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http断点续传简单实现(java)

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/* V"c 6Kdtd  
**SiteFileFetch.java nRyU]=-X  
*/ M5gWD==uP  
package NetFox; 7}M2bH} \K  
import java.io.*; X}+>!%W!}  
import java.net.*; 4R18A=X  
i3rH'B -I.  
hjZKUM G(k  
public class SiteFileFetch extends Thread { th;{V%:LW  
dFKM 8_jH  
`BlI@6th  
SiteInfoBean siteInfoBean = null; //文件信息Bean x)(|[  
long[] nStartPos; //开始位置 ep)>X@t  
long[] nEndPos; //结束位置 bv&;R  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t+9][Adf  
long nFileLength; //文件长度 v`M3eh@$A  
boolean bFirst = true; //是否第一次取文件 j4qJ.i  
boolean bStop = false; //停止标志 `@nl  
File tmpFile; //文件下载的临时信息 o!)3?  
DataOutputStream output; //输出到文件的输出流 )c `7( nY  
#Y$hNQQ$F  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \[y`'OD~  
public SiteFileFetch(SiteInfoBean bean) throws IOException e)(wss+d7P  
{ #{?qNl8F*J  
siteInfoBean = bean; |UX(+; n  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .ev?"!Vpp9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); J:Qa5MTWp  
if(tmpFile.exists ()) k |eBJ%  
{ 8uWa=C)  
bFirst = false; ZjF 4v  
read_nPos(); [n :<8ho  
} Y\No4w ^|d  
else T\D}kQM  
{ >U[j]V]  
nStartPos = new long[bean.getNSplitter()]; 4rLL[??  
nEndPos = new long[bean.getNSplitter()]; FY#C.mL  
} 5yP\I+Fm  
)v.=jup[  
MB]<Dyj,  
EwvoQ$#jv  
} g\&g N  
>s<^M|S07  
2Eu`u!jhx  
public void run() uC(V  
{ %-1O.Q|f  
//获得文件长度 'F9jq  
//分割文件 ]SLP}Jwy  
//实例FileSplitterFetch oYH^_V  
//启动FileSplitterFetch线程 .nx2";oi  
//等待子线程返回 %5"9</a&G  
try{ pSdI/Vj'=  
if(bFirst) ^LoUi1j  
{ P&*2pX:  
nFileLength = getFileSize(); @emK1iwm  
if(nFileLength == -1) Ezd_`_@R  
{ J;8IY=  
System.err.println("File Length is not known!"); %z,m B$LY  
} Ng~FEl  
else if(nFileLength == -2) H[U!%Z  
{ 3cK I  
System.err.println("File is not access!"); 0tT(W^ho g  
} :&V h?  
else ?kbiMs1;u  
{ c7x~{V8  
for(int i=0;i<nStartPos.length;i++) 4R1<nZ"e~  
{ vunHNHltW0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jtW!"TOY  
} S.-TOE  
for(int i=0;i<nEndPos.length-1;i++) '!!CeDy  
{ ! |<Fo'U  
nEndPos = nStartPos[i+1]; kuszb~`zPY  
} Oi8.8M  
nEndPos[nEndPos.length-1] = nFileLength; |EX(8y  
} TJ6*t!'*X  
} A>o *t=5  
5K>3My#  
+0nJ  
//启动子线程 dMv=gdY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nrub*BuA  
for(int i=0;i<nStartPos.length;i++) 4;yKOQD|  
{ keL&b/@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), | *2w5iR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )rn*iJ.e8  
nStartPos,nEndPos,i); OEA&~4&{7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'vbsvT  
fileSplitterFetch.start(); }ppN k:B  
} <Tzrj1"Q3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D9^h; 8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n|Q@UPb/=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cUKE   
nEndPos = " + nFileLength); Hq:X{)"  
// fileSplitterFetch[nPos.length-1].start(); 3no%E03p  
`T@i.'X  
u8&Z!p\  
//等待子线程结束 Y']\Jq{OS  
//int count = 0; E7j(QO f  
//是否结束while循环 SJb&m-  
boolean breakWhile = false; . qO@Q=  
2_HNhW  
qkDI](4  
while(!bStop) n8~N$tDU  
{ #Z?A2r!1  
write_nPos(); O_oPh] x)  
Utility.sleep(500); "l3_=Gua  
breakWhile = true; H1|?t+oP  
ype$ c  
gc_:%ki  
for(int i=0;i<nStartPos.length;i++) il4^zj82  
{ !/'t5~x[  
if(!fileSplitterFetch.bDownOver) <J< {l  
{ _S<3\%(0  
breakWhile = false; *+Ek0M  
break; #L=x%8B  
} e$<0 7Oc  
} ^oBtfN>4  
if(breakWhile) :~&~y-14  
break; c}lb%^;)E  
 VA6}  
at#ja_ hd  
//count++; ?~BC#B\>o  
//if(count>4) BKCA <  
// siteStop(); I0D(F i  
}  eI$oLl@  
lA| 5E?  
