http断点续传简单实现（java)

/* h?M'7Lti  
**SiteFileFetch.java \["1N-q b  
*/ fte!Ll'  
package NetFox; X*D5y8<  
import java.io.*; Z.Lx^h+U  
import java.net.*; WcQZFtW  
=t <:zLe  
Vz+=ZK r5  
public class SiteFileFetch extends Thread { =D;UMSf  
]*t*/j;N  
E$oA+n~  
SiteInfoBean siteInfoBean = null; //文件信息Bean R;N>#_9HU  
long[] nStartPos; //开始位置 *&~sr  
long[] nEndPos; //结束位置 Bil;@,Z#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M]pel\{M  
long nFileLength; //文件长度 A_8`YN"Xk  
boolean bFirst = true; //是否第一次取文件 `RL(N4H  
boolean bStop = false; //停止标志 $/-wgyP3m+  
File tmpFile; //文件下载的临时信息 gDjd{+LUo  
DataOutputStream output; //输出到文件的输出流 f^>lObvd  
UwzE'#Q-  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） X_EC:GU  
public SiteFileFetch(SiteInfoBean bean) throws IOException vs)HbQ  
{ g@N=N  
siteInfoBean = bean; <'+R%6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fM zAf3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P,LXZ  
if(tmpFile.exists ()) I NFzX  
{ V9);kD  
bFirst = false; "J0Oa?  
read_nPos(); l)2HHu<  
} kKI!B`j=  
else 6='_+{   
{ z;Gbqr?{{  
nStartPos = new long[bean.getNSplitter()]; 7m@^=w  
nEndPos = new long[bean.getNSplitter()]; zrWq!F*-V\  
}  K{7S  
)x5$io   
"m\UqQGX  
3IRRFIiO  
} cC(ubUR  
FK/ro91L  
9x 6ca  
public void run() 1Tts3O.  
{ U_=wL  
//获得文件长度 n=Z[w5  
//分割文件 GurE7J^=  
//实例FileSplitterFetch 5i wikC=y  
//启动FileSplitterFetch线程 cWy*K4O  
//等待子线程返回 71.:p,Z@z  
try{ <o"D/<XnB3  
if(bFirst) kAKqW7,q"  
{ ,nuDoc  
nFileLength = getFileSize(); .\hib.n3  
if(nFileLength == -1) PxCl]~v  
{ M,v@G$pW  
System.err.println("File Length is not known!"); 4<K ,w{
I  
} LMhY"/hAXa  
else if(nFileLength == -2) j#.-MfB  
{ D;T r  
System.err.println("File is not access!"); FZ'>LZ  
} l%)=s~6z  
else yvH#1F`{q  
{ IQ27FV|3  
for(int i=0;i<nStartPos.length;i++) QP-<$P;~  
{ -EX3' [*'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =.=. \K  
} \]d*h]Hms  
for(int i=0;i<nEndPos.length-1;i++) 8b#Yd  
{ <LA`PbQa  
nEndPos = nStartPos[i+1]; h-v&I>  
} w[$Wpae  
nEndPos[nEndPos.length-1] = nFileLength; ![."xHVeL  
} ZJJl944  
} ,uD*FSp>  
G5
eLs  
7>e~i,  
//启动子线程 Y=wP3q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Vp0GmZ  
for(int i=0;i<nStartPos.length;i++) 
S.)8&  
{ -QNMB4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c75vAKZ2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3YNkT"~T  
nStartPos,nEndPos,i); Up2\X#6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \gW\Sa ^  
fileSplitterFetch.start(); /;(%Xd&:  
} zR/p}Wu|!  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MZ+IorZl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SO jDtZ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", HjY-b*B  
