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http断点续传简单实现(java)

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/* G\Q0{4w8  
**SiteFileFetch.java NBO&VYs|  
*/ eXCH*vZY  
package NetFox; bdyIt)tK+  
import java.io.*; K~14;  
import java.net.*; V3[>^ZCA  
Jm3iYR+,  
q&@q /9kz  
public class SiteFileFetch extends Thread { .xg, j{%(  
{3G2-$yb  
J72 YZrc  
SiteInfoBean siteInfoBean = null; //文件信息Bean o%l|16DR  
long[] nStartPos; //开始位置 }>?"bcJ  
long[] nEndPos; //结束位置 k2DBm q;  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |\/V1  
long nFileLength; //文件长度 ILT.yxV  
boolean bFirst = true; //是否第一次取文件 5uD'Kd$H  
boolean bStop = false; //停止标志 J-Wphc!m  
File tmpFile; //文件下载的临时信息 FQw@ @  
DataOutputStream output; //输出到文件的输出流 !;.nL-NQ  
3t$)saQR  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) YCu9dBeVS  
public SiteFileFetch(SiteInfoBean bean) throws IOException #6za  
{ ("_tML 8/p  
siteInfoBean = bean; ^vr`t9EE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -MItZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 22"/|S  
if(tmpFile.exists ()) c{cJ>d 0  
{ =xPBolxm5U  
bFirst = false; qh 9Ix  
read_nPos(); b;$j h   
} gf U!sYZ  
else -{a&Zkz>V  
{ ['_G1_p  
nStartPos = new long[bean.getNSplitter()]; Hbi2amfBu  
nEndPos = new long[bean.getNSplitter()]; ~ H $q  
} Uv(Uj3D  
 ^6Y:9+  
S`&YY89{&  
4&^BcWqA*f  
} M;F&Ix  
:EZ"D#>y~  
r$z0C&5  
public void run() 9`v[Jm% $m  
{ Avi8&@ya  
//获得文件长度 Qh@A7N/L  
//分割文件 e X q}0-*f  
//实例FileSplitterFetch kV3Zt@+  
//启动FileSplitterFetch线程 ?#_]Lzn'  
//等待子线程返回  B!+`km5  
try{ ;c;PNihg  
if(bFirst) A+bU{oLr  
{ <e7  
nFileLength = getFileSize(); Mwd(?o  
if(nFileLength == -1) o;2QZ"v  
{ M}BqSzd*  
System.err.println("File Length is not known!"); \hFIg3  
} >$p|W~x  
else if(nFileLength == -2) cQldBc  
{ l]v>PIh~N  
System.err.println("File is not access!"); Rjz~n38.  
} KsBi<wY  
else RE}$(T=  
{ ({#M*=&"  
for(int i=0;i<nStartPos.length;i++) f S(IN~  
{ Ye) F{WqZ#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B&RgUIrFoY  
} #OVf2  "  
for(int i=0;i<nEndPos.length-1;i++) ::A]p@  
{ l:H}Y3_I  
nEndPos = nStartPos[i+1]; Ff @Cs0R  
} and)>$)|  
nEndPos[nEndPos.length-1] = nFileLength; c;pv< lX'  
} 6_h'0~3?`  
} O6$d@r;EK]  
fG*366W  
m6oaO9"K  
//启动子线程 uRfFPOYH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d y^zOqc  
for(int i=0;i<nStartPos.length;i++) ~kW[d1'c  
{ +>wBGVvS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FOx&'dH %@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O$,MdhyXC  
nStartPos,nEndPos,i); >|@i8?|E  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~i y]X:U  
fileSplitterFetch.start(); NLA/XZ  
} W6 U**ir.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [:(^n0%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w `0m[*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o0'!u  
nEndPos = " + nFileLength); Au-h#YV  
// fileSplitterFetch[nPos.length-1].start(); (+ibT;!]  