oK6tTK  
System.err.println("文件下载结束!"); ?GKb7Oj  
} >)fi^  
catch(Exception e){e.printStackTrace ();} q/4J.j L  
} 9UdM`v)(  
[M]  
=upeRY@u5  
//获得文件长度 u^@f&BIG]:  
public long getFileSize() }eCw6  
{ H%qsjB^  
int nFileLength = -1; 1gL2ia  
try{ b|l:fT?&  
URL url = new URL(siteInfoBean.getSSiteURL()); #^u$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `uv2H$  
httpConnection.setRequestProperty("User-Agent","NetFox"); W#9BNKL  
u_w#gjiC  
2Q/x@aT,h  
int responseCode=httpConnection.getResponseCode(); 2e+UM$  
if(responseCode>=400) SE@LYeC}dE  
{ \tf <B\oa  
processErrorCode(responseCode); !`Fxa4i>  
return -2; //-2 represent access is error >K_(J/&p  
} [_R~%Yh+'E  
,k +IPkN+  
CpUk Cgg  
String sHeader; o5Dk:Bw  
x[FJgI'r  
lHN5Dr  
for(int i=1;;i++) sXLq*b?  
{ ^bGNq X  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \pa"%c)  
//Utility.log(in.readLine()); ]R+mKUZ9  
sHeader=httpConnection.getHeaderFieldKey(i); {2O1"|s ,  
if(sHeader!=null) gh/EU/~d  
{ a@_4PWzF:  
if(sHeader.equals("Content-Length")) ~8'sBT  
{ -^&<Z 0m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Zi*2nv '  
break; kvL=> A  
} vv72x]  
} x,=&JtKVc  
else ;5]Lf$tZ  
break; 5Yg'BkEr  
} |kyX3~  
} ~8q)^vm>f?  
catch(IOException e){e.printStackTrace ();} [+rfAW>p}  
catch(Exception e){e.printStackTrace ();} >6ni")Q9  
D$w6V  
v,FU^f-'  
Utility.log(nFileLength); 3+)J @(a  
3 ]5^r}  
#3i3G(mQ  
return nFileLength; [;n9:Qxf  
} G?L HmTHg  
JrJo|0Q  
lUOF4U&r  
//保存下载信息(文件指针位置) Vh'P&W?[  
private void write_nPos() F%@A6'c  
{ E-T)*`e  
try{ u4t7Ie*Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kYzIp  
output.writeInt(nStartPos.length); )X1{  
for(int i=0;i<nStartPos.length;i++) !EvAB+`jLI  
{ F~,Mw8  
// output.writeLong(nPos); &Qf/>@ l}  
output.writeLong(fileSplitterFetch.nStartPos); A=$04<nP8!  
output.writeLong(fileSplitterFetch.nEndPos); W>${zVu  
} %^?fMeI|Y  
output.close(); Y@;CF  
} &C `Gg<  
catch(IOException e){e.printStackTrace ();} E(*0jAvO[z  
catch(Exception e){e.printStackTrace ();} wg9t)1k{e  
} *D'22TO[[!  