nEndPos = " + nFileLength); 7g<`wLAH  
// fileSplitterFetch[nPos.length-1].start(); {XUfxNDf  
J?=Ob?+ _  
pQ2)M8 gf  
//等待子线程结束 XU })3]/  
//int count = 0; @p'v.;~#  
//是否结束while循环 \?ws0Ax  
boolean breakWhile = false; X52jqXjg  
4lKbw4[a  
Gw\HL  
while(!bStop) r.G/f{=<@  
{ KD3To%  
write_nPos(); a0j.\g  
Utility.sleep(500); dfkTDG+
 
breakWhile = true; {q>4:lsS  
b2@x(5#  
e~~k}2~  
for(int i=0;i<nStartPos.length;i++) _e@qv;*  
{ F'_8pD7  
if(!fileSplitterFetch.bDownOver) <rI$"=7  
{ z=h5  
breakWhile = false; a} fS2He  
break; }Knq9cf  
} (uxQBy  
} =y(YMWGS  
if(breakWhile) _G*x:<  
break; 3g "xm  
TF3q?0  
}8]uZ)[p=  
//count++; 5J#gJFA  
//if(count>4) nv[Sb%/  
// siteStop(); ,* vnt6C*  
} s3RyLT
 
'\mZ7.Jj  
9}Ave:X^  
System.err.println("文件下载结束！"); {3uSg)  
} "RX5] eJc\  
catch(Exception e){e.printStackTrace ();} iOXP\:mPo  
} $u.T1v  
|g^W @.P  
s!!t  
//获得文件长度 eii7pbc  
public long getFileSize() m%(JRh  
{ PC7.+;1  
int nFileLength = -1; )Ua2x@j'C@  
try{ z4+6k-#):  
URL url = new URL(siteInfoBean.getSSiteURL()); 9wJmX<Rm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v@
s`l#  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;{7lc9uRj  
s(9rBDoY(8  
y#0Z[[I0  
int responseCode=httpConnection.getResponseCode(); d_qVk4h
\  
if(responseCode>=400) ;xH'%W9z  
{ c,%>7U(w_  
processErrorCode(responseCode); G[-jZ  
return -2; //-2 represent access is error f?^xh  
} Xz@;`>8i  
tf79Gb>  
nt`l6b  
String sHeader; RSeezP6#  
qNVw+U;2P  
uvM88#  
for(int i=1;;i++) )Bvu[rUy  
{ >A "aOV>K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LVtQ^ 5>8  
//Utility.log(in.readLine());  o%4+I>  
sHeader=httpConnection.getHeaderFieldKey(i); ul&7hHp_u%  
if(sHeader!=null) htSk2N/  
{ #_|^C(]!  
if(sHeader.equals("Content-Length")) HON[{Oq  
{ 54j $A  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .7rsbZzs  
break; GV[BpH  
} | N,nt@~  
} HliY  
else =gyK*F(RK  
break; 5h7DVr!  
} 7+-}8&syu  
} Rp9iX~A`e  
catch(IOException e){e.printStackTrace ();} S60`'!y  
catch(Exception e){e.printStackTrace ();} sgsMlZ3/  
<W^~Y31:0  
KePHn:c  
Utility.log(nFileLength); 0].5[Jo  
'Em($A(  
Di=6.gm[<  
return nFileLength; O]!DNN  
} DcDGrRuh  
5X-{|r3q  
!]T|=yw  
//保存下载信息（文件指针位置） '(>N gd[  
private void write_nPos() ?`}U|]c  
{ t\0JNi$2  
try{ m_f^#:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t!N>0]:mo  
output.writeInt(nStartPos.length); 39eoL;O_  
for(int i=0;i<nStartPos.length;i++) ^i7a2< z  
{ `Yve  
// output.writeLong(nPos); 4D
$E  
output.writeLong(fileSplitterFetch.nStartPos); Q+N @j]'  
output.writeLong(fileSplitterFetch.nEndPos); Y" |U$  
} w$H
C!  
