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http断点续传简单实现(java)

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/* ViT$]Nv  
**SiteFileFetch.java =}AwA5G  
*/ A|U_$!cLZ  
package NetFox; $lrq*Nf9c  
import java.io.*; HPR*:t  
import java.net.*; jG3i )ALx  
r*l:F{  
Aa/lKiiz  
public class SiteFileFetch extends Thread { lN^} qg><  
! =c&U.B  
{utIaMb]&v  
SiteInfoBean siteInfoBean = null; //文件信息Bean nK9A=H'Hc  
long[] nStartPos; //开始位置 6|:]2S  
long[] nEndPos; //结束位置 !23#Bz7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y|iALrx  
long nFileLength; //文件长度 PUViTb  
boolean bFirst = true; //是否第一次取文件 ^Ru/7pw 5  
boolean bStop = false; //停止标志 #nh;KlI 0  
File tmpFile; //文件下载的临时信息 K:eP Il{JE  
DataOutputStream output; //输出到文件的输出流 8.Ty ,7Z  
6,|)%~VUm  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) A5ps|zidI  
public SiteFileFetch(SiteInfoBean bean) throws IOException &Qdd\h#  
{ AiO29<  
siteInfoBean = bean; 0TI+6u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); P}QuGy[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); uB:utg  
if(tmpFile.exists ()) J5Tl62}  
{ COK7 i^  
bFirst = false; u{ .UZTn  
read_nPos(); x~tG[Y2F?  
} 7MT[fA8^  
else k iCg+@nT  
{ \/9uS.Kw  
nStartPos = new long[bean.getNSplitter()]; DjjG?(1  
nEndPos = new long[bean.getNSplitter()]; s],+]<qX  
} k w!1]N  
0:(@Y  
Q pY:L  
$fY4amX6Z  
} rX#} 2  
5sq#bvfJ o  
<zK9J?ZQW>  
public void run() ,9f$a n  
{ @BN cIJk9  
//获得文件长度 q<b;xx  
//分割文件 (k..ll p~  
//实例FileSplitterFetch J,E'F!{  
//启动FileSplitterFetch线程 h^5'i} @u  
//等待子线程返回 xla9:*pPn  
try{ toEmIa~o6  
if(bFirst) *Gm%Dn  
{ {=> <@]N  
nFileLength = getFileSize(); NTVdSK7z~H  
if(nFileLength == -1) v:<UbuJw  
{ KPUc+`cN%  
System.err.println("File Length is not known!"); |T9p#) ec2  
} (6G5UwSt  
else if(nFileLength == -2) RCq_FY  
{ KutR l$,  
System.err.println("File is not access!"); ;Q2p~-0Q  
} j%KLp4J/e  
else QO)Q%K,  
{ 16YJQ ue  
for(int i=0;i<nStartPos.length;i++) Ov)rsi  
{ A|Yq Bl  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); vF;%#P  
} ;ePmN|rq;  
for(int i=0;i<nEndPos.length-1;i++) *"Ipu"G5?  
{ dQt*/]{q  
nEndPos = nStartPos[i+1]; LRv-q{jP;  
} XH0R:+s  
nEndPos[nEndPos.length-1] = nFileLength; ?/~7\ '|Z  
} xU^Flw,4  
} uM0 z%z5b  
F[c;iM(^  
n}yqpW!%n  
//启动子线程 q"A(l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;#!`c gAh  
for(int i=0;i<nStartPos.length;i++) lFD$ Mc  
{ ~'HwNzDQc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ajhrsa\~a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), gBq,So  
nStartPos,nEndPos,i); 8lt P)K4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2|#3rF  
fileSplitterFetch.start(); ue$\ i=jw  
} . c+RFX@0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), fdN-Zq@'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N@^?J@#V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z| +/Wl-h  
nEndPos = " + nFileLength); Ne.W-,X^cL  
// fileSplitterFetch[nPos.length-1].start(); }yU,_:  
_#e='~;  
bI=\n)sEz  
//等待子线程结束 z1F[okLA  
//int count = 0; S~ }?6/G.  
