http断点续传简单实现（java)

/* NKRXY~zHh  
**SiteFileFetch.java g=.5*'Xlp  
*/ g7pFOcV  
package NetFox; cD\Qt9EI  
import java.io.*; iX28+weH  
import java.net.*; {BF\G%v;+  
{SJLM0=Z  
`
#V"@Go  
public class SiteFileFetch extends Thread { /D q]=P  
DuWP)#kg  
P|?z1JUd  
SiteInfoBean siteInfoBean = null; //文件信息Bean e0TnA N  
long[] nStartPos; //开始位置 d dPJx<  
long[] nEndPos; //结束位置 v7-'H/d.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 km^AX:r1  
long nFileLength; //文件长度 `C1LR,J  
boolean bFirst = true; //是否第一次取文件 ch&r.  
boolean bStop = false; //停止标志 Z6=!}a%  
File tmpFile; //文件下载的临时信息 #SdaTMLFf  
DataOutputStream output; //输出到文件的输出流 cA*%K[9  
s-*XAnot  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /X?Nv^Hy  
public SiteFileFetch(SiteInfoBean bean) throws IOException PIA&s6U  
{ L81"W`?  
siteInfoBean = bean; 9T]]TEv4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }yw\+fc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _FV.}%W<u  
if(tmpFile.exists ()) 5*CwQJC<  
{ IkvH8E  
bFirst = false; yDKX,  
read_nPos(); ^ey\ c1K  
} Vf@/}=X *  
else @.0,ka,X  
{ eZv0"FK X  
nStartPos = new long[bean.getNSplitter()]; ] !H<vR$8  
nEndPos = new long[bean.getNSplitter()]; YcI]_[  
} M_e!s}F  
 4@5<B  
qHj4`&  
VKlD"UTk  
} f9$98SI  
ql8:s>1T  
T|m+ULp~  
public void run() ~UnfS};
U  
{ @f$P*_G   
//获得文件长度 ;8A_-
$  
//分割文件 D,7! /u'  
//实例FileSplitterFetch <D=%55  
//启动FileSplitterFetch线程 G{J9Fb8  
//等待子线程返回 Pa.!:N-  
try{ hk=+t&Y<H  
if(bFirst) ovHbs^
H%  
{ Y,a.9AWw)  
nFileLength = getFileSize(); ^,X+ n5q;m  
if(nFileLength == -1) H1w;Wb1se  
{ ED6H  
System.err.println("File Length is not known!"); /#XO!%=7  
} V=c&QPP  
else if(nFileLength == -2) l`1ZS8 [.  
{ r8xH A  
System.err.println("File is not access!"); cz0tnF*&  
} * T-XslI  
else U3Q'ZT  
{ # WxH  
for(int i=0;i<nStartPos.length;i++) 8FMP)N4+  
{ d<whb2l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); CN >q`[!  
} Ywni2-)<  
for(int i=0;i<nEndPos.length-1;i++) )TWf/Lcp  
{ BG|Kw)z*KM  
nEndPos = nStartPos[i+1]; 4Qw!YI#40$  
} UeVF@rw  
nEndPos[nEndPos.length-1] = nFileLength; A[b'MNsv  
} iX,Qh2(ig  
} 7#RW4ZM  
j/W#=\xz  
KLxg  
//启动子线程 lmod8B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A*$vk
2VWw  
for(int i=0;i<nStartPos.length;i++) }3+(A`9h f  
{ CocvEoE*z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ao,lEjNI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xNx!
