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http断点续传简单实现(java)

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/* ~4"qV_M  
**SiteFileFetch.java W9NX=gE4  
*/ cw iX8e"3  
package NetFox; 45hF`b>%,  
import java.io.*; ca+5=+X7  
import java.net.*;  {o(j^@  
q, O$ %-70  
n; {76Q  
public class SiteFileFetch extends Thread { ;a:[8Yi  
LL:_L<  
%*BlWk!Q  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4apL4E"r  
long[] nStartPos; //开始位置 II6CHjW`;  
long[] nEndPos; //结束位置 x _c[B4Tw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MEB it  
long nFileLength; //文件长度 cnTaJ/o  
boolean bFirst = true; //是否第一次取文件 I? ,>DHUX  
boolean bStop = false; //停止标志 I`NjqyTW  
File tmpFile; //文件下载的临时信息 $DG?M6   
DataOutputStream output; //输出到文件的输出流 U&O: _>~  
e7wSOs  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) P.gb 1$7<  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]U"94S U:)  
{ 8OgLn?"P  
siteInfoBean = bean; H;RwO@v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N7e"@Ic  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 03C0L&  
if(tmpFile.exists ()) y5!KXAQ%  
{ a+n0|CvF  
bFirst = false; T=ev[ mS  
read_nPos(); x7O-Y~[2  
} 2}8v(%s p  
else |\pbir  
{ #U14-^7  
nStartPos = new long[bean.getNSplitter()]; 3Z1CWzq(  
nEndPos = new long[bean.getNSplitter()]; s{1sE)_  
} Jv^h\~*jH  
.V,@k7U,V  
9T<x&  
d3xmtG {i  
} F6z%VWU  
)ut&@]  
%7|9sQ:  
public void run() `nu''B H  
{ Ofs <EQ  
//获得文件长度 $< JaLS  
//分割文件 9 AJ(&qY(  
//实例FileSplitterFetch <7~'; K  
//启动FileSplitterFetch线程 A}l3cP; `#  
//等待子线程返回 WPQ fhr#|  
try{ a |X a3E  
if(bFirst) ui?  
{ &v@a5L  
nFileLength = getFileSize(); LGn:c;  
if(nFileLength == -1) }4,L%$@n  
{ 'dn]rV0(C  
System.err.println("File Length is not known!"); !z>6 Uf!{  
} 2'w?\{}D  
else if(nFileLength == -2) \.-bZ$  
{ gw!vlwC&T  
System.err.println("File is not access!"); w(L4A0K[  
} :> 5@cvc  
else DA\2rLs  
{ j:v@pzTD  
for(int i=0;i<nStartPos.length;i++) ZP(f3X@  
{ uLV#SQ=bZN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {e 14[0U-  
} YuO.yh_  
for(int i=0;i<nEndPos.length-1;i++) tS6qWtE  
{ vw9@v`k  
nEndPos = nStartPos[i+1]; M!o##* *`  
} a^I\ /&aw'  
nEndPos[nEndPos.length-1] = nFileLength; LcTP #  
} #"G]ke1l$  
} lgk  .CC  
{N+$Q'  
GB=X5<;  
//启动子线程 #AJM6* G9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $| @ (  
for(int i=0;i<nStartPos.length;i++) gDpVeBd[  
{ 1ukTA@Rj&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), EFM5,gB.m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Iy&!<r7:]0  
nStartPos,nEndPos,i); , K~}\CR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZQV6xoN;r  
fileSplitterFetch.start(); Jcd-  
} J| w>a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VZKvaxIk6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gi1^3R[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .[ICx  
nEndPos = " + nFileLength); RMdk:YvBg  
// fileSplitterFetch[nPos.length-1].start(); Hquc o  
`r9!zffyS  
m+]K;}.}R  
//等待子线程结束 X aMJDa|M  
//int count = 0; e w$ B)W  
//是否结束while循环 g,!L$,/F  
boolean breakWhile = false; ?Lk)gO^C  
\"P%`  C  
V2wb%;q  
while(!bStop) sBT2j~jhJ  
{ s Z].8.  
