http断点续传简单实现（java)

/* , - QR  
**SiteFileFetch.java 9 aY'0w
a  
*/ pTc$+Z73  
package NetFox; #E*@/ p/  
import java.io.*; nUiS<D2  
import java.net.*; J>&[J!>r  
CR%D\I$o  
SL6mNn9c  
public class SiteFileFetch extends Thread { Xq+!eOT  
VEL:JsY  
1R5Yn(  
SiteInfoBean siteInfoBean = null; //文件信息Bean mk#>Dpy?  
long[] nStartPos; //开始位置 X7t5b7  
long[] nEndPos; //结束位置 uCY(:;[<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 F~tm`n8Z  
long nFileLength; //文件长度 @~JB\j9  
boolean bFirst = true; //是否第一次取文件 P]|J?$1K  
boolean bStop = false; //停止标志 y2oB]^z&n  
File tmpFile; //文件下载的临时信息 1[26w_B3  
DataOutputStream output; //输出到文件的输出流 KK@ &q  
K4iI:  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） eKL]E!  
public SiteFileFetch(SiteInfoBean bean) throws IOException 3Cq6h;!#  
{ ^RYn8I  
siteInfoBean = bean; lF0K=L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D."cQ<sxpN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _{N0OX  
if(tmpFile.exists ()) T+`xr0  
{ *!._Ais,\  
bFirst = false; 6XQ*:N/4al  
read_nPos(); WAtg  
} j9{O0[v  
else  Ask' !  
{ |z.Gh1GCy  
nStartPos = new long[bean.getNSplitter()]; $ \? N<W  
nEndPos = new long[bean.getNSplitter()]; x, G6\QmA  
} i}.{m Et  
qzuQq94k  
it(LphB8  
A~qW.  
} qFvg}}^y  
~5lKL5w  
_
<u8%\  
public void run() vpZu.#5c  
{ 1"8Z y6t  
//获得文件长度 `4q5CJ2  
//分割文件 43vGgGW  
//实例FileSplitterFetch \4[c}l  
//启动FileSplitterFetch线程 )B-MPuB  
//等待子线程返回 ^VSt9&  
try{ yw;ghP;  
if(bFirst) UN cYu9[  
{ ^n\9AE3  
nFileLength = getFileSize(); AZh@t?)  
if(nFileLength == -1) utYnaeQcn  
{ P5'iYahCq_  
System.err.println("File Length is not known!"); XkMs
  
} i_j9/k  
else if(nFileLength == -2) b:N^Fe
 
{ Ha46U6_'h  
System.err.println("File is not access!"); J!21`M-Ue  
} i /O1vU#  
else [W^6u7~  
{ o0,UXBx  
for(int i=0;i<nStartPos.length;i++) C><<0VhU  
{ *(?U  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :z0s*,QH  
} LydbP17K}  
for(int i=0;i<nEndPos.length-1;i++) ek<PISlci  
{ hQgk.$g  
nEndPos = nStartPos[i+1]; FRl3\ZDqrb  
} 'hwV  
nEndPos[nEndPos.length-1] = nFileLength; ga4/,   
} MgJ%26TZ  
} DFt=%aV[  
_hAj2%SL  
0EL\Hd   
//启动子线程 ({;P#qCX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6v
D]@AF  
for(int i=0;i<nStartPos.length;i++) QU-7Ch#8  
{ %NF<bEV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wMlf3Uz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !Z<mrr;T@  
nStartPos,nEndPos,i); X_lUD?y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O,F]\  
fileSplitterFetch.start(); { ()p%#*
 
} t,--V|7-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jMm_A#V>p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N<#S3B?.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2*~JMbm  
nEndPos = " + nFileLength); }m=tzHB*  
// fileSplitterFetch[nPos.length-1].start(); p56KS5duI.  
