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http断点续传简单实现(java)

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/* (mOL<h[)IP  
**SiteFileFetch.java Xt9vTCox  
*/ >_'0 s  
package NetFox; I3,0vnE@  
import java.io.*; rm?C_  
import java.net.*; UVlh7wjg  
8_:j.(n  
 Jk>!I\  
public class SiteFileFetch extends Thread { G<:gNWXd\  
`)WC|=w2  
Rx,5?*b$  
SiteInfoBean siteInfoBean = null; //文件信息Bean g)L<xN8  
long[] nStartPos; //开始位置 [M/0Qx[,  
long[] nEndPos; //结束位置 ;m#_Rj6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?mn&b G  
long nFileLength; //文件长度 57( 5+Zme  
boolean bFirst = true; //是否第一次取文件 ;>*Pwz`~jT  
boolean bStop = false; //停止标志 ,Z$!:U  
File tmpFile; //文件下载的临时信息 U~I y),5  
DataOutputStream output; //输出到文件的输出流 Rv)*Wo!L  
nI7v:h4  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +%  !'~  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,,=VF(@G  
{ Ny` =]BA  
siteInfoBean = bean; 1EAQ ~S!2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tV"Jh>Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1uco{JX<S  
if(tmpFile.exists ()) *)D$w_06S  
{ 2|\WaH9P  
bFirst = false; FxdWJ|rN9D  
read_nPos(); /1h ${mo~  
} ^ /ZNdwx  
else f)1*%zg%  
{ VOGx  
nStartPos = new long[bean.getNSplitter()]; vw w>]Z}  
nEndPos = new long[bean.getNSplitter()]; Zdy{e|-Zn  
} -Dy":/Bk  
+F]=Z  
BT^HlW<  
y&L Lx[8 ^  
} ;Z.sK-NJ4  
p)Fi{%bc  
'y&DOy/|  
public void run() Mb:>  
{ YkF52_^_  
//获得文件长度 Rrw6\iO  
//分割文件 8DkZ @}  
//实例FileSplitterFetch o3cE.YUF  
//启动FileSplitterFetch线程 PS$g *x  
//等待子线程返回 "@YtxYTW-  
try{ tSVU,m  
if(bFirst) ^H`4BWc  
{ 4L/nEZ!Nsu  
nFileLength = getFileSize(); t03T1.:(Mg  
if(nFileLength == -1) 66{Dyn7J~  
{ Ia j`u  
System.err.println("File Length is not known!"); X:mm<4  
} oer3DD(  
else if(nFileLength == -2) I(uM`g  
{ +:3s f%0  
System.err.println("File is not access!"); =wznkqyhi  
} !CUM*<iV  
else d]vom@iI  
{ y<kg;-& 8  
for(int i=0;i<nStartPos.length;i++) p0Pmmp7r  
{ -,q qQf  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i hcSSUm  
} `_e5pW=:>  
for(int i=0;i<nEndPos.length-1;i++) 2$b JMx>  
{ }poLH S/  
nEndPos = nStartPos[i+1]; #_Z)2ESX  
} 8Om4G]*|,  
nEndPos[nEndPos.length-1] = nFileLength; XwIhD  
} %^l&:\ hy  
} R>hL.+l.  