write_nPos(); r7%I n^k  
Utility.sleep(500); "ut39si  
breakWhile = true; z7fp#>uw  
I 7{T  
#Lh;CSS  
for(int i=0;i<nStartPos.length;i++) *XIF)Q=<>  
{ kaVxT_  
if(!fileSplitterFetch.bDownOver) iv J@=pd)B  
{ |v 3T!  
breakWhile = false; ;,%fE2c  
break; gCB |DY  
} @niHl  
} Swig;`  
if(breakWhile) B|C2lu  
break; G3Hx! YW  
Ng2twfSl$  
\@c,3  
//count++; 52Z2]T c ,  
//if(count>4) LTQ"8  
// siteStop(); &]|?o_p3W  
}  iu=7O  
:(P9mt  
8e1UmM[  
System.err.println("文件下载结束!"); 3YOq2pW72G  
} "*e$aTZB\  
catch(Exception e){e.printStackTrace ();} qN9(S:_Px  
} -=)H{  
KQ% GIz x  
DEKP5?]  
//获得文件长度 Z>k#n'm^z  
public long getFileSize() "o-z y'I  
{ $ r@zs'N  
int nFileLength = -1; 6]WAUK%h  
try{ 98IJu  
URL url = new URL(siteInfoBean.getSSiteURL()); -b9\=U[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R'as0 u\  
httpConnection.setRequestProperty("User-Agent","NetFox"); SJn;{X>)q  
[}E='m}u9+  
 M^=zt  
int responseCode=httpConnection.getResponseCode(); On9A U:\  
if(responseCode>=400) @k,#L`3^  
{ P~>O S5^  
processErrorCode(responseCode); "c%0P"u  
return -2; //-2 represent access is error =(j1rW!  
} |6sp/38#p  
d;Ym=YHJtn  
:^6y7&o[  
String sHeader; *K8$eDNZ  
U)] oO  
/K@XzwM  
for(int i=1;;i++) ;PF<y9M  
{ &R'c.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); aFX=C >M  
//Utility.log(in.readLine()); !C ':  
sHeader=httpConnection.getHeaderFieldKey(i); uP)'FI  
if(sHeader!=null) _^Ubs>d=*  
{ /L g)i\R;  
if(sHeader.equals("Content-Length")) g[' ^L +hd  
{ 8Z8gRcv{p  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2j [=\K]  
break; C!<Ou6}!b  
} XPXIg  
} )4e.k$X^  
else vtg !8u4  
break; x}Eg.S  
} {T$9?`h~M  
} Cgk<pky1  
catch(IOException e){e.printStackTrace ();} y@S$^jk.  
catch(Exception e){e.printStackTrace ();} U`(ee*}o  
k_#ak%m/  
t%0VJB,Q2  
Utility.log(nFileLength); yW=::=  
y&$A+peJ1  
NZ:,ph  
return nFileLength; Y.(PiuG$G  
} %v M-mbX  
Ju@c~Xm  
{BN#h[#B{  
//保存下载信息(文件指针位置) t\dN DS  
private void write_nPos() :D5Rlfj  
{ L\J;J%fz.  
try{  ,f%S'(>w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ~g]Vw4pv  
output.writeInt(nStartPos.length); I3L<[-ZE  
for(int i=0;i<nStartPos.length;i++) zj{pJOM06  
{ gD @){Ip  
// output.writeLong(nPos); lgL%u K)  
output.writeLong(fileSplitterFetch.nStartPos); {UI+$/v#  
output.writeLong(fileSplitterFetch.nEndPos); N)X3XTY  
} IVY]EkEG~  
output.close(); Woy m/[i  
} reu*53r]  
catch(IOException e){e.printStackTrace ();} Q~ w|#  
catch(Exception e){e.printStackTrace ();} 0 1rK8jX  
} W' VslZG  
tCH!my_  
L ca}J&x]^  
//读取保存的下载信息(文件指针位置) v0{i0%d,?  
private void read_nPos() W:2( .?  
