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http断点续传简单实现(java)

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/* \gW\Sa ^  
**SiteFileFetch.java U8I~co:h  
*/ jU9zCMyNF  
package NetFox; 7g<`w LAH  
import java.io.*; 3U.B[7fOM  
import java.net.*; 06W=(fY  
qt&"cw  
01d26`G$i~  
public class SiteFileFetch extends Thread { X52jqXjg  
an5kR_=  
LB ^^e"  
SiteInfoBean siteInfoBean = null; //文件信息Bean :phD?\!w8t  
long[] nStartPos; //开始位置 #dm@%~B{.  
long[] nEndPos; //结束位置 _e@qv;*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F'_8pD7  
long nFileLength; //文件长度  DlkKQ  
boolean bFirst = true; //是否第一次取文件 .aH?H]^  
boolean bStop = false; //停止标志 }Knq9cf  
File tmpFile; //文件下载的临时信息 *B~:L"N  
DataOutputStream output; //输出到文件的输出流 v{*X@)$  
g~sNY|%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ImY*cW=M  
public SiteFileFetch(SiteInfoBean bean) throws IOException w`!foPE  
{ w 4gZ:fR=  
siteInfoBean = bean; nR'EuI~(}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \6 0WP-s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p$G3r0 @  
if(tmpFile.exists ()) FG36,6N%2j  
{ xla^A}{  
bFirst = false; *b l{F\  
read_nPos(); I; }%k;v6  
} [(UqPd$  
else k{w^MOHNg  
{ i/EiUH/~  
nStartPos = new long[bean.getNSplitter()]; ik NFW*p  
nEndPos = new long[bean.getNSplitter()]; A,[m=9V  
} RV*Zi\-X  
fJ lN'F7  
MAo,PiYb  
5GxM?%\  
} 9wJmX<Rm  
v@s`l#  
;{7lc9uRj  
public void run() s(9rBDoY(8  
{ y#0Z[[I0  
//获得文件长度 ~u& O  
//分割文件 m95$V&  
//实例FileSplitterFetch %}5"5\Zz  
//启动FileSplitterFetch线程 f?^xh  
//等待子线程返回 VCtiZ4  
try{ w% -!dbmb%  
if(bFirst) )g<qEyJR  
{ *B}R4Y|g  
nFileLength = getFileSize(); sO-R+G/^7  
if(nFileLength == -1) 3n)iTSU3  
{ %,q#f#  
System.err.println("File Length is not known!"); Cx'=2Y7  
} IL"#TKKv  
else if(nFileLength == -2) E4ee_`p  
{ VQx-gm8}!  
System.err.println("File is not access!"); %4^/.) Q  
} R~(.uV`#j  
else Ym2m1  
{ A2bV[+Q  
for(int i=0;i<nStartPos.length;i++) g%P4$|C9 i  
{ Vta;ibdeqW  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5DUPsV  
} df rr.i  
for(int i=0;i<nEndPos.length-1;i++) 3AL=*qq  
{ Q>*K/%KD  
nEndPos = nStartPos[i+1]; mpAh'f4$*  
} CfnCi_=[`  
nEndPos[nEndPos.length-1] = nFileLength; ne*aC_)bT  
} O5%F-}(:  
} oh~Dbu=%  
X0=- {<W  
XArLL5_L  
//启动子线程 <Y6>L};  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \Rt  
for(int i=0;i<nStartPos.length;i++) 41D[[Gh  
{ qz2d'OhmtH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TI&J>/z;$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <v^.FxId  
nStartPos,nEndPos,i); -e\kIK %  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~WLsqP5Y~a  
fileSplitterFetch.start(); &bx,6dX  
} _erH]E| [  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9K(b Z {  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q :|E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", emO!6]0gJ  
nEndPos = " + nFileLength); H9[.#+ln  
// fileSplitterFetch[nPos.length-1].start(); 50`r}s}  
cIkLdh   
j* ?MFvwE  
//等待子线程结束 svgi!=  
//int count = 0; qeGOSGc_  
//是否结束while循环 T^>cT"ux_  
boolean breakWhile = false; #2=30  
C`K/ai{4  
h UDEjW@S  
while(!bStop) r?7 ^@  
{ ~!u94_:  
write_nPos(); 2O>iAzc  
Utility.sleep(500); `Y9@?s Q  
breakWhile = true; ?-i&6i6Y  
AU2Nmf?]%  
l6O(+*6Us  
for(int i=0;i<nStartPos.length;i++) s5@^g8(+C  
{ >MLqOUr#  
if(!fileSplitterFetch.bDownOver) v\u+=}r l  
{ [c~zO+x  
breakWhile = false; 0' t)fnI#  
break; c-{]H8$v  
} sj2+|>  
} rv>6k:(  
if(breakWhile) :PJjy6,1  
break; S5M t?v|K  
7IR n  
 VPzdT*g]  
//count++; wu3ZSLY  
//if(count>4) >d |W>|8e  
// siteStop(); 14O/R3+  
} R lu;l  
T%F'4_~No  
i=rW{0c%  
System.err.println("文件下载结束!"); E.brQx#}  
} 0jq#,p=l;  
catch(Exception e){e.printStackTrace ();} kQtl&{;k?  
