFile = new RandomAccessFile(sName,"rw"); A;X3z-[[  
this.nPos = nPos; KtJc9dnX  
oSavedFile.seek(nPos); jHob{3  
} Mi NEf  
ouyZh0 G  
'h;qI&  
public synchronized int write(byte[] b,int nStart,int nLen) D?dS/agA  
{ Lo}T%0"G  
int n = -1; rR ^o  
try{ G/~b(V;>  
oSavedFile.write(b,nStart,nLen); ;Tk/}Od!VN  
n = nLen; 6i+AJCkC  
} Vxo?%Dj  
catch(IOException e) daCkjDGl\  
{ [T9]q8"  
e.printStackTrace (); %qqCpg4  
} ts@w9|  
/F^ Jn_  
n4B uM R  
return n; ,Y| ;V  
} G,+3(C  
D'%M#S0   
-`\n/"#X6i  
} Wm}T=L`  
s(Wys^[g  
-|u yJh  
/* nm_taER  
**SiteInfoBean.java /?j kVy*"  
*/ N2|NYDQs  
package NetFox; yXIJeo"  
j"Ew)6j  
`c ^ ">L  
public class SiteInfoBean { K[?@nl?,z  
?.-+U~  
KbciRRf!k  
private String sSiteURL; //Site's URL ,c`Wmp^AY  
private String sFilePath; //Saved File's Path Gh6U<;V?*  
private String sFileName; //Saved File's Name k|RY; 8_  
private int nSplitter; //Count of Splited Downloading File "Q\b6 7Ch  
wmX(%5vY^  
,jW a&7  
public SiteInfoBean() I\-M`^@  
{//nSplitter的缺省值为5 (i\{hq/  
//default value of nSplitter is 5 OrL4G `O  
this("","","",5); :}q)]W  
} M<= e~';H  
(]?M=?0\  
 6cjCn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *q\>DE=7  
{ f8UJ3vB  
sSiteURL= sURL; jUZ$vyT  
sFilePath = sPath; ;*+H&  
sFileName = sName; !M)] 1Y  
this.nSplitter = nSpiltter; uT=5zu  
*aFh*-Sj2I  
~$//4kES  
} S|KUh|=Q  
SY:ISzB}  
NYKYj`K  
public String getSSiteURL() ;gAL_/_  
{ B7Zi|-F  
return sSiteURL; +~:OUR*>  
} CRiqY_gBf  
e\-,e+  
AuM}L&`i^  
public void setSSiteURL(String value) 1fM`n5?"  
{ j,9/eZRZ  
sSiteURL = value; +BhJske  
} S{)K_x  
<gFisc/#r  
&Cm]*$?  
public String getSFilePath() " &`>+Yw  
{ m;1/+qs0  
return sFilePath; 9s7TLT k  
} N9*QQ0  
I\M }Dxpp  
]Nssn\X7  
public void setSFilePath(String value) ; bHS^  
{ QX&Y6CC`]  
sFilePath = value; @KHY8y7  
} o!&+ _BKw  
Vo.~1^  
fo~*Bp()-E  
public String getSFileName() WCk. K  
{ C1l'<  
return sFileName; OTAe#]#  
} O:~J_Wwl!  
MXDCOe~07  
 !I&,!$  
public void setSFileName(String value) P1^|r}  
{ 3xdJ<Lrq  
sFileName = value; Q W c^}#!!  
} $-jj%kS  
DvLwX1(l  
+7AH|v8  
public int getNSplitter() CY*GCkH  
{ i{:iRUC#  
return nSplitter; cF EO}  
} YdIZikF#  
19[!9ci  
MZWv#;.]  
public void setNSplitter(int nCount) j/NX  
{ p&4n"hC  
nSplitter = nCount; <5#2^(  
} nz#eJ  
}  T-+ uQ3  
'n\PS,[1R  
Hr7pcz/#l  
/* mb%U~Na  
**Utility.java =}I=s@  
*/ Aeo=m}C;  
package NetFox; 9x8Vsd  
%BT]h3dcSS  
u~JR]T  
public class Utility { a({N}ZDo  
Ro `Xs.X  
=1VZcLNt  
public Utility() rQ2TPX<?a  
{ !mB `FC  
C?W}/r[  
1{a4zGE?[  
} qzO5p=}  
suFk<^3  
//线程睡眠 jffNA^e  
public static void sleep(int nSecond) 3J/l>1[  
{ )iK:BL*Nw  
try{ cW"DDm g  
Thread.sleep(nSecond); jP2#w{xq  
} bC) <K/Q9  
catch(Exception e) rce._w }  
{ a"t~ K  
e.printStackTrace (); 4gVIuF*pS  
} 4vvQ7e7  
} R(8?9-w  
ma<uXq  
//日志 6R$Yh0%  
public static void log(String sMsg) o-AF_N  
{ ]$s b<o .a  
System.err.println(sMsg); 3)2{c  
} wf\7sz  
p&)d]oV>  
kd]CV7(7  
public static void log(int sMsg) EgbH{)u  
{ 7fSNF7/+  
System.err.println(sMsg); 0L,!o[L*  
} XJy.xI>;  
} 0_Elxc  
ukc 7Z OQ  
Tow!5VAM  
/* ~_F;>N~  
**TestMethod.java T (]*jaB  
*/ 0*oavY*  
package NetFox; 02NVdpo[wU  
 ylS6D  
guf*>qNr  
public class TestMethod { )^"V}z t  
Dfc% jWbA  
2+C:Em0yI  
public TestMethod() ;4GGXT++L  
{ ///xx/weblogic60b2_win.exe f4F%\ "  
try{ n6M#Xc'JA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  s_+.xIZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); F;kKn:XL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )`ixT)   
fileFetch.start(); VN\VTSZh?\  
} rl$"~/ oz  
catch(Exception e){e.printStackTrace ();} :O,r3O6  
CF\wR;6k  
ue@W@pj  
} jt9- v-  
U}k@%m,  
oR,zr  
public static void main(String[] args) _iEnS4$A8  
{ ;volBfv  
new TestMethod(); }; M@JMu,  
} :=5X)10  
} $/@  L  
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