>2w^dI2  
:7-2^7z)  
//等待子线程结束 `gFE/i18  
//int count = 0; ~'<ca<Go|  
//是否结束while循环 o)pso\;  
boolean breakWhile = false;  N\9 Wxz$  
<|MF\D'  
QZs ]'*=#  
while(!bStop) a{FCg%vD)  
{ =~f\m:Y  
write_nPos(); }hy, }2(8  
Utility.sleep(500); mjtmN0^SR  
breakWhile = true; e7^B3FOx  
kg^VzNX  
qu:nV"~_  
for(int i=0;i<nStartPos.length;i++) F+3}Gkn  
{ Lradyo44u\  
if(!fileSplitterFetch.bDownOver) |kXx9vGq@  
{ c/Ykk7T9--  
breakWhile = false; z[`O YwsW  
break; -]K9sy)I  
} R#x~f  
} ',Q|g^rF]  
if(breakWhile) 86AZ)UP2D  
break; ^Voi 4;  
{5, ]7=]  
_^5OoE"}!  
//count++; gx',~  
//if(count>4) p2/Pj)2  
// siteStop(); TC+L\7   
} ZcLW8L  
-)p S\$GC  
rV0X*[]J>  
System.err.println("文件下载结束!"); L H8iHB  
} ;0c -+,  
catch(Exception e){e.printStackTrace ();} 0<";9qN)6  
} (q]_&%yW  
?8GggJC  
p&nPzZQL(  
//获得文件长度 Oe["4C  
public long getFileSize() Fb0r(vQ^  
{ /5$;W 'I  
int nFileLength = -1; !RD<"  
try{ 3\B 28m  
URL url = new URL(siteInfoBean.getSSiteURL()); 4ru-qF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;qN;oSK  
httpConnection.setRequestProperty("User-Agent","NetFox"); cfP9b8JG  
!|#W,9  
?~p]Ey}~9  
int responseCode=httpConnection.getResponseCode(); c&GVIrJ  
if(responseCode>=400) P< 5v\\  
{ `UK'IN.il  
processErrorCode(responseCode); ]9P2v X   
return -2; //-2 represent access is error z?DI4 O#Up  
} ^.HvuG},O  
:+q d>;yf#  
7H l>UX,|  
String sHeader; -$2a@K,i  
,|RN?1?U  
L]kd.JJvy  
for(int i=1;;i++) G8t9Lx  
{ !w;oVPNg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R0A|} Ee*  
//Utility.log(in.readLine()); psFY=^69o  
sHeader=httpConnection.getHeaderFieldKey(i); }83a^E9L  
if(sHeader!=null) ^kO+NH40  
{ +>}LT_  
if(sHeader.equals("Content-Length")) ``?79MJ5  
{ Nm7YH@x*o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z)^1~!w0  
break; @?vC4+'  
} PptVneujI  
} @$aGVEcU$  
else LGdM40  
break; x=M%QFe  
} sW^e D;  
} J{!U;r!6  
catch(IOException e){e.printStackTrace ();} |Fi{]9(G2  
catch(Exception e){e.printStackTrace ();} M(/ATOJ(  
W2Ik!wEe&  
(xdC'@&  
Utility.log(nFileLength); e1OGGF%E n  
n(h9I'V8)F  
.US=fWyrb  
return nFileLength; [2$mo;E?  
} ?`lD|~  
v6 C$Y+5~  
nmuzTFs=  
//保存下载信息(文件指针位置) 2Wn*J[5  
private void write_nPos() K'_qi8Z  
{ C==yl"w  
try{ v8} vk]b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .sCj3sX*  
output.writeInt(nStartPos.length); omMOA  
for(int i=0;i<nStartPos.length;i++) Cvp!(<<gK  
{ ('k9XcTPP  
// output.writeLong(nPos); q S qS@+p  
output.writeLong(fileSplitterFetch.nStartPos); xWnOOE$i  
output.writeLong(fileSplitterFetch.nEndPos); +6`+Q2qi  
} fg)VO6Wo&  
output.close(); PS}'LhZ  
} KcvstC`  
catch(IOException e){e.printStackTrace ();} HSk_'g(\0  
catch(Exception e){e.printStackTrace ();} xfa-   
} :o 8XG  
S54q?sb_  
IE|? &O  
//读取保存的下载信息(文件指针位置) 2O 2HmL  
private void read_nPos() Xwo%DZKN  
{ ;=p3L<~c`K  
try{ ![i)_XO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ZfMs6`Wv 1  
int nCount = input.readInt(); KTq+JT u  
nStartPos = new long[nCount]; -|GKtZ]}  
nEndPos = new long[nCount]; oo\7\b#Jx  
for(int i=0;i<nStartPos.length;i++) g\% Z+Dc  
{ AU1U?En  
nStartPos = input.readLong(); E|vXM"zFl  
nEndPos = input.readLong(); 9Vru,7g  
} U4.$o ]58  
input.close(); 4`B3Kt`o  
} _ a#k3r  
catch(IOException e){e.printStackTrace ();} } J[Z)u  
catch(Exception e){e.printStackTrace ();} 4_`(c1oA  
} >qz#&  
Q+oV? S3{  
JC MUK<CG  
private void processErrorCode(int nErrorCode) V3>tW,z  
{ Z)}UCi+/".  
