http断点续传简单实现（java)

/* 0+h?Bk  
**SiteFileFetch.java Onyq'  
*/ @35]IxD  
package NetFox; qA[}\8}
h  
import java.io.*; `buTP?]4.  
import java.net.*;  =7@  
k{8N@&D  
pp_ddk  
public class SiteFileFetch extends Thread { l)bUHh5[  
0$ EJ4  
w|#79,&  
SiteInfoBean siteInfoBean = null; //文件信息Bean 9 f+7vC
A  
long[] nStartPos; //开始位置 S)h1e%f, f  
long[] nEndPos; //结束位置 ?os0JQVB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 EaL+}/q&  
long nFileLength; //文件长度 P0<uF`87  
boolean bFirst = true; //是否第一次取文件 \hX^Cn=6  
boolean bStop = false; //停止标志 evP`&23t
P  
File tmpFile; //文件下载的临时信息 CjCnh7tm  
DataOutputStream output; //输出到文件的输出流 W5 }zJ)x  
}])f^  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 9`b3=&i\  
public SiteFileFetch(SiteInfoBean bean) throws IOException o!&*4>tF  
{ )A"7l7?.n)  
siteInfoBean = bean; :W55JD'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dD!SgK[Jv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); N9Vcp~;  
if(tmpFile.exists ()) A&#Bf#!G  
{ KcE=m\h  
bFirst = false; J0o[WD$Ax  
read_nPos(); U[u6UG  
} tL|Q{+i yE  
else PVQ%y  
{ X?a67qL  
nStartPos = new long[bean.getNSplitter()]; umYdr'p!v  
nEndPos = new long[bean.getNSplitter()]; S([
De"y  
} F!'"mU<f  
mZ%\`H+  
SuSZ,>  
d?qz7#kc  
} XO>Y*7rO  
4|UIyDt8  
Pr"ESd>Y  
public void run() qKXn=J/0tA  
{ zyE yZc?  
//获得文件长度 v%w]Q B  
//分割文件 fk_i~K  
//实例FileSplitterFetch .l!Z=n|  
//启动FileSplitterFetch线程 Adm`s .  
//等待子线程返回 9`{cX  
try{ 'rgV]Oy  
if(bFirst) vJs/ett  
{ 7#`:m|$  
nFileLength = getFileSize(); O5w\oDhMb  
if(nFileLength == -1) *{bqHMd4L  
{ 7dRU7p>  
System.err.println("File Length is not known!"); uq_SF.a'v  
} "k/x+%!Spc  
else if(nFileLength == -2) u-$AFSt  
{ +iR;D$w  
System.err.println("File is not access!"); aJts  
} >#Yq&@G  
else Bf.RYLsh6  
{ xYq8\9Qb  
for(int i=0;i<nStartPos.length;i++) :A[/;|&  
{ H#:Yw|t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); im`^_zebj  
} ){Y2TWW&0  
for(int i=0;i<nEndPos.length-1;i++) 4+0Zj+ q";  
{ 62q-7nV  
nEndPos = nStartPos[i+1]; Y;WrfO$J  
} -K{ID$!p  
nEndPos[nEndPos.length-1] = nFileLength; 0ni5:tYy  
} R_&>iu'[  
} LxO'$oKZV  
0J"3RTt  
&W%TY:Da|  
//启动子线程 DX|kO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; cW2:D$Pe  
for(int i=0;i<nStartPos.length;i++) ,$Mw/fA  
{ :d;5Q\C`  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2t'&7>Ys{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :>;#/<3{  
nStartPos,nEndPos,i); J&?kezs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S;C3R5*:  
fileSplitterFetch.start(); gVc[`(@h  
} 0qv)'[O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), oT'XcMn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Jq->DzSmj/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", w K+2;*bI  
nEndPos = " + nFileLength); =W6P>r_  
// fileSplitterFetch[nPos.length-1].start(); :zCm$@  
+q(D]:@,[  
mTt 9 o9E  
//等待子线程结束 T &1sfS,  
//int count = 0; E_z@\z MB  
//是否结束while循环 Zo`^pQS  
boolean breakWhile = false; )xeVoAg  
7hc(]8eP  
t%%I.zIV7  
