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http断点续传简单实现(java)

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/* i>Cxi ZT  
**SiteFileFetch.java 2Qoj>Wy{  
*/ A0NNB%4|/  
package NetFox; a=55bEn  
import java.io.*; ~~.v*C[  
import java.net.*; C~2/ 5  
T4W"!4[  
jU#/yM "Y  
public class SiteFileFetch extends Thread { !  Z e  
S;o U'KOY  
)$#r6fQO  
SiteInfoBean siteInfoBean = null; //文件信息Bean dh7PpuN{  
long[] nStartPos; //开始位置 !U,^+"l'GP  
long[] nEndPos; //结束位置 -jZP&8dPH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /nK)esB1L  
long nFileLength; //文件长度 bw@Dc T&,  
boolean bFirst = true; //是否第一次取文件 qM`XF32A$  
boolean bStop = false; //停止标志 _{EO9s2FG  
File tmpFile; //文件下载的临时信息 ez2 gy"  
DataOutputStream output; //输出到文件的输出流 nP9@yI*7  
~YIGOL"?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;%1ob f 89  
public SiteFileFetch(SiteInfoBean bean) throws IOException [;c'o5M&  
{ a0"gt"q A  
siteInfoBean = bean; C?n3J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1MtvnPY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W#<&(s4  
if(tmpFile.exists ()) `ag7xd!  
{ $jYwV0  
bFirst = false; ub "(,k P  
read_nPos(); 5XNIX)H  
} 3:$hC8  
else !b O8apn  
{ JJnZbJti  
nStartPos = new long[bean.getNSplitter()]; SL;\S74  
nEndPos = new long[bean.getNSplitter()]; 0Fw0#eE  
} Ozk^B{{o  
+uF!.!}  
~Od4( }/G  
Sx,O)  
} :E|HP#iwu  
1i}Rc:  
mT.p-C  
public void run() O&# bC  
{ <v?9:}  
//获得文件长度 )x.}B4z  
//分割文件 k_9tz}Z  
//实例FileSplitterFetch U.oxLbJ`  
//启动FileSplitterFetch线程 (~oUd 4  
//等待子线程返回 ]fXMp*LvY  
try{ rK*s/mX <  
if(bFirst) +#5nk,1c>  
{ j+3~  
nFileLength = getFileSize(); 9=&e5Oq}  
if(nFileLength == -1) ?Z@FxW  
{ XA~Rn>7&H  
System.err.println("File Length is not known!"); <zN  
} S;$@?vF  
else if(nFileLength == -2) 9.| +KIRb  
{ d"nz/$  
System.err.println("File is not access!"); j.$#10*:  
} lz!F{mR  
else s-eC')w~E  
{ 0s = h*"[  
for(int i=0;i<nStartPos.length;i++) iTU 8WWY<  
{ JMu|$"o&{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %S8e:kc6  
} UA[2R1}d  
for(int i=0;i<nEndPos.length-1;i++) ,\;;1Kq  
{ 'Y+AU#1~H  
nEndPos = nStartPos[i+1]; ?lv{;4BC  
} &\][:kG;  
nEndPos[nEndPos.length-1] = nFileLength; 9?r|Y@xh]  
} \5^#5_<  
} lKs*KwG  
v]g/ 5qI&  
e-4XNL[F  
//启动子线程 ~R.8r-kD`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B&0^3iKFi  
for(int i=0;i<nStartPos.length;i++) b .k J&c  
{ 65VnH=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *LeFI%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3Ak,M-Jp  
nStartPos,nEndPos,i); ~V?O%1)k?\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9Ot;R?>(  
fileSplitterFetch.start(); U">D_ 8  
} TX]4Y953D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PY: l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "U34D1I )#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }N5>^y  