{ $t[FH&c(  
try{ 9s q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Tx# Mn~xD  
int nCount = input.readInt(); N#_H6TfMG  
nStartPos = new long[nCount]; L,/%f<wd  
nEndPos = new long[nCount]; .W%)*&WH\  
for(int i=0;i<nStartPos.length;i++) b{&)6M)zo  
{ M'O <h  
nStartPos = input.readLong(); ?dg [:1R}  
nEndPos = input.readLong(); Se}c[|8  
} j3V -LnA  
input.close(); 194)QeoFw  
} ydA8wL  
catch(IOException e){e.printStackTrace ();} TF\C@4Z  
catch(Exception e){e.printStackTrace ();} S9y}  
} b2Fe<~S{  
K($Npuu]  
6<QQ@5_  
private void processErrorCode(int nErrorCode) @Cyvf5|bL  
{ FDs>m #e  
System.err.println("Error Code : " + nErrorCode); Q Z  
} *L^,|   
n b?l TX~  
.|70;  
//停止文件下载 |0b`fOS  
public void siteStop() i[3'ec3  
{ [}=B8#Jl-C  
bStop = true; ![=yi tB  
for(int i=0;i<nStartPos.length;i++) f}P3O3Yv&  
fileSplitterFetch.splitterStop(); 6A-|[(NS  
904}Jh,  
G5 WVr$  
} |u<7?)mp  
} wlqksG[B  
//负责部分文件的抓取 ^6V[=!& H  
**FileSplitterFetch.java yNBfUj -L  
*/ &j"?\f?  
package NetFox; db7B^|Di  
g8% &RG  
#q=Efn'  
import java.io.*; 583|blL  
import java.net.*; '-~~-}= sJ  
1>h]{%I  
u&7[n_  
public class FileSplitterFetch extends Thread { z Rr*7G  
#)O6 5GI  
aX'*pK/-  
String sURL; //File URL _Y;W0Z  
long nStartPos; //File Snippet Start Position %P|/A+Mg"  
long nEndPos; //File Snippet End Position 3F2w-+L  
int nThreadID; //Thread's ID ?CPahU  
boolean bDownOver = false; //Downing is over bq*eH (qx  
boolean bStop = false; //Stop identical \_f(M|  
FileAccessI fileAccessI = null; //File Access interface on `3&0,.  
<>rneHl8  
m;QMQeGz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException hz@bW2S.  
{ E ~<JC"]  
this.sURL = sURL; rjYJs*#  
this.nStartPos = nStart; G_,jgg7  
this.nEndPos = nEnd; >|UOz&  
nThreadID = id; %IWPM"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2FJ*f/  
} ^<2p~h0 \  
LZY"3Jn[nQ  
lt8|9"9<  
public void run() A3/k@S-R2  
{ 1mG-}  
while(nStartPos < nEndPos && !bStop) kt:! 7  
{ vl:KF7:#m  
@\#td5'  
tG a8W  
try{ Gyc]?m   
URL url = new URL(sURL); u'BaKWPS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (*iHf"=\  
httpConnection.setRequestProperty("User-Agent","NetFox"); [{,1=AB  
String sProperty = "bytes="+nStartPos+"-"; SO!8Di  
httpConnection.setRequestProperty("RANGE",sProperty); VMWf>ZU  
Utility.log(sProperty); 0@oJFJrO  
 2JBR)P  
4,DeHJjAlE  
InputStream input = httpConnection.getInputStream(); t b}V5VH  
//logResponseHead(httpConnection); /k3:']G,s  
oCz/HQoBk  
/7YIn3  
byte[] b = new byte[1024]; <RL]  
int nRead; <)D$51 &0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9\7en%(M  
{ zTU0HR3A  
nStartPos += fileAccessI.write(b,0,nRead); 'D1xh~  
//if(nThreadID == 1) /j.9$H'y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;:NJCuG  
} +6+i!Sip  
eJ-nKkg~a  
E7hY8#G  
Utility.log("Thread " + nThreadID + " is over!"); 4o[{>gW  
bDownOver = true; sfl<qD+?  