System.err.println("Error Code : " + nErrorCode); zM,r0Z  
} C-@[=  
.* )e24`  
.P <3+  
//停止文件下载 *`q?`#1&&.  
public void siteStop() ", p5}}/  
{ %tMx48'N  
bStop = true; f"*k>=ETI  
for(int i=0;i<nStartPos.length;i++) EE^x34&=  
fileSplitterFetch.splitterStop(); o! l Ykud  
9Pb6Z}  
L#",.x  
} : r(dMU3%  
} <5? pa3  
//负责部分文件的抓取 .g3=L  
**FileSplitterFetch.java aeISb83Y|  
*/ }T0O~c{$i  
package NetFox; PY;tu#W!%  
<.mH-Y5i  
9Ta0Li  
import java.io.*; Sbl=U  
import java.net.*; n)~*BpL3  
u0GHcpOm  
`BQv;NtP  
public class FileSplitterFetch extends Thread { Vr|e(e.%  
u&w})`+u5  
"M, 1ElQ  
String sURL; //File URL pI:,Lt1B  
long nStartPos; //File Snippet Start Position .faf!3d  
long nEndPos; //File Snippet End Position \{}dn,?Fv  
int nThreadID; //Thread's ID N+ak{3  
boolean bDownOver = false; //Downing is over 8qqN0"{,  
boolean bStop = false; //Stop identical  vTgx7gP  
FileAccessI fileAccessI = null; //File Access interface _6Y+E"@zs  
lXg5UrW  
P}]o$nWT  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException xbBqR _ H_  
{ cGiL9|k  
this.sURL = sURL; 5f{P% x(  
this.nStartPos = nStart; :\vs kk),  
this.nEndPos = nEnd; sO` oapy  
nThreadID = id; n>?D-)g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +SR{ FF  
} 1X[^^p~^  
d=n@#|3  
V"Z8-u  
public void run() n m<?oI*\  
{ <|3%}?  
while(nStartPos < nEndPos && !bStop) P`ou:M{8  
{ . %s U)$bH  
=#/Kg_RKL  
m`9nDiV  
try{ J*[@M*R;&  
URL url = new URL(sURL); 4Wp5[(bg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'L7qf'RV  
httpConnection.setRequestProperty("User-Agent","NetFox"); qXg&E}]:=  
String sProperty = "bytes="+nStartPos+"-"; 'S1u@p,q  
httpConnection.setRequestProperty("RANGE",sProperty); G[\TbPh  
Utility.log(sProperty); #]x3(}3W  
VJ=>2'I  
 kDE-GX"Y  
InputStream input = httpConnection.getInputStream(); ~\mh\a&  
//logResponseHead(httpConnection); ujRXAN@mC  
+4.s4&f)  
 #D4  
byte[] b = new byte[1024]; odSPl{.>d  
int nRead; G0{Z@CvO'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >UMxlvTg&  
{ 4SZ,X^]I>  
nStartPos += fileAccessI.write(b,0,nRead); B ytx.[zbX  
//if(nThreadID == 1) {Q3OT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QJ3#~GYNr  
} P{-- R\  
9H/>M4RT  
f4h~c  
Utility.log("Thread " + nThreadID + " is over!"); R7/S SuG6\  
bDownOver = true; 4%^z=%  
//nPos = fileAccessI.write (b,0,nRead); {_Wrs.a'8  
} 755,=U8'wi  
catch(Exception e){e.printStackTrace ();} n&njSj/  
} W48RZghmx  
} RkE)2q[5  
Ln4]uqMG.  
