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http断点续传简单实现(java)

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/* >JUOS2  
**SiteFileFetch.java tA{B~>  
*/ 41oXOB  
package NetFox; ymo].  
import java.io.*; )Bo]+\2  
import java.net.*; :41Ch^\E  
zxhE9 [`*e  
/Y_)dz^@  
public class SiteFileFetch extends Thread { /UP1*L  
yR'%UpaE  
kl+^0i  
SiteInfoBean siteInfoBean = null; //文件信息Bean !=SBeq  
long[] nStartPos; //开始位置 ekV|a1)  
long[] nEndPos; //结束位置 tOT(!yz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p?idl`?^3  
long nFileLength; //文件长度 d(!g9H  
boolean bFirst = true; //是否第一次取文件 P7D__hoE  
boolean bStop = false; //停止标志 {I^@BW-  
File tmpFile; //文件下载的临时信息 ,B8u?{O  
DataOutputStream output; //输出到文件的输出流 n=1_-)  
8{)j"rghah  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) V X"! a  
public SiteFileFetch(SiteInfoBean bean) throws IOException _i@4R<  
{ X :wfmb  
siteInfoBean = bean; )z=L^ot  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E9 6` aF{]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `SM37({c  
if(tmpFile.exists ()) *w,C5 f  
{ lFT` WO  
bFirst = false; `~;`q  
read_nPos(); 0CR~ vQf#r  
} Q XLHQ_V  
else zNRR('B?  
{ =b_/_b$q  
nStartPos = new long[bean.getNSplitter()]; QFX/x  
nEndPos = new long[bean.getNSplitter()]; (Rs052m1  
} [#mRlL0yk  
(JI[y"2  
<yg! D21Y  
B$D7}=|kc  
} n~Qo@%Jr  
UY~N4IR8  
ms/!8X$Mz  
public void run() al@Hr*'  
{ +DwE~l  
//获得文件长度 OGWZq(c"6  
//分割文件 6i7+.#s  
//实例FileSplitterFetch JZ>E<U9&  
//启动FileSplitterFetch线程 J2avt  
//等待子线程返回 W<tw],M-#  
try{ ;w(tXcXZ  
if(bFirst) DU|>zO%  
{ a,`f`;\7N%  
nFileLength = getFileSize(); W:S?_JM  
if(nFileLength == -1) ]X\p\n'@j  
{ 'MK"*W8QRM  
System.err.println("File Length is not known!"); 7M,(!*b  
} -POsbb>  
else if(nFileLength == -2) eFXQ~~gOj  
{ PHU$<>  
System.err.println("File is not access!"); 0 qp Pz|h  
} ^+k~{F,)  
else #Mm1yXNu  
{ /#-zI#iK  
for(int i=0;i<nStartPos.length;i++) {NTMvJLm  
{ D&-cNxh  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HD!2|b ~@  
}  eo&^~OVT  
for(int i=0;i<nEndPos.length-1;i++) A(}D76o_  
{ IlfH  
nEndPos = nStartPos[i+1]; '4e, e|r  
} Boj#r ,x  
nEndPos[nEndPos.length-1] = nFileLength; >hv8zHOO:  
} 5KgAY;|  
} { YMO8  
,vs#(d6G  
ArVW2gL  
//启动子线程 uWDWf5@  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4`zK`bRcK#  
for(int i=0;i<nStartPos.length;i++) }CGA)yK~3  
{ PfjD!=yS=h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H84Zg/ ^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), f~ P~%  
nStartPos,nEndPos,i); 34c+70x7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8z)J rO}  
fileSplitterFetch.start(); K)N'~jCG  
} 9(pF!}1 %\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }P\J?8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kHz?vVE/l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rk8Cea  
nEndPos = " + nFileLength); Dj9ecV`  
// fileSplitterFetch[nPos.length-1].start(); EV[ BB;eb  
E>isl"  
Zt ;u8O  
//等待子线程结束 zXaA5rZO  
//int count = 0; 2ut)m\)/)  
//是否结束while循环 .g>0FP  
boolean breakWhile = false; XE($t2x,M  
$Y?[[>u  
fM!@cph(8  
while(!bStop) 1qm _Qs&  
{ {xu~Dx  
write_nPos(); 0lLg uBW@  
Utility.sleep(500); l&{+3aC:  
breakWhile = true; uFnq3m^u  
