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http断点续传简单实现(java)

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/* ]dvPx^`d{  
**SiteFileFetch.java nz4<pvC,*  
*/ `NBbTQtgO  
package NetFox; A_!QrM  
import java.io.*; O0^?f/&k  
import java.net.*; `/#f?Hk=  
\|CPR6I  
10p8|9rE}B  
public class SiteFileFetch extends Thread { y n SBVb!)  
` ^DjEdUN  
rwiw Rh  
SiteInfoBean siteInfoBean = null; //文件信息Bean  %BUEX  
long[] nStartPos; //开始位置 _ Yfmxn8V  
long[] nEndPos; //结束位置 3Jk[/ .h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H&M1>JtE  
long nFileLength; //文件长度 |xn#\epy@  
boolean bFirst = true; //是否第一次取文件 *HR +a#o  
boolean bStop = false; //停止标志 9B /s  
File tmpFile; //文件下载的临时信息 U^MuZ  
DataOutputStream output; //输出到文件的输出流 .%q$d d>>  
$@_{p*q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 93j{.0]X  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?w-1:NW jt  
{ I%oRvg|q  
siteInfoBean = bean; |,b2b2v ?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zj<ahg%z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \V,c]I   
if(tmpFile.exists ()) "!O1j r;  
{ U4BqO :sd  
bFirst = false; bmu6@jT  
read_nPos(); [F+(^- (  
} Y9F)`1 7  
else e}c&LDgU  
{ `ncNEHh7K  
nStartPos = new long[bean.getNSplitter()]; _a](V6  
nEndPos = new long[bean.getNSplitter()]; @Mm/C?#*O  
} ._?V%/  
%SAw;ZtQ:  
`Oq M8U @  
c!It ^*  
} Z7fg 25  
qj&b o  
owvS/"@  
public void run() fAGctRGH  
{ yub{8f;v  
//获得文件长度 v5_7r%Hiw  
//分割文件 69-:]7.g  
//实例FileSplitterFetch #)o7"PW:  
//启动FileSplitterFetch线程 Y25^]ON*\^  
//等待子线程返回 #02Kdo&Vy  
try{ ?]c+j1 i  
if(bFirst) 8V9 [a*9  
{ xACdZB(  
nFileLength = getFileSize(); 7Y1GUIRa3  
if(nFileLength == -1) wJe?t$ac?  
{ %%%S"$t  
System.err.println("File Length is not known!"); UUeB;'E+  
} /@hJpz|+   
else if(nFileLength == -2) {CtR+4KD  
{ aBhV3Fd[B  
System.err.println("File is not access!"); !SO8O  
} Mo D?2J  
else v!9i"@<!  
{ D8%AV; -Y  
for(int i=0;i<nStartPos.length;i++) qi(*ty  
{ b7HffO O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d H? ScXM=  
} .Pe9_ZH$W  
for(int i=0;i<nEndPos.length-1;i++) ZtK\HDdp  
{ PY`L$e  
nEndPos = nStartPos[i+1]; 1svi8wh  
} 9xFO]Y"  
nEndPos[nEndPos.length-1] = nFileLength; Pao%pA.<  
} KVkMU?6  
} wG 1l+^p  
Ts9ktPlm  
z x@$RS+]  
//启动子线程 "7,FXTaer  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; im]g(#GnKh  
for(int i=0;i<nStartPos.length;i++) PE"v*9k  
{ Ya#h'+}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), paW@\1Q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), : =Kx/E:1  
nStartPos,nEndPos,i); n((vY.NDV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $bvJTuw  
fileSplitterFetch.start(); ,lt8O.h-l  
} t 9^A(Vh"-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uLQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); cK@jmGj+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", xyA-P& N  
nEndPos = " + nFileLength); /6K Il  
// fileSplitterFetch[nPos.length-1].start(); krB'9r<wa`  
o31Nmy Ni  
`y^sITr  
//等待子线程结束 H={&3poBz  
//int count = 0; ;apzAF  
//是否结束while循环 ?kTWpXx"=  
boolean breakWhile = false; $s\UL}Gc  
;@3FF  
e5?PkFV^a1  
while(!bStop) a.@qGsIH  
{ :7g=b%;  
write_nPos(); T6#CK  
Utility.sleep(500); WC,+Cn e  
breakWhile = true; `.%JjsD<  
!ABiy6d  
eq[Et +  
for(int i=0;i<nStartPos.length;i++) &QNY,Pj  
{ O(z}H}Fv  
if(!fileSplitterFetch.bDownOver) cXnKCzSxZq  
{ -|S]oJy  
breakWhile = false; G8Z4J7^  
break; i3VW1~.8  
} Km#pX1]>e  
} *\uM.m0$  
if(breakWhile) _[K"gu  
break; Dg HaOAdU  
b'YE9E  
b:J(b?  