k>F>y|m  
} 8[  
//启动子线程 /^$n&gI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PQ2rNY6  
for(int i=0;i<nStartPos.length;i++) v;#0h7qd  
{ bFVY&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qRL45[ K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), MIY`"h0*  
nStartPos,nEndPos,i); -oi@1g @  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,z~"Mst  
fileSplitterFetch.start(); =g|5VXW5  
} !NMiWG4R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D< 0))r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); umN4|X  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V;"Rp-`^  
nEndPos = " + nFileLength); -`D<OSt7  
// fileSplitterFetch[nPos.length-1].start(); gI00@p:m  
9^E!2CJ  
^qLesP#   
//等待子线程结束 w\a6ga!xt"  
//int count = 0; S 59^$  
//是否结束while循环 tA^CuJR  
boolean breakWhile = false; l[^0Ik-G  
 0:$pJtx"  
O~|Y#T  
while(!bStop) xy]oj  
{ r-No\u_  
write_nPos(); piFZu/~Gq\  
Utility.sleep(500); 8WpZ "  
breakWhile = true; Ec&_&  
Z+_xX  
Y+eDE:4  
for(int i=0;i<nStartPos.length;i++) 0nZQ" {x  
{ [U:P&)  
if(!fileSplitterFetch.bDownOver) <Qt9MO`a  
{ [8&+4 <  
breakWhile = false; Y*sw;2Z;a  
break; u7  
} :Sn4Pg `Q  
} Q]<6voyy  
if(breakWhile) @U:PXCvh  
break;  |CAMdU  
vXg^K}a#  
_<'?s>(U'  
//count++; T1%}H3  
//if(count>4) +v/-qyA  
// siteStop(); ^O!;KIe{g  
} TLq^5,qG  
Js^(mRv=  
Zr(eH2}0D  
System.err.println("文件下载结束!"); eQ*zi9na  
} "q KVGd  
catch(Exception e){e.printStackTrace ();} rDGrq9  
} @sUec  
v6ei47-  
n<1*cL:8B  
//获得文件长度 D^6Q`o  
public long getFileSize() jp|*kBDq\  
{ 4I#@xm8)  
int nFileLength = -1; h]/3doP  
try{ gA gF$H .  
URL url = new URL(siteInfoBean.getSSiteURL()); E=91k.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \Nk578+AA  
httpConnection.setRequestProperty("User-Agent","NetFox"); sQ+s3x1y  
)4N1EuD6  
]|u7P{Z"R  
int responseCode=httpConnection.getResponseCode(); X^rFRk  
if(responseCode>=400) 53>(2 _/[r  
{ <d O ~;  
processErrorCode(responseCode); 1jE {]/Y7&  
return -2; //-2 represent access is error y;_F[m  
} 5s@xpWVot  
WWC&-Ni  
!w%p Gv.wg  
String sHeader; x~F YG  
7a=ul:  
O:ACp<@  
for(int i=1;;i++) ">Ms V/  
{ G cB<i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Zu 4au<  
//Utility.log(in.readLine()); J:OP*/@='  
sHeader=httpConnection.getHeaderFieldKey(i); 0sH~H[ap  
if(sHeader!=null)  smn~p/u  
{ >!%+9@a}  
if(sHeader.equals("Content-Length")) 6n~)R  
{ Q(O0z3b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Tp.:2[  
break; )l.AsfW%  
} ia,5=SKJ  
} O8Z+g{  
else D5:|CMQ  
break; H?,Dv>.#*  
} 14A(ZWwq9  
} ,/kZt!  
catch(IOException e){e.printStackTrace ();} g~U<0+&yw%  
catch(Exception e){e.printStackTrace ();} KpDb%j  
Qg0%r bE  
(" +clb`  
Utility.log(nFileLength); =uEpeL~d;+  
2vhP'?;K  
bjI3xAs~  
return nFileLength; ?H>^X)Ph  
} &[SFl{fx>-  
brG!TJ   
KzQFG)q,  
//保存下载信息(文件指针位置) y:_>R=sw  
private void write_nPos() u6%\ZK._ \  
{ )&Z`SaoP|J  
try{ I8c:U2D  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X&i;WI  
output.writeInt(nStartPos.length); PjXiYc&  
for(int i=0;i<nStartPos.length;i++) OUFy=5(%:  
{ 5z\,]  
// output.writeLong(nPos); F_I!qcEQ  
output.writeLong(fileSplitterFetch.nStartPos);  \< dg  
output.writeLong(fileSplitterFetch.nEndPos); ?uU_N$x  
} $zF%F.rln  
output.close(); l]j;0i  
} ]{|lGtK %  
catch(IOException e){e.printStackTrace ();} Q [C26U  
catch(Exception e){e.printStackTrace ();} #,97 ]  
} |'I>Ojm  
KW3<5+w]c  
<L<^uFB  
//读取保存的下载信息(文件指针位置) O#p_rfQ  
private void read_nPos() 9XKqsvdS  
{ Ep:hObWG)  