63HtZ=hO7  
]FEsN6  
for(int i=0;i<nStartPos.length;i++) [vn"r^P  
{ >=K~*$&>  
if(!fileSplitterFetch.bDownOver) (Qd@Q,@(s  
{ 4Ul*`/d  
breakWhile = false; -'rb+<v  
break; hh8U/dVk*  
} v-&@c  
} F@<^  
if(breakWhile) "Tnmn@  
break; 3U4h>T@s|  
Nn{/_QG  
Fd/Ra]@\Y  
//count++; Rja>N)MzBf  
//if(count>4) '#u=w yp  
// siteStop(); 0) Q*u  
} qk=OodEMK  
;nw}x4Y[  
H,Yrk(O-  
System.err.println("文件下载结束!"); f{+X0Oj  
} tvOyT6]  
catch(Exception e){e.printStackTrace ();} %`0*KMO3  
} $g  '4'  
[/Xc},HbMe  
4XNkto  
//获得文件长度 seiE2F[  
public long getFileSize() `teaE7^Wm  
{ %ZT I ?a  
int nFileLength = -1; Lm7fz9F%  
try{ ~}g) N  
URL url = new URL(siteInfoBean.getSSiteURL()); ?P"j5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xV.UM8  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?7dV:]%~2  
xcX^L84\  
4%*`' o$_  
int responseCode=httpConnection.getResponseCode(); CGs5`a  
if(responseCode>=400) ,:pKNWY)Q  
{ b5?k)s2  
processErrorCode(responseCode); PJ2m4ulY  
return -2; //-2 represent access is error 7-MyiCt  
} kk ZMoK  
bYwe/sR  
_Kg"l5?B  
String sHeader; no9=K4h`  
%h}3}p#4  
'Ooq.jaK;/  
for(int i=1;;i++) #K\;)z(?  
{ \ mg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @!mjjeG+1  
//Utility.log(in.readLine()); kY#sQz}8  
sHeader=httpConnection.getHeaderFieldKey(i); <ELqj2`c  
if(sHeader!=null) O6]X\Cwj%  
{ dF'oZQz  
if(sHeader.equals("Content-Length")) iCdq-r/r!6  
{ 23'Ac,{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); A?H.EZ  
break; aj}#~v1  
} hD,@>ky  
} [-2Tj)P C  
else $o^N_`l  
break; k@Bn}r  
} #R# |hw  
} ]]/p.#oD,  
catch(IOException e){e.printStackTrace ();} N[wyi&m4  
catch(Exception e){e.printStackTrace ();} oD_#oX5\  
M [6WcH0/T  
]?V2L`/  
Utility.log(nFileLength); 9` G}GU]@}  
!uN_<!  
T^H`$;\  
return nFileLength; *wV`7\@  
} Z(hRwIOF  
I ka V g L  
]lA.?  
//保存下载信息(文件指针位置) 6B@{X^6y  
private void write_nPos() M3YC@(N% k  
{ 8g6G},Y0  
try{ pF7S("#R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); E[tEW0ub  
output.writeInt(nStartPos.length); J" U!j  
for(int i=0;i<nStartPos.length;i++) o_?A^u  
{ -bp7X{&  
// output.writeLong(nPos); 6mC% zXR5  
output.writeLong(fileSplitterFetch.nStartPos); 0]2@T=*kTY  
output.writeLong(fileSplitterFetch.nEndPos); *7K)J8kq  
} 6Lz:J:Q)  
output.close(); e`;U9Z  
} Bu#\W  
catch(IOException e){e.printStackTrace ();} Mf`@X[-;  
catch(Exception e){e.printStackTrace ();} * NdL4c~  
} yYvv!w+@Q  
g BV66L  
7r$'2">K(  
//读取保存的下载信息(文件指针位置)  S/Gy:GIf  
private void read_nPos() leO..M  
{ ef]60OtP  
try{ 8~vE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); k[/`G5  
int nCount = input.readInt(); v:u=.by99  
nStartPos = new long[nCount]; V,>uM >$  
nEndPos = new long[nCount]; ,{g B$8z^  
for(int i=0;i<nStartPos.length;i++) )k&!&  
{ B/b S:  
nStartPos = input.readLong(); z+X DN:  
nEndPos = input.readLong(); C%;J9(r  
} e18}`<tW-  
input.close(); 6" |+\  
} Fes /8*-  
catch(IOException e){e.printStackTrace ();} HsAKz]Mq  
catch(Exception e){e.printStackTrace ();} fC!+"g55  
} (zhi/>suG  
u;=a=>05IR  
Xv?'*2J  
private void processErrorCode(int nErrorCode) |Whkq/Zg  
{ !T1)tGrH  
System.err.println("Error Code : " + nErrorCode); !z?;L_Lb  
} A9ru]|?  