//count++; V\]" }V)"  
//if(count>4) p(F" /  
// siteStop(); /) 4GSC}Gg  
} IA&L]  
Wg`AZ=t  
tK(g-u0N`(  
System.err.println("文件下载结束!"); ^|!I +  
} c{+AJ8  
catch(Exception e){e.printStackTrace ();} j*v40mXl`2  
} ? "/ fPV-  
 m#vL*]c}  
69K{+|  
//获得文件长度 N|g;W  
public long getFileSize() )~J>X{hy  
{ !7bw5H  
int nFileLength = -1; ?, r~=  
try{ )D&M2CUw"f  
URL url = new URL(siteInfoBean.getSSiteURL()); R6-n IY,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N6OMY P1  
httpConnection.setRequestProperty("User-Agent","NetFox"); [, RI-#n  
&MZ$j46  
y&m0Lz53Z  
int responseCode=httpConnection.getResponseCode(); $~0Q@):  
if(responseCode>=400) N==ZtKj F  
{ xo}b= v  
processErrorCode(responseCode); D]a:@x`+Bz  
return -2; //-2 represent access is error wxg^Bq)D*R  
} M 3 '$[  
l%ayI  
$rF=_D6  
String sHeader; eN? Y7  
TL$EV>Nr  
D4Al3fe  
for(int i=1;;i++) `;|5  
{ :<Y}l-x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [D-Q'"'A  
//Utility.log(in.readLine()); 9^"b*&>P  
sHeader=httpConnection.getHeaderFieldKey(i); g"s$}5{8:  
if(sHeader!=null) ,#FLM`  
{ 9E2j!  
if(sHeader.equals("Content-Length")) acP+3u?r  
{ :F,O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); SzwQOs*  
break; D\w h;r  
} Zv11uH-C  
} Ji1Pz)fq  
else *L6PLe  
break; PWRy7d  
} GZS1zTwBL  
} T{qTj6I  
catch(IOException e){e.printStackTrace ();} H1GRMDNXOA  
catch(Exception e){e.printStackTrace ();} Jj~EiA  
X"gCR n%tn  
A[IL H_w  
Utility.log(nFileLength); '{ I_\~*  
=deMd`=J  
TD[EQ  
return nFileLength; YjF|XPv+ l  
} ^, l_{  
?Xdak|?i  
)VL96did  
//保存下载信息(文件指针位置) !Fo*e  
private void write_nPos() NNhL*C[_7  
{ Xs&TJ8a  
try{ Pq*s{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V.ht, ~l  
output.writeInt(nStartPos.length); Zwcy4>8  
for(int i=0;i<nStartPos.length;i++) }i {sg#  
{ dzK{ Z  
// output.writeLong(nPos); yR{x}DbG  
output.writeLong(fileSplitterFetch.nStartPos); 7n]65].t  
output.writeLong(fileSplitterFetch.nEndPos); Uv YF[@  
} 7Dnp'*H  
output.close(); )jWO P,|  
} (,^*So/  
catch(IOException e){e.printStackTrace ();} O}9KJU  
catch(Exception e){e.printStackTrace ();} }$MN|s  
} r`)L ~/  
\s3]_1F;t  
+*\X]06  
//读取保存的下载信息(文件指针位置) JN^ &S  
private void read_nPos() SN4Q))dAU  
{  +`7KSwa  
try{ xq6cKtSv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,+`61J3W  
int nCount = input.readInt(); 'r(1Nj  
nStartPos = new long[nCount]; -a*K$rnB  
nEndPos = new long[nCount]; DD" $1o"  
for(int i=0;i<nStartPos.length;i++) 1/p*tZP8i  
{ ??TMSH  
nStartPos = input.readLong(); QL6C,#6  
nEndPos = input.readLong(); Kp+CH7I*  
} f.24:Dw,  
input.close(); ~GE$myUT\p  
} E?(xb B  
catch(IOException e){e.printStackTrace ();} o=FE5"t  