Jcwh|w9D8  
g|&.v2 '  
//等待子线程结束 J8sJ~FnUj  
//int count = 0; J6*\>N5W  
//是否结束while循环 {pcf;1^t  
boolean breakWhile = false; kjLsk-  
H(5S Kv5  
&A ;3; R  
while(!bStop) P?Gd}mdX?m  
{ `^XRrVX<  
write_nPos(); x
'E'jh%  
Utility.sleep(500); [?|l X$<  
breakWhile = true; lKh2LY=j  
VTy,43<  
_ 6+,R  
for(int i=0;i<nStartPos.length;i++) ?V&Ld$db  
{ F]K$u<U  
if(!fileSplitterFetch.bDownOver) \N# HPrv}  
{ ]t.WJC %  
breakWhile = false; zh#OD{  
break; ue6/EN;}  
} WL IDw@fv  
} bm|Jb"T0b  
if(breakWhile) Nt`F0 9S  
break; Z/V`Z* fy  
UA69_E{JCH  
)#b}qc#`  
//count++; mJ6t.%'d  
//if(count>4) PTuCN  
// siteStop(); )V[w:=*  
} yiv RpSL  
n}AR/3}  
p"hm.=
,  
System.err.println("文件下载结束！"); ++J Bbuzj!  
} .XV]<)<K$  
catch(Exception e){e.printStackTrace ();} dK0}% ]i3#  
} <'>d0:>N  
+BtLyQ  
yBYuDfeZ  
//获得文件长度 )o " SB1  
public long getFileSize() N27K  
{ WryW3];0OR  
int nFileLength = -1; )*^OPVt  
try{ >j(I[_g  
URL url = new URL(siteInfoBean.getSSiteURL()); Q>SPV8s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3<KZ.hr  
httpConnection.setRequestProperty("User-Agent","NetFox"); :)A.E}G  
VV0Egf
J  
%9~kA5Qj  
int responseCode=httpConnection.getResponseCode(); KV^:sxU  
if(responseCode>=400) q_9N+-?{7  
{ nK?k<  
processErrorCode(responseCode); DU*g~{8T$  
return -2; //-2 represent access is error .v #0cQX+.  
} 8T>3@kF  
y]QQvCJr3d  
|*]X\UE  
String sHeader; zCj*:n  
&;NNUT>Q  
d!}jdt5
%  
for(int i=1;;i++) xVHQ[I%  
{ fJF8/IQ4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V\k5h  
//Utility.log(in.readLine()); 7)8rc(58  
sHeader=httpConnection.getHeaderFieldKey(i); O
VQxZ~uQ  
if(sHeader!=null) {jx#^n&5R  
{ ;H m-,W  
if(sHeader.equals("Content-Length")) &geOFe}R  
{ 5H'b4Cyi`  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (04j4teE  
break; Ru9pb~K  
} 6?<`wGs(  
} k"DQbUy0L  
else %
4r!7X|O<  
break; 43}&w.AS  
} (<>Sz(  
} C~ }Wo5  
catch(IOException e){e.printStackTrace ();}  eo<~1w  
catch(Exception e){e.printStackTrace ();} WoClT
b>F  
-Iruua7b  
IJ #v"! D  
Utility.log(nFileLength); 5JU(@}Db  
X*>o9J45V  
<750-d!  
return nFileLength; <@x+
N%C  
} st'?3A  
$:-= >  
HkfSx rTgQ  
//保存下载信息（文件指针位置） QAO
k  
private void write_nPos() eHnei F  
{ "u,~yxYWl  
try{ 5EV8zf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <Hr@~<@~  
output.writeInt(nStartPos.length); 3*2&Fw!B  
for(int i=0;i<nStartPos.length;i++) {Gb)Et]<  
{ W(PW9J9  
// output.writeLong(nPos); &>) `P[x  
output.writeLong(fileSplitterFetch.nStartPos); <4!&iU+;  
output.writeLong(fileSplitterFetch.nEndPos); R^u^y{ohr  
} sxC{\iLY%  
output.close(); H,4,~lv|  
} g*w-"%"O  
catch(IOException e){e.printStackTrace ();} .2(@jx,[  
catch(Exception e){e.printStackTrace ();}
>ihe|WN  
}  ZZFI\o  
9TX
m Z  
cVP49r}}v  
//读取保存的下载信息（文件指针位置） k.? T.9  
private void read_nPos() 8tFyNl`c  
{ d~z<,_r5c  
try{ EbwZZSds1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); (PT?h>|St  
int nCount = input.readInt(); ,rl <ye*&  
nStartPos = new long[nCount]; RfKxwo|M<  
nEndPos = new long[nCount]; -JyODW#j  
for(int i=0;i<nStartPos.length;i++) n4r( Vg1GS  
{ <8z[,X}bM  
nStartPos = input.readLong(); 1Z$99  
nEndPos = input.readLong(); =|{,5="  
} q2j}64o_S  
input.close(); B'BbTI,  
} 2h? r![  
catch(IOException e){e.printStackTrace ();} fY\tvo%  
catch(Exception e){e.printStackTrace ();} {'wU&!  
