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http断点续传简单实现(java)

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/* ilHZx2 k  
**SiteFileFetch.java rgJKXl;@s  
*/ QJjqtOf>  
package NetFox; 3a_~18W  
import java.io.*; ZG"_M@S.  
import java.net.*; 5L'X3g  
s,)Z8H  
9s7sn*aB#5  
public class SiteFileFetch extends Thread { M<4~ewWJ  
ssUWr=mD  
-J[*fv@  
SiteInfoBean siteInfoBean = null; //文件信息Bean sFuB[ JJ}  
long[] nStartPos; //开始位置 4[v %]g`  
long[] nEndPos; //结束位置 IZoS2^:yw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !8(: G6Ne  
long nFileLength; //文件长度 9{]U6A*K0w  
boolean bFirst = true; //是否第一次取文件 R<I)}<g(A3  
boolean bStop = false; //停止标志 bk44 qL;8  
File tmpFile; //文件下载的临时信息 JmjqA Dex  
DataOutputStream output; //输出到文件的输出流 :q/%uca9  
K!;Z#$iw[  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) h(l4\)  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]yiwdQ  
{ 2x<,R/}  
siteInfoBean = bean; e3oHe1"hP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SvLI%>B=9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >08'+\~:b  
if(tmpFile.exists ()) -<h4I aM  
{ XvETys@d  
bFirst = false; SfLZVB  
read_nPos(); xp7 `[.  
} c@>Tzk%?"  
else p#g o<Y#  
{ Q'>pOtJG*J  
nStartPos = new long[bean.getNSplitter()]; NitsUg@<  
nEndPos = new long[bean.getNSplitter()]; Cdg/wRje  
} +twl`Z3n  
QH7"' u6  
589hfET  
Dukvi;\  
} jfF   
G<:_O-cPSv  
7uQiP&v  
public void run() N@6+DHt  
{ 4c^WQ>[  
//获得文件长度 @)k/t>r(  
//分割文件 |mvY=t %  
//实例FileSplitterFetch @K .{o'  
//启动FileSplitterFetch线程 EIQ`?8KSR  
//等待子线程返回 UEHJ? }  
try{ &y_Ya%Z3*e  
if(bFirst) = Lt)15  
{ RC?gozBFJ  
nFileLength = getFileSize(); >%LZ|*U  
if(nFileLength == -1) AQ+MjS,  
{ pZHx  
System.err.println("File Length is not known!"); >J(._K  
} AH-B/c5  
else if(nFileLength == -2) t$~CLq5ad  
{ *Cf5D6=Q  
System.err.println("File is not access!"); {02$pO  
} c[VVCN8dA  
else ;\a?xtIy  
{ bji5X')~#  
for(int i=0;i<nStartPos.length;i++) -4wr)zjfW  
{ lidVe]>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FJ-X~^  
} ./5LV)_`  
for(int i=0;i<nEndPos.length-1;i++) hNU$a?eVpR  
{ -J &y]'  
nEndPos = nStartPos[i+1]; Z:eB9R#2y  
} gi {rqM  
nEndPos[nEndPos.length-1] = nFileLength; k4T`{s}e  
} KEfN!6  
} Uzh#z eZ`<  
Z;/QB6|%  
qh9d .Q+n  
//启动子线程 O1+OE!w  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QrBb! .r  
for(int i=0;i<nStartPos.length;i++) L;RHs hTy  
{ !%X~`&9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nIZ;N!r=i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), da ' 1 H  
nStartPos,nEndPos,i); hufpky[&8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ICdfak  
fileSplitterFetch.start(); aFw \ w>*^  
} kB[l6`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O, .c gX   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'Nkd *  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -XASS%  
nEndPos = " + nFileLength); Dc@OrQu  
// fileSplitterFetch[nPos.length-1].start(); l6_dVK;s  
t]gZ^5  
L`3;9rO  
//等待子线程结束 !(gMr1}w  
//int count = 0; NJ^Bv`  
//是否结束while循环 _w}l,   
boolean breakWhile = false; k%D|17I  
gUr #3#  
Uc%kyTBm1  
while(!bStop)  #nq$^H  
{ M "\Iw'5$  
write_nPos(); {"PIS&]tR  
Utility.sleep(500); z!s1$5:"0  
breakWhile = true; ~n=oPm$pR  
t1`.M$  
1S+lHG92I  
for(int i=0;i<nStartPos.length;i++) 3-/F]}0y6  
{ H|)F-aL[  
if(!fileSplitterFetch.bDownOver) \X2r?   