output.close(); w]XBq~KO  
} IrM3Uh  
catch(IOException e){e.printStackTrace ();} kS!*kk*a  
catch(Exception e){e.printStackTrace ();} % m$Mnx  
} zg"ZXZ  
5%/%i}e~(  
ArMe[t0$  
//读取保存的下载信息（文件指针位置） GMI>$$<  
private void read_nPos() a$A S?`L  
{ $6Psq=|  
try{ i:To8kdO  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `Y9@?s Q  
int nCount = input.readInt(); b,`N;*  
nStartPos = new long[nCount]; Wc[)mYOSuO  
nEndPos = new long[nCount]; AU2Nmf?]%  
for(int i=0;i<nStartPos.length;i++) ibL;99#  
{ T]k@g_  
nStartPos = input.readLong(); r|8..Ll  
nEndPos = input.readLong(); ``D-pnKK  
} tzPe*|m<  
input.close(); Hqv(X=6E0  
} i^Q^F  
catch(IOException e){e.printStackTrace ();} cl5:|)  
catch(Exception e){e.printStackTrace ();} <L0_<T  
} C^'}{K  
3]A'C&  
KxI(#}5o&  
private void processErrorCode(int nErrorCode) SY.V_O$l}  
{ 5O*$#C;c  
System.err.println("Error Code : " + nErrorCode); nAOId90wue  
} g}7%3D  
QG ia(  
#4?3OU#  
//停止文件下载 \WEC1+@  
public void siteStop() MI3_<[  
{ &nn":  
bStop = true; $TiAJ}:  
for(int i=0;i<nStartPos.length;i++) ,P]{*uqGiB  
fileSplitterFetch.splitterStop(); lC{m;V2  
Wit1WI;18  
Pc-HQU  
} C_o.d~xm  
} ektFk"W3A\  
//负责部分文件的抓取 r\?*?sL  
**FileSplitterFetch.java iuRXeiG8  
*/ UlR7_  
package NetFox; 2t%)d9r32  
Gl(,%~F9i  
420K fVA  
import java.io.*; +=v|kd  
import java.net.*; A2 rRYzN;  
v?J2cL  
l!2.)F`x  
public class FileSplitterFetch extends Thread { $onliW|  
3/D fsv  
)U?W+0[=  
String sURL; //File URL ~ i,my31  
long nStartPos; //File Snippet Start Position  [iz  
long nEndPos; //File Snippet End Position TzjZGs W[V  
int nThreadID; //Thread's ID l1msXBC  
boolean bDownOver = false; //Downing is over Fwtwf{9I  
boolean bStop = false; //Stop identical ~Km8-b(&  
FileAccessI fileAccessI = null; //File Access interface $vd._j&  
`1dr$U  
[dUEe@P  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Mmn[ol
  
{ ) PtaX|U  
this.sURL = sURL; +4 dH
aj6  
this.nStartPos = nStart; e3.TGv7=  
this.nEndPos = nEnd; ;
6Z?O_zp4  
nThreadID = id; SJfsFi?n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -M:.D3,L  
} Wp ]u0w  
5 m:nh<)#  
?hO*~w;UU|  
public void run() pa7fTd  
{ Hmz[pTQ|87  
while(nStartPos < nEndPos && !bStop) *Z(qk`e.b  
{ ^gy(~u  
8EQ;+V  
|2Dlw]d  
try{ mdwY48b  
URL url = new URL(sURL); ck;owGlT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3N-(`[m{E  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6 J#C  
String sProperty = "bytes="+nStartPos+"-"; yq2Bz7P  
httpConnection.setRequestProperty("RANGE",sProperty); Nt)9-\T  
Utility.log(sProperty); D6D*RT
i4  
9Rpj&0Is  
m@~HHwj  
InputStream input = httpConnection.getInputStream(); /*[a>B4-q  
//logResponseHead(httpConnection); V6c?aZ,O  
#RcmO*
*  
q?6Zu:':  
byte[] b = new byte[1024]; /dO&r'!:  
int nRead; drH!?0Dpg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }I]9I _S  
{ ][.1b@)qV  
nStartPos += fileAccessI.write(b,0,nRead); 3Xy>kG}  
//if(nThreadID == 1) @{j-B IRZ0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?r/7:  
} lD(d9GVm{z  
X6PfOep  
j \SDw  
Utility.log("Thread " + nThreadID + " is over!"); W[b/.u5z:  
bDownOver = true; 2- )Ml*  
//nPos = fileAccessI.write (b,0,nRead); l{
k  
} 'lWNU  
catch(Exception e){e.printStackTrace ();} nV'B!q  
} R1U\/  
} iS{)Tll}&  
1oC/W?l^  
0-QkRr_I  
//打印回应的头信息 79&Mc,69  
public void logResponseHead(HttpURLConnection con) YO=;)RA  
{ KxvT}"k  
for(int i=1;;i++) +_+_`q>]  
{ ym:JtI69   
String header=con.getHeaderFieldKey(i); 4;
_.|!LN  
if(header!=null) r`lgK2r\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sbgRl%  
Utility.log(header+" : "+con.getHeaderField(header)); ;qvZ*  
else b{(:'.  
