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http断点续传简单实现(java)

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/* S|IDFDn  
**SiteFileFetch.java y] $- :^  
*/ }k8&T\V!  
package NetFox; XR#?gx.}  
import java.io.*; +]VW[ $W  
import java.net.*; KDDx[]1Q  
BT5~MYBl  
'sI @e s  
public class SiteFileFetch extends Thread { C\ cZ  
GMob&0l8_  
Az(J @  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5*$z4O:Aa  
long[] nStartPos; //开始位置 |X~vsM0  
long[] nEndPos; //结束位置 lstnxi%x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FvBnmYn W  
long nFileLength; //文件长度 7{=+Va5  
boolean bFirst = true; //是否第一次取文件 7b kh")^  
boolean bStop = false; //停止标志 tZD^<Q7}\  
File tmpFile; //文件下载的临时信息 v #Q(g/^  
DataOutputStream output; //输出到文件的输出流 \3j4=K'nE  
]#$r TWMl'  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -kzg(+sm  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]5eZLXM  
{ T@N)BfkB  
siteInfoBean = bean; Yp9%u9tNq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @'?7au ''  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `%0k\,}V  
if(tmpFile.exists ()) ~NO'8 Mr  
{ DEpn>   
bFirst = false; Vdf~rV  
read_nPos(); [\pp KC  
} mDIN%/S'  
else HwZ@T &_4  
{ \YF'qWB  
nStartPos = new long[bean.getNSplitter()]; x*F_XE1#M  
nEndPos = new long[bean.getNSplitter()]; t3aDDu  
} +0n,>eDjg^  
A)o%\j  
Kdd5ysTQ  
xy<)zKp  
} [~IFg~*,  
0Y ld!L  
fmk(}  
public void run() ^9*Jz{e  
{ |K$EULzz  
//获得文件长度 NiH.Pv)Oa'  
//分割文件 o7s<G8;?  
//实例FileSplitterFetch  EoHrXv  
//启动FileSplitterFetch线程 CZ/:(sOJ  
//等待子线程返回 uF\f>E)/N%  
try{ ;!/g`*?  
if(bFirst) MG0d&[  
{ BYsQu.N  
nFileLength = getFileSize(); q#1Cm Kt4R  
if(nFileLength == -1) Je;HAhL  
{ *6 P)HU@  
System.err.println("File Length is not known!"); H=7Nh6v  
} tY $4k26  
else if(nFileLength == -2) D,;6$Pvg^  
{ eWAgYe2  
System.err.println("File is not access!"); 6I$:mHEhd  
} ^Dw18gqr=@  
else -&_;x&k /  
{ ;CdxKr- d  
for(int i=0;i<nStartPos.length;i++) /s~&$(d59o  
{ Fo[=Dh*AqU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .2:S0=xt<  
} a$P$Ngi?S  
for(int i=0;i<nEndPos.length-1;i++)  8&KqrA86  
{ @c#M^:9Dc  
nEndPos = nStartPos[i+1]; ,O ]AB  
} :s'hXo  
nEndPos[nEndPos.length-1] = nFileLength; ;tu2}1#r  
} ?{*/VJl$  
} joJ:* oL  
Luu.p<   
#^&.*' z%z  
//启动子线程 {oc7Chv=/H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "jG-)k`a  
for(int i=0;i<nStartPos.length;i++) (dVrGa54  
{ Di8;Tq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :*{\oqFn~$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), iKN800^u  
nStartPos,nEndPos,i); *Me{G y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p?zh4:\F+  
fileSplitterFetch.start(); 1(12`3  
} f$^+;j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $*i"rlJC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -S%)2(f^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R~&i8n.  
nEndPos = " + nFileLength); K~JXP5`(  
// fileSplitterFetch[nPos.length-1].start(); z("Fy  
!~~j&+hK\  
mjz<,s`D  
//等待子线程结束 nzK"eNDN.  
//int count = 0; 6 C|]Fm  
//是否结束while循环 .JkF{&=B  
boolean breakWhile = false; nmrYBw>  
&,B91H*#  
_z3YB  
while(!bStop) ^  M4-O~  
{ oPA [vY  
write_nPos(); v lsS  
Utility.sleep(500); kGX;x}q  
breakWhile = true; hMiuv_EO!  