} 1^H<+0  
^)0{42!]  
d8BK
/b  
private void processErrorCode(int nErrorCode) KJvJUq  
{ 6'sFmC  
System.err.println("Error Code : " + nErrorCode); x_H7=\pX
]  
} cwW~ *90#  
?BWvF]p5/  
&<#BsFz  
//停止文件下载 Kn9=a-b?,  
public void siteStop() [>]VN)_J5  
{ ?=@Q12R)X  
bStop = true; aab4c^Ms=  
for(int i=0;i<nStartPos.length;i++) j>Bk;f|  
fileSplitterFetch.splitterStop(); OAnn`*5Up  
Mb/
6>  
PJ11LE  
} zH\;pmWiN9  
} j n&9<"W  
//负责部分文件的抓取 r;6YCI=z  
**FileSplitterFetch.java 0R^(rE"2#  
*/ j BQqpFH9  
package NetFox; gZ=9Y:$  
C2,c
yhr  
4[EO[x4C  
import java.io.*; v%8-Al^G  
import java.net.*; ThQEQ6y  
Ynh4oWUp  
^CZ|ci6bX  
public class FileSplitterFetch extends Thread { #y9K-}u  
^[\53\R~  
fN%5D z-e  
String sURL; //File URL *1$~CC7  
long nStartPos; //File Snippet Start Position +fQ$~vr{'  
long nEndPos; //File Snippet End Position O>):^$-K%  
int nThreadID; //Thread's ID #pn AK  
boolean bDownOver = false; //Downing is over tIy/QN_42  
boolean bStop = false; //Stop identical 2mp>Mn~K^  
FileAccessI fileAccessI = null; //File Access interface jvKaxB;e  
~i&< !O&  
0v)mgrl=,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?bYQZJ>&  
{ PH4bM  
this.sURL = sURL; Qs[EA_  
this.nStartPos = nStart; C%7)sLWjJS  
this.nEndPos = nEnd; X1z0'gvh  
nThreadID = id; 4y}a,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^d$e^cU  
} U &k3  
Pc ?G^ Xol  
o?hw2-mH  
public void run() VKfHN_m*  
{ \C\y'H5  
while(nStartPos < nEndPos && !bStop) A)a+LW'=u  
{ cz~11j#  
Ecl7=-y  
2+Y`pz47W  
try{ [Ik B/Xbw|  
URL url = new URL(sURL); BL^Hj  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;A'1
7B8  
httpConnection.setRequestProperty("User-Agent","NetFox"); \
hD bv5  
String sProperty = "bytes="+nStartPos+"-"; dSD}NM  
httpConnection.setRequestProperty("RANGE",sProperty); 9v3N
ba  
Utility.log(sProperty); &$Ip$"H  
2<./HH*f  
;}9Ws6#XQs  
InputStream input = httpConnection.getInputStream(); f2e$BA  
//logResponseHead(httpConnection); r|BKp,u9
  
{[y"]_B4  
^ J@i7FOb  
byte[] b = new byte[1024]; !Kqj&y5  
int nRead; -ddatc|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x=|@AFI  
{ I:)#U[tn0  
nStartPos += fileAccessI.write(b,0,nRead); 1`JN  
//if(nThreadID == 1) $[;eb,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \J g#X:d  
} F88SV6  
Pw{{+PBu R  
@%85k/(  
Utility.log("Thread " + nThreadID + " is over!"); .{ Lm  
bDownOver = true; 3'uES4+r  
//nPos = fileAccessI.write (b,0,nRead); Z"nuO\zH~  
} #Z5Wk  
catch(Exception e){e.printStackTrace ();} 3>3ZfFC  
} KEB>}_[  
} /FZ )ej\  
j|8{Vyqd  
7uH{UpslJ  
//打印回应的头信息 nE$ V<Co}  
public void logResponseHead(HttpURLConnection con) d"uM7PMs7x  
{ \V\ET  
for(int i=1;;i++) TbM*?\7  
{ `.Q3s?1F  
String header=con.getHeaderFieldKey(i); 0#GwhB  
if(header!=null) U.} =j'Us+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); yAkN2  
Utility.log(header+" : "+con.getHeaderField(header)); ?^GsR[-x  
else @ MoMU  
break; A+*(Pds  
} GB Un" _J  
} ?Og;W9i  
NGGd6V%'-  
!Bbwl-e`  
public void splitterStop() PEhLzZX+  
{ bvvx(?!  
