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http断点续传简单实现(java)

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/* S(G&{KG  
**SiteFileFetch.java x{1S!A^  
*/ M)CQ|P  
package NetFox; QaSRD/,M  
import java.io.*; F\-oZ#g  
import java.net.*; $mn+  
#fq&yjl#A  
7&1 dr  
public class SiteFileFetch extends Thread { AP0z~e  
3mT6HGSKR  
`\Te,  
SiteInfoBean siteInfoBean = null; //文件信息Bean \8/$ZEom  
long[] nStartPos; //开始位置 ||'A9  
long[] nEndPos; //结束位置 <+AvbqDe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 j "e]Ui  
long nFileLength; //文件长度 U^&y*gX1  
boolean bFirst = true; //是否第一次取文件 :nxBM#:xu  
boolean bStop = false; //停止标志 D4PjE@D"H  
File tmpFile; //文件下载的临时信息 fDKV`  
DataOutputStream output; //输出到文件的输出流 Qp~3DUM  
5KL??ao-  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) no7Q%O9  
public SiteFileFetch(SiteInfoBean bean) throws IOException "\rR0V!wA  
{ b.QL\$a &  
siteInfoBean = bean; k<k@Tlo  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y hNy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %D E_kwL  
if(tmpFile.exists ()) ~) vz`bD1  
{ /N=M9i\;  
bFirst = false; 5`{u! QE  
read_nPos(); ; e)vk|  
} Wqas1yL_  
else DUvF  
{ nOq`Cwh9  
nStartPos = new long[bean.getNSplitter()]; B\6%.R  
nEndPos = new long[bean.getNSplitter()];  Z6_fI  
} husk\  
""x>-j4  
!.[H !-V.  
]I(<hDuRp  
} '?qI_LP?  
%KW NY(m  
|^ J5YwCf  
public void run() :KBy(}V  
{ R)'[Tt`#R  
//获得文件长度 5@`dKFB5  
//分割文件 pU[5f5_  
//实例FileSplitterFetch nD#uOep9  
//启动FileSplitterFetch线程 G!g];7PG(  
//等待子线程返回 I4MZ JAYk  
try{ V7$-4%NL  
if(bFirst) 0 1:(QJ  
{ -[ xbGSj{  
nFileLength = getFileSize(); KqFiS9 N5  
if(nFileLength == -1) Ed>n/)Sm  
{ MsjC4(Xla.  
System.err.println("File Length is not known!"); R|R3Ob.e  
} -\V;Gw8mD  
else if(nFileLength == -2) .'=-@W*  
{  @zSj&4  
System.err.println("File is not access!"); {/K!cPp9  
} #s|,o Im  
else *DPKV$  
{ G'WbXX  
for(int i=0;i<nStartPos.length;i++) YbP}d&L  
{ # &Z1d(!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); JwcC9 O  
} 'Ad|*~  
for(int i=0;i<nEndPos.length-1;i++) [G7S  
{ \v p^[,SI  
nEndPos = nStartPos[i+1]; s Vg89I&  
} L?r\J8Ch<  
nEndPos[nEndPos.length-1] = nFileLength; 89a`WV@}  
} yvV]|B@sO  
} js)I%Z  
HQ`A.E2  
s-),Pv|  
//启动子线程 [OQ+&\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; i 2n66d  
for(int i=0;i<nStartPos.length;i++) -SKcS#IF  
{ `g:bvIV5x>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q7SRf$4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #4ii!ev  
nStartPos,nEndPos,i); "Sd2VSLg  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8 qwOZ d  
fileSplitterFetch.start(); :hUt7/3c  
} J3AS"+]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6x"|,,&MD0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $iOkn|~<@W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lpHz*NZ0  
nEndPos = " + nFileLength); ]0&ExD\4  
// fileSplitterFetch[nPos.length-1].start(); <zE~N~;  
Ve\=By-a|  
@E@5/N6M  
//等待子线程结束 CPS1b  
//int count = 0; @2Ca]2,4  
//是否结束while循环 +p#Q|o'  
boolean breakWhile = false; #Mmr{4m  
!K319 eE  
_|%l) KO  
while(!bStop) e#j kp'  
{ U6Ws#e  
write_nPos(); qD/X%`>Q  
Utility.sleep(500); = 7TK&  
breakWhile = true; =h se2f  
<fm0B3i?  
