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http断点续传简单实现(java)

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/* K/i*w<aPb7  
**SiteFileFetch.java ADDSCY=,  
*/ gkES5Q  
package NetFox; ="Ho%*@6  
import java.io.*; (tIo:j  
import java.net.*; gy#/D& N[  
3RYpJAH  
OB Otuu.  
public class SiteFileFetch extends Thread { p "n$!ilbm  
9 7GV2]-M  
=t9\^RIx)?  
SiteInfoBean siteInfoBean = null; //文件信息Bean Cs9.&Y  
long[] nStartPos; //开始位置 /fZe WU0W  
long[] nEndPos; //结束位置 jcuB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^l9N48]|?  
long nFileLength; //文件长度 9 Vkb>yFX'  
boolean bFirst = true; //是否第一次取文件 Nl^;A> <u  
boolean bStop = false; //停止标志 $ M`hh{ -  
File tmpFile; //文件下载的临时信息 M?Dfu .t  
DataOutputStream output; //输出到文件的输出流 o]yl ;I  
QZ6D7t Uc8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ,l !Ta "  
public SiteFileFetch(SiteInfoBean bean) throws IOException _FH`pv  
{ . $BUw  
siteInfoBean = bean; QEz? w}b*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +x0!*3q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); L^}_~PO N5  
if(tmpFile.exists ()) iII=;:p  
{ )wC?T  
bFirst = false; SxOC1+Oy  
read_nPos(); TW)c#P43K  
} (s.0P O`  
else )bS yB29S  
{ 8K:y\1  
nStartPos = new long[bean.getNSplitter()]; lAb*fafQy  
nEndPos = new long[bean.getNSplitter()]; AL9chYP}/  
}  6:b! F  
&e @2  
hs^zTZ_  
tSr8 zAV  
} oI }VV6vO  
?}wk.gt>  
#M9~L[nF S  
public void run() G<}()+L  
{ ?zh9d%R  
//获得文件长度 A\4D79>x  
//分割文件 -ws? "_w  
//实例FileSplitterFetch \k.{-nh  
//启动FileSplitterFetch线程 b*a#<K$T_  
//等待子线程返回 7m4ao K  
try{ ^q{9  
if(bFirst) nyQ&f'<   
{ wPQH(~k:  
nFileLength = getFileSize(); ]<ldWL  
if(nFileLength == -1) }AB, 8n`  
{ ~IYUuWF(  
System.err.println("File Length is not known!"); - Ajo9H  
} ] eotc2?u  
else if(nFileLength == -2) jyZ  (RB  
{ bo2H]PL*  
System.err.println("File is not access!"); =bfJ^]R  
} 7%5z p|3  
else @$ne{2J3  
{ $ `ov4W  
for(int i=0;i<nStartPos.length;i++) zd2)M@  
{ aOlT;h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `, OG7hg  
} @5N]ZQ9  
for(int i=0;i<nEndPos.length-1;i++) smlpD3?va  
{ ;rF\kX&Jh  
nEndPos = nStartPos[i+1]; 2;k*@k-t  
} h;p>o75O  
nEndPos[nEndPos.length-1] = nFileLength; <c2E'U)X  
} MI/MhkS ?  
} 94h]~GqNi  
&v56#lG  
[4YTDEv%  
//启动子线程 >"^ O"E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Nv#t:J9f  
for(int i=0;i<nStartPos.length;i++) ;Y 00TGU  
{ 2^r <{0@n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6</xL9#/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zBCtd1Xrni  
nStartPos,nEndPos,i); A 9( x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3x`|  
fileSplitterFetch.start(); " un]Gc   
} um jt]Gu[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }q_<_lQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 2M.fLQ?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Kz~ps 5  
nEndPos = " + nFileLength); j]{_s"O  
// fileSplitterFetch[nPos.length-1].start(); :*I# n  
_GV:HOBi  
6V$Avg\6\  
//等待子线程结束 N(; 1o.~  
//int count = 0; ,vr? 2k  
//是否结束while循环 HJ9Kz^TnC  
boolean breakWhile = false; t_o['F  
_dqzB$JV  
~5NXd)2+Ks  
while(!bStop) Zq^At+8+  
{ +[M6X} TQ  
write_nPos(); [A~y%bI"  
Utility.sleep(500); i`(XLi}k  
breakWhile = true; -)w@f~Q  
Dt}JG6S  
| z9*GY6RU  
for(int i=0;i<nStartPos.length;i++) ZGBd%RWjG_  
{ /kE6@  
if(!fileSplitterFetch.bDownOver) M||+qd W!  