9 &$y}Y  
-WY<zJ  
//读取保存的下载信息(文件指针位置) 7o7)0l9!  
private void read_nPos() 0eT(J7[ <  
{ LoURC$lS  
try{ UE8kpa)cQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vk}n,ecl  
int nCount = input.readInt(); OSRp0G20k\  
nStartPos = new long[nCount]; dcDyK!zz"  
nEndPos = new long[nCount]; !8TlD-ZT/  
for(int i=0;i<nStartPos.length;i++) MUaq7B_>  
{ +Zb;Vn4  
nStartPos = input.readLong(); (of#(I[m7  
nEndPos = input.readLong(); qrb[-|ie&  
} !]"@kl%  
input.close(); sfpZc7  
} y%&q/tk  
catch(IOException e){e.printStackTrace ();} q_MPju&*  
catch(Exception e){e.printStackTrace ();} [8Y:65  
} _'#n6^Us<  
ayn)5q/z  
:">!r.Q  
private void processErrorCode(int nErrorCode) BOX{]EOj  
{ T(#J_Y  
System.err.println("Error Code : " + nErrorCode); R}-(cc%5  
} 4zXFuTr($  
aHV;N#Lx3  
G0CW}e@)  
//停止文件下载 qz"}g/;?  
public void siteStop() xipU8'ac/  
{ Jz\%%C  
bStop = true; '*Z1tDFS  
for(int i=0;i<nStartPos.length;i++) C(eTR1  
fileSplitterFetch.splitterStop(); a4m n*,  
JYMiLph<  
I5X|(0es  
} ny]?I  
} :,3C 0T3r  
//负责部分文件的抓取 OTvPUkp*  
**FileSplitterFetch.java 1D7nkAy  
*/ 9>= ;FY  
package NetFox; 9"N~yKa`"K  
B~'vCuE  
>f|||H}Snw  
import java.io.*; P9/q|>F  
import java.net.*; `}D,5^9]  
kI,yU}<Fq  
g!FuY/%+  
public class FileSplitterFetch extends Thread { Giid~e33  
S){)Z  
rF3wx.  
String sURL; //File URL !eGC6o}f  
long nStartPos; //File Snippet Start Position Bj+S"yS  
long nEndPos; //File Snippet End Position #QS`_TlKk  
int nThreadID; //Thread's ID Q1T$k$n  
boolean bDownOver = false; //Downing is over IDad9 Bx  
boolean bStop = false; //Stop identical ] vz%iv_  
FileAccessI fileAccessI = null; //File Access interface fJ=0HNmX  
sSr&:BOsi  
$| zX|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d8DV[{^  
{ f- K+]aZ)  
this.sURL = sURL; @#l `iK  
this.nStartPos = nStart; ^\hG"5#  
this.nEndPos = nEnd; \q>bs|2  
nThreadID = id; DRSr%d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RaO-H  
} w0[6t#$F  
ZFA`s qT  
*2ZjE!A  
public void run() N&.H|5  
{ 9# 23FK  
while(nStartPos < nEndPos && !bStop) Yc`o5Q\>  
{ Fh)IgzFj  
48J@C vU  
-$t{>gO#Y  
try{ ^gN6/>]qrY  
URL url = new URL(sURL); @T@< _ ?)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v>6"j1Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~Sdb_EZ  
String sProperty = "bytes="+nStartPos+"-"; loEPr5 bL  
httpConnection.setRequestProperty("RANGE",sProperty); 5A,K6f@:g  
Utility.log(sProperty); ,j#XOy`mzy  
V"[g.%%Y  
; 8_{e3s  
InputStream input = httpConnection.getInputStream(); LHyB3V  
//logResponseHead(httpConnection); G ?9"Y%  
_Ym]Mj' ln  
zZ:>do\2  
byte[] b = new byte[1024]; bpOYHc6,*`  
int nRead; gK+ 4C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @Y?#Sl*  
{ e- ~N"  
nStartPos += fileAccessI.write(b,0,nRead); _H9 MwJ  
//if(nThreadID == 1) Mhm@R@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w{{gu1#]G  
} .nO\kgoK  
&U{#Kt5q  
fIM,lt  
Utility.log("Thread " + nThreadID + " is over!"); .14~J6  
bDownOver = true; #F:p-nOq  
//nPos = fileAccessI.write (b,0,nRead); 2kqup)82e  
} q'+)t7!  