#Qp.O@e  
)c$)am\I{  
for(int i=0;i<nStartPos.length;i++) @0>3))  
{ -'OO6mU  
if(!fileSplitterFetch.bDownOver) _ooSMp|  
{ ]XH}G9X^  
breakWhile = false; GI:$(<  
break; )tV^)n[w  
} eL+L {Ac  
} ?)~j>1"S  
if(breakWhile) _~ipO1*  
break; D< 4!7*9%  
HjFY >(e  
CF`fn6  
//count++; j>0~"A  
//if(count>4) KQ x<{-G6  
// siteStop(); rpNe8"sh  
} Q b|.;_  
Uieg4Iro  
S}hg*mWn{$  
System.err.println("文件下载结束!"); 92k}ON  
} j8G>0f)  
catch(Exception e){e.printStackTrace ();} '\2lWR]ndd  
} FDAREE\j  
jnoFNIW   
B43o_H|s  
//获得文件长度 "p\XaClpz  
public long getFileSize() M]>JI'8  
{ 79^on8k}  
int nFileLength = -1; W&>+~A  
try{ |7CH  
URL url = new URL(siteInfoBean.getSSiteURL()); TLL.Ch|#Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a`w)awb  
httpConnection.setRequestProperty("User-Agent","NetFox"); rr[9sk`^H  
IpxFME%!  
] 05Q4  
int responseCode=httpConnection.getResponseCode(); y^C; ?B<  
if(responseCode>=400) ?nFT51 t/4  
{ B%Yb+M&K  
processErrorCode(responseCode); ~P5!VNJ;r  
return -2; //-2 represent access is error A&5$eGe9  
} b)u9#%Q  
MjI}fs<   
K@{jY\AZNx  
String sHeader; (D8'qx-M  
f ( `.q  
XEZ6%Q_  
for(int i=1;;i++) 7l Aa6"Y68  
{ lb1(1 |#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >t8eVMMa  
//Utility.log(in.readLine()); q<JI!n1O  
sHeader=httpConnection.getHeaderFieldKey(i); |y%pP/;&!  
if(sHeader!=null) E"Xi  
{ LM _4.J  
if(sHeader.equals("Content-Length")) !*%3um  
{ ,)L.^<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2$NP46z}  
break; /KKX;L[D(  
} 2 ;B[n;Q{  
} ==(M vu`  
else 4r(rWlM  
break; ]Wa,a T'  
} ,75,~  
} 9/s-|jD  
catch(IOException e){e.printStackTrace ();} v;K\#uc_  
catch(Exception e){e.printStackTrace ();} ur#"f'|-  
& 8&WY1cU  
u gfV'  
Utility.log(nFileLength); v!`M=0k  
db%`- UST  
"Ln\ZYB]  
return nFileLength; `Ze fSmb  
} b'-gy0  
_F3vC#  
6 *8Ge  
//保存下载信息(文件指针位置) rbtPG=t_R  
private void write_nPos() ZRxB"a'  
{ \O/=g6w|t}  
try{ 7SqsVq`[~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V u! ,tpa.  
