http断点续传简单实现（java)

/* _jc_(;KPF  
**SiteFileFetch.java /O5&)%N  
*/ u&w})`+u5  
package NetFox; "M, 1ElQ  
import java.io.*;
pI:,Lt1B  
import java.net.*; .faf!3d  
Y hQ)M5  
ruQt0q,W3%  
public class SiteFileFetch extends Thread { 8
qqN0"{,  
 vTgx7gP  
_6Y+E"@zs  
SiteInfoBean siteInfoBean = null; //文件信息Bean lXg5UrW  
long[] nStartPos; //开始位置 tYXE$i  
long[] nEndPos; //结束位置 xbBqR_H_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 cGiL9|k  
long nFileLength; //文件长度 *f3StX  
boolean bFirst = true; //是否第一次取文件 :\vs kk),  
boolean bStop = false; //停止标志 |{&M#qXe  
File tmpFile; //文件下载的临时信息 )S 7+y6f&*  
DataOutputStream output; //输出到文件的输出流 +SR{FF  
S3:
AitGJ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） zs~Tu  
public SiteFileFetch(SiteInfoBean bean) throws IOException lH;V9D^  
{ }DXG;L  
siteInfoBean = bean; =gs-#\%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .%s U)$bH  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j)2I+[aoB  
if(tmpFile.exists ()) v
eH
e   
{ D8<C7  
bFirst = false; 37$ ^ie)  
read_nPos(); UXlZI'|He  
} puJB&u"4L  
else >v%js!`f  
{ IH;sVT$M  
nStartPos = new long[bean.getNSplitter()]; p"#\E0GM  
nEndPos = new long[bean.getNSplitter()]; %rMCiz  
} J Cq>;br.  
_0jR({\  
{G Jl<G1  
+]s,VSL5`  
} b?l>vUgAg  
GPGE7X'  
[Q0V5P~Q'  
public void run() v!8=B21  
{ t&xoi7!$  
//获得文件长度 Y@`uBB[  
//分割文件 U fyhd
 
//实例FileSplitterFetch c3O/#*  
//启动FileSplitterFetch线程 F?|Efpzow?  
//等待子线程返回 *m}8L%<
HT  
try{ HMCLJ/  
if(bFirst) W|7|XO  
{ \c -m\|  
nFileLength = getFileSize(); HiA E9  
if(nFileLength == -1) Vw1>d+<~-)  
{ }! EVf
 
System.err.println("File Length is not known!"); dgjK\pH`h  
} -BH/)$-$  
else if(nFileLength == -2) O|V0W
iY<  
{ !,$#i  
System.err.println("File is not access!"); K9lekevB  
} ZQ]qJDk  
else mUa#sTm  
{ 8u2k-_9  
for(int i=0;i<nStartPos.length;i++) hhze5_$_  
{ $Lr&V~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N<9 c/V  
} y)fMVD"(  
for(int i=0;i<nEndPos.length-1;i++) 7a1o#O  
{ ,7LfvZj4[  
nEndPos = nStartPos[i+1]; /[<F f  
} 2ZY$/  
nEndPos[nEndPos.length-1] = nFileLength; &em~+83  
} A$=ny6  
} :$$~$P  
nbF<K?  
d ItfR'$  
//启动子线程 orFwy!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &KjMw:l  
for(int i=0;i<nStartPos.length;i++) vN'+5*Cgy6  
{ !fzS' pkk.  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !+%gJiu:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XI\Slq  
nStartPos,nEndPos,i); Jh3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P |tyyjO  
fileSplitterFetch.start(); >$JE!.p%o  
} Y(g_h:lf,]  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 
Z 2N6r6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Vr EGR$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w$:\!FImx  
nEndPos = " + nFileLength); gx.\H3y  
// fileSplitterFetch[nPos.length-1].start(); In1W/?  
;OlnIxH(W  
c!ZZMCs  
//等待子线程结束 k( :Bl  
//int count = 0; rLsY_7!  
//是否结束while循环 E`o_R=%  
boolean breakWhile = false; /_0B5,6R  
,`}yJ*7  
pUHgjwT'U  
while(!bStop) !:&SfPv  
{ o8R_Ojh  
write_nPos(); itYoR-XJ  
Utility.sleep(500); Voo'ZeZa  
breakWhile = true; a;xeHbE
 