{ *{YlN}vA  
breakWhile = false; T/b6f;t-s  
break; 6"wlg!k8  
} y`VyQWW  
} IoxgjUa  
if(breakWhile) d?ex,f.  
break; gR&Q3jlIV  
SzAJ2:qhl  
B~6&{7 xc%  
//count++; P Y_u/<u  
//if(count>4) 34`'M+3  
// siteStop(); 8*W#DH!  
} .I7pA5V{#  
^hG-~z<  
UvJ}b  
System.err.println("文件下载结束!"); @'w"R/,n-@  
} :G [|CPm-  
catch(Exception e){e.printStackTrace ();} c?tBi9'Y]  
} q_Q/3rh  
y0Fb_"}  
69PE9zz  
//获得文件长度 |N4.u _hM  
public long getFileSize() sGi"rg#  
{ S ^"y4- 2  
int nFileLength = -1; )SaGH3~*C  
try{ YpWPz %`:  
URL url = new URL(siteInfoBean.getSSiteURL()); {ME2ImD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oL!EYbFD'Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); rxe >}ZO  
,-$LmECg  
9eGyyZg  
int responseCode=httpConnection.getResponseCode(); 4qO+_!x{)  
if(responseCode>=400) 6w*dKInG[-  
{ ot,jp|N>f~  
processErrorCode(responseCode); QCD .YFM  
return -2; //-2 represent access is error :nh_k4S@v  
} ? }Z1bH  
K`yRr`pW  
+Jlay1U&  
String sHeader; 6o!!=}'E[  
p09HL%~R  
3r<~Q7e  
for(int i=1;;i++) X@'u y<tI-  
{ (lXGmx8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S{Kiy#ltWc  
//Utility.log(in.readLine()); j:^#rFD4?  
sHeader=httpConnection.getHeaderFieldKey(i); 9`T)@Uj2n  
if(sHeader!=null) dV*]f$wQ  
{ +dWDxguE{w  
if(sHeader.equals("Content-Length")) |!1Y*|Q%s  
{ (jnzT=y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &x=.$76  
break; F<ZYh  
} =qoWCmg"&  
} zbXI%  
else uX"H4l O~  
break; }'5MK  
} dWM'fg  
} bo,_&4?  
catch(IOException e){e.printStackTrace ();} szb_*)k  
catch(Exception e){e.printStackTrace ();} G|[=/>~B  
.\\DKh%  
_mzW'~9wN  
Utility.log(nFileLength); aKV$pC<[o  
;PF`Wj  
,QOG!T4  
return nFileLength; +cD<:"L'g  
}  Qn^'  
:<ka3<0%  
<vnHz?71c  
//保存下载信息(文件指针位置) b1?#81  
private void write_nPos() Kc!} `Pm  
{ }wWKFX  
try{ ?# Mr  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8/DS:uM  
output.writeInt(nStartPos.length); QsGiclU  
for(int i=0;i<nStartPos.length;i++) :lX!\(E2  
{ H;D>|q  
// output.writeLong(nPos); heltgRt  
output.writeLong(fileSplitterFetch.nStartPos); )bA;?i  
output.writeLong(fileSplitterFetch.nEndPos); gMv.V{vD  
} )}''L{k-  
output.close(); q?,).x nN  
} kJWn<5%ayg  
catch(IOException e){e.printStackTrace ();} K}2Erm%A@y  
catch(Exception e){e.printStackTrace ();} ^aIPN5CK  
} qBU-~"2t  
hMzs*gK  
/Y*WBTV'  
//读取保存的下载信息(文件指针位置) 7@#>b E6  
private void read_nPos() 4]rnY~  
{ pny11C  
try{ _geWE0 E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #ml S}~n  
int nCount = input.readInt(); x"eRJii?  