_Xt/U>N  
//打印回应的头信息 16zReI(  
public void logResponseHead(HttpURLConnection con) V9,<>  
{ 8i154#l+\  
for(int i=1;;i++) dMH_:jb  
{ GLn=*Dh#  
String header=con.getHeaderFieldKey(i); r*+~(83k  
if(header!=null) .`}TND~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9h amxi  
Utility.log(header+" : "+con.getHeaderField(header)); q1T)H2S  
else ->rqr#  
break; {5~h   
} F(yR\)!C  
} SO=gG 2E  
 xgcxA:  
Cgx:6TRS  
public void splitterStop() k1<^Ept  
{ `Pvi+:6\Y  
bStop = true; |Dn Zk3M,  
} ZC N}iQu4  
[(heE  
%dzt'uz  
} TP rq:"K  
nzC *mPX8  
uQIPnd(V  
/* ?> }p'{I  
**FileAccess.java Z*m^K%qJ  
*//文件访问(定位,写) YGJ!!(~r  
package NetFox; hSm?Z!+  
import java.io.*; Hz.i$L0}  
[kg?q5F)  
2y - QH  
public class FileAccessI implements Serializable{ )X0=z1$  
uu.X>agg  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '4 *0Pw  
RandomAccessFile oSavedFile; <= o<lRU  
long nPos; ,c&u\W=p  
|9jK-F6   
x95s%29RS  
public FileAccessI() throws IOException t`Kpbfk  
{ @3.Z>KONx  
this("",0); uge r:cD  
} 9\4x<*  
AioW*`[WjA  
ij$NTY=u  
public FileAccessI(String sName,long nPos) throws IOException ubM1Qr  
{ ZaYiby@Ci  
oSavedFile = new RandomAccessFile(sName,"rw"); 2Mt$Dah  
this.nPos = nPos; ,Z~`aHhr  
oSavedFile.seek(nPos); !T,<p    
} x4I!f)8Q  
tnJ7m8JmC  
O2Qmz=%  
public synchronized int write(byte[] b,int nStart,int nLen) MJ JC6:  
{ SaXt"Ju,AH  
int n = -1; EHwb?{  
try{ klUV&O+=%  
oSavedFile.write(b,nStart,nLen); ^ 8}P_  
n = nLen; K1 "HJsj  
} yMNJHiE/  
catch(IOException e) K,g6y#1"  
{ M{J>yN  
e.printStackTrace (); 9<u&27.  
} h-96 2(LG  
>%tP"x{  
:^]Po$fl  
return n; $5i\D rs  
} ~^2w)-N  
,/?J!W@m  
oJTEN}fL  
} Ak?9a_f  
M2Nh3ijr  
KR ( apO  
/* PEI$1,z  
**SiteInfoBean.java {N2GRF~c-y  
*/ @@D/&}#F  
package NetFox; *|y'%y  
LA6XTgcu  
mW"e  
public class SiteInfoBean { L ci?  