? IHa>f:  
for(int i=0;i<nStartPos.length;i++) a]mPc^h  
{ eLc@w<yB  
if(!fileSplitterFetch.bDownOver) ui#K`.dn  
{ (<:mCPk(~  
breakWhile = false; _onEXrM  
break; .qjdi`v  
} E5U{.45  
} K!a4>Du{  
if(breakWhile) >UUT9:,plA  
break; t<QSp6n""  
wX!>&Gc.  
iAAlld1  
//count++; ;x=r.3OQy  
//if(count>4) h-`*S&mZ  
// siteStop(); 7 ,![oY[  
} 37M?m$BL  
iig ({b  
,\cO>y@  
System.err.println("文件下载结束!"); 5QoU&Hv  
} OG&X7>'3I{  
catch(Exception e){e.printStackTrace ();} A_vf3 *q  
} }*ZOD1j  
l~v BA$,  
U;Ne"Jh  
//获得文件长度 H LnizE  
public long getFileSize() O] nZr  
{ `p. O  
int nFileLength = -1; aAX(M=3  
try{ j;+!BKWy4  
URL url = new URL(siteInfoBean.getSSiteURL()); KW~fW r8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Vg+jF!\7  
httpConnection.setRequestProperty("User-Agent","NetFox"); u3>D vl@  
B- VhUS  
oy) 'wb~  
int responseCode=httpConnection.getResponseCode(); 0f<$S$~h  
if(responseCode>=400) - #ta/*TT:  
{ X+*"FKm S.  
processErrorCode(responseCode); qU) pBA  
return -2; //-2 represent access is error 'n)]"G|  
} 9se ,c  
jPjFp35;zb  
@4Ox$M  
String sHeader; JN Ur?+g  
A]FjV~PB  
oq>8  
for(int i=1;;i++) h 'F\9t  
{ v_zVhE tY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r^$4]@Wn  
//Utility.log(in.readLine()); }8W5m(Zq9n  
sHeader=httpConnection.getHeaderFieldKey(i); t*&O*T+fgy  
if(sHeader!=null) C6XZZ  
{ |Ir&C[QS{y  
if(sHeader.equals("Content-Length")) a_pNFe  
{ )ww#dJn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TZ]D6.mD  
break; D\Nhq Vw  
} cS'|c06  
} v/Z!Wp1LV  
else )$Erfu  
break; *)2& gQ&%+  
} &mM[q 'V  
} 0PK*ULwSN  
catch(IOException e){e.printStackTrace ();} wjr1?c  
catch(Exception e){e.printStackTrace ();} B[]v[q<  
Q+O3Wgjy  
E_aDkNT  
Utility.log(nFileLength); >q:0w{.TU  
jM E==)Y  
)T=cd   
return nFileLength; 8mCL3F  
} %Q}T9%Mtj  
k_2W*2'S  
0;b%@_E  
//保存下载信息(文件指针位置) 1w)#BYc=L  
private void write_nPos() gZFtV  
{ Uv(THxVh  
try{ qw!_/Z3[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5df~] -=0Y  
output.writeInt(nStartPos.length); >lo,0oG  
for(int i=0;i<nStartPos.length;i++) \&&jzU2  
{ A&$oiLc  
// output.writeLong(nPos); DL^}?Ve  
output.writeLong(fileSplitterFetch.nStartPos); QsaaA MGY  
output.writeLong(fileSplitterFetch.nEndPos); (Ut)APM  
} +$eEZ;4  
output.close(); Ol,Tw=?  
} ;_yp@.,\T  
catch(IOException e){e.printStackTrace ();} 7PDz ]i  
catch(Exception e){e.printStackTrace ();} \X=?+| 9  
} "g)@jqq:>  
PXZ ZPW/  
'g8~uP  
//读取保存的下载信息(文件指针位置) MLL4nkO,`  
private void read_nPos() ?mK`Wleh?  