{ icK>|   
breakWhile = false; Uee(1  
break; S:lie*Aux*  
} eC{St0  
} gWD46+A){  
if(breakWhile) A Xpg_JC  
break; <EKTFHJ!  
U3**x5F_  
N&yr?b'!-*  
//count++; m)l'i!Y  
//if(count>4) z[Ah9tM%  
// siteStop(); 8-B6D~i  
} =f?vpKq40  
*qZBq&7tb  
i&TWIl8  
System.err.println("文件下载结束!"); cY^'Cj  
} #=V\WQb  
catch(Exception e){e.printStackTrace ();} :u]QEZ@@  
} gb{8SG5ac  
:\Q#W4~p  
T@jv0/(+  
//获得文件长度 6bDizS}  
public long getFileSize() ~_SRcM{  
{ i@`qam   
int nFileLength = -1; V]Rt[l]  
try{ |b4f3n  
URL url = new URL(siteInfoBean.getSSiteURL()); 0Ke2%+yqJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +!Q*ie+q  
httpConnection.setRequestProperty("User-Agent","NetFox"); _vJ(F  
u!-v1O^[  
4L bll%[9  
int responseCode=httpConnection.getResponseCode(); [*J?TNk  
if(responseCode>=400) :85QwN]\  
{ WF_ v>g:g  
processErrorCode(responseCode); gNJdP!(t  
return -2; //-2 represent access is error 11vAx9  
} EQtYb"_  
y?V^S;}&]  
oj/#wF+  
String sHeader; %Yt;)q3U  
K&VMhMVb  
<0!<T+JQ  
for(int i=1;;i++) ;i?rd f  
{ WjBH2v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :K~sazs7J  
//Utility.log(in.readLine()); |It&1fz}  
sHeader=httpConnection.getHeaderFieldKey(i); Cg(&WJw(ep  
if(sHeader!=null) sd%m{P2  
{ Bg[_MDWc-P  
if(sHeader.equals("Content-Length")) xO^lE@a o  
{ }_BNi;H  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Wo(m:q(Om  
break; Eunmc  
} 3 a|pk4M  
} h1H$3TpP  
else QHxof7  
break; H$V`,=H  
} \.'[!GE*c  
} 1Va=.#<  
catch(IOException e){e.printStackTrace ();} F9"Xu-g  
catch(Exception e){e.printStackTrace ();} b<%c ]z  
Wecxx^vtv6  
Vr@tSc&  
Utility.log(nFileLength); R^mkQb>m.  
|c>.xt~  
c^rWS&)P  
return nFileLength; 6RG63+G  
} ,^7] F"5  
on;>iKta9  
FJ{/EloF  
//保存下载信息(文件指针位置) W] WH4.y  
private void write_nPos() gA`QV''/:  
{ "Zy:q'`o  
try{ jK".iqx2L  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zwU1(?]I{  
output.writeInt(nStartPos.length); t,n2N13  
for(int i=0;i<nStartPos.length;i++) +/bD9x1H  
{ s(?%A  
// output.writeLong(nPos); (d/!M n6L  
output.writeLong(fileSplitterFetch.nStartPos); +v~x_E5FP  
output.writeLong(fileSplitterFetch.nEndPos); \H9:%Tlp~4  
} d}%-vm} 0  
output.close(); ftKL#9,s(  
} ;%Px~g  
catch(IOException e){e.printStackTrace ();} NG`Y{QT6N  
catch(Exception e){e.printStackTrace ();} =XtQ\$Pax  
} ^i r)z@P?V  
O c.fvP^ZD  
O._\l?m  
//读取保存的下载信息(文件指针位置) R58NTPm  
private void read_nPos() F2\&rC4v  
{ 9|3sNFGX  
try{ /OYa1,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E%( s=YhW  
int nCount = input.readInt(); OwEu S#-  
nStartPos = new long[nCount]; <5^m`F5  
nEndPos = new long[nCount]; PD^G$LT  
for(int i=0;i<nStartPos.length;i++) r \[|'hA  
{ I:HrBhI)wP  
nStartPos = input.readLong(); |Y8}*C\M.h  
nEndPos = input.readLong(); 1szObhN-l  
} 4l{$dtKbI  
input.close(); 93Zij<bH?e  
} Mna yiJl  
catch(IOException e){e.printStackTrace ();} c%WO#}r|  
catch(Exception e){e.printStackTrace ();} <W>A }}q  
} ~ g-(  
g*(z .  