%<;PEQQ|C  
_2nNCu (  
//停止文件下载 H]&^>Pvh  
public void siteStop() ZR@PqS+O/  
{ W3Dtt-)E  
bStop = true; /Pgc W  
for(int i=0;i<nStartPos.length;i++) ^:,I #]  
fileSplitterFetch.splitterStop(); [ h~#5x  
T |ZJ$E0  
o7t#yw3  
} U$AV"F&!&}  
} "78BApjWT6  
//负责部分文件的抓取 Oo8"s+G  
**FileSplitterFetch.java d(;Qe}ok>  
*/ S'%!KGVe  
package NetFox; R^tDL  
hT[w" &3  
TW~9<c  
import java.io.*; D|X@aUp 8}  
import java.net.*; /|aD,JVN"  
%$}* y   
<#No t1R  
public class FileSplitterFetch extends Thread { _.K<#S  
i2 m+s;  
xGo,x+U*  
String sURL; //File URL {igVuZ(>en  
long nStartPos; //File Snippet Start Position Evb %<`gd  
long nEndPos; //File Snippet End Position ewp&QH4  
int nThreadID; //Thread's ID S$1dXXT  
boolean bDownOver = false; //Downing is over 2j*o[kAE  
boolean bStop = false; //Stop identical Yp8GW1@  
FileAccessI fileAccessI = null; //File Access interface Nk&$b  
s.K Hm L3  
ew\ZFqA;  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +oRwXO3W  
{ LM?UV)  
this.sURL = sURL; SKrkB~%z  
this.nStartPos = nStart; wEMg~Hh  
this.nEndPos = nEnd; ,5/zTLd   
nThreadID = id; mybvD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j;_ >,\  
} ~91) DNaE  
XonI   
B3-;]6  
public void run() DXc3u^ L  
{ dMjAG7U  
while(nStartPos < nEndPos && !bStop) qo62!q  
{ M_EXA _  
g=_@j`  
J:JkX>n%k=  
try{ "I)`g y&  
URL url = new URL(sURL); MPF;P&6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =r1 @?x  
httpConnection.setRequestProperty("User-Agent","NetFox"); .m_-L Y-  
String sProperty = "bytes="+nStartPos+"-"; |)IS[:X  
httpConnection.setRequestProperty("RANGE",sProperty); [SX>b"L  
Utility.log(sProperty); KL6FmL)HH  
.Pi8c[  
k\`~v$R3  
InputStream input = httpConnection.getInputStream(); "L~qsFL  
//logResponseHead(httpConnection); sQ>L3F;A`  
~ (/OB w  
S6bW?8`  
byte[] b = new byte[1024]; ?Z[`sm  
int nRead; wSd o 7Lb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QocR)aN=+  
{ Fi_JF;  
nStartPos += fileAccessI.write(b,0,nRead); 2fv`O  
//if(nThreadID == 1) IW-lC{hK  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (_'Efpg|  
} =&xN dc  
#gd`X|<Ch  
KG8Km  
Utility.log("Thread " + nThreadID + " is over!"); =TG[isC/F9  
bDownOver = true; P<{N)H 2r  
//nPos = fileAccessI.write (b,0,nRead); pQf5s7  
} d1=fA%pJ  
catch(Exception e){e.printStackTrace ();} WwBs_OMc  
} z~y=(T  
} 'k?*?XxG  