nStartPos = new long[nCount]; Xk:OL,c  
nEndPos = new long[nCount]; _G_Cj{w  
for(int i=0;i<nStartPos.length;i++) BoA/6FRi[  
{ R7]l{2V#^  
nStartPos = input.readLong(); k=2Lo  
nEndPos = input.readLong(); =31"fS@  
} *zNYZ#  
input.close(); V @rI`~$  
} {qDSPo  
catch(IOException e){e.printStackTrace ();} 9 ^o-EC!_  
catch(Exception e){e.printStackTrace ();} VJ84?b{c W  
} y9_V  
~aw.(A?MI  
]~844J p  
private void processErrorCode(int nErrorCode) ioa U*%  
{ h}-3\8 >  
System.err.println("Error Code : " + nErrorCode); 1ofKt=|=  
} XoXM ^*Vk  
 ,t}vz 7  
-_ I _W&  
//停止文件下载 -)s qc P  
public void siteStop() KTK <gV9:  
{ (w&F/ynO:  
bStop = true; Us%T;gW  
for(int i=0;i<nStartPos.length;i++) o-;E>N7t  
fileSplitterFetch.splitterStop(); K7$x<5+)  
yZd +^QN  
zFfoqb#*g  
} R= a|Blp  
} liEPCWl&  
//负责部分文件的抓取 O[# 27_dH  
**FileSplitterFetch.java d[r#-h> dS  
*/ 3E7ULK  
package NetFox; D@C-5rmq  
X"MB|N y  
fz;iOjr>  
import java.io.*; >82@Q^O  
import java.net.*; YgKZ#?*  
w'L\?pI  
mrTlXXz  
public class FileSplitterFetch extends Thread { |].pDwgt  
\ Fl+\?~D  
xrlmKSPa  
String sURL; //File URL :d3bt~b'  
long nStartPos; //File Snippet Start Position tzZ63@cm  
long nEndPos; //File Snippet End Position + r!1<AAE$  
int nThreadID; //Thread's ID ckV`OaRw4  
boolean bDownOver = false; //Downing is over oV)~@0B&0  
boolean bStop = false; //Stop identical avjpA ?Vz  
FileAccessI fileAccessI = null; //File Access interface aGK?x1_  
@*>@AFnf\Z  
4f@o mAM  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^<;V]cY`  
{ =b38(\  
this.sURL = sURL; U0=]  
this.nStartPos = nStart; "ZHW2l Mf  
this.nEndPos = nEnd; _\=`6`b)  
nThreadID = id; `(T,+T4C5k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 v. %R}Pa  
} Xf0M:\w=M  
Y;nZ=9Sw  
Z 1zVwHa_  
public void run() :iFIQpk  
{ ! N|0x`  
while(nStartPos < nEndPos && !bStop) .e3NnOzyxS  
{ %R1tJ(/  
LY6;.d$J  
H&F9J ^rC  
try{ A01AlK_B  
URL url = new URL(sURL); Ny_lrfh)[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z:ni$7<.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1[kMOp  
String sProperty = "bytes="+nStartPos+"-"; -r#X~2tPzD  
httpConnection.setRequestProperty("RANGE",sProperty); whonDG4WP  
Utility.log(sProperty); @vpf[j  
M@h|bN  
CQwL|$)]Y  
InputStream input = httpConnection.getInputStream(); G,TM-l_uw  
//logResponseHead(httpConnection); Fd?"-  
17D"cP  
A3vUPWdDk  
byte[] b = new byte[1024]; tcI}Ca>u  
int nRead; x2@U.r"zo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?!wgH9?8  
{ 'jmTXWq*  
nStartPos += fileAccessI.write(b,0,nRead); m1n.g4Z&*  
//if(nThreadID == 1) W-Fu-Cz=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZPc@Zr`z  
} }>)@WL:q  
lJ+0P2@h*  
x8!ol2\`<  
Utility.log("Thread " + nThreadID + " is over!");  XEC(P  
bDownOver = true; Av?2<  
//nPos = fileAccessI.write (b,0,nRead); \2nUa ;  
} Q F-LU  
catch(Exception e){e.printStackTrace ();} UUF ;p2{f  
} 3VI4X  
} Q s.pGi0W  
pX/n)q[  
zR `EU,  
//打印回应的头信息 ~)qtply  
public void logResponseHead(HttpURLConnection con) qud\K+  
{ GFfq+=se  
for(int i=1;;i++) 1J6,]M  
{ "oWwc zzO  
String header=con.getHeaderFieldKey(i); MepuIh  
if(header!=null) 1mfs 4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {*[\'!d--.  