while(!bStop) `u-}E9{  
{ n\ZFPXP  
write_nPos(); 5"sF#Y&  
Utility.sleep(500); ifkA3]  
breakWhile = true; 0-FbV,:;  
_i&\G}mrC  
mnePm{  
for(int i=0;i<nStartPos.length;i++) $T6<9cB@  
{ >&TktQO_T  
if(!fileSplitterFetch.bDownOver) al2v1.Y}  
{ >wn&+%i&  
breakWhile = false; W^x[maz  
break; @1pdyKK  
} B3D4fYQ  
} gm8H)y,  
if(breakWhile) ^a]:G
Pc  
break;
nL$tXm-x  
Au {`oxD  
zAH+{4lC+  
//count++; k $);<= ZI  
//if(count>4) `>V.}K^4  
// siteStop(); ZE9*i}r  
} OygYP  
?E`J-ncP  
_tjH=Ff$  
System.err.println("文件下载结束！"); %w@(V([(c  
} 9}4L8?2  
catch(Exception e){e.printStackTrace ();} qIk6S6  
} i|<*EXB"  
4bO7rhve  
?;$g,2n  
//获得文件长度 XDn$=`2  
public long getFileSize() YpWu\oP  
{ PU8R 0r2k\  
int nFileLength = -1; k";;Snk  
try{ '?d[ ip  
URL url = new URL(siteInfoBean.getSSiteURL()); 0-5:"SN'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $R^"~|m3M  
httpConnection.setRequestProperty("User-Agent","NetFox"); h1BdASn_  
H=dj\Br`  
/f#sg7)  
int responseCode=httpConnection.getResponseCode(); T57S!CJ^$5  
if(responseCode>=400) }b-?Dm_H  
{ :{sX8U%  
processErrorCode(responseCode); Mfgd;FsX#  
return -2; //-2 represent access is error
7SQu  
} /A>/]2(  
r4-r z+x  
jj^CW"IB  
String sHeader; Q|0[B4e^:  
m\t %wr  
YrdK@I  
for(int i=1;;i++)
`pKQ|zGw  
{ 29E^]IL?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); w<'mV^S  
//Utility.log(in.readLine()); <"t >!I  
sHeader=httpConnection.getHeaderFieldKey(i); 'd28YjtoX  
if(sHeader!=null) rlds-j''  
{ /q>"">  
if(sHeader.equals("Content-Length")) @M(vaJB8u  
{ hGpaHY>My  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v/kYyz  
break; eVy,7goh  
} 9;@6iv  
} 8T%z{A1T  
else old}}>_  
break; 2sXWeiJy;  
} T# 8O:  
} s^6S
{XJ  
catch(IOException e){e.printStackTrace ();} +>s[w{Svy  
catch(Exception e){e.printStackTrace ();} F`
3I~(  
rUj]6j=e  
y:457R2F  
Utility.log(nFileLength); L:S[QwQu8  
<5nz:B
/  
b[/-lNrc  
return nFileLength; 'a0$74fz  
} z-()7WY  
k:c)|2  
Oh|Hy/&6W  
//保存下载信息（文件指针位置）
j
/9'L^]  
private void write_nPos() a.q
=  
{ SL*B `P~{  
try{ m:'fk;khN  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N!,@}s  
output.writeInt(nStartPos.length); zW\&q!`IRP  
for(int i=0;i<nStartPos.length;i++) #t;@x_2yD\  
{ -qs9a}iL  
// output.writeLong(nPos); WT1ch0~2  
output.writeLong(fileSplitterFetch.nStartPos); P[D^*}  
output.writeLong(fileSplitterFetch.nEndPos); H3&$:h  
} A$ s4Q0Mf  
output.close(); vmL0H)q  
} ba ,2.|  
catch(IOException e){e.printStackTrace ();} @o_-UsUX  
catch(Exception e){e.printStackTrace ();} R7vO,kZ6Q  
} )4DF9JpD  
q),yY]5  
JD,/oL.KA  
//读取保存的下载信息（文件指针位置） A9[l5E  
private void read_nPos() 32dR`qb  
{ +}%4]O;  
try{ MbF.KmV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <zrGPwk  
int nCount = input.readInt(); UE*M\r<  
nStartPos = new long[nCount]; hH%@8'1v  
nEndPos = new long[nCount]; 2jA-y!(e  
for(int i=0;i<nStartPos.length;i++) 6VIi nuOW  
{  d':c  
nStartPos = input.readLong(); <D=U=5  
nEndPos = input.readLong(); uP<
tP:  
} ZMoN  
input.close(); q*
52|?  