bStop = true; ptfADG  
} wWswuhq<  
2Ps`!Y5  
GgZf6~b1J  
} \:28z
  
dL"i\5#%A  
=v"{EmT[$  
/* !t{!.  
**FileAccess.java *M5C*}dl  
*//文件访问(定位，写) uT2cHzqKB  
package NetFox; ;8kfgpM_  
import java.io.*; @}RyW&1Z  
$\H46Ji  
I#e*,#'S  
public class FileAccessI implements Serializable{ QNBzc {XB  
%?wE/LU>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EU~'n-  
RandomAccessFile oSavedFile; @&> +`kgU-  
long nPos; Ki\jiflc7  
(~o+pp!  
5mBk[{  
public FileAccessI() throws IOException lK@r?w|<M  
{ '*.};t~;"d  
this("",0); 5< nK.i,  
} (acRYv(  
D4T+Gk"n  
|,f6c Omf  
public FileAccessI(String sName,long nPos) throws IOException B}T72!a  
{ l/M+JT~R  
oSavedFile = new RandomAccessFile(sName,"rw"); g}h0J%s
 
this.nPos = nPos; M,lu)~H  
oSavedFile.seek(nPos); y5 +&P  
} -v&srd^  
V!!'S h  
_Y~?.hs^  
public synchronized int write(byte[] b,int nStart,int nLen) v:b%G?o  
{ |9JYg7<  
int n = -1; I<#kw)W!  
try{ 4K% YS  
oSavedFile.write(b,nStart,nLen); "fwuvT 1  
n = nLen; <VPtbM@(m  
} 1yf&ck1R  
catch(IOException e) H[oi? {L  
{ ?RyvM_(N6  
e.printStackTrace (); U:(
t9NX b  
} ?+
_"2XY  
(ZJ_&8C#  
> [7vXm4  
return n; 3EdPKM j&  
} :eO0{JN4T  
nQC[[G*x  
o!d0  
} rkp0ej2-  
o)DKP>IM#  
JJa?"82FXZ  
/* i[lH@fJm_  
**SiteInfoBean.java O%{>Zo_<  
*/ ],m-,K  
package NetFox; eSf:[^  
U)6
JJv  
]5CFL$_Q{  
public class SiteInfoBean { ~*WbMA  
H2p;J#cv@  
q3t@)+l>*  
private String sSiteURL; //Site's URL uWQ.h ,  
private String sFilePath; //Saved File's Path
==9Ez
  
private String sFileName; //Saved File's Name l0V@19Ec  
private int nSplitter; //Count of Splited Downloading File N*;/~bt7P  
H(|v  
#{a<{HX  
public SiteInfoBean() (C|%@61S  
{//nSplitter的缺省值为5 zyE yZc?  
