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http断点续传简单实现(java)

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/* x{pj`'J)  
**SiteFileFetch.java &{Z+p(3Gj  
*/ hi(b\ ABx  
package NetFox; 5iw\F!op:  
import java.io.*; I'5[8  
import java.net.*; sX"L\v  
ntIR#fB  
%e:+@%]  
public class SiteFileFetch extends Thread { EID-ROMO  
F$UL.`X _/  
1)~|{X+~  
SiteInfoBean siteInfoBean = null; //文件信息Bean OC&BJNOi  
long[] nStartPos; //开始位置 EB3/o7)L  
long[] nEndPos; //结束位置 f&vMv.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !KI^Z1dP(  
long nFileLength; //文件长度 Fg`<uW]TFZ  
boolean bFirst = true; //是否第一次取文件 p*<Jg l  
boolean bStop = false; //停止标志 a4s't% P  
File tmpFile; //文件下载的临时信息 \|>% /P  
DataOutputStream output; //输出到文件的输出流 lat5n&RP Y  
dk7x<$h-h0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /`m* PgJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;Rv WF )  
{ Q&I #  
siteInfoBean = bean; Uh0g !zzp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }XUL\6U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wqG#jC!5  
if(tmpFile.exists ()) yy5|8L  
{ ]y#'U  
bFirst = false; g[~{iu_$d  
read_nPos(); y(DT ^>0  
} 2*sTU  
else &<><4MQ  
{ M[qhy.  
nStartPos = new long[bean.getNSplitter()]; 2sGKn a  
nEndPos = new long[bean.getNSplitter()]; : ;8L1'  
} ^|<>`i6  
kI"9T`owR  
! >F70  
nReIi;pi  
} ! VT$U6  
{+lU4u  
s17)zi,?4  
public void run() r`- 8+"P  
{ T'6`A<`3  
//获得文件长度 l$5nv5r  
//分割文件 6"_pCkn;c<  
//实例FileSplitterFetch 1L`V{\_0s  
//启动FileSplitterFetch线程 @v`.^L{P  
//等待子线程返回 ViW2q"4=  
try{ Ys.GBSlHG  
if(bFirst) .-YE(}^  
{ Yz;7g8HI  
nFileLength = getFileSize(); 3D6&0xTq  
if(nFileLength == -1) 53hX%{3  
{ &B5&:ib1D  
System.err.println("File Length is not known!"); Z,p@toj'  
} d%I7OBBx@  
else if(nFileLength == -2) o~'p&f  
{ qUfoEpW2=6  
System.err.println("File is not access!"); GLIY!BU<C  
} "$N$:B@U  
else jOCV)V9}  
{ F=Xb_Gd`  
for(int i=0;i<nStartPos.length;i++) 3rK\ f4'  
{ *ELU">!}G  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  j=pg5T  
} K Zg NL|  
for(int i=0;i<nEndPos.length-1;i++) O)W+rmToI  
{ t<dFH}U`w  
nEndPos = nStartPos[i+1]; Jt}`oFQ5l  
} :2KPvp 7?  
nEndPos[nEndPos.length-1] = nFileLength; 8Dl(zYK;  
} 1BmKwux:  
} I Tl>HlS  
p9jC-&:  
yT:2*sZRc  
//启动子线程 WZ`i\s1#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~rb]u Ny-  
for(int i=0;i<nStartPos.length;i++) Qq6'[Od  
{ PK|qiu-O&*  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bLS10^g5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6&]Z'nW0k  
nStartPos,nEndPos,i); VsTgK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); auGK2i  
fileSplitterFetch.start(); BEax[=&W  
} |(l]Xr&O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r<kgYU`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LL);Ym9d  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6|lsG6uf  
nEndPos = " + nFileLength); 5mV!mn:H:  
// fileSplitterFetch[nPos.length-1].start(); 8 a)4>B  
9_==C"F  
1?w=v|b:P)  
//等待子线程结束 !4<D^ eh  
//int count = 0; ^O<v'\!z-  
//是否结束while循环 `oe=K{aX  
boolean breakWhile = false; //N="9)@  
YFu>`w^Y  
]gX8z#*k  
while(!bStop) 3~R,)fO;  
{ /$clk=  
write_nPos(); :' 5J[]J  
Utility.sleep(500); y=pW+$k  
breakWhile = true; P(yLRc  
Wgs6}1b g  
sMAj?]hI$  
for(int i=0;i<nStartPos.length;i++) Q7e4MKy7  
{  6p@[U>`  
if(!fileSplitterFetch.bDownOver) nCwA8AG  
{ =c 9nC;C  
breakWhile = false; '4 d4i  
break; ysi=}+F.  