{ -?A,N,nnX  
try{ ,FvBZ.4c3=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,cR=W|6cQm  
int nCount = input.readInt(); PKoB~wLH  
nStartPos = new long[nCount]; K<HF!YU#I2  
nEndPos = new long[nCount]; 7b,5*]oZ  
for(int i=0;i<nStartPos.length;i++) FbMX?T"yH  
{ Z:l.{3J$  
nStartPos = input.readLong(); Yg5m=Lis  
nEndPos = input.readLong(); OPp>z0p%6X  
} *&b~cyC  
input.close(); "#T3l^@  
} >&0)d7Nu8m  
catch(IOException e){e.printStackTrace ();} -5Qsc/ s&  
catch(Exception e){e.printStackTrace ();} 26fbBt8nP  
} <$WRc\}&g  
2TN+ (B#Z!  
V9:h4]  
private void processErrorCode(int nErrorCode) $?^#G8J  
{ A^PCI*SN[  
System.err.println("Error Code : " + nErrorCode); "(uEcS2<  
} zG_e=   
iyw "|+  
<Z^t^ O  
//停止文件下载 WN?1J4H  
public void siteStop() 0ad -4  
{ <(Ub(  
bStop = true; }(AgXvRq  
for(int i=0;i<nStartPos.length;i++) "Jw6.q+  
fileSplitterFetch.splitterStop(); B;A^5~b  
=;.#Bds  
uJ<sa;  
} >|jSd2_p  
} ^ q]BCOfJ(  
//负责部分文件的抓取 eR.ucTji  
**FileSplitterFetch.java {s}@$rW  
*/ >jjuWO3T  
package NetFox; uX*H2"A  
M9{?gM9  
yW.s?3X  
import java.io.*; 3 }Z [d  
import java.net.*; 7Wg0-{yK4  
oXG,8NOdC  
SGn:f>N  
public class FileSplitterFetch extends Thread { vKppXm1  
H"W%+{AR  
SS@F:5),  
String sURL; //File URL kQXtO)  
long nStartPos; //File Snippet Start Position E 5PefD\m  
long nEndPos; //File Snippet End Position :70cOt~Z  
int nThreadID; //Thread's ID E<;C@B  
boolean bDownOver = false; //Downing is over 0IoS|P}6a  
boolean bStop = false; //Stop identical #"%=7(  
FileAccessI fileAccessI = null; //File Access interface e$|g  
j;eR9jI$T  
SEQ bw](ss  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException EeWCy5W  
{ 6bCC6G  
this.sURL = sURL; 4`uI)N(}*  
this.nStartPos = nStart; @~Z:W<X  
this.nEndPos = nEnd; lqe;lWC0Z  
nThreadID = id; . Rxz;-VA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :M(%sv</  
} \:C@L&3[  
}ex2tkz  
:i+Tf~k{  
public void run() ;Ad$Q9)EE  
{ =if5$jE3  
while(nStartPos < nEndPos && !bStop) 'VCF{0{H~  
{ E`.dU<8HE  
.x7d!t:(D  
nE)?P*$3Z  
try{ DWZ!B7Ts  
URL url = new URL(sURL); 1QXv}36#3n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O7bTu<h=  
httpConnection.setRequestProperty("User-Agent","NetFox"); "1_eZ`  
String sProperty = "bytes="+nStartPos+"-"; k_.%(ZE  
httpConnection.setRequestProperty("RANGE",sProperty); 9r!psRA:`)  
Utility.log(sProperty); MHJH@$|]  
^0ZabR'  
K1 a$ m2  
InputStream input = httpConnection.getInputStream(); -4{sr| lm  
//logResponseHead(httpConnection); `qp[x%7^  
vFXih'=_  
7HzO_u%H1  
byte[] b = new byte[1024]; %{g<{\@4(;  
int nRead; hl?G_%a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |]sh*<:?,  
{ !8M]n  