//nPos = fileAccessI.write (b,0,nRead); \'O"~W  
} )Pv%#P-<  
catch(Exception e){e.printStackTrace ();} IH+|}z4N?>  
} UkFC~17P  
} Z,PPu&lmE/  
Qo|\-y-#  
tKXIk9e  
//打印回应的头信息 *s3/!K  
public void logResponseHead(HttpURLConnection con) 7@W>E;go  
{ X"eYK/7  
for(int i=1;;i++) vnuN6M{  
{ Ig{0Z">  
String header=con.getHeaderFieldKey(i); f3y=Wxk[  
if(header!=null) c-sfg>0^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); El8,,E  
Utility.log(header+" : "+con.getHeaderField(header)); |2A:eI8 ^  
else SOIN']L|V[  
break; do'GlU oMC  
} 'LDQgC*%  
} \s\?l(ooq"  
wUJcmM;  
r5^eNg k  
public void splitterStop() k+*u/neh  
{ x]j W<A  
bStop = true; %8v\FS  
} 1< ?4\?j  
x kD6Iw  
MF'JeM;H  
} 6ik$B   
o)/ 0a  
"#g}ve,  
/* iWR)ke  
**FileAccess.java <F'\lA9  
*//文件访问(定位,写) ~wdGd+ez  
package NetFox; cU  
import java.io.*; {_*yGK48n  
)t%b838l%  
Dw"\/p:-3  
public class FileAccessI implements Serializable{ 7zj{wp!  
nO-#Q=H,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h{qgEIk&  
RandomAccessFile oSavedFile; 8eRLy/`gd  
long nPos; #<xm.  
6aj!Q*(WT  
\{NO?%s0p  
public FileAccessI() throws IOException VIbq:U  
{ E{vbO/|kf  
this("",0); 3OB"#Ap8<  
} &7s.`  
4skD(au8  
yf,z$CR  
public FileAccessI(String sName,long nPos) throws IOException qxc[M8s  
{ x?<FJ"8"k  
oSavedFile = new RandomAccessFile(sName,"rw"); % ] U  
this.nPos = nPos; vP,n(reM  
oSavedFile.seek(nPos); 7xR\kL.,  
} _#8MkW#]~  
"J1 4C9u   
!<F3d`a  
public synchronized int write(byte[] b,int nStart,int nLen) ?V=CB,^  
{ 6L~n.5B~o  
int n = -1; E?@m?@*/  
try{ CvdN"k  
oSavedFile.write(b,nStart,nLen); : rVnc =k  
n = nLen; cz$2R  
} T u'{&  
catch(IOException e) :23P!^Y  
{ !5N.B|N t  
e.printStackTrace (); 5lum$5  
} |':{lH6+1  
Y4YJJYvD  
.RL=xb|[  
return n; {4PwLCy  
} GA.8@3  
z(~_AN M4,  
u1.BN>G  
} ~>XxGjxe  
eJX#@`K  
ji= "DYtL  
/* R@2X3s:  
**SiteInfoBean.java A=>u 1h69  
*/ D m9sL!  
package NetFox; X wtqi@zlE  
h yIV.W/  
[-x7_=E#  
public class SiteInfoBean { k;W XB|k  
5-A\9UC*@  
_VXN#@y  
private String sSiteURL; //Site's URL }GIt!PG  
private String sFilePath; //Saved File's Path Yr|4Fl~U  
private String sFileName; //Saved File's Name !Z6{9sKR=]  
private int nSplitter; //Count of Splited Downloading File o !7va"  
<oeIcN7d  
v-Sd*( 6  
public SiteInfoBean() ,"ql5Q4  
{//nSplitter的缺省值为5 cc3 4e  
//default value of nSplitter is 5 *lb<$E]="!  