//是否结束while循环 &S<tX]v  
boolean breakWhile = false; Vrf` :%  
d;(L@9HHD  
Ni{ (=&*=  
while(!bStop) PS@` =Z  
{ |]]Xee]  
write_nPos(); a)[XJLCQ  
Utility.sleep(500); N Q{ X IN~  
breakWhile = true; `96:Z-!}  
t4UKG&[a  
iR(A ^  
for(int i=0;i<nStartPos.length;i++) {`~{%2ayq7  
{ ts%@1Y?  
if(!fileSplitterFetch.bDownOver) S0g5Ym ia  
{ 2[Q*?N  
breakWhile = false; wI}5[m  
break; E'&UWD h  
} 7##nY3",^  
} ^`\c;!)F<  
if(breakWhile) IX^k<Jqr  
break; Jnm{i|6N  
f 7et  
7^Jszd:c08  
//count++; }jfU qqFd  
//if(count>4) MlsF?"H p  
// siteStop(); 9 YU7R)  
} 7 4aap2^  
T8ZBQ;o  
FymA_Eq  
System.err.println("文件下载结束!"); OgS6#X  
} qw0tw2|  
catch(Exception e){e.printStackTrace ();} z(>{"t<C  
} #v')iR"  
{`KgyC W:  
pR&cdO RsP  
//获得文件长度 3. Qf^p  
public long getFileSize() <h U ZD;  
{ RoLUPy9U  
int nFileLength = -1; bP Er+?fu  
try{ * C~  
URL url = new URL(siteInfoBean.getSSiteURL()); 23y7l=.b/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); djPr 4Nog  
httpConnection.setRequestProperty("User-Agent","NetFox"); v (=fV/  
rc*&K#? B  
RV^2[Gdi  
int responseCode=httpConnection.getResponseCode(); 4G@vO {$  
if(responseCode>=400) zY\v|l<T  
{ Q]w;o&eo  
processErrorCode(responseCode); fmA&1u/xMs  
return -2; //-2 represent access is error ,^,Vq]$3  
} ^;NM'Z  
1B6Go  
+fAAkO*GP  
String sHeader; dj?.Hc7od  
u-pE ;|  
A86#7  
for(int i=1;;i++) |>A1J:  
{ u$&7fmZ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aAwnkQ$  
//Utility.log(in.readLine()); }o=R7n%  
sHeader=httpConnection.getHeaderFieldKey(i); Gc4N)oq)}b  
if(sHeader!=null) =@binTC4  
{ cIja^xD  
if(sHeader.equals("Content-Length")) 9 o-T#~i  
{ 1F/`*z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); gUL`)t\}*  
break; ePIBg(  
} =a?l@dI]  
} {.H}+@0  
else |vTirZP  
break; .-`7Av+7  
} K,|Gtaa~  
} s3_i5,y  
catch(IOException e){e.printStackTrace ();} Z=R>7~H  
catch(Exception e){e.printStackTrace ();} (~}yt.7K  
20 zIO.&o  
B HoZ}1_  
Utility.log(nFileLength); %9-).k  
=NF},j"  
>efYpd#^  
return nFileLength; //Hn[wEOh  
} -YA1Uk  
Kdx?s;i  
,, ]y 8P  
//保存下载信息(文件指针位置) tV*g1)'zX  
private void write_nPos() }.o rfW  
{ zL3~,z/o  
try{ %nF6n:|:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \[]36|$LS  
output.writeInt(nStartPos.length); :8E(pq|1PB  
for(int i=0;i<nStartPos.length;i++) 5U3="L  
{ k2<VUeW5  
// output.writeLong(nPos); \ zhT1#O  
output.writeLong(fileSplitterFetch.nStartPos); H]UM2.  