2MrR;  
nStartPos,nEndPos,i); F'"-4YV>&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]\GGC]:\@  
fileSplitterFetch.start(); dx~F [  
} Sy8Og] a   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 20J
:_+=]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F|"NJ*o}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", aWit^dp  
nEndPos = " + nFileLength); .Wr7?'D1M  
// fileSplitterFetch[nPos.length-1].start(); s*VZLKO  
vzVl2  
dCc*<S  
//等待子线程结束 2;q6~Y,  
//int count = 0; wp@c;gK7  
//是否结束while循环 pIh@!C  
boolean breakWhile = false; t!PFosFp  
{}.c.W+  
Gjzhgz--  
while(!bStop) T\]z0M  
{ }e82e  
write_nPos(); q k!Q2W  
Utility.sleep(500); y(q1~73s  
breakWhile = true; F[J;u/Z  
[@/G?sAQm\  
:@pmgp  
for(int i=0;i<nStartPos.length;i++) lD{9o2  
{ ArF+9upGY  
if(!fileSplitterFetch.bDownOver) V57^0^Zp`  
{ +pDuRr  
breakWhile = false; QK;A>]  
break; 2Qn%p[#n  
} V{(ve#y7`{  
} $biCm$a  
if(breakWhile) 1tD4I  
break; D F0~A  
ql],Wplg  
1N2:4|woe  
//count++; Rk"_4zJk  
//if(count>4) m+1MoeR  
// siteStop(); >bmL;)mc&  
} SA}]ZK P  
ZY{,//  
}n8,Ga%  
System.err.println("文件下载结束！"); 03#r F@e  
} 7|H !(a'  
catch(Exception e){e.printStackTrace ();} A/GEDG ?  
} dGZVWEaPfx  
xH*OEzN  
2<<,a
L*  
//获得文件长度 ][D<J0  
public long getFileSize() [<bfwTFsl  
{ U+nwLxe'  
int nFileLength = -1; bPiJCX0d  
try{ (3 B; V  
URL url = new URL(siteInfoBean.getSSiteURL()); Z~$fTW6g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E@t^IGDr  
httpConnection.setRequestProperty("User-Agent","NetFox"); UiW(/L  
, Lhgv1  
~,dj)x 3M  
int responseCode=httpConnection.getResponseCode(); RaG-9gujI  
if(responseCode>=400) nz+DPk["  
{ hCc I >[H5  
processErrorCode(responseCode); ;clF\K>  
return -2; //-2 represent access is error =XyK/$  
} Gv3a<Knn4  
0E{$u  
^-mz!{  
String sHeader; 4RJ8 2yq-  
vlx wt~  
QD q2<  
for(int i=1;;i++) .#Z}}W#  
{ q4Qm:|-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m?bb/o'
B  
//Utility.log(in.readLine()); +#n5w8T)M  
sHeader=httpConnection.getHeaderFieldKey(i); wbVM'E/&  
if(sHeader!=null) ;?bRRW  
{ bvs0y7M='  
if(sHeader.equals("Content-Length")) }8 fG+H.  
{ ,~%Qu~\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QV7K~qi  
break; NZmmO )p4  
}  E~jNUTq  
} zZGPA j  
else ^`Vt<DMT  
break; :>;-uve8'  
} v`bX#\It  
} pu,/GBG_  
catch(IOException e){e.printStackTrace ();} q^>$YY>F  
catch(Exception e){e.printStackTrace ();} R84g<  
i%D/@$\D6  
!nC Z,  
Utility.log(nFileLength); 78Nli/U  
Ilsh Jo  
@| qnD  
return nFileLength; &>p2N  
} coiTVDwA  
s=u0M;A0Q  
V :*GG+4  
//保存下载信息（文件指针位置） J9mLW}I?NW  
private void write_nPos() l3)
(aay!  
{ lKxv SyD  
try{ yIh>j.P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JIjqGxR  
output.writeInt(nStartPos.length); `3*>tq  
for(int i=0;i<nStartPos.length;i++) Oh5(8.<y  
{ #<M
LW4P  
// output.writeLong(nPos); ?,;|*A  
output.writeLong(fileSplitterFetch.nStartPos); --dGN.*xb4  
output.writeLong(fileSplitterFetch.nEndPos); e(6g|h  
} UW. F1)  
output.close(); A|c
:&i  
} pzCD' !*  
catch(IOException e){e.printStackTrace ();} JwRdr8q  
catch(Exception e){e.printStackTrace ();} cJGA5m/{I  
} d]} 7]  
f)vD2_E  
>8#(GXnSt  
//读取保存的下载信息（文件指针位置） ~2S`y=*:  
private void read_nPos() mdoy1a  
{ <u&uwD~A  
try{ V89!C?.[]1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iePpJ>(  
int nCount = input.readInt(); ,D  [  
nStartPos = new long[nCount]; @R9  
nEndPos = new long[nCount]; Z>Rd6o'  
for(int i=0;i<nStartPos.length;i++) :2 n5;fp  
{ |rq~.cA  
nStartPos = input.readLong(); BT2[@qH|qF  
nEndPos = input.readLong(); EJNj.c-#  
} Z>7Oez>  
input.close(); BO#fzq%  
} 3BKW  
catch(IOException e){e.printStackTrace ();} FJ!