this("","","",5); >-c8q]()ly  
} K,UMqAmk  
.G\7cZ  
fXB0j;A  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `F6C-  
{ ?@89lLD  
sSiteURL= sURL; :v 4]D4\o  
sFilePath = sPath; IR bfNq^:  
sFileName = sName; FgO)DQm  
this.nSplitter = nSpiltter; _vZOZKS+  
IGN1gs  
B/C,.?Or  
} -F>jIgeC2v  
I}Q2Vu<  
T9&1VW  
public String getSSiteURL() wQLSf{2  
{ DTs;{c  
return sSiteURL; h `wD  
} B erwI 7!=  
K|@G t%Y  
 2Rz  
public void setSSiteURL(String value) QSj]ZA  
{ L%5%T;0'~  
sSiteURL = value; \j.:3X r  
} @ .KGfNu  
FPTK`Gd0  
h7@6T+#WoT  
public String getSFilePath() A)~6Im  
{ B-ESFATc  
return sFilePath; "w _aM7x_  
} i?;Kq~,  
'f|o{  
L rPkxmR  
public void setSFilePath(String value) y?!"6t7&  
{ ET >](l9  
sFilePath = value; uIrG*K  
} |&jXp%4T  
w=@Dv  
YoE3<[KD(  
public String getSFileName() JN6B~ZNf  
{ 'm9` 12 H  
return sFileName; uVU)d1N  
} zn(PI3+]!  
Ct|A:/z(  
A70d\i  
public void setSFileName(String value) 'H!XUtFs"  
{ FgI3   
sFileName = value; l+0P  
} ?hM64jI|  
y3ikWnx  
59-c<I/}f  
public int getNSplitter() ,2)6s\]/b  
{ lys#G:H]  
return nSplitter; &~w}_Fjk  
} }&3 ~|kP~O  
q,6DEz  
P }uOJVQ_  
public void setNSplitter(int nCount) -%dCw6aX+  
{ {_dvx*M  
nSplitter = nCount; %K QQ,{ b  
} d5l UGRg  
} QdC<Sk!G  
a}u Sm/S  
w*MpX U<  
/* Ca3~/KrM  
**Utility.java t0I{q0  
*/ =rK+eG#,  
package NetFox; >OK^D+v"j  
8.~kK<)!  
 yOKI*.}  
public class Utility { {}x^ri~  
]+$?u&0?w  
[trwBZ^D~  
public Utility() bJ;'`sw1  
{ ;UP$yM;  
UY 2OZ& &  
2Hv+W-6v  
} yiI1x*^  
>"<Wjr8W!$  
//线程睡眠 !g.?  
public static void sleep(int nSecond) qjc4.,/  
{  RX5dO%  
try{ 8KNZ](Dj  
Thread.sleep(nSecond); r"R#@V\'1b  
} OUXR  
catch(Exception e)  rXU\  
{ DFTyMB1H  
e.printStackTrace (); \^%}M!tan  
} <d_!mKw  
} @OHm#`~  
:/Qq@]O>  
//日志 4a]P7fx-  
public static void log(String sMsg) ]g&TKm  
{ PiYxk+N  
System.err.println(sMsg); })?GzblI&  
} pHJ3nHLQ  
vZoaT|3 G]  
-D$8  
public static void log(int sMsg) "w.3Q96r  
{ xZv#Es%#  
System.err.println(sMsg); YUIi;  
} ?S$P9^ii'  
} "FKOaQ%IH  
W{gb:^;zb  
:4%k9BGAj"  
/* # 4PVVu<  
**TestMethod.java ^ovR7+V  
*/ {> 0wiH#!E  
package NetFox; Z/;aT -N  
Vy, DN~ag  
5o8EC" 0  
public class TestMethod { {,~3.5u   
}~e%J(  
/Mu @,)''  
public TestMethod() Hg$lXtn]  
{ ///xx/weblogic60b2_win.exe 46&/gehr  
try{ 4Wm@W E  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P}7'm M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'y3!fN =h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :A'y+MnK<  
fileFetch.start(); %n:k#  
} .UY^oR=b{  
catch(Exception e){e.printStackTrace ();} 8eHyL  
3x'|]Ns  
 O+Y6N  
} k{SAvKx=  
wT8DSq  
HqT#$}rv  
public static void main(String[] args) @'!SN\?W8  
{ JB[~;nLlC  
new TestMethod(); zv,jM0-  
} oHn Ky[1  
} #Kex vP&*  
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