-dM~3'  
B&_:20^y~  
private String sSiteURL; //Site's URL \^(#b,k#  
private String sFilePath; //Saved File's Path }rJqMZ]w  
private String sFileName; //Saved File's Name 6|EOB~|  
private int nSplitter; //Count of Splited Downloading File i3)3. WK^  
jwk+&S  
Tv|'6P  
public SiteInfoBean() }ekNZNcuM  
{//nSplitter的缺省值为5 k M /:n  
//default value of nSplitter is 5 0kUhz\"R:q  
this("","","",5); &`m.]RV  
} P'Y(f!%  
u0wu\  
j EbmW*   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1|p\rHGd  
{ ;l;jTb^l  
sSiteURL= sURL; "Erphn  
sFilePath = sPath; NuO@N r  
sFileName = sName; DNmC   
this.nSplitter = nSpiltter; oc"p5Y3,Os  
Zna6-0o  
~;HASHu  
} Kh3i.gm7g  
[\ku,yd%0  
\;-Yz  
public String getSSiteURL() niS\0ZA  
{ YMw,C:a4  
return sSiteURL; 4m\Cc_:jO  
} @>z.chM;  
F[c oa5  
eYv^cbO@:  
public void setSSiteURL(String value) q,sO<1wAT\  
{ D!* SA  
sSiteURL = value; CRo @+p10  
} QO$18MBcc  
<@M5 C -hH  
bzG vnaTt  
public String getSFilePath() J)g +I  
{ /[Nkk)8-  
return sFilePath; "I=Lbh-`  
} -d?<t}a  
):Fg {7b]n  
Wgf f+7k  
public void setSFilePath(String value) 9vi+[3s/=;  
{ _&HFKpHQ  
sFilePath = value; vm gd  
} F~v0CBcAL  
F4=X(P_6  
Ne9VRM P  
public String getSFileName() %5L~&W}^"  
{ l%V+] skS  
return sFileName; ."Pn[$'.  
} Ks3YrKk;p  
"U9e)a0v  
~e|E5[-i  
public void setSFileName(String value) <YCjo[(~  
{ GB+$ed5@<  
sFileName = value; ZXhNn<  
} vmxS^_I  
^E, #}cW  
l )r^|9{  
public int getNSplitter() 1^AQLOiRE1  
{ yu#m6K  
return nSplitter; E.C=VfBW  
} 1&h\\&ic  
nVpDjUpN  
"wVisL2+.  
public void setNSplitter(int nCount) )[99SM   
{ Z2;~{$&M+  
nSplitter = nCount; ,wr5DQ  
} B|syb!g  
} Bz{"K  
/?>W\bP<  
f3;[ZS  
/* -R9{Ak  
**Utility.java UnDX .W*2  
*/ -4Q\FLC'k  
package NetFox; fda2dY;  
Y;\@ 5TgQ,  
a{e1g93}  
public class Utility { ZkibfVwe  
1< b~="  
mJ8EiRSE  
public Utility() HII@Ed f?  
{ uEsF 8  
 zW?=^bE  
'Q* .[aJt  
} lNe5{'OrO  
"Z';nmv'N  
//线程睡眠 f. h3:_r  
public static void sleep(int nSecond) $U&p&pgH=W  
{ .' v$PEy  
try{ Gp_flGdGQ  
Thread.sleep(nSecond); i1{)\/f3  
} 4<EC50@.  
catch(Exception e) Ga^:y=m  
{ "6~+ -_:  
e.printStackTrace (); A{3nz DLI  
} ]:#W$9,WL  
} h1Y^+A_  
tPk> hzW  
//日志 ^S|}<6~6b  
public static void log(String sMsg) p=[I;U-#H  
{ Eb'M< ZY  
System.err.println(sMsg); t@2MEo  
} 5HB*  
5rtE/ {A  
PTQN.[bBh  
public static void log(int sMsg) =OrVaZ0  
{ DLq'V.M:  
System.err.println(sMsg); .5~3D97X&  
} -Zg.o$  
} )*}?EI4.  
@]]\r.DG  
A)#Fyde  
/* eOb)uIF  
**TestMethod.java P-Gp^JX8  
*/ H ~<.2b  
package NetFox; F${}n1D  
F)aF.'$-/  
R-k~\vCW  
public class TestMethod { l?X)]1  
P#:nXc$  
9*s:Vff{  
public TestMethod() +wEsfYW  
{ ///xx/weblogic60b2_win.exe Tj2pEOu  
try{ ^ %1u3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a!j{A?7Kw.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z0 c|;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;b|=osyT\  
fileFetch.start(); n "I{aJ]K  
} X4k|k>  
catch(Exception e){e.printStackTrace ();} +wGvY r  
ws;|fY  
M>*xbBl  
} b-#oE{(\'  
$}H,g}@0  
nbv}Q-C  
public static void main(String[] args) z wn#E  
{ :@Ml-ZE  
new TestMethod(); JGYJ;j{E]  
} gP ^A  
} I!Fd~g9I4  
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