http断点续传简单实现（java)

/* b8O }XB  
**SiteFileFetch.java j"4]iI+{"  
*/ 8h{;*Wr-  
package NetFox; 1\LK[tvh  
import java.io.*; @tfatq+q  
import java.net.*; /I@`B2  
Y{`hRz`  
*USzzLq  
public class SiteFileFetch extends Thread { XJguw/[wm  
q6T>y%|FZ  
Pm=i(TBS/  
SiteInfoBean siteInfoBean = null; //文件信息Bean eFz!`a^dX  
long[] nStartPos; //开始位置 52v@zDY  
long[] nEndPos; //结束位置 A5 <T7~U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rXF=/  
long nFileLength; //文件长度 (@3?JJ]1  
boolean bFirst = true; //是否第一次取文件 hNL_e3  
boolean bStop = false; //停止标志 J]gtgt^   
File tmpFile; //文件下载的临时信息 ZK?:w^Z  
DataOutputStream output; //输出到文件的输出流 j=V2~ xA6  
Lv<)Dur0K  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _n12Wx{  
public SiteFileFetch(SiteInfoBean bean) throws IOException FX&)~)  
{ lfe^_`ij(+  
siteInfoBean = bean; e)Pm{:E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'l41];_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Vd+5an?  
if(tmpFile.exists ()) &^JYIRn1\  
{ ibxtrt=  
bFirst = false; yiAusl;  
read_nPos(); Zoyo:vv&  
} z\6/?5D#
v  
else k}908%w  
{ kT,2eel  
nStartPos = new long[bean.getNSplitter()]; 1g1gu=|Q  
nEndPos = new long[bean.getNSplitter()]; B[{Ie G'  
} ^SJa/I EZ.  
|X0Ys8f  
mP+rPDGp  
[+ N 5  
} qp`G5bw  
.9u,54t  
Sp~gY]:  
public void run() 2\
L}Ka|v  
{ fS- 31<?  
//获得文件长度 h@D</2>  
//分割文件 .ta*M{t  
//实例FileSplitterFetch xyaU!E*  
//启动FileSplitterFetch线程 SO}en[()O  
//等待子线程返回 Z<~^(W7h  
try{ Nbm=
;FHB`  
if(bFirst) c[E>2P2-_  
{ F
<^93a9  
nFileLength = getFileSize(); 90]{4]y;  
if(nFileLength == -1) Nk/Ms:57y  
{ c69M   
System.err.println("File Length is not known!"); Jm{~H%  
} R:FyCT_,  
else if(nFileLength == -2) hP]zC1s  
{ %{K6
 
System.err.println("File is not access!"); &Vi0.o  
} sAKQ.8$h*  
else #Cz6
c%yK  
{ t.td
Y  
for(int i=0;i<nStartPos.length;i++) hXM2B2[  
{ MESPfS+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); A}Gj;vaw  
} ^p!4`S  
for(int i=0;i<nEndPos.length-1;i++)
{1j[RE  
{ D[iIj_CKQ  
nEndPos = nStartPos[i+1]; "Gm:M  
} fP 5!`8  
nEndPos[nEndPos.length-1] = nFileLength; ?.&?4*u  
} p!w}hB598  
} k.CHMl]  
oO)KhA?y  
k%v/&ojI  
//启动子线程 l5d> YTK+5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,wlSNb@'  
for(int i=0;i<nStartPos.length;i++) TAn.5 wH9t  
{ w=H4#a?fc  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SsF 5+=A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M[ZuXH}  
nStartPos,nEndPos,i); mca9 +v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jw!QjVuRN%  
fileSplitterFetch.start(); @5-+>\Hd^t  
}  /,Sd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vaEAjg*To<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tXIre-. 2}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Oz1ou[8k  
nEndPos = " + nFileLength); /+F|+1   
// fileSplitterFetch[nPos.length-1].start(); Fttny]  
4ng*SE_  
P$|DiiH  
//等待子线程结束 mmn1yX:d  
//int count = 0; k^PqB+P!  
//是否结束while循环 (B zf
~#]~  
boolean breakWhile = false;  YErn50L  
7F{=bL  
@tLoU%  
while(!bStop) ^2PQ75V@.  