Utility.log(header+" : "+con.getHeaderField(header)); 994` ua+  
else %Rz&lh/  
break; 9m|kgY# 4  
} p`nPhk,:b  
} ;2@BO-3K  
Vm5c+;  
Qd=^S^}(  
public void splitterStop() V?Z.\~  
{ $KUo s+%  
bStop = true; qP2ekI:y  
} 7a#4tqM#  
)foq),2  
hdnTXs@z  
} ET_W-  
4Y,R-+f  
_2k]3z?  
/* 1^ _U;O:I  
**FileAccess.java I/M_p^  
*//文件访问(定位,写) 4 SHU  
package NetFox; Rop'e8Q  
import java.io.*; MS>t_C(  
rSxxH]-  
TlI<1/fP}  
public class FileAccessI implements Serializable{ fBgEnz/  
!_+8A/  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 IP``O!WP  
RandomAccessFile oSavedFile; rEHkw '  
long nPos; ^zEwA  
[01.\eh  
'\Jj8oJQj  
public FileAccessI() throws IOException B.g[c97  
{ y_*PQZ$c<  
this("",0); {88gW\GL  
} ZiYm:$CJ  
"Vw m  
t<T[h2Wd  
public FileAccessI(String sName,long nPos) throws IOException ( {1e%  
{ AjJURn0`,!  
oSavedFile = new RandomAccessFile(sName,"rw"); _<=S_ <$2  
this.nPos = nPos; {o!KhF:[  
oSavedFile.seek(nPos); NZP.0coY  
} w?zKjqza=v  
56e r`=ms  
~/8M 3k/  
public synchronized int write(byte[] b,int nStart,int nLen) 4(Ov1a>  
{ .!1S[  
int n = -1; 5k6mmiaKk  
try{ < 'f dkW  
oSavedFile.write(b,nStart,nLen); &;XAuDw4+i  
n = nLen; Eo\UAc  
} '" X_B0k  
catch(IOException e) KhCzD[tf  
{ TMs,j!w?I  
e.printStackTrace (); Mva3+T  
} Z4A!U~  
W%.v.0   
L KCb_9  
return n; U\veOQ;mW  
} PqyA1  
J4"mK1N(  
-+7uy.@cS  
} ?lbH02P{v  
vKq^D(&cl  
|o2sbLp  
/* 7_.11$E=H  
**SiteInfoBean.java ,g7.rEA  
*/ a-"k/P#  
package NetFox; i^_#%L  
q}/WQ]p} <  
uKz,SqX  
public class SiteInfoBean { i `s|,"0o  
e$u4vC~  
c&X{dJWD   
private String sSiteURL; //Site's URL o\88t){/kB  
private String sFilePath; //Saved File's Path  *[r!  
private String sFileName; //Saved File's Name tG8jFou  
private int nSplitter; //Count of Splited Downloading File %/c+`Wd/l$  
b+6"#/s  
oEx\j+}@n  
public SiteInfoBean() ?Zc"C  
{//nSplitter的缺省值为5 Rx*BwZ  
//default value of nSplitter is 5 `%E8-]{uS  
this("","","",5); X=6y_^  
} P+!"wX0*N  
i]=&  
EyI}{6~F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4-kZJ\]  
{ !IC-)C,q  
sSiteURL= sURL; v?0r`<Mn  
sFilePath = sPath; &-czStQ  
sFileName = sName; [U@ *1  
this.nSplitter = nSpiltter; "+z?x~rk  
K]qM~v<A  
yf?h#G%24  
} -*~CV:2iq-  
N7b1.]<  
OdQT2PA_  
public String getSSiteURL() /wxE1][.  