try{ %I{>H%CjE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6J@,bB jVz  
int nCount = input.readInt(); C%{2 sMJz  
nStartPos = new long[nCount]; 78 ]Kv^l^_  
nEndPos = new long[nCount]; 'X6Z:dZY  
for(int i=0;i<nStartPos.length;i++) g4YlG"O[~  
{ !aKu9SR^e  
nStartPos = input.readLong(); 2-jXj9kp`  
nEndPos = input.readLong(); f~/hsp~Hp  
} 7WY~v2SDF  
input.close(); 1Kr$JIcd  
} s:_a.4&Y  
catch(IOException e){e.printStackTrace ();} wwQ2\2w>Hm  
catch(Exception e){e.printStackTrace ();} NHe)$%a=H  
} vVIN D  
J*Ie# :J]  
+6$ -"lf  
private void processErrorCode(int nErrorCode) (:O6sTx-hE  
{ <&gs)BY  
System.err.println("Error Code : " + nErrorCode); T>7N "C  
} "6U@e0ht  
<QC7HR  
uPapINj  
//停止文件下载 &:u3-:$:9  
public void siteStop() #I*{_|}=  
{ M d8(P23hS  
bStop = true; sC.r$K+k5  
for(int i=0;i<nStartPos.length;i++) `9gV8u  
fileSplitterFetch.splitterStop(); 4:^MSgra  
pLCS\AUTsv  
!]E ]Xd<  
} $ZZ?*I  
} K=E+QvSG  
//负责部分文件的抓取 gat;Er  
**FileSplitterFetch.java 5j$&Zgx51  
*/ r!O[|h  
package NetFox; BFhEDkk  
nB5\ocJ  
\13Q>iAu  
import java.io.*; *3!r &iY  
import java.net.*; *9xxX,QT8Q  
<2L,+  
q5JQx**g  
public class FileSplitterFetch extends Thread { fA]sPh4Uag  
Q672iR\#)  
"I:*  
String sURL; //File URL ^IyQzBOj  
long nStartPos; //File Snippet Start Position .'Q*_};W  
long nEndPos; //File Snippet End Position I8% -ii  
int nThreadID; //Thread's ID WTM  
boolean bDownOver = false; //Downing is over Pk;yn;  
boolean bStop = false; //Stop identical  7U1 M;@y  
FileAccessI fileAccessI = null; //File Access interface ,4`Vl<6  
Ea][:3  
g/ShC8@=u  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9 nY|S{L  
{ J~4mp\4b  
this.sURL = sURL; rx 74v!  
this.nStartPos = nStart; 9S[.ESI{>  
this.nEndPos = nEnd; kB=B?V~#  
nThreadID = id; { dh,sbl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 H&%oHyK  
} TwVkI<e0s?  
e`H>}O/ai  
O[eU{ ;P  
public void run() 0Zp5y@ V8  
{ US3)+6  
while(nStartPos < nEndPos && !bStop) rXT?w]4  
{ y N9~/g  
MRK=\qjD  
::'Y07  
try{ ~piE$"]&  
URL url = new URL(sURL); HeO&p@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =nc;~u|]  
httpConnection.setRequestProperty("User-Agent","NetFox"); M!mw6';k  
String sProperty = "bytes="+nStartPos+"-"; K(lSR  
httpConnection.setRequestProperty("RANGE",sProperty); O cPgw/ I  
Utility.log(sProperty); AXte&l=M  
bZ:+q1 D  
d$x vEm  
InputStream input = httpConnection.getInputStream(); cYe2 a "  
//logResponseHead(httpConnection); u-s*k*VHoc  
]!P8{xmb@  
S]|sK Y  
byte[] b = new byte[1024]; rc<Ix  
int nRead; V|B4lGS&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 64mD%URT  
{ OIpT9  
nStartPos += fileAccessI.write(b,0,nRead); \'[tfSB  
//if(nThreadID == 1) Ii5U) "  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [7HBn  
} 1 I.P7_/  
~E y+  
Wa.xm_4s2  
Utility.log("Thread " + nThreadID + " is over!"); 8Dtpb7\o  
bDownOver = true; 53ZbtEwhwr  
//nPos = fileAccessI.write (b,0,nRead);  <82&F  
} e1E_$oJP  
catch(Exception e){e.printStackTrace ();} oQ/T5cOj  
} oIx|)[  
} (~{Y}n]s  
94dd )/a  
6| o S 5  
//打印回应的头信息 v<g~ EjzCf  
public void logResponseHead(HttpURLConnection con) febn?|@  
{ u/S>*E  
for(int i=1;;i++) w xte  
{ 7B\NP`l  
String header=con.getHeaderFieldKey(i); 0gW{6BtPWm  
if(header!=null) 3h>L0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (`E`xb@E,=  
Utility.log(header+" : "+con.getHeaderField(header)); %,z;W-#gnY  
else 4%8den,|  
break; ?E+f<jol  
} u kZK*Y9P  
} CadIu x^  
%xG<hNw/  
nh5=0{va|L  
public void splitterStop() _izjvg  
{ g] }!  