N)`[  
catch(Exception e){e.printStackTrace ();} 2Qc&6-;`  
} <(>v|5K0]  
Ni"fV]'  
:{E3H3  
private void processErrorCode(int nErrorCode) OE}L})"  
{ t8U)za  
System.err.println("Error Code : " + nErrorCode); |*Z'WUv  
} \@*cj8e  
jQ4Pv`  
g5M-Vu  
//停止文件下载 ]W5s!T_  
public void siteStop() 7 G~MqnO|  
{  &j2L-)  
bStop = true; )d>"K`3  
for(int i=0;i<nStartPos.length;i++) n?YGXW/  
fileSplitterFetch.splitterStop(); )m\%L`+  
k#5S'sCF<  
ceH7Rq:4W  
} :kOLiko!4>  
} 5u~Ik c~  
//负责部分文件的抓取 DJr 8<u  
**FileSplitterFetch.java <Zl0$~B:5  
*/ ?N,a {#w  
package NetFox; @H]g_yw [:  
6$%]p1"!K  
A^3cP, L  
import java.io.*; b3#c0
GL  
import java.net.*; B5=L</Aj  
nO\|43W  
v9x $`  
public class FileSplitterFetch extends Thread { (x&#>5  
!}l)okQH<#  
pZlBpGQf  
String sURL; //File URL OAOG&6xu8  
long nStartPos; //File Snippet Start Position Nr:%oD_G*  
long nEndPos; //File Snippet End Position v~L} :  
int nThreadID; //Thread's ID O<L/m[]  
boolean bDownOver = false; //Downing is over )n5]+VTZ5  
boolean bStop = false; //Stop identical MR#j
I  
FileAccessI fileAccessI = null; //File Access interface !`=r('l  
u32wS$*8  
87YT;Z;U&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tE(x8>5A:  
{ q>]v~  
this.sURL = sURL; j9y,UT  
this.nStartPos = nStart; dbB2/RI  
this.nEndPos = nEnd; HR['y9U  
nThreadID = id; z*zLK[t+  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e7]IEBbX2O  
} V=3NIw18  
nFw&vR/q  
QTcngv[  
public void run() Y49kq}  
{ ?#,\,  
while(nStartPos < nEndPos && !bStop) gA" =so  
{ P)(Ly5$*  
hL67g  
Y5c( U)R8  
try{ *Ty>-aS1  
URL url = new URL(sURL); SDA +XnmH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *`|.:'  
httpConnection.setRequestProperty("User-Agent","NetFox"); :d)@|SR1  
String sProperty = "bytes="+nStartPos+"-"; XfViLBY( >  
httpConnection.setRequestProperty("RANGE",sProperty); G1$DVGo  
Utility.log(sProperty); /5U?4l(6[f  
AGLzA+6M
 
r[EN`AxDb  
InputStream input = httpConnection.getInputStream(); ,i>5\Yl%  
//logResponseHead(httpConnection); _ F@>?\B  
>]ZojdOl)  
B quyPG"  
byte[] b = new byte[1024]; M?)>, !Z)  
int nRead; dRW
p/3 }  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BCsW03sQ  
{ ~Z.lvdA_5  
nStartPos += fileAccessI.write(b,0,nRead); EBK\.[  
//if(nThreadID == 1) FIC 2)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (VC{#^2l  
} z4UeUVfZ}  
+]5JXt^  
~|l>bf  
Utility.log("Thread " + nThreadID + " is over!"); (Pvch!  