output.writeInt(nStartPos.length); /|DQ_<*  
for(int i=0;i<nStartPos.length;i++) jN {ED_  
{ d#z67Nl6  
// output.writeLong(nPos); \|&5eeE@  
output.writeLong(fileSplitterFetch.nStartPos); TOuFFR  
output.writeLong(fileSplitterFetch.nEndPos); zR<jZwo]#  
} >$"bwr}'4B  
output.close(); RZ.5:v6  
} 7I.[1V`  
catch(IOException e){e.printStackTrace ();} Aio0++ r-  
catch(Exception e){e.printStackTrace ();} d~_OWCg`  
} ):[[Ch_  
V?rI,'F>N  
,,iQG' *  
//读取保存的下载信息(文件指针位置) yi%B5KF~Al  
private void read_nPos() @LmUCP~  
{ ?D~uR2+Z  
try{ n_+Iw,a'm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )i>KYg w  
int nCount = input.readInt(); eeX>SL5'i  
nStartPos = new long[nCount]; +<|w|c  
nEndPos = new long[nCount]; JL$RBr  
for(int i=0;i<nStartPos.length;i++) C eg6 o &^  
{ G dooy~cn  
nStartPos = input.readLong(); @rdC/=Y[  
nEndPos = input.readLong(); U--ER r8  
} RcE%?2l D  
input.close(); w7W-=\Hvh  
} nAYjSE  
catch(IOException e){e.printStackTrace ();} k{#:O=  
catch(Exception e){e.printStackTrace ();} { p/m+m  
} u J$"2<O  
AuCVpDH  
XU54skN  
private void processErrorCode(int nErrorCode) n#R!`*[  
{ aG ,uF  
System.err.println("Error Code : " + nErrorCode); S&0x:VW  
} B?4\IXek  
8 , =$>@u  
o]j*  
//停止文件下载 $OO[C={v[  
public void siteStop() t&oNJq{  
{ I@B7uFj  
bStop = true; D'&L wU,o  
for(int i=0;i<nStartPos.length;i++) ~DD/\V  
fileSplitterFetch.splitterStop();  96BMJE'  
w*}9;l  
hG67%T'}A  
} B?M+`;  
} ?-f>zx8O  
//负责部分文件的抓取 pA2U+Q@  
**FileSplitterFetch.java fS ~.K9  
*/ U!5@$Fu  
package NetFox; 0v_8YsZ!`$  
A_.QHUjpx  
=bDG|:+  
import java.io.*; GxkG$B  
import java.net.*; ,jn?s^X6Dj  
cNVdGY%&  
a:fHTU=\p  
public class FileSplitterFetch extends Thread { ,uv$oP-  
aPC!M4#  
I%p#E#[G  
String sURL; //File URL _x!pM j(A  
long nStartPos; //File Snippet Start Position ZeeuH"A  
long nEndPos; //File Snippet End Position (Ka# 6   
int nThreadID; //Thread's ID e-VL U;  
boolean bDownOver = false; //Downing is over +6=!ve}  
boolean bStop = false; //Stop identical BUb(BzC  
FileAccessI fileAccessI = null; //File Access interface 0 OBkd  
?@1'WD t  
.H"hRYPC?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a3;.{6el)H  
{ ~laZ(Bma);  
this.sURL = sURL; {UcIt LjY  
this.nStartPos = nStart; Pio^5jhB6  
this.nEndPos = nEnd; IfcFlXmt2  
nThreadID = id; yShHFlO=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ju#6 3  
} =lwS\mNs  
q}5A^QX  
c #kV+n<  
public void run() i7rq;t<  
{ M2}<gRL*}J  
while(nStartPos < nEndPos && !bStop) RY{tX`  
{ { rT`*P~  
D@^ZpN8r  
>|?T|  
try{  qR qy  
URL url = new URL(sURL); $J6.a!5IE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PAHlj,n)  
httpConnection.setRequestProperty("User-Agent","NetFox"); Gq*)]X{U a  
String sProperty = "bytes="+nStartPos+"-"; &r%*_pX  
httpConnection.setRequestProperty("RANGE",sProperty); B5:g{,C  
Utility.log(sProperty); :,m)D775S  
>|)0Amt  
v=tj.Vg  
InputStream input = httpConnection.getInputStream(); #ja`+w}  
//logResponseHead(httpConnection); (x qA.(F  
kA__*b}8UK  
cA? x(  
byte[] b = new byte[1024]; 6[.Mx}h6  
int nRead; zU~..;C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /\rq$W_  
{ ,:4DN&<  
nStartPos += fileAccessI.write(b,0,nRead); v9U(sEDq  
//if(nThreadID == 1) -vHr1I<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P]"d eB|  
} 5L}>+js2  
jJ!-hg4?]  
nKB&|!  