LuHRB}W  
private void processErrorCode(int nErrorCode) &2U%/JqY  
{  WzoI0E`  
System.err.println("Error Code : " + nErrorCode); Faa>bc~E  
} {6WG  
s7HKgj  
^{{a v?h  
//停止文件下载 q)f_!N  
public void siteStop() 0}"\3EdAbD  
{ E .28G2&  
bStop = true; [& Z- *a  
for(int i=0;i<nStartPos.length;i++) 1r};cY6  
fileSplitterFetch.splitterStop(); KK5;6b  
-8Hc M\b  
5eE\ X /  
} o2=):2x r{  
} Y9|!= T%  
//负责部分文件的抓取 d:w/{m% #  
**FileSplitterFetch.java wJ pb$;  
*/ /a<UKh:A[  
package NetFox; U<Tv<7`  
7y&6q`y E  
Jfk#E^1  
import java.io.*; NJ+$3n om  
import java.net.*; FZO&r60$E  
iCA-X\E  
N$=9R  
public class FileSplitterFetch extends Thread { c|JQ0] K  
;ne`ppz0  
k*n~&y:O  
String sURL; //File URL .d}yQ#5z  
long nStartPos; //File Snippet Start Position Lui6;NY  
long nEndPos; //File Snippet End Position Q(cLi:)X2  
int nThreadID; //Thread's ID e@ D}/1~=  
boolean bDownOver = false; //Downing is over rAAx]nQ@  
boolean bStop = false; //Stop identical >Oj$ Dn=  
FileAccessI fileAccessI = null; //File Access interface ;l~a|KW0  
l^}u S|c(  
)c&ya|h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (oR~%2K  
{ xZ)K#\  
this.sURL = sURL; l`N4P  
this.nStartPos = nStart; )DhE~  
this.nEndPos = nEnd; iN. GC^l  
nThreadID = id; 5I,NvHD4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~?Vod|>  
} E0Q6Ryn  
auc:|?H~1n  
['Lo8 [  
public void run() &Z[+V)6,,  
{ Pj]^ p{>  
while(nStartPos < nEndPos && !bStop) ZzNHEV  
{ M9A1 8d|  
.B- b51Uz  
$u.rO7)  
try{ (*P`  
URL url = new URL(sURL); ;akW i]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B* mZxY1  
httpConnection.setRequestProperty("User-Agent","NetFox"); .:f ao'  
String sProperty = "bytes="+nStartPos+"-"; g%"SAeG<K  
httpConnection.setRequestProperty("RANGE",sProperty); l[IL~  
Utility.log(sProperty); | n)4APX\Q  
:d9GkC  
T)sIV5bk  
InputStream input = httpConnection.getInputStream(); k kAg17 ^  
//logResponseHead(httpConnection); {q`8+$Z;  
>n3GvZ5%  
] 1pIIX}  
byte[] b = new byte[1024]; p<H_]|7$7U  
int nRead; 1t^y?<)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x}pH'S7  
{ "i(f+N,)  
nStartPos += fileAccessI.write(b,0,nRead); \ t1#5  
//if(nThreadID == 1) 'DVn /3?X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K=o {  
} XJPIAN~l  
o]4BST(A  
.pWRV<25  
Utility.log("Thread " + nThreadID + " is over!"); s7sd(f]=  
bDownOver = true; &hkD"GGe  
//nPos = fileAccessI.write (b,0,nRead); 3'kKbrk [  
} 7Z`4Kdh .  