{ hY*0aZ|(  
return sSiteURL; &n[~!%(  
} i\4hR?  
osOVg0Gyj  
+B'8|5tPX  
public void setSSiteURL(String value) 4<lQwV6=  
{ B aO1/zk  
sSiteURL = value; Tzt,/e  
} [L6w1b,  
^9_U Uzf\  
c(U  
public String getSFilePath() [w0/\]o  
{ Z2Zq'3*  
return sFilePath; 2[B4f7  
} SR^_cpZoi  
kF{*(r=.o  
&(z fa&j|  
public void setSFilePath(String value) X53mzs  
{ 4"@GNk~e  
sFilePath = value; 6AvHavA^Y  
} R#n%cXc|  
K7e4_ZGI  
Y7GF$}%UL  
public String getSFileName() tp:\j@dB  
{ Um)>2|rp}  
return sFileName; ? b[n|^wS  
} C{Asp  
MlJVeod  
(>=7ng^  
public void setSFileName(String value) YB)3X[R+0  
{ E15vq6DKF  
sFileName = value; ~gI{\iNF/  
} "o&HE@t  
n;8'`s  
[U8$HQ+x  
public int getNSplitter() 1z*kc)=JF8  
{ b?Pj< tA  
return nSplitter; -h-oMqgu(  
} ,&7Wa-vf  
 :Pq.,s  
659v\51*  
public void setNSplitter(int nCount) 1/ZR*f a  
{ 451'>qS  
nSplitter = nCount; mPPk )qy  
} ~=&t0D  
} 85IMdZ7I  
]~>K\i  
y/? &pKH^  
/* SQWafD  
**Utility.java J4 tcQ  
*/ >p])it[q&$  
package NetFox; 3Z>YV]YbeU  
JI|6B  
}wwe}E-e  
public class Utility { \aP6_g:N}  
`7+j0kV)  
U>S`k6  
public Utility() "R9Yb,tIN  
{ D);'pKl  
m-V02's  
.5> 20\b2  
} Nf9fb?  
y69J%/c ra  
//线程睡眠 P2 0|RvE  
public static void sleep(int nSecond) k_GP> b\"k  
{ YCy22@C  
try{ ( 0Naf  
Thread.sleep(nSecond); ?Qqd "=k4  
} R^MiP|?ZH  
catch(Exception e) C+K=[   
{ .G>t72DpU  
e.printStackTrace (); T~gW3J  
} VY+>=!  
} !asqr1/  
zzZg$9PT[  
//日志 wH"kk4^  
public static void log(String sMsg) XTqm]  
{ kGN||h  
System.err.println(sMsg); pKJK9@Ad  
} LD(C\  
V/"}ku  
/&Jv,[2kV  
public static void log(int sMsg) z,*:x4}F  
{ ?M6ag_h3  
System.err.println(sMsg); ujgLJ77  
} qJ8-9^E,L  
} oP,9#FC|(  
t7F.[uWD  
!0 Q8iW:  
/* xi'<y  
**TestMethod.java h ?#@~  
*/ jB@4b 'y  
package NetFox; !rTmR@e$/  
(:\LWJX0=  
(paf2F`~#  
public class TestMethod { S7n"3.k  
X)uDSI~  
m-1?\bs  
public TestMethod() _MYx%Z  
{ ///xx/weblogic60b2_win.exe ;?IT)sNY  
try{ `Y3(~~YGn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }qC SS<a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); xRDiRj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &K:' #[3V  
fileFetch.start(); $W!]fcZlB  
} A%ywj'|z  
catch(Exception e){e.printStackTrace ();} *,#q'!Hq  
IftxSaP  
+T_ p8W+j  
} "dN < i  
!Qu PG/=X  
`?o=*OS7Y  
public static void main(String[] args) H`<?<ak6'M  
{ 73DlRt *  
new TestMethod(); E`p'L!z  
} f =_^>>.  
} a&/HSf_G  
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