} u>d,6 !
 
catch(IOException e){e.printStackTrace ();} G/=tC8eX  
catch(Exception e){e.printStackTrace ();} ]x?`&f8i  
} RH~KaV3  
06L/i,  
S)p1[&" M  
private void processErrorCode(int nErrorCode) 3s"x{mtH  
{
A=Dzd/CUO  
System.err.println("Error Code : " + nErrorCode); ;jS~0R  
} GXf"a3  
Eufw1vDa  
KxqJlben  
//停止文件下载 8eQ 4[wJY  
public void siteStop() jo/-'Lf{?  
{ um,Zt  
bStop = true; ~^ Q`dJL  
for(int i=0;i<nStartPos.length;i++) !5&% P b  
fileSplitterFetch.splitterStop(); hjs[$,1  
fpu^  
]|'Mf;  
} r+ k5Bk'  
} oF8#gn_  
//负责部分文件的抓取 (@[c;+x  
**FileSplitterFetch.java %,1bh  
*/ =UT*1-yhR  
package NetFox; d%8hWlffz  
xXQDHc-Ba  
)BmK'H+l  
import java.io.*; +<7`Gn(n3  
import java.net.*; |]*]k`o<)  
v?vm-e  
{ LZ` _1D  
public class FileSplitterFetch extends Thread { >+LFu?y  
R$sG*=a!8j  
9/'zk
  
String sURL; //File URL [AA'Ko  
long nStartPos; //File Snippet Start Position AQ7w5}g+V  
long nEndPos; //File Snippet End Position %dw@;IZ#8{  
int nThreadID; //Thread's ID f+d
[Q1  
boolean bDownOver = false; //Downing is over }\?UmuolQ  
boolean bStop = false; //Stop identical AT+7!UGL  
FileAccessI fileAccessI = null; //File Access interface 3]$qY_|7  
G&y< lh
 
N D`?T &PK  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y`.FSs  
{ B}Qpqa=_c  
this.sURL = sURL; BUvE~l.,|  
this.nStartPos = nStart; q&]I  
this.nEndPos = nEnd; t4X:I&l-M:  
nThreadID = id; 86y)+h`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _=S4H  
} ?H3L
s~R  
D;*P'%_Z  
L"e8S%UqX  
public void run() Po_y78ZD  
{ bVO{,P2o  
while(nStartPos < nEndPos && !bStop) qp;eBa  
{ G 
|033(j  
Y)lYEhF  
l3[2b Qx  
try{ RzgA;ZC'  
URL url = new URL(sURL); W:VRLT>w>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3g ep_aC  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,aq0Q<}~lc  
String sProperty = "bytes="+nStartPos+"-"; ^/b3_aM5d  
httpConnection.setRequestProperty("RANGE",sProperty); '~{bq'7`m  
Utility.log(sProperty); M^S
<G  
:rR)rj'  
dX^ ^ @7  
InputStream input = httpConnection.getInputStream(); \k&2nYVHf  
//logResponseHead(httpConnection); kn9ul3c  
QmxI;l  
->_rSjnM{  
byte[] b = new byte[1024]; /z
V&ebN]  
int nRead; ;=r_R!