bDownOver = true; ]E[Mv} =  
//nPos = fileAccessI.write (b,0,nRead); 9FcCq*D  
} xjR/K&[m  
catch(Exception e){e.printStackTrace ();} R4@C>\c%m  
} DX4 95<6*  
} -PEpy3dMY  
{{@3r5KGl  
;M@/AAZ  
//打印回应的头信息 +c\fDVv  
public void logResponseHead(HttpURLConnection con) r
o^Y$;G  
{ A6TNtXk  
for(int i=1;;i++) )ae/+Q8  
{ ew}C*4qH  
String header=con.getHeaderFieldKey(i); mgH4)!Z*56  
if(header!=null) U{i9h6b"18  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OEq8gpqY  
Utility.log(header+" : "+con.getHeaderField(header)); /+02BP  
else e:NzpzI"v  
break; NrS1y"#d9  
} -!w
m]kx f  
} Z^h'&c#  
E$smr\  
LLaoND6  
public void splitterStop() ^[^uDE <  
{ ffuV$#  
bStop = true;
.+.Y`0  
} `9b D%M  
D/@:wY  
)M'#l<9B  
}  BX+-KvT  
>q[Elz=dI  
|D`Zi>lv  
/* p]=8=pE<  
**FileAccess.java
gy9!T(z  
*//文件访问(定位，写) - DL/Hk_r  
package NetFox; $~zqt%}  
import java.io.*; I:AlM?  
jf.ikxm  
~mmI] p
C  
public class FileAccessI implements Serializable{ !Y`nKC(=z  
TZ-n)rC)v  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n'%*vdHKm  
RandomAccessFile oSavedFile; IxgnZX4N  
long nPos; |wVoJO!O}  
}Ct_i'Ow  
\=,+weGw@  
public FileAccessI() throws IOException fN8A'p[  
{ C+-~Gmrb(7  
this("",0); shnfH  
} HTkce,dQ  
q& 4Z.(  
%o+bO}/9  
public FileAccessI(String sName,long nPos) throws IOException HHa7Kh|-H  
{ q0DoR@  
oSavedFile = new RandomAccessFile(sName,"rw"); ruF+X)  
this.nPos = nPos; P,D >gxl  
oSavedFile.seek(nPos); Gash3}+  
} 83;1L:}`  
QF[9Zn  
*~2jP;$  
public synchronized int write(byte[] b,int nStart,int nLen) <Hm:#<\  
{ 2/?pI/W  
int n = -1; B:+}^=  
try{ dpJi5fN  
oSavedFile.write(b,nStart,nLen); G?>~w[#mQR  
n = nLen; MH{vFA4:,  
} kD MS7y<s  
catch(IOException e) ((;9%F:/$  
{ YJeZ{Wws  
e.printStackTrace (); 5g/^wKhKG  
} 8q_3*++D  
rv|k8  
|mY<TWoX  
return n; SuGlNp>#qm  
} EkWe6m  
z?1G
J8  
): Q5u6  
} Y k~ i.p  
jCKRoao  
_mXq]r0  
/* t'm]E2/  
**SiteInfoBean.java jcx/ZR  
*/ /1n}IRuw  
package NetFox; &sx/qS#,VL  
y^M
'&@F  
w[4SuD  
public class SiteInfoBean { *;"^b\f5_  
8 _`Lx_R  
iF61J%3-  
private String sSiteURL; //Site's URL G/<{:R"  
private String sFilePath; //Saved File's Path YhR?*Di  
private String sFileName; //Saved File's Name \4zvknk<  
private int nSplitter; //Count of Splited Downloading File <w{W1*R9  
U@Aq@d+n  
:*c@6;2@  
public SiteInfoBean() n!HFHy2  
{//nSplitter的缺省值为5 z{!wQ~ j  
//default value of nSplitter is 5 RA.@(DN&  
this("","","",5); hh:)"<[  
} H~Q UN  
nR"k%$  
z:<(b   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c%uhQ62  
{ Ej.D!@   
sSiteURL= sURL; 7Dm^49H  
sFilePath = sPath; to:hMd1T  
sFileName = sName; _Q.3X[88C  
this.nSplitter = nSpiltter; _}JygOew  
;y5cs;s
  
7zQD.+&L  
} "#e2"=3*  
!lu$WJ{M  
#o yvsS8  
public String getSSiteURL() 4eIu@ ";!  