catch(Exception e){e.printStackTrace ();} 7( #:GD  
} T*I{WW  
} ]q\b,)4 e  
<c*FCblv  
4aug{}h("  
//打印回应的头信息 ?(xnSW@r  
public void logResponseHead(HttpURLConnection con) LY+@o<>  
{ BfXgh'Z~  
for(int i=1;;i++) K> %Tq  
{ CVDV)#JA  
String header=con.getHeaderFieldKey(i); 36.Z0Z1'F>  
if(header!=null) ke!?BZx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'Oxy$U   
Utility.log(header+" : "+con.getHeaderField(header)); oph}5Krd)  
else ;^+\K-O]c  
break; .7^c@i[  
} .4S.>~^7  
} ]z;P9B3@&  
)tG\vk=@  
NxfOF  
public void splitterStop() {0r0\D>bw  
{ V[mT<Lc  
bStop = true; 2v:]tj  
} 9/9j+5}+  
'_<{ p3M  
sXqz+z$*  
} bkRLC_/d  
n*o-Lo+Fe.  
f0!))/rSD  
/* 6d:zb;Iz  
**FileAccess.java <<UB ^v m  
*//文件访问(定位,写) 6 o^,@~:R  
package NetFox; `34zkPB??  
import java.io.*; j 'FVz&  
?}qttj  
S&e0u%8mc  
public class FileAccessI implements Serializable{ !H#bJTXB  
O3;u G.:1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ky8_UnaO  
RandomAccessFile oSavedFile; *F WMn.  
long nPos; +2(I1  
iyN:%ofh  
'Jiw@t<o3`  
public FileAccessI() throws IOException 9y6-/H ,  
{ ,y1PbA0m  
this("",0); # q~e^A b  
} xg30x C[  
Gw=B:kGk  
?yZ+D z\  
public FileAccessI(String sName,long nPos) throws IOException 1}S S+>`  
{ rUwZMli  
oSavedFile = new RandomAccessFile(sName,"rw"); bw(a6qKK  
this.nPos = nPos; 'QJ:`)z  
oSavedFile.seek(nPos); 90Pl$#cb2  
} dMPc:tJT  
c>,KZ!  
s:?SF.  
public synchronized int write(byte[] b,int nStart,int nLen) ``V" D  
{ WJ$bf(X*  
int n = -1; i1UiNJh86  
try{ Ha(c'\T (\  
oSavedFile.write(b,nStart,nLen); dW_KU}  
n = nLen; d^@dzNv  
} I?]ohG K  
catch(IOException e) @#<D ^"  
{ Q`~jw>x  
e.printStackTrace (); ^pxX]G]  
} 7X`l&7IXP  
bW$,?8(  
)}g(b=  
return n; *RDn0d[  
} 2SD`OABf#  
Ut*`:]la  
tankR9(o  
} vhe>)h*B  
7z/|\D_{  
w+C7BPV&  
/* t\?ik6  
**SiteInfoBean.java mGtdO/C#B  
*/ FFl!\y*0z  
package NetFox; cIUHa  
\}+_Fo/  
R}'bP  
public class SiteInfoBean {  R(!s  
UXeN8  
;"KJ7p  
private String sSiteURL; //Site's URL mkMq  
private String sFilePath; //Saved File's Path yu;+o3WlK  
private String sFileName; //Saved File's Name t!*?dr  
private int nSplitter; //Count of Splited Downloading File kv]~'Srk  
Z"Zmo>cV4  
<x@}01 ~  
public SiteInfoBean() YO#M/%^j  
{//nSplitter的缺省值为5 :Uz|3gq  
//default value of nSplitter is 5 J\/cCW-rF  
this("","","",5); 2I%MAb&1@  
} J{'>uD.@  
*Tas`WA  
a!ud{Dx  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #G .ulX  
{ zxJ]" N  
sSiteURL= sURL; 0f~C#/[t7  
sFilePath = sPath; d^ Inb!%w  
sFileName = sName; u_hD}V^x4  
this.nSplitter = nSpiltter; kEJj=wx  
.GV;+8HzS  
zepm!JR1  
} x%}^hiO<q  
,">]`|?  