catch(Exception e){e.printStackTrace ();} T@.+bD  
} G gA:;f46  
} X!LiekU!D  
9ybR+dGm+  
Z(c SM  
//打印回应的头信息 ;Us6:}s  
public void logResponseHead(HttpURLConnection con) SQ> Yf\  
{ Bo8f52|  
for(int i=1;;i++) Z(tJd ,  
{ :*,!gf  
String header=con.getHeaderFieldKey(i); D((/fT)eD  
if(header!=null) )s^gT]"N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); fqbeO9x  
Utility.log(header+" : "+con.getHeaderField(header)); 9) ]`le  
else eA(\#+)X `  
break; Ncbe{}<md  
} O0z-jZ,])  
} h ChO  
]}].A q  
@xBb|/I  
public void splitterStop() #&IrCq+  
{ Qx E%C  
bStop = true; ty~Sf-Pri  
} d!:/n  
w^&UMX}  
g]HxPq+O  
} ]kmAN65c  
/<LjD  
p gLhxc:  
/* N?{Zrff2"O  
**FileAccess.java y'8T=PqY[t  
*//文件访问(定位,写) \G v\&_  
package NetFox; -u%o);B  
import java.io.*; nt|n[-}  
Q+K]:c  
*8a[M{-X  
public class FileAccessI implements Serializable{ /_cpS q  
UdkNb}L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p%>!1_'(  
RandomAccessFile oSavedFile; ~l'[P=R+8  
long nPos; / zNVJhC  
:/=P6b;  
4IfkYM  
public FileAccessI() throws IOException w/o8R3 F  
{ 9m>L\&\_e  
this("",0); Th%w-19,8  
} lmoYQFkYP  
&f'Lll  
hOLlZP+  
public FileAccessI(String sName,long nPos) throws IOException l>`S<rGe  
{ 8b,Z)"(U3  
oSavedFile = new RandomAccessFile(sName,"rw"); #Qz 9{1\G  
this.nPos = nPos; K ~\b+  
oSavedFile.seek(nPos); qfFa" a  
} LL3| U  
EiM\`"o  
~8k`~t!  
public synchronized int write(byte[] b,int nStart,int nLen) gPK O-Fsd"  
{ |Zn,|-iW  
int n = -1; S?v;+3TG  
try{ \J(~ Nv5!  
oSavedFile.write(b,nStart,nLen); X J]+F  
n = nLen; 2i6P<&@  
} ^v;8 (eF  
catch(IOException e) Gv)*[7  
{ f~=e  
e.printStackTrace (); }o GMF~  
} "0G)S'  
Aj\m57e,6  
QxEmuiN  
return n; O&.gc p!  
} uKIR$n"  
iN u k5  
<4?(|Vh[m]  
} ;erxB6*  
!&KE">3Qu  
65 &+Fv  
/* }VH` \g}  
**SiteInfoBean.java z9AX8k(B6  
*/ E0r#xmk  
package NetFox; :]\-GJV5  
* e,8o2C$  
M#],#o*G  
public class SiteInfoBean { 9J49s1  
6 ;\>,  
y>UQm|o<W  
private String sSiteURL; //Site's URL /WAOpf5  
private String sFilePath; //Saved File's Path `a7b,d  
private String sFileName; //Saved File's Name K^AIqL8  
private int nSplitter; //Count of Splited Downloading File <3k9 y^0  
\@6w;tyi  
B$97"$#u  
public SiteInfoBean() i"!j:YEo  
{//nSplitter的缺省值为5 LGRhCOP:  
//default value of nSplitter is 5 G @L `[Wu  
this("","","",5); r`0oI66B/  
} ![%:X)?  