SZF 8InyF  
^2~ZOP$A  
for(int i=0;i<nStartPos.length;i++) Kk8wlC  
{ 8"j$=T6;W  
if(!fileSplitterFetch.bDownOver) c["1t1G  
{ q[\3
,Y  
breakWhile = false; ,^([aK  
break; pG#tMec  
} 98Vv K?  
} p(n0(}eVC'  
if(breakWhile) \}$|Uo$O  
break; -TF},V~  
K1 "HJsj  
yMNJHiE/  
//count++; TRi'l#m4  
//if(count>4) ,Vi_~b  
// siteStop(); 6
TW<,SM  
} ]`$6=)_X  
IU8zidn&  
cb^IJA9}  
System.err.println("文件下载结束！"); $VmV>NZ  
} e3ZRL91c  
catch(Exception e){e.printStackTrace ();} F_qApyU,7  
} rr tMd  
k*C69  
/(^-=pAX  
//获得文件长度 4;6"I2;zfG  
public long getFileSize() =3035{
\  
{ nX (bVT4i  
int nFileLength = -1; Z
?+ )ox  
try{ ,7B7X)m{3  
URL url = new URL(siteInfoBean.getSSiteURL()); P8YnKyI,.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LA6XTgcu  
httpConnection.setRequestProperty("User-Agent","NetFox"); g=\(%zfsxr  
!0l|[c4 e>  
jA1S|gV  
int responseCode=httpConnection.getResponseCode(); xRWfZ3E#  
if(responseCode>=400) oDZZ  
{ T
B>_#+:  
processErrorCode(responseCode); aH"d
~Y^  
return -2; //-2 represent access is error #`_W?-%^  
} K6->{!8]k  
]V/5<O1  
q]="ek&_  
String sHeader; E:9RskI  
&}u_e`A  
w: BJ4bi=  
for(int i=1;;i++) ._0$#J S[  
{ 5S4Nx>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X?haHM#]  
//Utility.log(in.readLine()); /RB%m8@;  
sHeader=httpConnection.getHeaderFieldKey(i); %`bs<ZWT  
if(sHeader!=null) %Ik5|\ob?  
{ JYc:@\   
if(sHeader.equals("Content-Length")) s]m]b#1!r  
{ %72# tY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 
1O Ft}>1  
break; lz`\Q6rZ  
} #X)DFAtb  
} 9BakxmAc  
else |KJGM1]G  
break; aUMiRm-  
} \l=A2i7TQ  
} iX?j"=!  
catch(IOException e){e.printStackTrace ();} .Yk}iHcW.  
catch(Exception e){e.printStackTrace ();} 4M"'B A<  
Ue9d0#9  
|}77'w :  
Utility.log(nFileLength); '@24<T]  
k x:+mF  
8;qOsV)UDT  
return nFileLength; mg*iW55g  
} !"hlG^*9  
Z84w9y7O<  
-d?<t}a  
//保存下载信息（文件指针位置） `&=%p|  
private void write_nPos() t]sk[  
{ }D1?Z7p  
try{ HxR5&o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |$tF{\  
output.writeInt(nStartPos.length); \/dOv