bStop = true; bHx@   
} tJ6Q7 J;n  
~8mz.ZdY  
hgW1g#  
} ^,^MW  
uM_ww6  
TI l 'Z7  
/* 4@Db $PHs  
**FileAccess.java U*\K<fw   
*//文件访问(定位,写) l4r >#n\yj  
package NetFox; s$fX ;  
import java.io.*; Ai[@2AyU  
SpU|Q1Q/h  
:Z2997@Y  
public class FileAccessI implements Serializable{ @#N7M2/  
PWx%~U.8~j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @MTv4eC}e  
RandomAccessFile oSavedFile; @~|;/OY>"  
long nPos; X])iQyN  
Nb !i_@m%s  
U?{oxy_[2  
public FileAccessI() throws IOException Wu|MNB?M  
{ o8<~zeI  
this("",0); KN657 |f  
} 'NCqI  
Gds(.]_  
[?9 `x-Q  
public FileAccessI(String sName,long nPos) throws IOException %dW ;P[0  
{ umq6X8K  
oSavedFile = new RandomAccessFile(sName,"rw"); T* 0;3&sA  
this.nPos = nPos; f -F}~S  
oSavedFile.seek(nPos); b/R7 Mk1  
} o/V T"cT  
Z:N;>.3i  
*w _o8!3-  
public synchronized int write(byte[] b,int nStart,int nLen) 5XHejHn>  
{ 6.KEe^[-  
int n = -1; ] L#c <0  
try{ Jh&DL8`  
oSavedFile.write(b,nStart,nLen); M@h"FuX:  
n = nLen; :n{{\SSIgX  
} D^m2iW;  
catch(IOException e) 0?/gEr  
{ ^zO{Aks  
e.printStackTrace (); XL aD#J  
} U_PH#e  
i6n,N)%H  
F09%f"9  
return n; "h[)5V{  
} fvH{ va.  
%(khE-SW  
fw,,cu`YA  
} m{RXt  
nM.g8d K  
d ([~o  
/* yc3/5]E&  
**SiteInfoBean.java &}P#<"Fo8Q  
*/ vw3[(_MV3_  
package NetFox; [fT$# '6  
uyk;]EYjHZ  
y3 N[F  
public class SiteInfoBean { gU|:Y&lFZg  
xcmg3:s  
\rxjvV4fcZ  
private String sSiteURL; //Site's URL :X'B K4EN  
private String sFilePath; //Saved File's Path [[<TW}  
private String sFileName; //Saved File's Name uQdy  
private int nSplitter; //Count of Splited Downloading File =gJ{75tV3  
D>W&#A8&y  
fUWrR1  
public SiteInfoBean() JmR2skoV,  
{//nSplitter的缺省值为5 >I~Q[  
//default value of nSplitter is 5 =Jw*T[E  
this("","","",5); Fs4shrt  
} |3B<;/v5  
7~Inxk;  
W =Bw*o-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l\V1c90m  
{ 'R-\6;3E>9  
sSiteURL= sURL; -o"b$[sf=Z  
sFilePath = sPath; WUz69o be  
sFileName = sName;  NnHaHX  
this.nSplitter = nSpiltter; aBaiXv/*  
}F.k,2  
L(Twclrb  
} {vW0O&[  
LFi* O&  
;DnUeE8  
public String getSSiteURL() vI(LIfe;  
{ }2RbX,0l9  
return sSiteURL; E+XS7':I  
} LB]3-FsU+  
K O\HH  
+l)t5Mg\  
public void setSSiteURL(String value) c\rP -"C  
{ }UGSE2^1  
sSiteURL = value; )Z/w|5<  
} P nE7}  
9{A4>  
*?1\S^7R  
public String getSFilePath() Tb2#y]27  
{ psIo[.$rTk  
return sFilePath; j96}E/gF  
} IZ>l  
}qp)VF  
H6K8.  