output.writeLong(fileSplitterFetch.nEndPos); x~j%  
} \P}~ICZA  
output.close(); vsqfvx  
} "]*0)h_  
catch(IOException e){e.printStackTrace ();} ( y2%G=.j  
catch(Exception e){e.printStackTrace ();} `"zX<  
} eO (VSjo'`  
1U@qR U  
+To{Tm-  
//读取保存的下载信息(文件指针位置) sA3 4`ZAa  
private void read_nPos() D gY2:&0  
{ lb{*,S  
try{ N: d`L+tcc  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); GLnj& Ve  
int nCount = input.readInt(); %OfaBv&  
nStartPos = new long[nCount]; w;}P<K  
nEndPos = new long[nCount]; rbO9NRg>  
for(int i=0;i<nStartPos.length;i++) 9"=:\PE  
{ 46Nl];g1`  
nStartPos = input.readLong(); *1ku2e]z  
nEndPos = input.readLong(); #kA/,qyM  
} IA$:r@QNx8  
input.close(); opte)=]J  
} }j+ZF'#  
catch(IOException e){e.printStackTrace ();} iZg v VH  
catch(Exception e){e.printStackTrace ();} BGLJ>zkq  
} `cy_@Z5A  
+7^%fX;3pW  
=MB[v/M59w  
private void processErrorCode(int nErrorCode) mAk)9`f/  
{ >e=tem~/  
System.err.println("Error Code : " + nErrorCode); 6Nj\N oS  
} ^Ml)g=Fq  
(t>BO`,  
jNaK]  
//停止文件下载 $MfHA~^  
public void siteStop() S,n*1&ogj  
{ G9N6iKP!  
bStop = true; o" &7$pAh  
for(int i=0;i<nStartPos.length;i++) XlV#)JX  
fileSplitterFetch.splitterStop(); lDCoYX_  
_j}|R(s*+V  
vtCt6M  
} vbmi_[,U  
} <^ @1wg  
//负责部分文件的抓取 la</IpC  
**FileSplitterFetch.java ,wlF n  
*/ XcR2]\  
package NetFox; (O\5gAx  
 zy  
$FNj>1  
import java.io.*; 8}XtVF;  
import java.net.*; Z8z.Xn  
Wf-i)oc4I  
9K@`n:Rw  
public class FileSplitterFetch extends Thread { +Z/ *=;  
Cc$!TZq=  
;R@zf1UYA  
String sURL; //File URL sn@gchO9s  
long nStartPos; //File Snippet Start Position r[q-O&2&  
long nEndPos; //File Snippet End Position QPg QM6  
int nThreadID; //Thread's ID O:{I9V-=>s  
boolean bDownOver = false; //Downing is over k_ UY^vz.  
boolean bStop = false; //Stop identical Ra%RcUf~sh  
FileAccessI fileAccessI = null; //File Access interface [ZZ~^U5  
W[AX?  
8jMw7ti  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %qV=PC  
{ 4sP0oe[h  
this.sURL = sURL; PL@hsZty~c  
this.nStartPos = nStart; vCb3Ra~L`  
this.nEndPos = nEnd; )%-FnW  
nThreadID = id; =XzrmPu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \v)Dy)Vhg2  
} QpBgG~h"  
&;&i#ZO  
(]w_}E]N  
public void run() Dwj!B;AZ_  
{ "|{ NRIE  
while(nStartPos < nEndPos && !bStop) (Dlh;Ic r9  
{ $.a<b^.Xi  
o:.={)rX  
5@ %$M$E  
try{ P%8 Gaa=  
URL url = new URL(sURL); sG=D(n1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?w#V<3=  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^vn8s~#  
String sProperty = "bytes="+nStartPos+"-"; yS[:C 2v  
httpConnection.setRequestProperty("RANGE",sProperty); 0BMKwZg  
Utility.log(sProperty);  s X.L  
EeIV6ug  
F=7X,hK  
InputStream input = httpConnection.getInputStream(); zflq|dW  
//logResponseHead(httpConnection); ^HgQ"dD <  
, ;W6wj  
q6bi{L@/R  
byte[] b = new byte[1024]; f=+|e"i #p  
int nRead; r{!]` '8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B8F.}M-!  