d@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p`N+9t&I4  
{ fXD9w1  
nStartPos += fileAccessI.write(b,0,nRead); >JVdL\3  
//if(nThreadID == 1) ~$w9L998+  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zp.-=)D4e  
} tr?U/YG  
[C@|qAh  
!W2dMD/  
Utility.log("Thread " + nThreadID + " is over!"); A~0eJaq+  
bDownOver = true; wX/0.aZ|  
//nPos = fileAccessI.write (b,0,nRead); z'"e|)  
} xfegi$  
catch(Exception e){e.printStackTrace ();} EnW}>X
N  
} ,r_%p<lOFu  
} VCf/EkC  
oyC5M+shP9  
VkW N1A  
//打印回应的头信息 |tn.ZEgw3~  
public void logResponseHead(HttpURLConnection con) WtS5i7:<Y  
{ J> Z.2  
for(int i=1;;i++) \%BII>VS  
{ 5TynAiSD_>  
String header=con.getHeaderFieldKey(i); +V Oczl=  
if(header!=null) ?2q4dx0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "@ 1+l&  
Utility.log(header+" : "+con.getHeaderField(header)); FW=`Fm@z%%  
else ?cur}`  
break; !a9`]c  
} 4J5 RtK  
} .30eO_msK  
1buVV]*~  
tXXnHEz  
public void splitterStop() ^K3Bn  
{ -F7P$/9  
bStop = true;
$Sls9H+.  
} ;]vJ[mi~  
9u0<$UY%  
Ie"eqO!  
} aWS_z6[t#6  
u,~/oTgO  
|X47&Y  
/* %^KN
Y ;E  
**FileAccess.java (ay((|)  
*//文件访问(定位，写) >}H3V]  
package NetFox; BZP{{  
import java.io.*; Ht4A   
P!xN]or]u  
$Cnv]1%  
public class FileAccessI implements Serializable{ X+
7@8)1(  
Qo\+FkhYq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &RB{0Q
hx  
RandomAccessFile oSavedFile; &*j# [6  
long nPos; Q'~3Ik  
|\BxKwS^  
EBMZ7b-7  
public FileAccessI() throws IOException bDtb"V8e  
{ %LjhK,'h  
this("",0); O&g$dK!Rad  
} 2%_UOEayU  
,z5B"o{Et
 
LS%;ZKJ  
public FileAccessI(String sName,long nPos) throws IOException $97EeE:{M  
{ q=x1:^rVH  
oSavedFile = new RandomAccessFile(sName,"rw"); ^~`t q+  
this.nPos = nPos; CNM
pyr  
oSavedFile.seek(nPos); =wquFA!c  
} S;tv4JY  
lvp8{]I<  
>Q#\X=a>  
public synchronized int write(byte[] b,int nStart,int nLen) zvOSQxGQ  
{ +'V ,z  
int n = -1; }cO}H2m  
try{ ~0V,B1a  
oSavedFile.write(b,nStart,nLen); |%$mN{  
n = nLen; {Rtl<W0  
} 2fFGS.l  
catch(IOException e) (@i2a  
{ ItxC}qT  
e.printStackTrace (); y^}00Z+l  
} 7El:$H  
v5A8"&Jr  
)-\[A<(  
return n; IA~wmOF  
} tB#-}Gf  
I*4g ;1x  
fI }v}L^  
} B&Iy_;  
1kczlTF  
Oi4y~C_Xd  
/* e)#f`wM  
**SiteInfoBean.java NR.YeKsBq  
*/ q[
5&  
package NetFox; f9a_:]F   
><w=  
_ lE d8Cb  
public class SiteInfoBean { VRA0p[  
~#PC(g  
@QbTO'UzK`  
private String sSiteURL; //Site's URL O Ce;8^  
private String sFilePath; //Saved File's Path X;Q
hK] Z  
private String sFileName; //Saved File's Name wPQRm[O|  
private int nSplitter; //Count of Splited Downloading File q3e^vMK"  
ss'`[QhR2  
js F96X{  
public SiteInfoBean() &XZS}n  
{//nSplitter的缺省值为5 EF8'ycJk+  
//default value of nSplitter is 5 HwxME%w  
this("","","",5); " "{#~X}  
} !9g>/9h  
hngdeGa  
859ID8F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dS)c~:&+  
{ l g43  
sSiteURL= sURL; hx:"'m5  
sFilePath = sPath;
]#P>wW  
sFileName = sName; 0Q5fX}  
this.nSplitter = nSpiltter; g3kF&+2i  
$zD}hO9  
o 4cqLMu  
} Wer.VL  
8jjq)d4#  
-Ou@T#h"  
public String getSSiteURL() c~v(bK  
{ *c'hmAs  
return sSiteURL; 0k6S`e9gI  
} tY0C& u2  
Pj7n_&*/  
f+>g_Q  
public void setSSiteURL(String value) B^lm'/,@  
{ H
iPd|D  
sSiteURL = value; ofHe8a8  
} {/K_NSg+h  
5/C#*%EH'  
xZ(f_Oy  
public String getSFilePath() ,-.