nEndPos = " + nFileLength); 4NL Tt K  
// fileSplitterFetch[nPos.length-1].start(); "GP!]3t  
irCS}Dbw  
euM7> $`  
//等待子线程结束 AiSO|!<.N  
//int count = 0; BQv+9(:fQB  
//是否结束while循环 S\GC^ FK  
boolean breakWhile = false; ?eT^gWX  
]#N2:ych  
)((Jnm D  
while(!bStop) 2%N$Y]  
{ nBL7LocvR  
write_nPos(); ~C< X~$y&  
Utility.sleep(500); WO$PW`k  
breakWhile = true; @L^2VVWk^  
^Sx 0t  
< pI2}  
for(int i=0;i<nStartPos.length;i++) _3h(R`VdWO  
{ cTm oz.0  
if(!fileSplitterFetch.bDownOver) s;q]:+#7g  
{ xA]CtB*o7  
breakWhile = false; <CJua1l\  
break; gF1q Z=<  
} vpx8GiV  
} AwB ]0H  
if(breakWhile) 1?"vKm  
break; C$\|eC j  
<OF7:f  
o:_}=1nh  
//count++; l2>G +t(,  
//if(count>4) ^8aj\xe(  
// siteStop(); _{&znXf>?6  
} _n_lO8mK  
7f#[+i  
QJp _>K  
System.err.println("文件下载结束!"); 6}  !n0  
} ?:Y{c#w>  
catch(Exception e){e.printStackTrace ();} =?T\zLN=  
} zJ7vAL  
`@ULG>   
"aK3 ylz;  
//获得文件长度 ?hvPPEJf  
public long getFileSize() j$^3  
{ EtJyI&7VK  
int nFileLength = -1; * 7.!"rb8A  
try{ Gvv~P3Dm  
URL url = new URL(siteInfoBean.getSSiteURL()); (E59)z -  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3N(s)N_P M  
httpConnection.setRequestProperty("User-Agent","NetFox"); p>=YPi/d  
[=9-AG~}  
j[gX"PdQ  
int responseCode=httpConnection.getResponseCode(); lDO9GNz$  
if(responseCode>=400) 4&)*PKq  
{ ]uX'[Z}t  
processErrorCode(responseCode); *}Zd QJL  
return -2; //-2 represent access is error cBM A.'uIL  
} ),0_ C\  
z`((l#(  
eIK8J,-  
String sHeader; +ZtqR  
xn1  
G!k&'{2  
for(int i=1;;i++) `C`CU?D  
{ oEU %"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W$ #FM$U  
//Utility.log(in.readLine()); D4<nS<8  
sHeader=httpConnection.getHeaderFieldKey(i); Bp 6jF2  
if(sHeader!=null) v9INZ1# v  
{ x)l}d3   
if(sHeader.equals("Content-Length")) g}0}$WgH:  
{ 1Vt7[L*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dON 4r2-yC  
break; qI\qpWS\  
} CE-ySIa  
} br+{23&1R#  
else < i"U%Ds(  
break; 4.7OX&L'G  
} UvRa7[<y%%  
} (Mhj-0xf$  
catch(IOException e){e.printStackTrace ();} Ev%4}GwO4  
catch(Exception e){e.printStackTrace ();} MFcN.M  
g e:UliHJ  
5i7,s  
Utility.log(nFileLength); "0 \U>h  
id@!kSR  
&Eg>[gAIlp  
return nFileLength; 1w'iD X  
} ~F^=7oq  
zg2A$Fd[j  
Oyhl*`-*t  
//保存下载信息(文件指针位置) [>::@[  
private void write_nPos() _aL:XKM  
{ |;ycEB1  
try{ :XcU@m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9d^o2Y o  
output.writeInt(nStartPos.length); 5WgdgDb@L  
for(int i=0;i<nStartPos.length;i++) DtG><g}[]  
{ |1X^@  
// output.writeLong(nPos); ~Y@(  
output.writeLong(fileSplitterFetch.nStartPos); e4u$+  
output.writeLong(fileSplitterFetch.nEndPos); He^+>XIam  
} >/nS<y>  
output.close(); VS@o_fUx)  
} kX."|]  
catch(IOException e){e.printStackTrace ();} E8J `7sa  
catch(Exception e){e.printStackTrace ();} +Tc<|-qQn  