o9#8q_D9  
R@Kzdeo  
//打印回应的头信息 2%*mL98WK  
public void logResponseHead(HttpURLConnection con) YqSkz|o}m  
{ -kI;yL  
for(int i=1;;i++) x=~$ik++  
{ '#p2v'A  
String header=con.getHeaderFieldKey(i); 7lYiufg  
if(header!=null) G>yTv`-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >^q7:x\  
Utility.log(header+" : "+con.getHeaderField(header)); 0281"aO  
else c-gpO|4>  
break; POtwT">z  
} 6o!Y^^/U  
} }:2GD0Ru  
rS^+y{7  
]E!b&  
public void splitterStop() /a:sWmxMT  
{ c mI&R(  
bStop = true; uF89B-t  
} 236,o {9e  
 8%W(",nd  
! >l)*jN8  
} V$';B=M  
i r/-zp_  
MX\v2["FoV  
/* zv}3Sl@  
**FileAccess.java 3}lT"K  
*//文件访问(定位,写) :kz"W ya.  
package NetFox; Q"2J2211  
import java.io.*; :$J4T;/{  
_bm8m4Lk  
EmO{lCENk  
public class FileAccessI implements Serializable{ @0{vA\  
=2rkaBFC  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1?}5.*j<  
RandomAccessFile oSavedFile; u|}p3-z|Y  
long nPos; x%d\}%]  
XFv)]_G  
s}5,<|DL  
public FileAccessI() throws IOException e0; KmQjG  
{ ) ir*\<6Y=  
this("",0); [@LA<Z_  
} N=[# "4I  
\2Atm,#4  
v@^P4cu;  
public FileAccessI(String sName,long nPos) throws IOException ? f\ ~:Gm/  
{ "q,.O5q}Y  
oSavedFile = new RandomAccessFile(sName,"rw"); y (w&6:  
this.nPos = nPos; ;:5Ahfo \  
oSavedFile.seek(nPos); O h{ >xg  
} ]6BV`r]  
^;@Q3~DpP%  
f;7I{Z\<  
public synchronized int write(byte[] b,int nStart,int nLen) NplWF\5y  
{ .lt|$["  
int n = -1; -mur` tC  
try{ B !}/4"  
oSavedFile.write(b,nStart,nLen); \p%,g& ^ x  
n = nLen; ]W9{<+&  
} n 9X:s?B/  
catch(IOException e) Op2@En|d  
{ #5b}"xK{  
e.printStackTrace (); 9nrmz>es|-  
} td"D&1eQ@  
<bbC &O\  
)=]u]7p}  
return n; -cL{9r&X  
} &}q;,"  
4[o/p8*/  
cU  
} c?H@HoF  
e#/SFI0m  
5_ \+8A*  
/* @3_[NI%  
**SiteInfoBean.java jMV9r-{*+  
*/ -Y=o  
package NetFox; 94CHxv  
#i1z&b#@  
yy(.|  
public class SiteInfoBean { a2!;$B%  
CL)*cu6zG  
N" =$S|Gs  
private String sSiteURL; //Site's URL 9-( \\$%  
private String sFilePath; //Saved File's Path BdQ/kXZu+  
private String sFileName; //Saved File's Name }F<=  
private int nSplitter; //Count of Splited Downloading File ]aN]Ha  
vkgAI<  
q0y#Y  
public SiteInfoBean() Fk*C8  
{//nSplitter的缺省值为5 cq#=Vb  
//default value of nSplitter is 5 &]_2tN=S$  
this("","","",5); dum(T  
} j : $Ruy  
4!k 0  
li7"{+ct  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L7rH=gZ&!]  