a! a  
{ [RFF&uy  
return sFilePath; Hl b%/&  
} $Oi@B)=4d+  
XfYhLE  
%\QK/`krp  
public void setSFilePath(String value) 9Netnzv%  
{ 18];fC  
sFilePath = value; UCL aCt -  
} _7Rp.)[&  
! C|VX,w  
kSq1Q#Bxq  
public String getSFileName() \'.#of  
{ TaTs-]4  
return sFileName; 5*IfI+}  
} flzHZH  
l4smAT  
iQ
J[?l`  
public void setSFileName(String value) p`}'-A|@  
{ W*/0[|n*  
sFileName = value; - }2AXP2q  
} FatLc|[  
bL"!z"NA  
QGpAG#M9?  
public int getNSplitter() YNV4'  
{ +?[,{WtV  
return nSplitter; dzn[4  
} *eb2()B%  
@$ggPrs  
*D6X&Hg&5  
public void setNSplitter(int nCount) Ln C5"
 
{ 6x8P}?  
nSplitter = nCount; M9scZuj  
} ic]b"ItD  
} kjVJ!R\  
daakawn+  
{ i2QLS  
/* `7mRUDz  
**Utility.java 3HI-G.]hC  
*/ Sp>v`{F  
package NetFox; gvl3NQQ%t  
Y&JK*d  
L/sMAB  
public class Utility { YN>k5\M_v  
D8S3YdJ  
EBl?oN7E  
public Utility() [;n/|/m,  
{ jQIb :\0#  
O<EFm}Ae  
okv`+VeA  
} E)}& p\{E  
Z2cumx(  
//线程睡眠 swGp{wJ  
public static void sleep(int nSecond) 6+s10?  
{ b)1v:X4Bv=  
try{ `HO_t ek  
Thread.sleep(nSecond); Ub_!~tb}?  
} CfMCc:8mL  
catch(Exception e) 8uZM%7kI6+  
{ t5"g9`AL  
e.printStackTrace (); ZD(VH6<g%  
} b2<((H  
} V~%C me  
B2/d%B  
//日志 "xK#%eJjWd  
public static void log(String sMsg) 6";ew:Ih^  
{ lH#C:n  
System.err.println(sMsg); ah9P C7[  
} -\dcs?  
Q 2mTu[tx  
rTmVHt  
public static void log(int sMsg) )oU%++cdo  
{ tP0\;W  
System.err.println(sMsg); K}j["p<!  
} j2GTo~muq  
} fb*h.6^y9  
LjEG1$F>  
BJNZH#"  
/* J\%SAit@  
**TestMethod.java JOUZ"^v  
*/ mQka?_if)  
package NetFox; z9qF<m  
L#6!W  
^1mnw@04  
public class TestMethod { N}\%r&KR=  
o0}kRL  
6a!b20IZh  
public TestMethod() V<&^zIJUR  
{ ///xx/weblogic60b2_win.exe ARd*c?Om  
try{ nd#owjB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m<liPl uv  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ][TA7pDPV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); + \jn$>E  
fileFetch.start(); vXLGdv::  
} Mc@_[q!xY?  
catch(Exception e){e.printStackTrace ();} vBLs88  
/Y#Q<=X  
`37%|e3bQ  
} B{hV|2  
B"Hz)-MW  
qvC2BQ  
public static void main(String[] args) #6F|
}E  
{ 8c3/n   
new TestMethod(); N#<X"&-_#  
} )zv"<>Q 6  
} \TS.9 >\  
点击下载更多相关资料