[  
for(int i=0;i<nStartPos.length;i++) p_xJKQS  
{ /\fR6|tJ  
// output.writeLong(nPos); sB0]lj-[Un  
output.writeLong(fileSplitterFetch.nStartPos); fbI5!i#lz  
output.writeLong(fileSplitterFetch.nEndPos); iw.F8[})  
} -.)f~#8  
output.close(); <e Y2}Ml  
} tG]W!\C'h  
catch(IOException e){e.printStackTrace ();} [Qr_0O  
catch(Exception e){e.printStackTrace ();} ~p+ `pwjY1  
} \V~B+e  
v#d3W| ~  
fhk(<KZvJ  
//读取保存的下载信息（文件指针位置） oJVdFE  
private void read_nPos() Zp/P/97p  
{ "wVisL2+.  
try{ yTc&C)Jba  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F
S7D  
int nCount = input.readInt(); >uJu!+#  
nStartPos = new long[nCount]; N/C$8D34  
nEndPos = new long[nCount]; oVl:g:K40  
for(int i=0;i<nStartPos.length;i++) ?RE"<L  
{ )3F}IgD  
nStartPos = input.readLong(); U7LCd+Z5X  
nEndPos = input.readLong(); G=e'H-  
} dM"5obEb  
input.close(); YxnZ0MY  
} DW,Z})9  
catch(IOException e){e.printStackTrace ();} dRs\e(H'  
catch(Exception e){e.printStackTrace ();} #-L<  
} 'QpDx&~QP  
mJ8EiRSE  
HII@Ed f?  
private void processErrorCode(int nErrorCode) uEsF 8  
{ U*EBH  
System.err.println("Error Code : " + nErrorCode); 4tkb7D q  
} akj#.aYk  
KsTE)@F:  
$LBgBH&z  
//停止文件下载 \1u^?cBd  
public void siteStop() Yl1l$[A
$  
{ Ut%{pc 7^F  
bStop = true; HH3Z?g  
for(int i=0;i<nStartPos.length;i++) f4`Nws-dP  
fileSplitterFetch.splitterStop(); [+@T"2h2b  
P e} T  
"6~+-_:  
} F.Bij8\  
} X&Ospl@H  
//负责部分文件的抓取 $;";i:H`  
**FileSplitterFetch.java O*F= xG  
*/ N+]HJ`K  
package NetFox; t@2MEo  
N5MWMN[6aP  
29z@ !  
import java.io.*; PTQN.[bBh  
import java.net.*; =OrVaZ0  
DLq'V.M:  
+Lr`-</VF  
public class FileSplitterFetch extends Thread { Eg4&D4TGp  
nh+h3"-d  
Ix@nRc'  
String sURL; //File URL Dz$dJF1 8  
long nStartPos; //File Snippet Start Position "-HWw?rx/  
long nEndPos; //File Snippet End Position jlyuu  
int nThreadID; //Thread's ID 4y)6!p  
boolean bDownOver = false; //Downing is over 1Fsa}UK  
boolean bStop = false; //Stop identical H.Z<T{y;  
FileAccessI fileAccessI = null; //File Access interface ErQGVE;zk  
!h^_2IX  
g/!tp;e  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 
*I9O63  
{ iII%!f?{[  
this.sURL = sURL; Qdy/KL1]  
this.nStartPos = nStart; F$s:\N  
this.nEndPos = nEnd; OJFWm
Z(X  
nThreadID = id; $7O3+R/=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~A(^<  
} ;b|=osyT\  
n"I{aJ]K  
j\@&poJ(,  
public void run() <pFbm  
{ xjYH[PgfX  
while(nStartPos < nEndPos && !bStop) y?iW^>|?L=  
{ !@h)3f]`1G  
MbQ%'z6D  
/.UISArH  
try{ S2 -J1x2N  
URL url = new URL(sURL); (V
}?y:)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q0XSQOl  
httpConnection.setRequestProperty("User-Agent","NetFox"); xd`\Ai  
String sProperty = "bytes="+nStartPos+"-"; 7<*g'6JG[  
httpConnection.setRequestProperty("RANGE",sProperty); wF-H{C'  
Utility.log(sProperty); H:q;IYE+a  
"`KT7  
VTO92Eo  
InputStream input = httpConnection.getInputStream(); nwi8>MG  
//logResponseHead(httpConnection); 0,cU^HMA  
B}I9+/|{
 