{ lC|{{?m  
write_nPos(); +/Lf4??JV  
Utility.sleep(500); fKY1=3  
breakWhile = true; ~-w  
<#9zc'ED:  
/@bLc1"  
for(int i=0;i<nStartPos.length;i++) K!9rH>`\  
{ |V|)cPQ  
if(!fileSplitterFetch.bDownOver) tK|hC[  
{ cMEM}Qh T  
breakWhile = false; vAE?^*F  
break; 5B<G;if,  
} kty,hAXe  
} Px4zI9;cB  
if(breakWhile) u?
f3&pA  
break; #dGg !D  
\[+\JWJj  
"Rp]2'?  
//count++; dkQA[/k  
//if(count>4) nA]dQ+5sT  
// siteStop(); C"IP1N  
} Hvq< _&2  
7=ZB;(`L1  
xUD$i?3z  
System.err.println("文件下载结束！"); F*
d{<  
} u[jdYWQa  
catch(Exception e){e.printStackTrace ();} 2r~ Nh](  
} <>JDA(F"  
>gr6H1  
!P!|U/|c  
//获得文件长度 [VPqI~u5)  
public long getFileSize() ytmlG%  
{ ~^"cq S(  
int nFileLength = -1; w I@ lO\  
try{ [21tT/  
URL url = new URL(siteInfoBean.getSSiteURL()); ~::gLm+f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9&W\BQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); =k[!p'~jD  
3RRZVc* ^  
" I@Z:[=2  
int responseCode=httpConnection.getResponseCode(); ^U_B>0`ch  
if(responseCode>=400) $XI5fa4Tt  
{ _pNUI{De  
processErrorCode(responseCode); "7)F";_(^  
return -2; //-2 represent access is error kx1-.~)p(z  
} d~|qx  
^D B
0C  
;<q@>p[  
String sHeader; l{Hi5x'H  
{F k]X#j  
"MXd!  
for(int i=1;;i++) )}c$n  
{ Vb 4Qt#o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ]'_z(s}  
//Utility.log(in.readLine()); US7hKNm.  
sHeader=httpConnection.getHeaderFieldKey(i); _jZDSz|Yb  
if(sHeader!=null) Q$,8yTM  
{ nwN<Q\]S  
if(sHeader.equals("Content-Length")) KX<RD|=  
{ jVRd[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); } 2)s%  
break; uB,B%XHj  
} !4jS=Lhe>  
} oqDW}>.  
else %e%nsj6  
break; 8XJ%Yuu  
} @;<w"j`r  
} ]jHB'Y  
catch(IOException e){e.printStackTrace ();} Y=3Y~  
catch(Exception e){e.printStackTrace ();} 1}8e@`G0.]  
_ksp;kH?)  
v!F(DP.)Z  
Utility.log(nFileLength); V6$v@Zq  
.<42-IEc  
~*
B1}#;  
return nFileLength; z7PPwTBa  
} lGLZIp  
RFK N,oB  
\k1Wh-3  
//保存下载信息（文件指针位置） x2ol  
private void write_nPos() RV(}\JU  
{ +Kq>r|;  
try{  74Q?%X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); g>im2AD+e  
output.writeInt(nStartPos.length); o3WkbMJWM  
for(int i=0;i<nStartPos.length;i++) Z^fF^3x  
{ ~hvhT}lE  
// output.writeLong(nPos); e-}PJ%!,T  
output.writeLong(fileSplitterFetch.nStartPos); aYj3a;EmU  
output.writeLong(fileSplitterFetch.nEndPos); 8:&@MZQ&!  
} TVFGonVY  
output.close(); ,XA;S5FE  
} Pm?6]] 7  
catch(IOException e){e.printStackTrace ();} )%tf,3  
catch(Exception e){e.printStackTrace ();} s*l_O*$'  
} 2s{yg%U(  
R9CAw>s  
CYrL|{M]  
//读取保存的下载信息（文件指针位置） XbH X,W$h  
private void read_nPos() _u:#2K$  
{ <![T~<.  
try{ ZY/at/v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;C"J5RA  
int nCount = input.readInt(); p-7dJ  
nStartPos = new long[nCount]; ;%jt;Xv9  
nEndPos = new long[nCount]; /BIPLDN6  
for(int i=0;i<nStartPos.length;i++) If&p$pAH?  