{ 2sittP  
return sSiteURL; ?cg+RNI  
} 2M1yw "  
G9VzVx#T#  
:B=`^>RK  
public void setSSiteURL(String value) gVq{g,yi  
{ Ii[rM/sG  
sSiteURL = value; `L9o!OsQ  
} (!M
l2  
sV[|op  
r-Dcc;+=Q  
public String getSFilePath() aG=Y 6j G  
{ (<%i8xu2  
return sFilePath; ;\#u19  
} AA05wpu8  
2]4R`[#  
Gl1`Nx0  
public void setSFilePath(String value) 88G[XkL$2  
{ !' sDqBZ&7  
sFilePath = value; jq
=-Y  
} cUy6/x9&  
s0nihX1Z-  
sDbALAp +  
public String getSFileName() 4Nq n47|>e  
{ K"=v|a.  
return sFileName; MuO>O97  
} pr;L~$JW  
eY&UFe  

c~C :"g.y  
public void setSFileName(String value) /H3,v8J@  
{ }.T$bj1B;V  
sFileName = value; 4|:{a
pH  
} =#+Z KD  
;'<K}h
 
,#"AW
Q  
public int getNSplitter() PDpIU.=!0  
{ ; 9'*w=V  
return nSplitter; 5T8!5EcS*  
} 8^4X/n  
&`@Jy|N\  
LR
bevpZ,  
public void setNSplitter(int nCount) C]r$  
{ Z;n}*^U  
nSplitter = nCount; g#70Sg*d  
} BtqJkdK!;1  
} ZE=~ re  
:+R||qi  
)8Q|y  
/* 2nEj X\BY  
**Utility.java awC&xVf  
*/ 6DR8(j)=[%  
package NetFox; e=F' O] 5  
3cfkJ|fuwe  
+ S%+Ku  
public class Utility { N[42al  
@:c
 1+  
_5X}&>>lhF  
public Utility() 2ag]p  
{ chiQ+  
&[s^`e  
#2WBYScW0  
} 1-qQp.Wj  

m_]"L
 
//线程睡眠 p jrA:;  
public static void sleep(int nSecond) qi)(\  
{ rgP$\xn-  
try{ Az.Y-O<$\  
Thread.sleep(nSecond);  6f{c  
} 6dinC <[}  
catch(Exception e) Gpgi@ Uf  
{ -|3U0:'m  
e.printStackTrace (); h]D=v B  
} 7'&Xg_  
} "?N`9J|j)~  
H?aB8=)  
//日志 r^ "mPgY  
public static void log(String sMsg) VyI%^S ]sS  
{ {$s:N&5  
System.err.println(sMsg); e~-Dk .i  
} r7Ihm
dA  
7C 4Njei"  
w6E?TI  
public static void log(int sMsg) @lmke>  
{ rSZWmns  
System.err.println(sMsg); @*_K#3  
} 0<s)xaN>Y  
} ,O-lDzcw  
a;h:o>Do5  
Us%VBq  
/* pa\]@;P1  
**TestMethod.java ~\oJrRYR`  
*/ MP3E]T~:  
package NetFox; d>aZpJ[.  
=9)ypI-2  
4,aBNuxWd  
public class TestMethod { B"EMir'  
2dq{n.cgs  
Ti'O 2k  
public TestMethod() R4v=i)A~Z  
{ ///xx/weblogic60b2_win.exe zO+nEsf^O  
try{ U}5uy9A  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '<Vvv^Er  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `Y[zF1$kz^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); nnE@1X3  
fileFetch.start(); &=/.$i-w$  
} X;0EgIqh3  
catch(Exception e){e.printStackTrace ();} 7v
?Ygtv  
AX&1-U  
PCU6E9~t2  
} % ,X(GwX  
'WOWm$2  
QK@z##U  
public static void main(String[] args) wHY;Y-(ZT  
{ :N[2*
.c[  
new TestMethod();  /!9949XV  
} s9'iHe  
} HD`%Ma Yhc  
点击下载更多相关资料