{ |L}zB,  
nStartPos += fileAccessI.write(b,0,nRead); [<\k  
//if(nThreadID == 1) 12`q9Io"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c@wSv2o$  
} .vE=527g)  
^I4'7]n-  
# ` Q3Z}C  
Utility.log("Thread " + nThreadID + " is over!"); Jz&a9  
bDownOver = true; Cc/h|4  
//nPos = fileAccessI.write (b,0,nRead); [=7=zV;}4  
} 2BZYC5jy  
catch(Exception e){e.printStackTrace ();} sD H^l)4h  
} /2N'SOX  
} G0oY`WXOB  
4wjy)VD_  
)h6hN"#V5  
//打印回应的头信息 gHdNqOy c  
public void logResponseHead(HttpURLConnection con) UCG8=+t5T  
{ M<s16  
for(int i=1;;i++) a"SH_+T{  
{ AFE6@/'  
String header=con.getHeaderFieldKey(i); i8iv{e2  
if(header!=null) )hs"P%Zg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;\ ^'}S|3Z  
Utility.log(header+" : "+con.getHeaderField(header)); Jmrs@  
else 8mjPa^A  
break; 3#N'nhUzA  
} 1/X@~  
} r<VZE bm)  
a~ q_2S]h  
5$f vI#NO<  
public void splitterStop() Uc%n{ a-a  
{  ,5!&}  
bStop = true; +`tl<r g;  
} 4<}!+X7m  
> %h7)}U  
% `Q[?(z  
} c%y(Z5  
z"#iG&>a,  
)3K#${p  
/* .c__<I<G<  
**FileAccess.java wJyrF  
*//文件访问(定位,写) tpu2e*n-|  
package NetFox; URU,&gy=  
import java.io.*; `_%U K=m  
sB!#`kh  
e_RLKFv7  
public class FileAccessI implements Serializable{ }L mhM  
#&zM.O1Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~o{GQ>  
RandomAccessFile oSavedFile; .#^ta9^t7  
long nPos; & -r^Q  
 N>ncv  
e&~vO| 3w%  
public FileAccessI() throws IOException LGnb"ZN  
{ )/HbmtXqI  
this("",0); eTg8I/ )%B  
} "/e_[_j  
R[_Q}W'HG  
(=A61]yB  
public FileAccessI(String sName,long nPos) throws IOException #(@!:f1  
{ G47(LE"2b  
oSavedFile = new RandomAccessFile(sName,"rw"); !8g419Yg  
this.nPos = nPos; hcn $uyP  
oSavedFile.seek(nPos); ?^Gi;d5  
} 9S 'u 1%  
6U.A/8z  
OaTnQ|*  
public synchronized int write(byte[] b,int nStart,int nLen) G5WQTMzf&  
{ d]A.=NAc  
int n = -1; PP*6nW8  
try{ x[?N[>uw  
oSavedFile.write(b,nStart,nLen); [U5@m]>^  
n = nLen; 4X-"yQ<U  
} CdBpz/  
catch(IOException e) vCvjb\S  
{ ak,KHA6u  
e.printStackTrace (); m^k$Z0  
} oX=dJJ E  
v~8Cp C  
8F>u6Y[P  
return n; (Q5rOrA"  
} .7 K)'  
&9Y ^/W  
< `$svM  
} mpr_AL!ZO~  
rn$G.SMgz  
Cn"_x  
/* 1Kjqs)p^  
**SiteInfoBean.java ]I,(^Xq3a(  
*/ V0)bPcS/  
package NetFox; ^C=dq(i=[  
Vc[aNpE  
3_bE12  
public class SiteInfoBean { ZLjEH7  
SFu]*II;{  
FR9w0{o  
private String sSiteURL; //Site's URL L@5sY0 M  
private String sFilePath; //Saved File's Path }SfS\b{|~  
private String sFileName; //Saved File's Name ,? >{M  
private int nSplitter; //Count of Splited Downloading File LC1WVK/  
zqHG2:MN"  
OV G|WC  
public SiteInfoBean() ^4b;rLfk@  
{//nSplitter的缺省值为5 -9] ucmN  
//default value of nSplitter is 5 nND; lVQSO  
this("","","",5); Z~0TO-Q  
} `uKsFX M  
vjL +fH<0:  
6"Ze%:AZZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F9} zt 9  
{ lw]uH<v  
sSiteURL= sURL; eo@kn yA<&  
sFilePath = sPath; 5cvvdO*C0  
sFileName = sName; H#S`m  
this.nSplitter = nSpiltter; Y\,aJL$  
eJ*u]GH U  
t$Bu<frQ  
} q+znb'i-x  
8(Cs<C!  