{ kcYR:;y  
nStartPos = input.readLong(); M}5C;E*  
nEndPos = input.readLong(); THua?,oyW  
} 7k$8i9#  
input.close(); _+;x4K;  
} z{n=G  
catch(IOException e){e.printStackTrace ();} S&=B&23T  
catch(Exception e){e.printStackTrace ();} !X
.N$0  
} by06!-P0[  
Ti)n(G9$  
0"QE,pLe4  
private void processErrorCode(int nErrorCode) Zka;}UL&Q  
{ g]ihwm~  
System.err.println("Error Code : " + nErrorCode); =;{S>P!I(t  
} Z9sg6M@s  
m|7g{vHVV  
NFSPw`f  
//停止文件下载 u51/B:+  
public void siteStop() hNoN=J  
{ ^Ue.9#9T&g  
bStop = true; c"z%AzUV'  
for(int i=0;i<nStartPos.length;i++) 9/%|#b-z  
fileSplitterFetch.splitterStop(); rb_G0/R  
ZE
\t{s0  
v[|iuOU  
} 9]YmP8  
} n)=&=Uj`f  
//负责部分文件的抓取 \D[BRE+  
**FileSplitterFetch.java Qxvz}r.l]  
*/ QAJ>93  
package NetFox; @KpzxcEoO  
7uDUZdJy  
vn_avYwiy  
import java.io.*; @!MbPS  
import java.net.*; foFn`?LF  
X%-4x  
wd]Yjr#%Ii  
public class FileSplitterFetch extends Thread { 
t!=S[  
<7&b|f$CL  
vK{K#{  
String sURL; //File URL "_l[4
o[D  
long nStartPos; //File Snippet Start Position )} #r"!  
long nEndPos; //File Snippet End Position ]d[q:N]z  
int nThreadID; //Thread's ID +|?c_vD  
boolean bDownOver = false; //Downing is over  A:!{+  
boolean bStop = false; //Stop identical >r*Zm2($MR  
FileAccessI fileAccessI = null; //File Access interface j;y|Ys)I  
c1<g!Q&E  
u<8Q[_E&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &qU[wn:1  
{ ~9c9@!RA2  
this.sURL = sURL; aj,ZM,Ad  
this.nStartPos = nStart; y,x~S\>+  
this.nEndPos = nEnd; Gt%ko
k  
nThreadID = id; O>Sbb2q?"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 QCo^#-   
} =,'Z6?%p  
gMvvDP!Wp  
9j"\Lr*o"  
public void run() Z~|J"2.  
{ QEgv,J{  
while(nStartPos < nEndPos && !bStop) 9N29dp>g{{  
{ .3&m:P8zV  
xr/k.Fz  
st2>e1vg  
try{ s`B'v
yoaa  
URL url = new URL(sURL); p\WUk@4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $!f$R`R^Q\  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~<%cc+;`  
String sProperty = "bytes="+nStartPos+"-"; )yP>}ME  
httpConnection.setRequestProperty("RANGE",sProperty); F"=MU8  
Utility.log(sProperty); fz&}N`n  
kUt9'|9!  
_#O?g=1  
InputStream input = httpConnection.getInputStream(); #r:`bQ0;  
//logResponseHead(httpConnection); ,2`d3u^CW  
fh^_=R(/  
~roHnJ>  
byte[] b = new byte[1024]; +XE21hb   
int nRead; a}K+w7VY\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ASvPr*q/  
{ 3$8}%?i  
nStartPos += fileAccessI.write(b,0,nRead); [1C#[Vla  
//if(nThreadID == 1) f#~Re:7.c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ge[i&,.&z  
} 
7N"Bbl  
["}A#cO652  
IT(c'}  
Utility.log("Thread " + nThreadID + " is over!"); M\&~Dmd  
bDownOver = true; UjaC( c  
//nPos = fileAccessI.write (b,0,nRead);  ~^S-  
} z aF0nov  
catch(Exception e){e.printStackTrace ();} mSfhl(<L  
} =oME~oB~  
} S;'eoqN8  
/aqN`  
EVFfXv^  
//打印回应的头信息 (UZ*36@PJx  
public void logResponseHead(HttpURLConnection con) u-_$?'l;~  
{ 7gwZ9Fob  
for(int i=1;;i++) IdxToMr  
{ 4AYc8Z#'  
String header=con.getHeaderFieldKey(i); Xoy1Gi?  