break; Q.nEY6B_  
} CnO$xE|{  
} xx%WIY:}  
r+>9O  
1~j.jv
$  
public void splitterStop() 3p7*UVR"  
{ thOCzGJ$  
bStop = true; p@P[pzxI  
} X,~8) W  
4}gwMjU-B  
Odagaca  
} am`eist:  
J9/w_,,R$  
f}*Xz.[bCp  
/* E_$ST3  
**FileAccess.java %e_WO,R  
*//文件访问(定位，写) U9Y'eP.2  
package NetFox; u+{5c5_  
import java.io.*; r,F'Jd5  
(33[N  
l.C{Ar  
public class FileAccessI implements Serializable{ ]t<%v_K  
/+'@}u |  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -5.>9+W8I  
RandomAccessFile oSavedFile; j&8U:Q,  
long nPos; MEg|AhP  
9~a_^m/  
~]N% {;F}  
public FileAccessI() throws IOException 2PRGwK/  
{ ctj.rC)6n  
this("",0); j+s8V-7(  
} u6I# D _  
7 0KZXgBy_  
rsrv1A=t?  
public FileAccessI(String sName,long nPos) throws IOException .3$iOMCH  
{ N#|c2n+  
oSavedFile = new RandomAccessFile(sName,"rw"); /bg8oB4  
this.nPos = nPos; brZ3T`p+.P  
oSavedFile.seek(nPos); wp$SO^?-  
} H.'_NCF&;L  
Lc+)#9*d  
iTD{  
public synchronized int write(byte[] b,int nStart,int nLen) =PXNg!B}D*  
{ N$pO] p  
int n = -1; 9n$$D;  
try{ I4u'b?* je  
oSavedFile.write(b,nStart,nLen); |U12fuQ  
n = nLen; |`#[
jHd  
} Ie``Wb=  
catch(IOException e) p_tMl%K  
{ P^+Og_$  
e.printStackTrace (); *,mbZE=<  
} u{8Wu;  
tw^V?4[Miu  
5JQq?e)n  
return n; cpf8f i  
} ~ 5`Ngpp  
3"%:S_[  
60-LpGhvy  
} *_U z**M  
QD7>S(p  
uI.4zbgl[  
/* C!v0*^i  
**SiteInfoBean.java `4XfT.9GT  
*/ k5W5 9tz  
package NetFox; uPb9j;Q?  
s|dL.@0,L  
A
Q@A$  
public class SiteInfoBean { )p(XY34]  
))u$j4V  
/ZX8gR5x  
private String sSiteURL; //Site's URL J>x)J}:;  
private String sFilePath; //Saved File's Path :N(L7&<
 
private String sFileName; //Saved File's Name 61CNEzQ  
private int nSplitter; //Count of Splited Downloading File HnZrRHT0  
{{:MJ\_"h_  
("wPkm^  
public SiteInfoBean() CEt_wKzf  
{//nSplitter的缺省值为5
|(Io(e  
//default value of nSplitter is 5 \U p<m>3
\  
this("","","",5); I5PaY.i  
} 2
L ~U^  
lYU_uFOs\  
RQv`D&u_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ykM(` 1`m  
{ W>'R<IY4#N  
sSiteURL= sURL; s|YY i~  
sFilePath = sPath; R>#T{<<L  
sFileName = sName; t:$p8qR  
this.nSplitter = nSpiltter; t4h5R  
6<FJ`l]U9  
E9QNx62  
} 7vgz=- MZ#  
dEns|r  
si0jXue~j\  
public String getSSiteURL()  XW`&1qx  
{ ^i#F+Q`1  
return sSiteURL; QfRt3\^`  
} mLKwk6I  
liPUK#  
^hTq~"  
public void setSSiteURL(String value) YgrBIul  
{ '^}l|(  
sSiteURL = value; Ch^Al2)=  
} G,$RsP  
%;9wToyK>  
|\Jpjm)?  