catch(Exception e){e.printStackTrace ();} 85 EQ5yY  
} #%J5\+ua  
OD' ]:  
$$:ZX  
private void processErrorCode(int nErrorCode) tXJU vish  
{ BCe_@  
System.err.println("Error Code : " + nErrorCode); aP'"G^F   
} ARcv;H 5  
8|E'>+ D_-  
n wI!O  
//停止文件下载 ih?^t(i  
public void siteStop() n|GaV  
{ TO%dw^{_`  
bStop = true; hhoEb(BA  
for(int i=0;i<nStartPos.length;i++) f+rz|(6vs{  
fileSplitterFetch.splitterStop(); GGhM;%H_99  
6} FO[  
%OgS^_tu  
} fgihy  
} FU=w(< R;  
//负责部分文件的抓取 wts=[U`(  
**FileSplitterFetch.java uEc<}pV  
*/ - 0?^#G}3}  
package NetFox; g$dsd^{O7  
JG{j)O|L  
.z13 =yv  
import java.io.*; 52upoU>}2  
import java.net.*; f|u#2!7  
7JSNYTH  
eNiaM6(J  
public class FileSplitterFetch extends Thread { jA#/Z  
?\8?%Qk  
j~j\\Y  
String sURL; //File URL hHqh{:q{v  
long nStartPos; //File Snippet Start Position G,;,D9jO7  
long nEndPos; //File Snippet End Position vkLC-Mzm<  
int nThreadID; //Thread's ID s,a}?W  
boolean bDownOver = false; //Downing is over ^5r9 5  
boolean bStop = false; //Stop identical sg E-`#  
FileAccessI fileAccessI = null; //File Access interface s+:=I e  
fO#vF.k%  
LJoGpr 8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException e8'wG{3A  
{ AIA6yeaU  
this.sURL = sURL; 7)h[Zy,A  
this.nStartPos = nStart; ?f/n0U4w  
this.nEndPos = nEnd; ;-UmY}MU  
nThreadID = id; 9n}p;3{f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !|c|o*t{  
} +2 Af&~T  
_)]CzBRq\6  
!x'/9^i~v  
public void run() |lv|!]qAma  
{ XD"_Iq!  
while(nStartPos < nEndPos && !bStop) G%d (  
{ ioPUUUb)  
yoAfc  
|p$spQ  
try{ ePIiF_X  
URL url = new URL(sURL); _=|vgc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l7De6A"  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6"dD2WV/  
String sProperty = "bytes="+nStartPos+"-"; klUQkz |<a  
httpConnection.setRequestProperty("RANGE",sProperty); eW|^tH  
Utility.log(sProperty); O{ /q-~_  
JI vo_7{  
F[ewn/]n  
InputStream input = httpConnection.getInputStream(); NWxUn.Gy9  
//logResponseHead(httpConnection); OT&k.!=  
Y2'cs~~$Ce  
Ali9pvE  
byte[] b = new byte[1024]; 7t.!lh5G%  
int nRead; ,]b~t0|B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k%^lF?_0I  
{ h;3cd0  
nStartPos += fileAccessI.write(b,0,nRead); 3j3N!T9  
//if(nThreadID == 1) &HSq(te  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vzmc}y G  
} x`6<m!d`  
-\#0]F:-  
r_;9' #&'  
Utility.log("Thread " + nThreadID + " is over!"); }<'5 z qS  
bDownOver = true; F5o+kz$;  
//nPos = fileAccessI.write (b,0,nRead); TwgrRtj'  
} } (!EuLL  
catch(Exception e){e.printStackTrace ();} }%D^8>S  
} LY+|[qka  
} `Qeg   
VE8;sGaJ  
*-xU2  
//打印回应的头信息 fw[y+Bi& ?  