if(header!=null) zq.&Mw
?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]3xa{h~4  
Utility.log(header+" : "+con.getHeaderField(header)); dYd~9  
else WDdi}i>2  
break; E/ZJ\@gzD  
} ]eW|}V7A:  
} 1Ol]^'y7)  
}|Tg_+   
LrMFzd}_O  
public void splitterStop() -y?Z}5-rs  
{ h'~-K`  
bStop = true; !yX<v%>_0  
} >U<nEnB$?  
yk<jlVF$j  
N o(f0g.  
} 2.D!4+&  
/8}+#h)[  
_oTT3[7P  
/* x\.i`ukx  
**FileAccess.java >k}/$R+  
*//文件访问(定位，写) Y:%)cUxA  
package NetFox; 2\{uqv  
import java.io.*; cJEz>Z6[  
dyzwJ70K  
]7kGHIJ|  
public class FileAccessI implements Serializable{ s;s-6%p  
|WU`p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 nnL$m_K~  
RandomAccessFile oSavedFile; oks=|'&  
long nPos; x{
>Y$t]  
iBQBHF   
W \}}gIEM+  
public FileAccessI() throws IOException 7;'.5,-3c  
{ XDko{jEJ  
this("",0); )8 :RiG2B  
} xH_ie  
_(`X .D  
mN{ajf)@  
public FileAccessI(String sName,long nPos) throws IOException B"m:<@ "  
{ =9 M|o0aY  
oSavedFile = new RandomAccessFile(sName,"rw"); :.o=F
`W  
this.nPos = nPos; T[h}A"yK;  
oSavedFile.seek(nPos); -\'.JA_  
} qTHg[sME  
l5';?>!s  
p@8krOo`  
public synchronized int write(byte[] b,int nStart,int nLen) kgI=0W>  
{ @P"`=BU&  
int n = -1; o+-Ge J  
try{ >|/? Up  
oSavedFile.write(b,nStart,nLen); udD*E~1q  
n = nLen; 7G[ GHc>  
} #)mkD4  
catch(IOException e) [gkRXP[DGs  
{ A Ok7G?Y  
e.printStackTrace (); h0GdFWN  
} /P!X4~sTM  
wYQ1Z  
9Ir~X|}\iL  
return n; y-<PsP-I  
} B:- KZuO  
|369@un6  
O\?5#.   