}'p*C
$  
byte[] b = new byte[1024]; MMQ\V(C  
int nRead; 0Y!~xyg/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) F\<{:wu   
{ ,9buI='  
nStartPos += fileAccessI.write(b,0,nRead); C)cuy7<  
//if(nThreadID == 1) i2)$%M&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $%1oZ{&M  
} T'5MO\  
+^$E)Ol  
BWkTQd<t  
Utility.log("Thread " + nThreadID + " is over!"); z|<?=c2P  
bDownOver = true; ^_=bssaOd  
//nPos = fileAccessI.write (b,0,nRead); b:x~Jz#%2  
} =|V#~p*  
catch(Exception e){e.printStackTrace ();} Om8Sgy?  
} >=Na,D  
} Ibv`/8xh  
p3IhK>  
)|&FBz;  
//打印回应的头信息 ;YrmT9Jx6  
public void logResponseHead(HttpURLConnection con) fKkS_c 2  
{ 9$ixjkIg  
for(int i=1;;i++) F>k/;@d  
{ LP>GM=S#"  
String header=con.getHeaderFieldKey(i); dp }zG+  
if(header!=null) Upc_"mkI.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); DNRWE1P2bg  
Utility.log(header+" : "+con.getHeaderField(header)); o}L\b,])  
else 7! /+[G  
break; {afIr1j/m  
} %/r:iD  
} wYd{X 8
$  
xeRoif\4c  
"i\^GK=  
public void splitterStop() :>3?|Z"Aj  
{ ZkF6AF   
bStop = true; ?V =#x.9  
} PSU}
fo  
Bf$`Hf6  
wd2z=^S~  
} B*}:YV  
2GRv%:rZ  
U ?6.UtNf  
/* 'On%p|s)H  
**FileAccess.java K#x|/b'5d  
*//文件访问(定位，写) WS\Ir-B  
package NetFox; 4@9xq<<5  
import java.io.*; eY
`o=xN  
Hw,@oOh.  
@lCyH(c%  
public class FileAccessI implements Serializable{ %vRCs]  
9bUFxSH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =DXN`]uN  
RandomAccessFile oSavedFile; Eg_ram`\R  
long nPos; iE^=Vf;  

$AdBX}{  
=A_fL{ SM  
public FileAccessI() throws IOException +EH"A  
{ [`!%u3  
this("",0); n"Wlfd0  
} ,3Aiz|v-  
scy_  
CWSc#E  
public FileAccessI(String sName,long nPos) throws IOException UYhxgPGsj  
{ 1P G"IaOb  
oSavedFile = new RandomAccessFile(sName,"rw"); Cq}E5M  
this.nPos = nPos; yXCH
Bz6&  
oSavedFile.seek(nPos); %0%Tp  
}
tcJ
N`N  
D/Py?<n-B  
2~%^y6lR  
public synchronized int write(byte[] b,int nStart,int nLen) *_K*GCy  
{ !9_'_8  
int n = -1; ,k}(]{ -  
try{ R#W=*cN  
oSavedFile.write(b,nStart,nLen); G|z%T`!U1;  
n = nLen; #@P0i^pFTB  
} f8)fm2^09  
catch(IOException e) BR:Mcc  
{ eaDG7+iS  
e.printStackTrace (); D=}\]Krmay  
} #j)"#1IE2W  
)D&xyC}  
|u+!CR  
return n; HbJ^L:/  
} 9u%(9Ae  
Dv~jVIXu  
@DSKa`  
} <4582x,G  
m%s:4Z%=  
7\yh<?`V8  
/* k&17 (Tv$  
**SiteInfoBean.java es<  
*/ U|x#'jGo'  
package NetFox;
[gj>ey8T  
@]Lu"h#u=  
LX#gc.c  
public class SiteInfoBean { 8k;il54#  
#gXxBM  
iWIq~t*,H]  
private String sSiteURL; //Site's URL }lGui>/D  
private String sFilePath; //Saved File's Path Y} 6@ w  
private String sFileName; //Saved File's Name Zr[B*1,ZV  
private int nSplitter; //Count of Splited Downloading File `Ay:;I  
-\2hSIXj  
e(Rbq8D  
public SiteInfoBean() %a!gN  
{//nSplitter的缺省值为5 %Rk DR  
//default value of nSplitter is 5 :TkMS
8  
this("","","",5); e9>~mtx  
} `UTUrM  
aa{+,(  
%^[D+1ULb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /O~Np|~v  
{ B:Hr{%O  
sSiteURL= sURL; c:""&>Z  
sFilePath = sPath; ri6KD  
sFileName = sName; <,D*m+BWn  
this.nSplitter = nSpiltter; _tE55X&  
8 #:k  
5G
GO:
  