nStartPos += fileAccessI.write(b,0,nRead); q-O=Em<*  
//if(nThreadID == 1) @#$5_uU8\(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }8Tr M0q8  
} TyVn5XHl^  
[f,; +Ze  
I5PI;t+  
Utility.log("Thread " + nThreadID + " is over!"); E'zLgU)r`  
bDownOver = true; {H{u[XR[z  
//nPos = fileAccessI.write (b,0,nRead); 4% )I[-sH  
} >AI65g  
catch(Exception e){e.printStackTrace ();} `8xt!8Z$  
} <z+5+h|^  
} 4`Qu+&4J  
\zCT""'i  
1TeYA6 t  
//打印回应的头信息 xG i,\K\:  
public void logResponseHead(HttpURLConnection con) +@>K]hdr  
{ hOjy$Z  
for(int i=1;;i++) uc4#giCD  
{ (;-< @~2  
String header=con.getHeaderFieldKey(i); dq[X:3i  
if(header!=null) X}C }  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q_K8vGm4e  
Utility.log(header+" : "+con.getHeaderField(header)); *^+8_%;1  
else z)N8#Y~vn  
break; CU'$JF  
} jt5en;AA[  
} $/sIdFZi  
#wn`choT'  
f/Cf2 K  
public void splitterStop() ,x#5.Koz  
{ >.^/Z/[.L  
bStop = true; G`3/${ti  
} e7rD,`NiV  
&0A^_Z .nA  
. Z 93S|q  
} ?QuD:v ck  
!Wn^B|  
^p3"_;p)h  
/* GSck^o2{  
**FileAccess.java Bg.~#H  
*//文件访问(定位,写) BVAxeXO  
package NetFox; 8XFs)1s[  
import java.io.*; aYc*v5Q N3  
'a8{YT4  
x,)|;HXm  
public class FileAccessI implements Serializable{ Rs*]I\  
P_Rh& gkuK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z{<&2*  
RandomAccessFile oSavedFile; |^: A,%>  
long nPos; R'M=`33M  
3.[ fTrzJ  
[=f(u wY>g  
public FileAccessI() throws IOException pGS!Nn;K2  
{ >/W  
this("",0); s.VtmAH  
} S.G"*'N  
`cu W^/c  
-B+Pl*  
public FileAccessI(String sName,long nPos) throws IOException r1vF/yt(  
{ 2VB|a;Mo  
oSavedFile = new RandomAccessFile(sName,"rw"); =8`!Ph@(  
this.nPos = nPos; &1Zq C;  
oSavedFile.seek(nPos); Xyz w.%4c  
} {jK:hQX  
VuU{7:  
F]fBFDk  
public synchronized int write(byte[] b,int nStart,int nLen) per$%;5E"  
{ NQ9/,M  
int n = -1; w$`[C+L  
try{ Oh&k{DWE$  
oSavedFile.write(b,nStart,nLen); G (Ky7S Z  
n = nLen; yJ0q)x sS  
} T09'qB  
catch(IOException e) EFk9G2@_  
{ @ ,9cpaL3  
e.printStackTrace (); 6Fe$'TP  
} 9 SBVp 6'  
_ Vo35kA  
GW;\ 3@o  
return n; *)8!~Hs   
} 79yF {  
:(?F(Q^  
u]<_6;_  
} H1fKe=$1  
o<\u Hr3  
g> <*qd?t  
/* 8*7,qX  
**SiteInfoBean.java O]1aez[  
*/ p7Xe[94d^  
package NetFox; 23iMG]J&  
Y9w^F_relL  
^C|N  
public class SiteInfoBean {  yh'uH  
N!Cy)HnS\w  
UVUoXv)N  
private String sSiteURL; //Site's URL "<Q,|Md  
private String sFilePath; //Saved File's Path vIQu"J&fE  
private String sFileName; //Saved File's Name ?]]7PEee*  
private int nSplitter; //Count of Splited Downloading File 3[UB3F 4K  
Qw@_.I  
T4e-QEH  
public SiteInfoBean() +\yQZ{4'@  
{//nSplitter的缺省值为5 ~2L]K4Z^  
//default value of nSplitter is 5 C?h}n4\B^?  