} F u)7J4Z  
J<D =\  
3@SfCG&|e  
//获得文件长度 yuWrU<Kw  
public long getFileSize() ! >V 1zk  
{ NaIVKo  
int nFileLength = -1; 3dfSu'  
try{ YjT #^AH  
URL url = new URL(siteInfoBean.getSSiteURL()); |RdSrVB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O4{&B@!  
httpConnection.setRequestProperty("User-Agent","NetFox"); O1PdM52  
[ q}WS5Cp  
7O j9~3o4  
int responseCode=httpConnection.getResponseCode(); |tkmO:  
if(responseCode>=400) ,;g:qe3D$  
{ b $!l* r  
processErrorCode(responseCode); a+d|9y/k  
return -2; //-2 represent access is error BL7%MvDQ  
} Vj1AW<  
6gn|WO=W f  
mvnK)R_  
String sHeader; u]"R AH  
n=~?BxB  
1RLSeT  
for(int i=1;;i++) ! JN@4  
{ 0Pe.G0 #  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /TdTo@  
//Utility.log(in.readLine()); :Wln$L$  
sHeader=httpConnection.getHeaderFieldKey(i); ( s*}=  
if(sHeader!=null) E^s>S,U[y  
{ Nz8iU@!a  
if(sHeader.equals("Content-Length")) [(1O_X(M  
{ ;:OJQFu%4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |2 Dlw]d  
break; "D+QT+sD  
} +KZc"0?  
} iw%DQ }$  
else yTk9+>  
break; -kkXyO8js  
} ZD*>i=S  
} g`6S*&8I  
catch(IOException e){e.printStackTrace ();} K% ;O$ >  
catch(Exception e){e.printStackTrace ();} !zeBxR$&o  
^^Y0 \3.  
IkupW|}rc  
Utility.log(nFileLength); x&sF_<[  
({)_[dJ'  
i ):el=  
return nFileLength; m{X;|-DK[  
}  W* YfyM  
;YB8X&H$  
r&#q=R},p  
//保存下载信息(文件指针位置) ^T" A9uaG  
private void write_nPos() >Kx l+F  
{  mJ-@:5  
try{ {Su]P {oJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oR~+s &c  
output.writeInt(nStartPos.length); jRGG5w}  
for(int i=0;i<nStartPos.length;i++) 0\/7[nwS  
{ /H)l\m +  
// output.writeLong(nPos); )K}b,X`($  
output.writeLong(fileSplitterFetch.nStartPos); cWm.']  
output.writeLong(fileSplitterFetch.nEndPos); ]uP {Sj  
} i^=an?}/  
output.close(); f,$FrI,  
} %j'lWwi  
catch(IOException e){e.printStackTrace ();} #ws6z`mt  
catch(Exception e){e.printStackTrace ();} REa%kU  
} ?C_%"!GR  
6rk/74gI,a  
Wd[XQZ<  
//读取保存的下载信息(文件指针位置) CN zK-,  
private void read_nPos() #SL/Jr DZ  
{ #)XO,^s.  