} OsPx-|f S~  
zI8Q "b  
A>(m}P  
//读取保存的下载信息(文件指针位置) *,{. oO9#  
private void read_nPos() ;H /*%2  
{ 2+ F34  
try{ &^FCp'J-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iq-n(Rfw~  
int nCount = input.readInt(); 2-j+-B|i  
nStartPos = new long[nCount]; ,.uu/qV}w  
nEndPos = new long[nCount]; RzQ1Wq  
for(int i=0;i<nStartPos.length;i++) 55MsF}p  
{ 8:0QIkqk  
nStartPos = input.readLong(); 3]WIN_h  
nEndPos = input.readLong(); =_I2ek  
} %/b?T]{  
input.close(); frbKi _1  
} ZXljCiNn+\  
catch(IOException e){e.printStackTrace ();} 01}az~&;35  
catch(Exception e){e.printStackTrace ();} j0^~="p%C  
} n( l!T 7  
G<OC99;8  
f!a[+^RB:  
private void processErrorCode(int nErrorCode) Q ,30  
{ SdBv?`u|g  
System.err.println("Error Code : " + nErrorCode); D oX!P|*  
} &0SX*KyI  
A#M#JI-Y  
p#hs8xz  
//停止文件下载 DxR__  
public void siteStop() &H$ 3`"p5u  
{ c-3AzB#[  
bStop = true; )a.Y$![  
for(int i=0;i<nStartPos.length;i++) m619bzFlB  
fileSplitterFetch.splitterStop(); jhrmQS  
4YM!SE-I  
W_9-JM(r  
} vt<r_&+ pJ  
} UhYeyT  
//负责部分文件的抓取 U(3+*'8r,1  
**FileSplitterFetch.java /+pbO-rW*  
*/ I>o+INb:  
package NetFox; d a we!w!  
vpcx 1t<  
rM#jxAb  
import java.io.*; K@Q_q/(%;  
import java.net.*; H_m(7@=  
]c]rIOTN  
asb-syqU  
public class FileSplitterFetch extends Thread { *,5V;7OR  
<uDEDb1|l  
w'z ?1M(*  
String sURL; //File URL @G[P|^B  
long nStartPos; //File Snippet Start Position 0b+OB pqN  
long nEndPos; //File Snippet End Position ~[d U%I>L^  
int nThreadID; //Thread's ID 2Un~ Iy  
boolean bDownOver = false; //Downing is over 1OK,r`   
boolean bStop = false; //Stop identical <DP_`[+C  
FileAccessI fileAccessI = null; //File Access interface dqO!p6  
_"_ W KlN  
z OD5a=[1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X> :@`}bq  
{ #XR<}OYcL  
this.sURL = sURL; GY,l&.&  
this.nStartPos = nStart; ]J+ }WR  
this.nEndPos = nEnd; YMOy 6C  
nThreadID = id; k v1q \  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #\KSv Z  
} Q*}#?g  
P1)f-:;  
W#87T_7T[  
public void run() U.is:&]E  
{ VXXo\LQUU  
while(nStartPos < nEndPos && !bStop) l|z 'Lwwm5  
{ ?9xaBWf  
?F]Yebp^  
Xd/gvg{??0  
try{ y E-H-r~I  
URL url = new URL(sURL); 8Kt_irD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^IGutZov  
httpConnection.setRequestProperty("User-Agent","NetFox"); eKi/Mt  
String sProperty = "bytes="+nStartPos+"-"; n_\V G[f  
httpConnection.setRequestProperty("RANGE",sProperty); 5!u.w  
Utility.log(sProperty); w^Qb9vTa8  
ln%xp)t  
J/S 47J~  
InputStream input = httpConnection.getInputStream(); _Qg^>}]A1  
//logResponseHead(httpConnection); \PU3{_G]  
/Y@^B,6 \  
yep`~``_  
byte[] b = new byte[1024]; DqyJ]}|  
int nRead; FJKW=1 =,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g3Q]W(F%$  
{ X{zg-k(@  
nStartPos += fileAccessI.write(b,0,nRead); //cj$}Rn!  