{ &s>E~M0+J  
sSiteURL= sURL; ?Tr\r1s]  
sFilePath = sPath; }VDJ  
sFileName = sName; (S)jV 0  
this.nSplitter = nSpiltter; (ibj~g?U,  
]r\d 5  
T_NN.Ol   
} qvN`46c  
WLkfo6Nw  
`vc?*"  
public String getSSiteURL() sb"h:i>O4  
{ kmZ  U;Z  
return sSiteURL; vZJu =t  
} I/`\>Hk  
*ud/'HR8]  
t8_i[Hw6D  
public void setSSiteURL(String value) )~LqBh  
{ >9i%Yuy](  
sSiteURL = value; l/6$BP U`  
} t[=teB v<  
ul!e!^qwx  
FNy-&{P2  
public String getSFilePath() S #6:!  
{ L[a A4`  
return sFilePath; #-{^={p "  
} t}x^*I$*  
7S.E,\Tws  
$s`#&.>c-  
public void setSFilePath(String value) ,he1WjL  
{ Ca k-J~=  
sFilePath = value; R^+,D  
} FwaYp\z  
yD:}&!\}  
;9"6g=q  
public String getSFileName() Cj1nll8c  
{ DR c-L$bD  
return sFileName; 5ji#rIAhxh  
} sMHP=2##  
uz'MUT(68  
:vo#(  
public void setSFileName(String value) kB3@;z:  
{ O&@pi-=o  
sFileName = value; ay`A Gr  
} .0b4"0~T6  
? e<D +  
rcU*6`IWA  
public int getNSplitter() ''3b[<  
{ dk[MT'DV  
return nSplitter; aYrbB#  
} 6)j/"9oY  
qfS ]vc_N  
*)xjMTJ%  
public void setNSplitter(int nCount) W0;MGBfb  
{ (_Ky' .  
nSplitter = nCount; e{E8_2d  
} I|/\L|vo  
} KbM1b  
u.9syr  
"*JyNwf  
/* `Ti?hQm/  
**Utility.java uB>OS 1=  
*/ 6X[Mn2wYW  
package NetFox; rGUu K0L&  
pZV=Co3!I  
MYMg/>f[  
public class Utility { mr<camL5  
MCO`\"`l  
y\@INA^  
public Utility() 1T/ 72+R0  
{ r"bV{v  
4ztU) 1  
\Jm^XXgS  
} >})W5Y+  
z 8y.@<6  
//线程睡眠 y41,T&ja  
public static void sleep(int nSecond) 5Zy%Nam'gN  
{ W+`T:Mgh  
try{ $c1xh.  
Thread.sleep(nSecond); =.\PG [  
} ?*dt JL  
catch(Exception e) ck\TTNA  
{ `g^bQ x  
e.printStackTrace (); -APbN(Vi  
} :O/QgGZN$  
} ;nbbKQ]u  
G' 0JK+=o  
//日志 s~g0VNu Y  
public static void log(String sMsg) R@A"U[*  
{ [|tlTk   
System.err.println(sMsg); #H-EOXy  
} kJk6lPSqi7  
A?4s+A@Eg  
1;"DIsz@d  
public static void log(int sMsg) zY2o;-d|4  
{ x't@Mc  
System.err.println(sMsg); ?AYb@&%  
} B'8T+qvA  
} |DkK7gw  
M&J$9X  
'h3yxf}\  
/* r O-=):2  
**TestMethod.java K_o[m!:jU  
*/ u5rHQA0%  
package NetFox; :)DvZxHE@  
ZIs=%6""&  
Apbgm[m|{  
public class TestMethod { kj/v$m  
iCNJ%AZ H  
I~) A!vp  
public TestMethod() QQ\\:]iM  
{ ///xx/weblogic60b2_win.exe k<QZ_*x}G  
try{ f?W"^6Df  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5KC Zg'h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /j"aOLL|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); x9i^ _3Z  
fileFetch.start(); TxvvCV^  
}  >B$J  
catch(Exception e){e.printStackTrace ();} $5N\sdyZxg  
s}g3*_"  
tf4clzSTa  
} o[B"J96b  
O~4Q:#^c  
*yqke<o9)  
public static void main(String[] args) DsCbMs=Y  
{ tJ9gwx7Pg  
new TestMethod(); ZYs?65.  
} <8YIQA  
} !P@4dG  
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