7_%"BVb"  
public String getSSiteURL() {`J)j6;  
{ Hv!U| L  
return sSiteURL; o%v0h~tn  
} kr+D,h01  
{,3>"  
!i{aMxUP  
public void setSSiteURL(String value) } uO);k5H  
{ !5.8]v  
sSiteURL = value; OSlvwH%(EE  
} V}bjK8$$  
R?68*} `7  
j!_;1++q  
public String getSFilePath() H#NCi~M>3  
{ %4ePc-  
return sFilePath; gMY1ts}Z  
} Lilr0|U+  
l%[EXZ  
?6yjy<D)$e  
public void setSFilePath(String value) YX=a#%vrl  
{ kv3E4,<9  
sFilePath = value; 3_txg>P"  
} 4~y(`\0?4  
tro7Di2Q  
?h.wK  
public String getSFileName() TX$r `~  
{ JM=JH 51`  
return sFileName; GYJ80k|  
} MJOz.=CbhR  
 ;hY S6  
6;u$&&c(  
public void setSFileName(String value) iEd\6EZ  
{ /h+8A' ,  
sFileName = value; ?6Jx@Sh  
} e91aK  
m=?KZ?U`  
&f"-d  
public int getNSplitter() mk1bcK9  
{ Id'X*U7Q  
return nSplitter; ]4~lYuI4  
} plUZ"Tr  
,-i zEr  
FB  _pw!z  
public void setNSplitter(int nCount) 'h/CoTk@,  
{ ZNf6;%oGG  
nSplitter = nCount; v 0 }@  
} %`OJ.:k  
} #1`-*.u  
>ZPsjQuf"  
=4[v 3Qx  
/* AmaT0tzJC  
**Utility.java ]e^c=O`$  
*/ }R1< 0~g  
package NetFox; E}Y!O"CAV  
)f}YW/'  
R<[qGt|L  
public class Utility { V=zi >o`   
'$|[R98  
V^JV4 `o  
public Utility() Z3{>yYR+  
{ #bMuvaP~  
/4c\K-Z;  
 {k>Ca  
} y=`2\L" O  
e?opkq\f  
//线程睡眠 R#2t)y  
public static void sleep(int nSecond) ZT,B(#m  
{ Q,p}:e  
try{ U'R)x";=  
Thread.sleep(nSecond); dik:4;  
} ]3VI|f$$  
catch(Exception e) Ko;{I?c  
{ > ;L6xt3  
e.printStackTrace (); '@p['#\uI  
} 9:,V5n=  
} WpF2)R}G=  
q0$ !y!~  
//日志 {P{bOe  
public static void log(String sMsg) HR ;)|j{!  
{ ;k7xMZs  
System.err.println(sMsg); nx8a$vI-TY  
} #Yr9AVr}K  
.Jt[(;  
et,f_fd7v  
public static void log(int sMsg) O>^C4c!  
{ "NgxkbDEbG  
System.err.println(sMsg); 3~}uqaGt  
} &K/ya7  
} gA:5M  
t: #6sF  
HuwU0:*  
/* pcT:]d[1)  
**TestMethod.java JcbwDlUb  
*/ >p.O0G gg  
package NetFox; J(c{y]`J  
1E73i_L  
y($%;l   
public class TestMethod { po$ /7  
wvbPnf^y  
rb1`UG"h$  
public TestMethod() $% 1vW=d  
{ ///xx/weblogic60b2_win.exe %n hm  
try{ q o\?o    
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )yTm.F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q|Qk2M  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]`&Yqg  
fileFetch.start(); p;W.lcO`0  
} `FsH}UPu b  
catch(Exception e){e.printStackTrace ();} ]3g?hM6  
'ow.=1N-  
\ gLHi~  
} c zm& ~n6$  
'B@e8S) y  
Y]L9Y9  
public static void main(String[] args) B<~ NS)w  
{ ^my].Qpt  
new TestMethod(); *cC_j*1@  
} qUxRM_7U  
} =:/BV=tv  
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