this("","","",5); c*N>7IF,  
} gc[BP>tl\  
#[ TOe  
(kFg2kG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VQ(l=k:}2  
{ %h^ f?.(:  
sSiteURL= sURL; sqE? U*8.-  
sFilePath = sPath; =hq+9 R8=  
sFileName = sName; .ZVADVg\  
this.nSplitter = nSpiltter; )ePQN~#K}  
1c19$KHu  
(O`2$~mIM  
} tGVC"a  
3j} @}2D  
g7g^iLU  
public String getSSiteURL() /s|4aro  
{ EpdSsfDP  
return sSiteURL; w\`u |f;Aq  
} ;cfmMt!QWJ  
 }0f"SWO>  
;%V)lP"o  
public void setSSiteURL(String value) ]<g`rR7}  
{ xa]e9u%  
sSiteURL = value; )a0%62  
} %5rC`9^  
GX-V|hLaGX  
|b^+= "  
public String getSFilePath() !eE;MaS>  
{ @eOD+h'  
return sFilePath; :+*q,lX8  
} x_VD9  
!]*Cwbh. u  
9hn+eU  
public void setSFilePath(String value) n4%ZR~9WH  
{ kACgP!~/1  
sFilePath = value; Z\. n6  
} Y5,[udF:O  
Md[M}d8  
6)j4-  
public String getSFileName() /|MHZ$Y9w?  
{ h}$g}f%$+  
return sFileName; /; {E}`  
} K~6,xZlDWM  
F)n^pT  
kVeR{i<*(  
public void setSFileName(String value) R!Lh ~~@{(  
{ vOQ 3A%/  
sFileName = value;  oo4aw1d  
} %<]4]h  
@]F1J  
;U)xZ _Ew~  
public int getNSplitter() tPqWe2  
{ EJ@&vuDd$  
return nSplitter; DV{0|E  
} 0aM&+j\q}  
 Qo$j'|lD  
B9(@ .  
public void setNSplitter(int nCount) JEh(A=Eu>  
{ 1W r,E#+C  
nSplitter = nCount; euiP<[|h=  
} `~k`m{4.a  
} {$xt.<  
{3`cSm6c  
$H8B%rT]  
/* 6"YcM:5~  
**Utility.java FKBI.}A?!'  
*/ d+o.J",E  
package NetFox; G$mAyK:  
!*e1F9k  
~J:]cy)Q  
public class Utility { <q.Q,_cW  
E< Y!BT[X  
~YRG9TK  
public Utility() )lZoXt_3  
{ NH'Dz6K5  
0PD=/fh[  
m gE r+  
} ]_(J8v  
e);`hNLih  
//线程睡眠 IqAML|C  
public static void sleep(int nSecond) Qg]+&8!*  
{ LU $=j  
try{  alH6~  
Thread.sleep(nSecond); yu>)[|-  
} g{^~g  
catch(Exception e) @1N .;]|  
{ 9? y&/D5O  
e.printStackTrace (); tj4/x7!  
} %<0'xJ%%Q  
} v`@M IOv  
FBxg^g%PB@  
//日志 B~B,L*kC2  
public static void log(String sMsg) ezb*tN!  
{ 1ixBwnp?  
System.err.println(sMsg); A{p_I<  
} v{SZ(;  
]P/i}R:  
%xrldn%  
public static void log(int sMsg) h S)lQl:^  
{ 8]mRX~  
System.err.println(sMsg); ,N1pww?  
} d$^ @$E2f  
} -tIye{  
UD=[::##  
2HO2  
/* [y~kF?a  
**TestMethod.java S!rVq,| d  
*/ ,FwpHs $A  
package NetFox; (mplo|>  
D#P]tt.Z   
NL,6<ZOon,  
public class TestMethod { CG;+Z-"X  
7g$*K0m`  
)t((x  
public TestMethod() @?>5~  
{ ///xx/weblogic60b2_win.exe Oyb0t|do+  
try{ osc A\r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %(|-+cLW+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PhAD: A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +/ {lz8^,  
fileFetch.start(); |8tKN"QG  
} ,Wtgj=1!.  
catch(Exception e){e.printStackTrace ();} c/^l2CJ0  
qI>,PX  
&c}2[=  
} LP !d|X  
HQwrb HS  
#0?3RP  
public static void main(String[] args) ;66{S'*[  
{ n0G@BE1Y=  
new TestMethod(); \r9E6LL X'  
} I:w+lchAMe  
} [kTckZv  
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