} IAzFwlO9  
} I++ Le%w  
if(breakWhile) .Y2Hd$rs  
break; NRG06M  
q_ ^yma  
$Tv~ *|a  
//count++; ,d*1|oUw  
//if(count>4) A",}Ikh='`  
// siteStop(); oj.J;[-  
} G:1QXwq\j  
]#DCO8Vk  
u(yN81  
System.err.println("文件下载结束!"); Ohj^Z&j  
} b00$3,L   
catch(Exception e){e.printStackTrace ();} EdqB4-#7  
} _t"[p_llo  
fe<7D\Sp@  
Y=|20Y\K  
//获得文件长度 2%fzRXhu%  
public long getFileSize() ~tTn7[!  
{ s>G]U)d<'  
int nFileLength = -1; W;T0_=  
try{ D^h! ].3 T  
URL url = new URL(siteInfoBean.getSSiteURL()); F0&ubspt\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WJ-.?   
httpConnection.setRequestProperty("User-Agent","NetFox"); AvZ5?rN$  
Zgp9Uu}"  
a_/4^+  
int responseCode=httpConnection.getResponseCode(); doTbol?+  
if(responseCode>=400) 7xB]Z;:  
{ >Vx_Xv`Jwb  
processErrorCode(responseCode); ]v5/K  
return -2; //-2 represent access is error )uAY_()/  
} DazoY&AWE  
&n8Ja@Y]  
Fab]'#1q4  
String sHeader; bBc<p{  
KF(y`(8f  
` ;mQ"lO  
for(int i=1;;i++) # hn  
{ R+ \%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d0}(d Gl  
//Utility.log(in.readLine()); K"t?  
sHeader=httpConnection.getHeaderFieldKey(i); r aOuD3  
if(sHeader!=null) N LQ".mM+  
{ f U=P$s  
if(sHeader.equals("Content-Length")) AfhJ6cSIE  
{ aaf}AIL.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V:j^!*  
break; E<tR8='F  
} Eo ^m; p5  
} "(W;rl  
else ha;fxM]  
break; +1yi{!j1  
} L?;UcCB  
} ,<K+.7,)E  
catch(IOException e){e.printStackTrace ();} ZY7-.  
catch(Exception e){e.printStackTrace ();} %E#Ubm!  
b==jlYa=  
qov<@FvE0  
Utility.log(nFileLength); T=~d. &J  
/N%i6t<xU  
l i?@BHEf  
return nFileLength; + \%]<YO  
} 6 %aaK|0  
lr;ubBbT  
H;_Ce'oU(  
//保存下载信息(文件指针位置) ct|0zl~  
private void write_nPos() {*n<A{$[ m  
{ [G|(E  
try{ $ S3b<]B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); A p?,y?  
output.writeInt(nStartPos.length); \kUQe-:he  
for(int i=0;i<nStartPos.length;i++) _IOUhMo  
{ 3^&`E} r  
// output.writeLong(nPos); k ?6d\Q  
output.writeLong(fileSplitterFetch.nStartPos); 2`;XcY4A  
output.writeLong(fileSplitterFetch.nEndPos); 1}c /l<d  
} ~.G$0IJY  
output.close(); mE{QTZS  
} H[s+.&^  
catch(IOException e){e.printStackTrace ();} #m UQ@X@K  
catch(Exception e){e.printStackTrace ();} C4PT(cezR  
} #6#n4`%ER  
@+zWLq!1pB  
W //+[  
//读取保存的下载信息(文件指针位置) *) B \M>  
private void read_nPos() *re?V9  
{ j3%Wrt  
try{ A)!W VT&2A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RAhDSDf  
int nCount = input.readInt(); WzR)R9x]  
nStartPos = new long[nCount]; ^J-Xy\ X  
nEndPos = new long[nCount]; |[5;dt_U/  
for(int i=0;i<nStartPos.length;i++) 2 KHT!ik  
{ n2-+.9cY  
nStartPos = input.readLong(); ami>Pp  
nEndPos = input.readLong(); 3 SbZD   
} 2+)h!y]  
input.close(); t>%b[(a  
} IFr"IOr'l  
catch(IOException e){e.printStackTrace ();} _hl| 3 eW5  
catch(Exception e){e.printStackTrace ();}  r90tXx  
} `EMGrw_  
=ZU!i0 K  
W\Scak>  
private void processErrorCode(int nErrorCode) kk<%VKC  
{ !wd wo0  
System.err.println("Error Code : " + nErrorCode); wDoCc:  
} c-NUD$  
}yrs6pQ  
&I)tI^P}  
//停止文件下载 g%]<sRl:-  
public void siteStop() PCgr`($U  
{ ]Z\W%'q+  
bStop = true; l}-k>fug  
for(int i=0;i<nStartPos.length;i++) ,MJddbcg  
fileSplitterFetch.splitterStop(); [cEGkz  
# SCLU9-  
&,PA+#  
} .WN&]yr,  
} |zfFB7}v  
//负责部分文件的抓取 y_W?7 S  
**FileSplitterFetch.java @VOegf+N  
*/ NRG~ya >  
package NetFox; ?xMTO  
6ZI7V!k  
gU&+^e >  
import java.io.*; MTl @#M  
import java.net.*; ^)Y3V-@t  