14-uy.0[  
@DR?^ qp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) It'PWqZtG  
{ Q?m= a0g  
sSiteURL= sURL; y7R{6W_U>  
sFilePath = sPath; ?y*yl  
sFileName = sName; Z +}# Ic  
this.nSplitter = nSpiltter; Y#-pK)EeU  
U3>ES"N  
.a]av   
} '! ;Xxe5  
3AuLRI  
L{6Vi&I84[  
public String getSSiteURL() R /c-sV  
{ Wzh#dO?7  
return sSiteURL; MIAC'_<-e  
} gAGcbepX  
<^A1.o< GN  
c30 kb  
public void setSSiteURL(String value) *zPz)3;  
{ t+WUz#i"  
sSiteURL = value; 5@Xy) z  
} Kv\uBMJNW  
P<xCg  
Wf$P+i*  
public String getSFilePath() ,n{ |d33  
{ 7}e{&\0=l  
return sFilePath; %i9*2{e#~  
} .TRp74  
\G]vTK3  
qZ+^ND(I  
public void setSFilePath(String value) W(*?rA-PP  
{ Y5Z<uD  
sFilePath = value; z6Yx )qBE<  
} ];}7 %3  
#J c)v0_  
pB]+c%\  
public String getSFileName() Je~Ybh  
{ ]M9r<x*  
return sFileName; ZEU/6.  
} ^5gB?V,  
|f&=9%  
&uTK@ G+  
public void setSFileName(String value) 7;:Uv=  
{ o>4GtvA*  
sFileName = value; ?pF uV`Zm  
} }W R?n  
;=ERm=  
3H/4$XJB  
public int getNSplitter() <Okl.Iz>  
{ ji|tc9#6  
return nSplitter; v4x1=E  
} yB^_dE  
c3aF lxW  
K0?:?>*b#  
public void setNSplitter(int nCount) f9&po2Pzf  
{ o4pe>hn  
nSplitter = nCount; =arrp:  
} olf7L%  
} wTY8={p]  
Jq?"?d|:  
0NG<uZ  
/* 2l!* o7  
**Utility.java zINziAp{  
*/ {B lM<  
package NetFox; G^Yg[*bJ^$  
z@em1W0?Z  
d_}q.%*  
public class Utility { >NN&j#;x~  
;v1&Rs  
6>B_ojj:  
public Utility() |;_uN q9  
{ @5\ns-%  
|\~!o N  
U*6)/.J  
} rYMHc@a9(  
+gOv5Eno-  
//线程睡眠 S+(-k0  
public static void sleep(int nSecond) Od:, r  
{ #\fxU:z~r  
try{ v81H!c.*  
Thread.sleep(nSecond); n$T'gX#5  
} <U() *0  
catch(Exception e) CwVORf,uA  
{ 42: 6=\  
e.printStackTrace (); ;4 ON  
} 9Iod[ x  
} ]1 OZY@  
r|tTDKGQ  
//日志 S2 0L@e"U  
public static void log(String sMsg) @eGJ_ J  
{ 2U;ImC1g  
System.err.println(sMsg); tk <R|i  
} eO:wx.PW  
IZkQmA=  
-?$Hr\  
public static void log(int sMsg) z!GLug*j`  
{ \L: ;~L/  
System.err.println(sMsg); ?xuhN G@  
} J,k|_JO  
} oopACE>  
.UuCTH;6`  
u/BCl!`  
/* }vbs6u  
**TestMethod.java hs"=>(P)  
*/ o4"7i 9+g  
package NetFox; M1/Rba Q  
ZsPT!l,  
t:G67^<3  
public class TestMethod { C"P40VQoo  
5xawa:K  
(ft8,^=4  
public TestMethod() _8CE|<Cn  
{ ///xx/weblogic60b2_win.exe m*MfGj(  
try{ .;0?r9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D^knN-nZ*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?m?DAd~ZY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {\Eqo4A5}  
fileFetch.start(); ul$^]ZWkI  
} <Yk#MeiEp  
catch(Exception e){e.printStackTrace ();} <y}`PmIM I  
Qf|=xV,F  
/{';\?w  
} c.u$NnDU6  
wYrb P11  
m|)Mc VV  
public static void main(String[] args) -4&SYCw  
{ f"j"ZM{~U  
new TestMethod(); :i&ZMH,O  
}  4_E{  
} ^hhJ6E_W  
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