try{ d;f,vN(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bf3)^ 49}  
int nCount = input.readInt(); 4>(?R[:p)  
nStartPos = new long[nCount]; 8F%T Z M  
nEndPos = new long[nCount]; M 3^p,[9r#  
for(int i=0;i<nStartPos.length;i++) g?`w)O 7v  
{  /8.;  
nStartPos = input.readLong(); ;$nK ^  
nEndPos = input.readLong(); m^`X|xK-  
} D}:D,s8UP  
input.close(); SN+&'?$WD  
} j,Mp["X&  
catch(IOException e){e.printStackTrace ();} 7I HWj<  
catch(Exception e){e.printStackTrace ();} _ TUw0:&  
}  -"<eq0  
;e-iiC]PI  
L%fWa2P'  
private void processErrorCode(int nErrorCode) NvYgRf}uh  
{ D4@=+  
System.err.println("Error Code : " + nErrorCode); %$b 5&>q  
} fY>\VY$>  
!\p-|51  
KExfa4W 3{  
//停止文件下载 A1i-QG/6  
public void siteStop() z8A`BVqI  
{ qoOHWh&  
bStop = true; qWo|LpxWt  
for(int i=0;i<nStartPos.length;i++) b\}`L"  
fileSplitterFetch.splitterStop(); "|f;   
e7<~[>g)  
A=BpB}b  
} Q&wBX%@^L  
} JG4Tb{F=  
//负责部分文件的抓取 T `N(=T^*  
**FileSplitterFetch.java Xa-]+_?Q  
*/ 9gjx!t>`H  
package NetFox; tEb2>+R  
XfB;^y=u8  
X!r!lW  
import java.io.*; O#9Q+BD  
import java.net.*; h4sEH  
 xU)~)eK  
P||u{]vU  
public class FileSplitterFetch extends Thread { >GqIpfn  
H.'_NCF&;L  
Lc+)#9*d  
String sURL; //File URL iTD{  
long nStartPos; //File Snippet Start Position / Z \zB  
long nEndPos; //File Snippet End Position I_v]^>Xw  
int nThreadID; //Thread's ID 1298&C@  
boolean bDownOver = false; //Downing is over H3MT.Cpd  
boolean bStop = false; //Stop identical S# SA:>8s  
FileAccessI fileAccessI = null; //File Access interface N+h|Ffnp  
W C}mt%H*O  
n_iq85  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vVE^Y  
{ ;0 @"1`  
this.sURL = sURL; \}Hk`n)Aq  
this.nStartPos = nStart; b@nbXm]Z  
this.nEndPos = nEnd; H,] D}r  
nThreadID = id; ;b(/PH!O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZN^9w"A  
} BC&Et62*  
)\p@E3Uxf  
* _U z**M  
public void run() QD7>S(p  
{ DAJh9I  
while(nStartPos < nEndPos && !bStop) 'M YqCfIK  
{ 2Ask]  
-0lpsF  
M1VRc[ RRo  
try{ S tn[M|  
URL url = new URL(sURL); =T;%R^@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )p(XY34]  
httpConnection.setRequestProperty("User-Agent","NetFox"); ))u$j4 V  
String sProperty = "bytes="+nStartPos+"-"; julAN$2  
httpConnection.setRequestProperty("RANGE",sProperty); J>x)J}:;  
Utility.log(sProperty); 8&H1w9NrX_  
Xig%Q~oMp  
6]na#<  
InputStream input = httpConnection.getInputStream(); bSBI[S  
//logResponseHead(httpConnection); ,1QU  
CEt_wKz f  
& 9IMZAo  
byte[] b = new byte[1024]; h|_G2p^J+"  
int nRead; !dGy"-i$h  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1 BVivEG  
{ f H}`  
nStartPos += fileAccessI.write(b,0,nRead); m&b!\"0  
//if(nThreadID == 1) Q-Bci Bh$  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DH @*Oz-  
} P6;L\9=H<  
.GLotc  
{P(IA2J'S  
Utility.log("Thread " + nThreadID + " is over!"); zaR~fO  
bDownOver = true; (eG#JVsm9  
//nPos = fileAccessI.write (b,0,nRead); 7vgz=- MZ#  
} dEns|r  
catch(Exception e){e.printStackTrace ();} si0jXue~j\  
}  XW`&1qx  
} ^i#F+Q`1  
QfRt3\^`  
\Ui8Sgeei  
//打印回应的头信息 v:<u0B-)$  
public void logResponseHead(HttpURLConnection con) j =[Td   
{ g7#_a6  
for(int i=1;;i++) ,!PNfJA2  
{ dLG5yx\js  
String header=con.getHeaderFieldKey(i); 4e1Zyi!  