XS}-@5TI  
public String getSSiteURL() 216`rQ}z  
{ 2Z-[x9t  
return sSiteURL; `fuQ t4  
} YQ$LU \:  
)3 I~6ar  
O#<F"e;$  
public void setSSiteURL(String value) A`--*$8\  
{ +CVB[r#hu  
sSiteURL = value; M }! qH.W  
} n^q%_60H   
qyBC1an5,  
{wDq*va  
public String getSFilePath() +/[L-&,  
{ x?UAj8z6  
return sFilePath; {?;qy\m]o  
} `;=-71Gn~  
"38L ,PW0Z  
28LBvJVq@  
public void setSFilePath(String value) ~<.{z]*O  
{ /-knqv  
sFilePath = value; 6HguZ_jC  
} soRY M  
}[{9u#@#  
O14\_eAu6  
public String getSFileName() A<] $[2qPj  
{ ?y]R /?  
return sFileName; i[?VF\Y(  
} nC%<BatQ  
 _!_^B  
'yosDT2{#  
public void setSFileName(String value) Hd\. ,2a"  
{ f}~=C2R1<!  
sFileName = value; Q #X'.](1  
} <O1os"w  
V|hwT^h  
3RX9LJGX  
public int getNSplitter() 0h~{K  
{ !{4'=+  
return nSplitter; )7{r8a  
} pw&k0?K#  
ymp ik.'  
.l hS  
public void setNSplitter(int nCount) ,1g_{dMx  
{ ?@z/#3b  
nSplitter = nCount; =:Yrb2gP_\  
} VP~(;H5%  
} !7f,gvk  
mrq,kwM  
_s+G02/q1  
/* OkAgO3>Y/  
**Utility.java ^D1gcI  
*/ }$'XV.  
package NetFox; GKbbwT0T|  
@tJ4^<`P{  
')}itS8  
public class Utility { {+ Ibi{  
0~EGrEt  
s3T7M:DM4  
public Utility() [K@(,/$  
{ c|d,:u#  
'7pzw>E=:  
RH:vd|q+  
} o*artMkG  
v k= |TE  
//线程睡眠 oeZUd}P  
public static void sleep(int nSecond) HYmUD74FR  
{ t`'jr=e,~  
try{ P^# 4m  
Thread.sleep(nSecond); Y]*&\Ex"\  
} A|,qjiEJCc  
catch(Exception e) +~BP~  
{ 7x=4P|(\}  
e.printStackTrace (); @)x*62r+  
} ,a?oGi  
} aNs8T`  
j74hWz+p4  
//日志 Q% d1O  
public static void log(String sMsg) m[(_fOd  
{ kh{3s:RQfC  
System.err.println(sMsg); C=|8C70[%N  
} MRw4?HqB  
?:M4GY" gV  
[KFCc_:  
public static void log(int sMsg) UM#.`  
{ {NQCe0S+p  
System.err.println(sMsg); Mvue>)g~>  
} ' tHa5`  
}  VM:|I~gJ  
 }JWkV1  
o$Ylqb#  
/* 9pPLOXr ,  
**TestMethod.java [= BMvP5  
*/ P;@j  
package NetFox; G@`ZDn  
)[cuYH>  
c{dabzL y  
public class TestMethod { _;U%`/T b  
=-_hq'il  
UX[s5#  
public TestMethod() j#2E Q  
{ ///xx/weblogic60b2_win.exe u]7wd3(  
try{ a??8)=0|}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A)4XQF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :s&dn%5N"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UPP"-`t  
fileFetch.start(); #qmsZHd}b  
} SE43C %hv  
catch(Exception e){e.printStackTrace ();} 122s 7A  
dCS f$5  
]jm:VF]4  
} }IZw6KiN  
kxd*B P  
W1M322]>L  
public static void main(String[] args) {l5fKVb\C  
{ W7b m}JHn  
new TestMethod(); $2}#):`  
} JB].ht  
} L-:@Om!  
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