//default value of nSplitter is 5 v%w]Q B  
this("","","",5); fk_i~K  
} .l!Z=n|  
^ TS\x/P  
MvA_tRO  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~Fh(4'  
{ yDrJn* r^  
sSiteURL= sURL; 2 r)c?  
sFilePath = sPath; 3]Mx,u  
sFileName = sName; zjS<e XLs[  
this.nSplitter = nSpiltter; EWi@1PAZK  
Odu
Tg^R  
jTJ[2WaS  
} :4dili4|/  
oc3/ IWII  
]0O$2j_7  
public String getSSiteURL() ZBWe,Xvq  
{ yO)Qg*r  
return sSiteURL; -_dgd:or  
} ;DOz92X
94  
TfOZ>uR"g  
O_q_O  
public void setSSiteURL(String value) s&l[GKR  
{ PsVA>Q,4!.  
sSiteURL = value; mCo5Gdt  
}  u[u=:Y+  
,b8AB_yw  
\v<}{\.|$  
public String getSFilePath() R:E:Y|&#  
{ LxO'$oKZV  
return sFilePath; 0J"3RTt  
} &W%TY:Da|  
_nt%&f  
!E8JpE|z#  
public void setSFilePath(String value) ,$Mw/fA  
{ :d;5Q\C`  
sFilePath = value; 2t'&7>Ys{  
} :>;#/<3{  
0#ph1a<  
>_".  
public String getSFileName() 5VN4A<))  
{ b< rM3P;  
return sFileName; \]D;HR`vo  
} e-WaK0Ep  
)8_0d)  
7g$t$cZby,  
public void setSFileName(String value) QZY(S*Up  
{ VmW_,  
sFileName = value; b({2|R  
} BdTj0{S1
u  
j8b:+io  
Cn,dr4J[  
public int getNSplitter() t t=$:}A  
{ t%%I.zIV7  
return nSplitter; `u-}E9{  
} n\ZFPXP  
5"sF#Y&  
ifkA3]  
public void setNSplitter(int nCount) 0-FbV,:;  
{ +RM3EvglDQ  
nSplitter = nCount; cGDA0#r  
} (8{Z@  
} (]JJ?aAF  
%+.
]>''a  
S'WmPv  
/* _
n>0!  
**Utility.java >2rFURcD  
*/ z<ek?0?yS  
package NetFox; a7Jr} "B  
tf,_4_7#$  
r&qD!l5y  
public class Utility { BBX4^;t  
0Ec -/   
2a
G<^3  
public Utility() P>H'od  
{ Av'H(qB\K  
4DNZ y2`  
I|.B-$gH  
} ,Ubnz  
/xmd]XM=_  
//线程睡眠 zUh(b=,  
public static void sleep(int nSecond) D -jew&B  
{ ,UP6.C14  
try{ mHP1
.Z`  
Thread.sleep(nSecond); :+YFO.7  
} lfhB2^^  
catch(Exception e) ZE :oK  
{ Deam%)bXM]  
e.printStackTrace (); b~|B(lL6Xm  
} {kC]x2 U  
} j>6{PDaT  
H;^6%HV1  
//日志 mr*zl*  
public static void log(String sMsg) \+,jM6l
}-  
{ BKIt,7j  
System.err.println(sMsg); n4:WM+f4  
}  2}`OjVS  
rnW i<Se  
DCNuvrZ  
public static void log(int sMsg) U{ Y)\hR-  
{ A_2ppEG  
System.err.println(sMsg); i,~{{XS<  
} (<f[$ |%  
} N>/U%01a  
wC[J=:]tA5  
-0W;b"]+A  
/* +n0y/
0Au  
**TestMethod.java SZgH0W("L  
*/ |h3YL!  
package NetFox; {30A1>0#P  
6S<pWR~  
$FAl9  
public class TestMethod { {u:DC4eut  
hGpaHY>My  
v/kYyz  
public TestMethod() eVy,7goh  
{ ///xx/weblogic60b2_win.exe 9;@6iv  
try{ uto4bs:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uv@4/M`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OaEOk57%de  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8\[6z0+;  
fileFetch.start(); LOQEU?z  
} m\Dbb.vBvW  
catch(Exception e){e.printStackTrace ();} # wG}T .*  
2nwP-i  
(j'[t  
} .rS0zU  
E;+3VJ+F"  
)37|rB
E  
public static void main(String[] args) C9~CP8  
{ `=FfzL  
new TestMethod(); X&K1>dgWP  
} $FD0MrB_+  
} N[AX29  
点击下载更多相关资料