if(header!=null) rQ. j$U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); O zY&^:>  
Utility.log(header+" : "+con.getHeaderField(header)); ytr~} M%  
else %F1 Ce/  
break; 7teg*M{  
} 2A {k>TjQ  
} KYd2=P6  
n+j'FfSz  
#W'jNX,h  
public void splitterStop() >=[w{Vn'Mf  
{ ,]1K^UeZ  
bStop = true; !dStl:B  
} `QAotSO+  
jcv3ES^  
:1=mNrg  
} Jc:*X4-'  
.Mdxbs6.C  
D@FJVF7c  
/* -i7W|X"  
**FileAccess.java 4:5CnK  
*//文件访问(定位,写) 315Rk!{AJ  
package NetFox; Y M/^-[k3  
import java.io.*; @y{Whun~  
|'b=xeH.^<  
m?>$!B4jFB  
public class FileAccessI implements Serializable{ ES<"YF  
bY&s $Ry3"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #*1\h=bzmW  
RandomAccessFile oSavedFile; i{ eDV  
long nPos; dGTAZ(1W  
7[ *,t  
0:Ak 4L6k  
public FileAccessI() throws IOException f LxFF  
{ 7-Fh!=\f/  
this("",0); iVREkZ2SC  
} N:Q}Lil  
00n6v;X  
bxK1v7  
public FileAccessI(String sName,long nPos) throws IOException `4g m'C  
{ }`\+_@ w  
oSavedFile = new RandomAccessFile(sName,"rw"); ;HgV(d#X  
this.nPos = nPos; owJPEx  
oSavedFile.seek(nPos); }I9\=jT  
} O5LB&s   
ie=tM'fb  
iw12x:  
public synchronized int write(byte[] b,int nStart,int nLen) 7P.C~,+D%P  
{ YSs9BF:a  
int n = -1; $:t;WXc.<  
try{ Nq"/:3@4  
oSavedFile.write(b,nStart,nLen); X-e)w  
n = nLen; W{?7Pn?1`  
} *R0Ae 4  
catch(IOException e) OtrO"K  
{ {xMY2I++  
e.printStackTrace (); 1wi{lJaz  
} W,}HQ  
=;i@,{ ~  
CT6a  
return n; l{E+j%  
} 5kofO  
oost}%WxN  
ZS4lb=)G  
} { P&l`  
LTm2B_+  
AN\:  
/* '&xv)tno  
**SiteInfoBean.java K\`L>B. 1  
*/ mflH&Bx9  
package NetFox; x$cs_q]J  
^$4d'  
4M}u_}9  
public class SiteInfoBean { HUfH/x3zj]  
bYYyXM  
3;u*_ ]N_  
private String sSiteURL; //Site's URL k"LbB#Q  
private String sFilePath; //Saved File's Path w q% 4'(  
private String sFileName; //Saved File's Name >u4%s7 v  
private int nSplitter; //Count of Splited Downloading File CVyqr_n65/  
+>@<'YI<  
EX~ U(JB6  
public SiteInfoBean() +3(1QgYM%  
{//nSplitter的缺省值为5 KE]!7+8-  
//default value of nSplitter is 5 AVyqtztQ  
this("","","",5); k ?X  
} tq8B)<(]  
2a3h m8%U  
SYOND>E  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ik=~`3Zp0  
{ S ])Ap'E  
sSiteURL= sURL; D ?1$I0=  
sFilePath = sPath; xVao3+r  
sFileName = sName; L6fc_Mo.EE  
this.nSplitter = nSpiltter; b?hdWQSW7  
7q<I7Wt  
P%]li`56-c  
}  !NUsfd  
Rf+ogLa=  
]2T=%(*  
public String getSSiteURL() @V Bv}Jo  
{ ]!E|5=q  
return sSiteURL; ^z-e"  
} R+ lwOVX  
" 6Hka{  
==F[5]?  