public void logResponseHead(HttpURLConnection con) Qyy.IPTP  
{ kY'T{Sm1^  
for(int i=1;;i++) Li Kxq=K  
{ `mN4_\]  
String header=con.getHeaderFieldKey(i); \rPbK+G.  
if(header!=null) O(_[ayE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [|l?2j\  
Utility.log(header+" : "+con.getHeaderField(header)); } CfqG?)  
else IIyI=Wl pG  
break; 6S~sVUL9`  
} V%Sy"IG  
} VU@9@%TN  
|<O9Sb_  
t:fFU1x  
public void splitterStop() Q?X>E3=U  
{ @$T 9Ll  
bStop = true; *&f$K1p  
} D.mHIsX6\  
/JT#^Y  
a.z;t8  
} @/ k@WhFZ  
5ms""LD/  
S%`0'lzzj  
/* GH[wv<  
**FileAccess.java ~}<DG1!  
*//文件访问(定位,写) H9CS*|q6r  
package NetFox; B,{K*-7)MX  
import java.io.*; be +4junf  
+a*tO@HG  
PiA0]>  
public class FileAccessI implements Serializable{ Q~T$N  
{P*m;a`}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :^(>YAyHj^  
RandomAccessFile oSavedFile; DY^;EZ!hb  
long nPos; QV\eMuNy  
` Jdb;  
~s5SZK*  
public FileAccessI() throws IOException RSo& (Uv  
{ %plo=RF  
this("",0); <n#DT  
} *BR^U$,e  
]KmO$4  
"&3h2(#%  
public FileAccessI(String sName,long nPos) throws IOException ~ yX2\i"  
{ KGg3 !jY  
oSavedFile = new RandomAccessFile(sName,"rw"); e;(0(rI  
this.nPos = nPos; y99mC$"Ee`  
oSavedFile.seek(nPos);  #B\" '8#  
} !50[z:  
& \f{E\A#  
$*?,#ta  
public synchronized int write(byte[] b,int nStart,int nLen) )6aAB|  
{ ?Ec7" hK  
int n = -1; f`Fi#EKT  
try{ zE_i*c"`  
oSavedFile.write(b,nStart,nLen); D gaMO,  
n = nLen; ,I,\ml  
} mWvl 38  
catch(IOException e) X*\ J_  
{ #{\%rWnCm  
e.printStackTrace (); JeE ;V![  
} dN$Tf  
R47\Y  
)KAEt.  
return n; rh^mJU h  
} r3PT1'P?L  
cMOyo<F#^=  
LSRk7'0  
} b1( $R[  
7"C$pm6  
j}C}:\-fY  
/* Ct>GYk$  
**SiteInfoBean.java ruy}/7uf  
*/  \*<d{gZ~  
package NetFox; >m$ 1+30X  
&e!7Z40w@&  
SBS3?hw  
public class SiteInfoBean { bR)(H%I  
.*)2SNH  
a8UwhjFO  
private String sSiteURL; //Site's URL ?pd8w#O  
private String sFilePath; //Saved File's Path :\o {_  
private String sFileName; //Saved File's Name VFys.=  
private int nSplitter; //Count of Splited Downloading File H7DJ~z~J  
>o=-$gz`  
# }y2)g  
public SiteInfoBean() BGX.U\uc  
{//nSplitter的缺省值为5 sdo [D  
//default value of nSplitter is 5 nX`u[ks  
this("","","",5); ] @u6HH~^  
} RtM8yar+sn  
EU+S^SyZi  
=aTv! 8</  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1waTTT?"Ho  
{ L}pt)w*V1j  
sSiteURL= sURL; 3zcU%*  
sFilePath = sPath; \r+8qC[,  
sFileName = sName; XY3v_5~/1F  
this.nSplitter = nSpiltter; Xx>X5Fy  
OL^l 3F  
,]d /Q<  
} @W"KVPd  
z+n,uHs  
ybKWOp:O  
public String getSSiteURL() lE(a%'36  
{ W~7A+=&  
return sSiteURL; LF& z  
} oc>{?.^  
,1+y/{S  
)`O~f_pIC  
public void setSSiteURL(String value) #;2n;.a  
{ 8p:e##%  
sSiteURL = value; CmoE _8U>  
} v : OR   
F}/S:(6LF2  
o9dY9o+Z  
public String getSFilePath()  abfW[J  
{ /Y2}a<3&0  
return sFilePath; U ^5Kz-5.  