//if(nThreadID == 1) HKr")K%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); im{'PgiR  
} yzr>]"o  
|3{DlZ2S  
y%)5r}S^  
Utility.log("Thread " + nThreadID + " is over!"); .4Ob?ZS(  
bDownOver = true; >ch{u{i6  
//nPos = fileAccessI.write (b,0,nRead); {vYmK#}  
} Dz/I"bZLC  
catch(Exception e){e.printStackTrace ();} jV Yt=j*"V  
} <Z5ak4P  
} KD?~ hpg  
`l,=iy$  
6}^0/ 76^,  
//打印回应的头信息 d2lOx|jt  
public void logResponseHead(HttpURLConnection con) k_%2Ok   
{ b);Pw"_2  
for(int i=1;;i++) RaT(^b(  
{ n B4)%  
String header=con.getHeaderFieldKey(i); y;Xb." e~  
if(header!=null) sPY *2B  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n ^P=a'+  
Utility.log(header+" : "+con.getHeaderField(header)); @/h_v#W  
else %}jwuNGA  
break; 9k8ftxB^  
} -BUxQ8/,  
} %^s;{aN*!  
aiVd^(  
q<` YJ,  
public void splitterStop() N1$lG? )+  
{ 'U ',9  
bStop = true; U ^1Xc#Ff  
} ~01 o  
T P'  
A5-y+   
} OJ8ac6cJ  
!9=hUpRN  
f1MKYM%^x  
/* =g4^tIYq  
**FileAccess.java "3o{@TdU  
*//文件访问(定位,写) 2?YN8 n9n  
package NetFox; *Wk y#  
import java.io.*; ,9<}V;(  
~$XbYR-  
o`S|  
public class FileAccessI implements Serializable{ UwOZBF<  
.,zrr&Po  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yoa"21E$  
RandomAccessFile oSavedFile; xLX<. z!r  
long nPos; 58\rl G  
#(& ! ^X3  
usEd p  
public FileAccessI() throws IOException gQaBQq9  
{ 9EzXf+f  
this("",0); P5s'cPX  
} J'^H@L/E  
"?EoYF_  
i? 5jl&30  
public FileAccessI(String sName,long nPos) throws IOException ixF '-  
{ +F3@-A  
oSavedFile = new RandomAccessFile(sName,"rw"); (t'hWS  
this.nPos = nPos; ,jJ&x7ra8  
oSavedFile.seek(nPos); ?"f\"N  
} vQB;a?)o  
2RXU75VY  
=H&{*Ja  
public synchronized int write(byte[] b,int nStart,int nLen) 8 tMfh  
{ QA?e2kd  
int n = -1; ^FNvVbK|`  
try{ 5&a4c"fU  
oSavedFile.write(b,nStart,nLen); M{I8b<hY  
n = nLen; ipU,.@~#  
} SA_5..  
catch(IOException e) =au7'i|6  
{ 4mR{\ d  
e.printStackTrace (); $g&,$7}O_  
} lc1?Vd$  
l/9V59Fv9  
*olV Y/'O  
return n; gyi<ot;  
} 1{@f:~v?  
Uywi,9f  
!K a!f1  
} iXt1{VP'K  
J.'}R2gT1  
t.wB\Kmt\  
/* 1L722I @  
**SiteInfoBean.java ,)%al76E  
*/ ELoE-b)Cb  
package NetFox; o,l3j|1  
P,5gaT)  
J6pQ){;6  
public class SiteInfoBean { q]Y [W1  
4oW6&1  
} LuPYCzpu  
private String sSiteURL; //Site's URL <=WSX{_D  
private String sFilePath; //Saved File's Path 1F?`.~q  
private String sFileName; //Saved File's Name L=Cm0q 3 v  
private int nSplitter; //Count of Splited Downloading File A0{ !m  
y4* }E  
3LXS}~&  
public SiteInfoBean() *s4h tt  
{//nSplitter的缺省值为5 57r?`'#*  
//default value of nSplitter is 5 R T/T+Q!  