Utility.log("Thread " + nThreadID + " is over!"); zpqGh  
bDownOver = true; Cc)P5\j h  
//nPos = fileAccessI.write (b,0,nRead); 8e!DDh  
} A&c@8  
catch(Exception e){e.printStackTrace ();} P0e""9JOo  
} UMuuf6  
} m SzpRa  
*frJ^ Ws{  
cEc,eq|  
//打印回应的头信息 lVdT^"~3  
public void logResponseHead(HttpURLConnection con) 3gG+`{<  
{ e(~'pk"mZ  
for(int i=1;;i++) SgpZ;\_  
{ K)/!&{7n}a  
String header=con.getHeaderFieldKey(i); |,;twj[?4  
if(header!=null) >wKu6- ]a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `u#;MUg  
Utility.log(header+" : "+con.getHeaderField(header)); 1xO!w+J#  
else >; &s['H  
break; ]eYd8s+  
} . QXG"R  
} j9URl$T:  
X<~k =qwA  
N^ h |h  
public void splitterStop() SqXy;S@  
{ Ak5[PBbW  
bStop = true; K/vxzHSl  
} eC6>yD6D  
m7r j>X Y  
K`Bq(z?/  
} VY/|WD~"CW  
.4Qb5I2#  
,< @,gZru  
/* 4llD6&%  
**FileAccess.java ]?0{(\  
*//文件访问(定位,写) ;OOj[%.  
package NetFox; \G$QNUU  
import java.io.*; >vWEUE[  
+ a-wv  
SU%mmw ES3  
public class FileAccessI implements Serializable{ .E+OmJwD  
k"">2#V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #^|| ]g/N  
RandomAccessFile oSavedFile; MV:W@)rg  
long nPos; f).*NX  
EXA^!/)  
N'I(P9@  
public FileAccessI() throws IOException JY{X,?s  
{ UT3bd,,  
this("",0); 9s! 2 wwh  
} sYGR-:K  
a9[mZVMgUK  
gU l1CH&  
public FileAccessI(String sName,long nPos) throws IOException bb|}'  
{ Hx$.9'Oq\Q  
oSavedFile = new RandomAccessFile(sName,"rw"); A-Mj|V  
this.nPos = nPos; glv ;C/l  
oSavedFile.seek(nPos); (tepmcf  
} 'KH lrmnr  
WtIMvk  
{'NBp0i  
public synchronized int write(byte[] b,int nStart,int nLen) d] U`?A,  
{ R.K?  
int n = -1; PPEq6}  
try{ rfYP*QQY  
oSavedFile.write(b,nStart,nLen); 5J  ySFG3  
n = nLen; Us'Cs+5XcG  
}  Nj+a2[  
catch(IOException e) `|nH1sHFq  
{ rn;<HT  
e.printStackTrace (); z<!O!wX_aI  
} FC{})|yh }  
vd`O aM}#U  
xk& NAB  
return n; }3Qc 24`  
} `?l3Ct*  
E>E*ZZuhj  
g0PT8]8  
} ;`DD}j`  
qe<Hfp/p  
OZf6/10O/  
/* OVZP x%a  
**SiteInfoBean.java D93gH1z  
*/ U9 #w  
package NetFox; 3f"C!l]Xu  
V43TO  
AotCX7T2T  
public class SiteInfoBean { dN< , %}R  
|#k@U6`SG  
/2xSNalC  
private String sSiteURL; //Site's URL 5MR,UgT  
private String sFilePath; //Saved File's Path M diw Ri  
private String sFileName; //Saved File's Name Lkn4<'un  
private int nSplitter; //Count of Splited Downloading File )qv2)a!H  
cL G6(<L  
`<U5z$^QTw  
public SiteInfoBean() &dr@6-xaq  
{//nSplitter的缺省值为5 Or8kp/d  
//default value of nSplitter is 5 {WQq}-(  
this("","","",5); z8"7u /4v{  
} X %4Kj[I^  
BJk Z2=  
:QPf~\w?  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !X]8dyW  
{ ; b*i3*!g  
sSiteURL= sURL; wP<07t[-g  
sFilePath = sPath; 9%tobo@J~n  
sFileName = sName; ?IF)+]  
this.nSplitter = nSpiltter; q9]IIv  
+.kfU)6@  
aJzLrX  
} 5Sva}9H  
i{Ds&{  
]Y`Ib0$  
public String getSSiteURL() ]{GDS! )  
{ `XKVr  
return sSiteURL; 2YlH}fnH  
} <%P2qgz5  
YlF%UPp  
}Wh6zT)  
public void setSSiteURL(String value) O9"/ kmB  
{ ypdT&5Mqb!  