} fy@<&U5rg  
oUQ,61H  
^Xq 6:  
public void setSFilePath(String value) %UERc{~o*,  
{ e9U9Uu[  
sFilePath = value; ?Yth0O6?sb  
} $m-2Hh qZ  
(Hb:?(  
4i(JZN?  
public String getSFileName() UKT%13CO4U  
{ FWG6uKv  
return sFileName; 3@$,s~+ 3  
}  VoWNW  
jk[1{I/  
_n50C"X=&(  
public void setSFileName(String value) sg3OL/"  
{ T^k7o^N>  
sFileName = value; 9Hb6nm  
} 'O_3)x5  
!C3MFm{B  
|es?;s'  
public int getNSplitter() PuA9X[=  
{ D"2&P^-  
return nSplitter; BMG3|N^  
} xg;+<iW  
YSic-6z0Ms  
lJ}_G>GJ  
public void setNSplitter(int nCount) DpvI[r//'*  
{ %Q fO8P  
nSplitter = nCount; e]$}-i@#  
} 1Vrh4g.l  
} QLvHQtzwX  
?R$F)g7<  
qzKdQ&vO  
/* 2db3I:;E  
**Utility.java ZQ%'`q\c  
*/ U4C 9<h&  
package NetFox; 2a`o &S  
L\xk:j1[  
Ez fN&8E  
public class Utility { vyK7I%T'R  
gM u"2I5  
t!W(_8j  
public Utility() CUBEW~X}M  
{ :OhHb #D  
KWowN;  
e478U$  
} >>t@}F)  
Eg#K.5hJ  
//线程睡眠 wnEyl[ac  
public static void sleep(int nSecond) "$+Jnc!!  
{ lm-dW'7&  
try{ P3x= 8_#  
Thread.sleep(nSecond);  ' V^6XI  
} Q  Nh|Wz  
catch(Exception e) 4ew" %Cs*  
{ N~goI#4  
e.printStackTrace (); (_mnB W  
} N`5,\TR2f  
} ' g=  
cdl&9-}  
//日志 Zw5Ni Xj  
public static void log(String sMsg) F4}]b(L  
{ Z<1FSk,[  
System.err.println(sMsg); "U>JM@0DNm  
} 4:$4u@   
-Ta9 pxZk  
8dZSi  
public static void log(int sMsg) Lsq A**=  
{ iNtaDX| %/  
System.err.println(sMsg); B%)%  
} O`x;,6Vr  
} 1PVtxL?1P  
xW)2<m6C&  
=9O^p@Q#W  
/* WM7oM~&{6  
**TestMethod.java 4B =7:r  
*/ nm5cpnNl  
package NetFox; ~dgDO:)  
?I_s0k I  
%GjM(;Tk  
public class TestMethod { p{amC ;cI$  
=9'RM>  
9YIM'q>`v  
public TestMethod() 8uc1iB  
{ ///xx/weblogic60b2_win.exe +Mo9kC  
try{ ov ` h  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p Dx1z|@z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &=Ar  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z &Pg"a?\  
fileFetch.start(); E4`N-3  
} X@ +{5%  
catch(Exception e){e.printStackTrace ();} 2,$8icM  
Cc+t}"^  
l2zFKCGF(  
} @Owb?(6?  
cs,N <|  
+%zAQeb  
public static void main(String[] args) BZ94NOOdw  
{ fxgPhnaC>  
new TestMethod(); 4ni<E*  
} #C~+JL  
} rq8K_zp  
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