public String getSFilePath() 2~~Q NWN  
{
z&9vKF  
return sFilePath; w9l)=[s=  
} ?zKDPBj  
*}cF]8c5W  
MZ6?s(mkx  
public void setSFilePath(String value) '9H]SEw  
{ MX6;ww  
sFilePath = value; `fc2vaSH =  
} O>)8< yi$  
&PgbFy  
*_3+ DF  
public String getSFileName() /k(0}g=\  
{ :1=
mNrg  
return sFileName; Jc:*X4-'  
} .Mdxbs6.C  
D@FJVF7c  
L0_R2EA  
public void setSFileName(String value) u%3Z +[  
{ \<a(@#E*~  
sFileName = value; qtD3<iWV  
} #2{ };)  
``K.4sG  
-E?h^J&U  
public int getNSplitter() !~"q$T>@  
{ UvxJ _  
return nSplitter; I4gyGg$H  
} YjoN:z`b  
Of SYOL7o  
i{ eDV  
public void setNSplitter(int nCount) ,z<\Z!+=  
{ %)u5
A!"  
nSplitter = nCount; \c_1uDRoUn  
} ZSU;>&>%v  
} qbFzA i  
yd2v_  
>:!TfuU^R  
/* JEL=,0J  
**Utility.java Yv\.QrxPm  
*/ awQf$  
package NetFox; =W"BfG  
v|C)Q %v  
* xdS<  
public class Utility { !2s< v
 
Nc:, [8{l  
OM*N)*  
public Utility() ;Y5"[C9|  
{ _Il/ i&  
4h\MSTF*  
QijEb  
} $m]~d6  
n*(Vf'k  
//线程睡眠 d?C8
rkV'  
public static void sleep(int nSecond) qRT1Wre 3  
{ `d2}>  
try{ )eop:!m  
Thread.sleep(nSecond); }\k"azQ`  
} ^o}!=aMr  
catch(Exception e) Pf5RlpL:p  
{ &2C6q04b  
e.printStackTrace (); ~gQ$etPd  
} .<}(J#vC  
} z1X
Fc*5  
kFZw"5hb  
//日志 PXof-W  
public static void log(String sMsg) h4N!zj[  
{ o65:)z u  
System.err.println(sMsg); {Hm0Q  
} u;18s-NY  
%wn|H>  
%p6"Sg*  
public static void log(int sMsg) [,e[~J`C  
{ ,rVm81-2  
System.err.println(sMsg); gq~>S1  
} r\Nf309~  
} !7"-9n  
o_ka'|  
`VX]vumG  
/* >MZWm6M8  
**TestMethod.java ac%%*HN,  
*/ o<ak&LX`9  
package NetFox; e0Cr>I5/e  
9AK<<Mge.  
]CsF} wr'z  
public class TestMethod { Z? u\  
]`)50\pdw  
Mk9'  
public TestMethod() pt.0%3  
{ ///xx/weblogic60b2_win.exe UhQ[|c  
try{ XF(0>-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N+%E=D>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ${Cb1|g>j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5RCQ<1  
fileFetch.start(); }UNRe]ft$  
} ieXhOA  
catch(Exception e){e.printStackTrace ();} ]4wyuP,up  
Tn2nd  
>fRI^Q,  
} Q/&H3N  

d~@&*1}  
o"dX3jd  
public static void main(String[] args) w=5D>]  
{ ovJ#2_  
new TestMethod(); m"*j J.MX  
} |fnP@k  
} vn<z\wVbf  
点击下载更多相关资料