public void setSSiteURL(String value) R%Gh4y\nF  
{ h3$.` >l  
sSiteURL = value; U N1HBW;  
} : |#Iw  
)@DH&  
p6$ QTx  
public String getSFilePath() z _~ 5c  
{ RMMx6L|-:  
return sFilePath; {'4h.PB+r  
} J@54B  
,3Y~ #{,i  
u.YPb@  
public void setSFilePath(String value) g4cmYg3  
{ *z!!zRh3x  
sFilePath = value; m64 6|G5  
} J*Dj`@`4`g  
-9Wx;u4]o  
@%q0fj8b  
public String getSFileName() lR\=] ]7I>  
{ HaXlc8  
return sFileName; >:!TfuU^R  
} rj&  
6TvlK*<r=  
~'2)E/IeV  
public void setSFileName(String value) DBYD>UA  
{ 9JV(}v5[  
sFileName = value; rlqn39  
} ^} P|L  
2s_shY<=}L  
dVmI.A'nbp  
public int getNSplitter() PsU.dv[  
{ 4h\MSTF*  
return nSplitter; QijEb  
} $m]~d6  
n*(Vf'k  
cVv+,l4 V0  
public void setNSplitter(int nCount) RbKAB8  
{ Mt(wy%{zK  
nSplitter = nCount; # 8 0DM  
} ?sWPx!tU  
} r+-KrO'  
xWWfts1t  
-K hXb  
/* h~)oiT2v  
**Utility.java B- =*"H?q  
*/ xwhH_[  
package NetFox; 2qLRcA=R  
SV}q8z\  
/~)vma1<  
public class Utility { rs2G{a  
+e+hIMur  
-e_ IDE  
public Utility() _IBI x\F  
{ i,=greA]"  
xa#0y   
^=D=fX"8%  
} L\|p8jJ  
gq~>S1  
//线程睡眠 Sr Z\]  
public static void sleep(int nSecond) iK8aj)%Q@  
{ o_ka'|  
try{ `VX]vumG  
Thread.sleep(nSecond); >MZWm6M8  
} VRurn>y0  
catch(Exception e) L\_MZ*<0[  
{ R`q*a_  
e.printStackTrace (); 0i/l2&x*k]  
} ??0C"8:[  
} vY0C(jK  
Cg<:C?>!p  
//日志 Rs,\{#  
public static void log(String sMsg) 25]Mi2_  
{ (dn(:<_$  
System.err.println(sMsg); dmI,+hHtL  
} ;S5*n:d  
h^h,4 H\r  
o?@,f/" 5  
public static void log(int sMsg) ~?4'{Hc'  
{ l&2A]5C  
System.err.println(sMsg); 5RCQ<1  
} d%VG@./xq  
} T8+A`z=tSb  
. #`lW7  
%SuEfCM  
/* :fz&)e9  
**TestMethod.java awLN>KI]</  
*/ aTF~rAne<  
package NetFox; t<s:ut)Q!  
sN0S~}F+  
N)|mA)S)  
public class TestMethod { L1ZhH3}X  
yo]!Zn  
W<C \g~\  
public TestMethod() pi7Fd\A  
{ ///xx/weblogic60b2_win.exe (]7&][  
try{ +>mbBu!7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #s'9Ydd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ka? |_(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vHSX3\(  
fileFetch.start(); fWiefv[&  
} C9>tj=yEY  
catch(Exception e){e.printStackTrace ();} Sn=|Q4ZN  
AB<|iJC  
?Iy$'am]L  
} _ #]uk&5a  
^*(*tS|M  
V)#se"GV  
public static void main(String[] args) lj0"2@z3"E  
{ VL= .JwK  
new TestMethod(); ;1PnbU b  
} }9yAYZ0q{b  
} !wy Qk  
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