} M~~)tJYsu  
UqNUX?(  
n}c~+0`un  
public String getSSiteURL() bAwKmk9C  
{ egVKAR-  
return sSiteURL; 4is
sj$  
} 8e1Z:axn0  
}_5R9w]"  
hw(\3h()  
public void setSSiteURL(String value) B<0Kl.V  
{ Sb(OG 6  
sSiteURL = value; h}kJ,n  
} -gUp/#l1  
%Aqf=R_^  
$lq.*UQ;0  
public String getSFilePath() SmIcqM  
{ b
`@J"E}  
return sFilePath; 7VL|\^Y`q  
} na"!"C s3  
T"<)B^8f  
7Gy:T47T\@  
public void setSFilePath(String value) 'u~0rMe4})  
{ jcb&h@T8kv  
sFilePath = value; |gIE$rt-~W  
} fH$#vRcq  
mhy='AQJ  
9zY6hh**  
public String getSFileName() vrcIwCa  
{ *"OUwEla  
return sFileName; b` va\'&3  
} ~]q>}/&YLo  
e['<.Yf+  
}1W@  
public void setSFileName(String value) 8KYIHw  
{ 8QoxU" c&  
sFileName = value;
x0WinLQ  
} gY8$Rk %  
.ws86stFSb  
/(.:l +[w[  
public int getNSplitter() : ]
+6l  
{ C511hbF  
return nSplitter; aYDo0?kF'  
} ?)186dp  
lRb>W31"  
Z&U:KrFH  
public void setNSplitter(int nCount) M&/%qF15  
{ ?{e}ouKYX1  
nSplitter = nCount; 5OzEY7K)  
} *@H\J e`  
} gKQV99  
W"GW[~ h  
eLnS1w2  
/* 1m#.f=u{R  
**Utility.java qR_>41JU"  
*/ ^'a#FbMtt  
package NetFox; bwH[rT!n  
WTJ{M$  
&*%x]fQ@  
public class Utility { t%%()!|)j  
Cs7ol-\)  
y.c6r> }  
public Utility() n:P:im?,y*  
{ h<TZJCt  
QS5t~rb  
E6ZkO/  
} \2e^
x  
`$S&:Q,  
//线程睡眠 &J
catI  
public static void sleep(int nSecond) -5 D<zP/  
{ %1.F;-GdsW  
try{ YO$D-  
Thread.sleep(nSecond); f&mi nBU  
} BdF/(Pg  
catch(Exception e) yCvtglAJ4  
{ S#?2E8  
e.printStackTrace (); XUA@f*  
} -1RMyVx  
} zh*D2/r  
FK593z  
//日志 ?-vWNv  
public static void log(String sMsg) 849,1n^  
{ :C(/yg  
System.err.println(sMsg); #[bL9R5NC  
} }#7rg_O]>  
yV )fJ_  
0hV#]`9`gN  
public static void log(int sMsg) nqm=snh  
{ Z$JJ0X  
System.err.println(sMsg); UZ2_FP  
} YLGE{bS  
} kuD$]A Q`&  
,1#? 0q  
LwK]fFtu  
/* o_BTo5]  
**TestMethod.java jD6HCIjd'  
*/ ]i$y;]f  
package NetFox; :sJ7Wok6~  
YE~IO5   
ds9'k.  
public class TestMethod { N=KtW?C  
XPO-u]<W  
6]Hwr_/tk  
public TestMethod() {tUe(  
{ ///xx/weblogic60b2_win.exe TZ5TkE;1  
try{ $R/@8qnP W  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _&BK4?H@b  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); suwR`2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "!V`_ S;  
fileFetch.start(); ]s AuL
!  
} Z%]K,9K
 
catch(Exception e){e.printStackTrace ();} G?'^"ae"Z  
gV
fFEF.  
mn?F;=qE  
} 95z|}16UK  
1>j,v+  
qBX_v5pvVA  
public static void main(String[] args) '-YiV  
{ B_Q{B|eEt&  
new TestMethod(); )|xu5.F  
} Q_0+N3  
} FL^ _)`  
点击下载更多相关资料