this("","","",5); A[20ic  
} mqL&bmT  
iW.4'9   
On%21L;JG  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Hc.r/  
{ pzcV[E1  
sSiteURL= sURL; 9_yO 6)`  
sFilePath = sPath; pw;  
sFileName = sName; "fWAp*nI3t  
this.nSplitter = nSpiltter; `I*W}5  
0I6[`*|SX  
S[!sJ-rG  
} & h)G>Sqc  
/H 3u^  
Vs@[="  
public String getSSiteURL() AITV+=sN  
{ W vh3Y,|3  
return sSiteURL; Q1tZ]Q.6  
} TAfLC)  
5 :O7cBr  
m$nT#@l5bH  
public void setSSiteURL(String value) C1=7.dPr  
{ ^R\et.W`s  
sSiteURL = value; !OwRx5  
} :4 9ttJl  
yZ7aH|Q81B  
_@U?;73"5  
public String getSFilePath() ]Tmx;[D  
{ jSMvZJX3n  
return sFilePath; y&8' V\  
} +E.}k!y  
i4 BCm/h  
8r"$o1!  
public void setSFilePath(String value) 6J/"1 _  
{ .hI3Uv8[  
sFilePath = value; z?o1 6o-:  
} r$3{1HXc  
O'tVZ!C#J  
#i$/qk= N  
public String getSFileName() "#7~}Z B  
{ z"4UObVs  
return sFileName; ~!o\uTVr  
} 3`y9V2&b  
#H]cb#  
32DT]{-N!  
public void setSFileName(String value) CXC,@T  
{ QcZ*dI7]:  
sFileName = value; l| 1O9I0Gd  
} /?<tjK' "H  
*#ccz  
=HJ)!(  
public int getNSplitter() _T[=7cn  
{ th&?  
return nSplitter; W i a%rm  
} 5sbMp;ZM  
! Jh/M^  
k-;%/:Om  
public void setNSplitter(int nCount) qJq49}2  
{ UhQsT^b_  
nSplitter = nCount; {(mT,}`4  
} &(H;Bin'  
} 1pe eecE  
DPENYr  
IyTL|W6  
/* t__UqCq~h  
**Utility.java nCMv&{~  
*/ A`E7V}~  
package NetFox; \@yx;}bdI  
2-G he3  
 _N`:NOM  
public class Utility { :Ny.OA  
*5( h,s3&  
/mMRV:pd  
public Utility() N[$bP)h7  
{ . J"g.Q  
*Xh)22~T  
/cn=8%!N  
} z[kz [  
sZ`C "1cX  
//线程睡眠 >)g`;iO  
public static void sleep(int nSecond) b$/TfpNdo  
{ bZ!*s  
try{ 9qIdwDRY  
Thread.sleep(nSecond); cID{X&or  
} H{*~d+:ol  
catch(Exception e) p4m9@ \gn  
{ anwMG0  
e.printStackTrace (); .+1.??8:+  
} sflH{!;p  
} 0fgt2gA33  
[%U(l<  
//日志 21Z}Zj  
public static void log(String sMsg) HWe?vz$4"  
{ !acm@"Ea  
System.err.println(sMsg); BR1oE3in  
} l{U-$}  
9b`J2_ ]k  
U=_O*n?N-d  
public static void log(int sMsg) XA`<*QC<  
{  .PyPU]w  
System.err.println(sMsg); |Sg FHuA  
} xE/r:D#  
} :S Tj <  
B+:'Ld](  
1EvAV,v"  
/* V=!tZ[4z$h  
**TestMethod.java 'J+dTs ;0  
*/ B j!{JcM-^  
package NetFox; O+vuv,gNi  
]Lg$p  
N?`-$C ]  
public class TestMethod { CRy;>UI  
r+8%oWj  
r5ONAa3.  
public TestMethod() G(7!3a+  
{ ///xx/weblogic60b2_win.exe K07b#`NF6  
try{ JTu^p]os?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3Qt-%=b&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); n(-1vN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UEeD Nl$^u  
fileFetch.start(); 3nVdws  
} 96fzSZS,  
catch(Exception e){e.printStackTrace ();} LfD7 0r\  
02Z># AE  
2/.E uf   
} n6T@A;_g  
iU^KmM I  
DgOO\  
public static void main(String[] args) h+o-h4X  
{ s53 Pw>f  
new TestMethod(); h WvQh  
} `usX(snY  
} 1#H=<iJ  
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