public void setSFilePath(String value) mUP!jTF  
{ ju[y-am$/  
sFilePath = value; 'JdK0w#  
} rWNe&gFM  
L#a!fd  
)O+Zbn  
public String getSFileName() R|)l^~x  
{ ZoJq JWsd  
return sFileName; %$o[,13=  
} = )3\B  
s92ol0`  
nPI$<yW7F  
public void setSFileName(String value) N3#^Ifn[  
{ 3D@3jyo:  
sFileName = value; }[!=O+g O  
} zTMLE~w  
;Q vQ fV4  
q#8\BOTP |  
public int getNSplitter() L|#0CRiN  
{ zq$L[ X  
return nSplitter; +\ "NPK@3  
} O[U`(A:  
@.k^ 8hc  
M'R ] ''  
public void setNSplitter(int nCount) ~QUNR?h  
{ 4*f+np  
nSplitter = nCount; > JA-G@3i  
} |LLpG37_  
} |dHtv6I  
9wf"5c  
ZZHQ?p-  
/* v\G 7V  
**Utility.java `q^qe>'  
*/ k_u!E3{~  
package NetFox; 7uw-1F5x7  
Z6Mjc/  
W)f=\.7  
public class Utility { vmNI$ KZM  
&J9 + 5L8  
32aI0CT  
public Utility() Xe: ^<$z  
{ !9r%d8!z  
H2[0@|<<  
0>-}c>  
} t~ I;IB  
St!0MdCH  
//线程睡眠 K@[Hej6d  
public static void sleep(int nSecond) P$y'``  
{ q4!\^HwQ  
try{ vY.VFEP/  
Thread.sleep(nSecond); dJrUcZBr  
} $E;Tj|W  
catch(Exception e)  ydY( *]  
{ rrgOp5aV"  
e.printStackTrace (); nLk`W"irM  
} 6/g 82kqpk  
} /L(}VJg-  
+]wM$bP  
//日志 =Sr<d|\O  
public static void log(String sMsg) ] FvGAG.*  
{ "B +F6  
System.err.println(sMsg); Pz D30VA  
} QAo/d4  
u~ FVI  
Oop6o $k  
public static void log(int sMsg) wmR~e  
{ ^@=4HtA  
System.err.println(sMsg); Fo ;J3<U)  
}  yoe@]c=  
} =5^1Bl  
2-UD^;0  
$g VbeQ  
/* >;j&]]-&  
**TestMethod.java W79.Nj2`  
*/ |${ImP  
package NetFox; :6(@P1vA 6  
yXEI%2~)  
UYy #DA  
public class TestMethod { {=J:  
}C[ "'tLX  
EAWBgOO8iC  
public TestMethod() %}~(%@qB>+  
{ ///xx/weblogic60b2_win.exe @}PX:*c  
try{ Vz-q7*o $S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pih 0ME}z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r.Z g<T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e9Gu`$K  
fileFetch.start(); vy={ziJ  
} "u$XEA  
catch(Exception e){e.printStackTrace ();} /D|q-`*K  
s]A8C^;c  
[%6)  
} xf7YIhL^*  
7l*vmF6Z  
U6H3T0#  
public static void main(String[] args) a\,V>}e  
{ NZ8X@|N  
new TestMethod(); Tz9 (</y  
} j}tGcFwvSN  
} ofz?L#:2  
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