sSiteURL = value; F(,UA+$A  
} F_H82BE+3  
-7{ $ Vj  
!.TLW  
public String getSFilePath() k{I 01  
{ IzLQhDJ1  
return sFilePath; S DLvi!y  
} p B;3bc  
OLC{iD#  
#oni:]E!m  
public void setSFilePath(String value) 8}s.Fg@tE  
{ Wwujh2g"0|  
sFilePath = value; 5jxQW ;  
} ,yd=e}lQx  
jMNU ?m:  
\S~Vx!9w  
public String getSFileName() hr GH}CU"  
{ 2*iIjw3g  
return sFileName; 9f+>ix,ek*  
} OTDg5:>  
umi5Wb<  
QPt Gdd  
public void setSFileName(String value) Q[F}r`  
{ Z|" p*5O,  
sFileName = value; ?>"Yr,b?  
} T"7~AbgNU  
*3/T;x.  
a ^d8I  
public int getNSplitter() ?L&|Uw+  
{ YH&bD16c3  
return nSplitter; ^z6_Uw[  
} YuZ"s55zU{  
V'*~L\;pU  
] e. JNo  
public void setNSplitter(int nCount) +)o}c"P!  
{ [ i#zP  
nSplitter = nCount; $/!{OU.t`  
} ;JZS^Wa  
} dT,o=8fg  
hW!)w  
P) 3mX.(}  
/* y6]vl=^L  
**Utility.java E4 m`  
*/ Y"A/^]  
package NetFox; a5a($D  
y~()|L[  
Sb~MQ_  
public class Utility { RV@*c4KvO+  
C z\Ppq  
xhcK~5C  
public Utility() sc,Xw:YO  
{ 0}_[DAd6  
M Y|w  
x c{hC4^V  
} ~NW32 O)/  
GnvL'ESa@M  
//线程睡眠 h@a+NE8  
public static void sleep(int nSecond) rRFhGQq1m  
{ XQw>EZdj_N  
try{ Ja9e^`i;  
Thread.sleep(nSecond); VkZ7#  
} Yk=PS[f  
catch(Exception e) ~6p[El#tS  
{ ,c NLkoN  
e.printStackTrace (); YpqrZWvh  
} >y,-v:Vy  
} r?/'!!4  
K.0:C`C  
//日志 ~c\e'&sc;  
public static void log(String sMsg) x)@G;nZ  
{ b9!FC$^J  
System.err.println(sMsg); R rda# h^  
} *c2YRbU(  
EVGt 5z  
>rf'-X4n  
public static void log(int sMsg) Y=Kc'x[,Zj  
{ ~;N^g4s  
System.err.println(sMsg); x@ms  
} 9E6_]8rl  
} _ jsK}- \  
"yS _s  
s=;uc] 9g  
/* .nVa[B |.  
**TestMethod.java }|pwz   
*/ 9?SZNL['V  
package NetFox; :>C2gS@  
sr{a(4*\  
H5Io{B%=  
public class TestMethod { ,=[?yJy  
ye,>A.  
oaIi2=Tf  
public TestMethod() W>j!Q^?  
{ ///xx/weblogic60b2_win.exe MB~=f[cUnd  
try{ ^y<<>Y'I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); XMxSQ B1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); uc){+'[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); c"B{/;A  
fileFetch.start(); T[g[&K1Y  
} .N ,3 od@  
catch(Exception e){e.printStackTrace ();} 1ng!G 7g  
kH G"XTL  
zem8G2#c  
} ~f$|HP}  
|#]@Z)xa  
BRgXr  
public static void main(String[] args) 7/I,HxXp!  
{ UG+d-&~Ll  
new TestMethod(); Uq^#riq  
} jIC_[  
} old(i:2  
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