} IEoR7:  
;}eEG{`Y  
A,lw-(.z4Z  
/* ss`q{ARb  
**SiteInfoBean.java k;fnC+Y$s  
*/ 2x`xyR_Q.R  
package NetFox; -{8Q= N  
im\YL<  
a&s"#j  
public class SiteInfoBean { QE#-A@c  
( X 'FQ  
/ik)4]>  
private String sSiteURL; //Site's URL jO&f*rxN  
private String sFilePath; //Saved File's Path Gp
^ owr  
private String sFileName; //Saved File's Name TtwJ,&b  
private int nSplitter; //Count of Splited Downloading File  Z|:_c  
Og$eQS  
}`9fZK{. @  
public SiteInfoBean() e(n2+S#N  
{//nSplitter的缺省值为5 RM^?&PM85  
//default value of nSplitter is 5 0$"Q&5Y  
this("","","",5); Nx4DC  
} c;21i;&,9  
`!,\kc1  
v[,v{5b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >^T,U0T])  
{ |P. =  
sSiteURL= sURL; n$hqNsM  
sFilePath = sPath; HV*:<2P%D  
sFileName = sName; E%k ]cZ  
this.nSplitter = nSpiltter; `FYtiv?G  
Ng."+&  
XU;{28P  
} 4lY&=_K[)  
@}&,W N%  
uD ?I>7  
public String getSSiteURL() p9&gEW  
{ 3)C6OF>7  
return sSiteURL; OP|.I._I  
} xyS2_Q  

8V=HyF#  
v E3{H  
public void setSSiteURL(String value) f>s#Ngvc  
{ )WP]{ W)r  
sSiteURL = value; >uyeI&z  
} c69U1  
r?"}@MRW  
1&8j3"  
public String getSFilePath() l${Hgn+  
{ h=v[i!U-eY  
return sFilePath; [NCXn>Z  
}  +eDN,iv  
s]F?=yEp  
}"&n[/8~  
public void setSFilePath(String value) f*|8n$%  
{ ubzb  
sFilePath = value; {
hvQ<7b  
} fz<|+(_>J  
EBj,p
k5M  
d739UhKC  
public String getSFileName() r|\5'ZMx  
{ 7E!";HT  
return sFileName; [Q7->Wo|S:  
} k Z+q  
o7c%\v[  
8`AcS|k  
public void setSFileName(String value) 9&[)(On74  
{ fR]p+\#8u*  
sFileName = value; E,*JPK-A x  
} !~lVv&YO  
3P+4S|@q(4  
nJldz;  
public int getNSplitter() z^ aCQ3E  
{ NSMjr_  
return nSplitter; Pg*?[^*  
} abTDa6 /`v  
|aI|yq)  
IL+#ynC  
public void setNSplitter(int nCount) 
4DQ07w  
{ RQj`9F  
nSplitter = nCount; xVsa,EX b  
} ;uM34^  
} ,-cpsN  
u=d`j  
v5&xY2RI7  
/* lgCHGv2@  
**Utility.java D+ah ok  
*/ Hl^aUp.c  
package NetFox; VL_)]LR*)  
4f{[*6 GX  
k8InbX[  
public class Utility { 2|0Je^$|  
;H7EB`  
q5:0&:m$4$  
public Utility() wo7N7R5  
{ '|YtNhWZ?  
K:>NGGY8r  
L<f-Ed9|  
} tl{]gz  
ql!5m\  
//线程睡眠 p/ziFp
U  
public static void sleep(int nSecond) Ek"YM[  
{ vO}qjw  
try{ Ap F*a$),  
Thread.sleep(nSecond); *ajFZI  
} !7:EE,W~  
catch(Exception e) ]iz_w`I\  
{ q=P f^Xp  
e.printStackTrace (); 652uZ};e  
} bjM-Hd/K  
} 8eOl@}bV  
'sm[CNzS  
//日志 ~u_K&X  
public static void log(String sMsg) 17V\2=Io  
{ c^
ixdk  
System.err.println(sMsg); &_Cxv8  
} paq8L{R  
;el]LnV!O  
5S&aI{;9<  
public static void log(int sMsg) q Axf5  
{ B]'e$uyL7  
System.err.println(sMsg); Tjd&^m  
} [=XZza.z  
} v;)BVv  
<ldid]o #  
c+szU}(f6(  
/* .Lr`j8  
**TestMethod.java :@:g*w2K  
*/ QT`fix{  
package NetFox; pu\b`3C(  
#D!$~h&i  
20 jrv'f  
public class TestMethod { S 3{Dn  
7ZF}0K$^B  
O"@?U  
public TestMethod() c_~XL^B@  
{ ///xx/weblogic60b2_win.exe =ied}a :[  
try{ I?f"<5[0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0^J*+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K&j'c  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z`\#$  
fileFetch.start(); bcq@N  
} -(6eVI  
catch(Exception e){e.printStackTrace ();} .[edln  
PLO\L
W  
"F&Tnhh4  
} LTg?5GwD\j  
\ua9thO
G  
kFS0i%Sr  
public static void main(String[] args) jFgZ}Xp  
{ cNdu.c[@  
new TestMethod(); L=d$"Q  
} a^@+%?X  
} r`?&m3IOP
 
点击下载更多相关资料