&Q"vXs6Gt  
N GnE  
public class FileSplitterFetch extends Thread { bvZD@F`2  
3;}YW^oXq  
"#0P*3-c  
String sURL; //File URL yr>J^Et%_  
long nStartPos; //File Snippet Start Position p}!)4EI=  
long nEndPos; //File Snippet End Position O\;Lb[`lb  
int nThreadID; //Thread's ID 3HP { a  
boolean bDownOver = false; //Downing is over <bCB-lG*Kb  
boolean bStop = false; //Stop identical 6K8v:yYPa  
FileAccessI fileAccessI = null; //File Access interface 6?US<<MQ  
_'Vo3b  
uw8g%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7u^wO<  
{ bL0]Yuh  
this.sURL = sURL; ~MB)}!S:  
this.nStartPos = nStart; $X.F=Kv  
this.nEndPos = nEnd; ?XyrG1('  
nThreadID = id; }lPWA/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |SMigSu r`  
} #>_fYjT  
}2BNy9q@  
hF^JSCDz l  
public void run() >zJkG9a  
{ yCkWuU9  
while(nStartPos < nEndPos && !bStop) ^hEN  
{ "3Dnp?gB  
r:0RvWif  
tZ@&di:-F  
try{ hTby:$aCg  
URL url = new URL(sURL); J'=s25OWU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n 78!]O  
httpConnection.setRequestProperty("User-Agent","NetFox"); \?e2qu/ C  
String sProperty = "bytes="+nStartPos+"-"; 3bC-B!{;g  
httpConnection.setRequestProperty("RANGE",sProperty); f]Aa$\@b  
Utility.log(sProperty); j;j~R3B  
fWfhs}_  
13 JG[,w  
InputStream input = httpConnection.getInputStream(); ;2fzA<RkK  
//logResponseHead(httpConnection); K]>4*)A:  
{nA+-=T  
~KGE(o4p  
byte[] b = new byte[1024]; "k [$euV  
int nRead; $[cB6  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) UDcr5u eKn  
{ IWN18aaL?  
nStartPos += fileAccessI.write(b,0,nRead); Gk58VODo  
//if(nThreadID == 1) VOATza`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A9DFZZ0  
} at*DYZBjDB  
+dq2}gM  
wp~KrUlR  
Utility.log("Thread " + nThreadID + " is over!"); T72Z<h|<  
bDownOver = true; Avljrds+7  
//nPos = fileAccessI.write (b,0,nRead); zKYN5|17  
} h= YTgJ  
catch(Exception e){e.printStackTrace ();} <R2SV=]Sq#  
} i+I.>L/S  
} n3/ Bs  
l_ x jsu  
1dp8'f5^  
//打印回应的头信息 PDgZb  
public void logResponseHead(HttpURLConnection con) O6-';H:I]L  
{ :u@ w ;  
for(int i=1;;i++) v,rKuvc'  
{ /!"sPtIh  
String header=con.getHeaderFieldKey(i); yQu/({D  
if(header!=null) 5|bfrc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~ U8#yo  
Utility.log(header+" : "+con.getHeaderField(header)); 9K&YHg:1  
else )r*F.m{&:  
break; |N^8zo :  
} ;uZq_^?:9&  
} B~< bc  
y?}<SnjP:  
a)+*Gf7?  
public void splitterStop() ), VF]  
{ 9a1R"%Z  
bStop = true; \)MzUOZn  
} VeFfkg4  
V5jy,Qi)  
b|k(:b-G&.  
} pwVGe|h%,  
J<cY'?D  
.k!2{A  
/* a*_" nI&lr  
**FileAccess.java sC :.}6  
*//文件访问(定位,写) Y{4nBu  
package NetFox; #iD`Bg!VXc  
import java.io.*; PEKXPF N  
V3 ~&R:Z9e  
J}@.f-W\j  
public class FileAccessI implements Serializable{ _t X1z ^  
J6zU#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C6tfFS3bq  
RandomAccessFile oSavedFile; 7.yCs[Z  
long nPos; hx~rq `{  
J?&%fI  
6LT.ng  
public FileAccessI() throws IOException bSTTr<W  
{ z=rSb4"W  
this("",0); >dDcm  
} P!&yYR\  
S*ie$}ZX  
7$L*nf  
public FileAccessI(String sName,long nPos) throws IOException `P;3,@ e  
{ =$kSn\L,  
oSavedFile = new RandomAccessFile(sName,"rw"); ~>%% kQt  
this.nPos = nPos; cS#| _  
oSavedFile.seek(nPos); >(Wt  
} [/J(E\9  
6*tky;  
7u%OYt D E  
public synchronized int write(byte[] b,int nStart,int nLen) "@xL9[d  
{ 4%jQHOZ  
int n = -1; cm>+f^4?n  
try{ ~^g*cA t}  
oSavedFile.write(b,nStart,nLen); %W2 o`W$  
n = nLen; S)^eHuXPI  
} jyRz53  
catch(IOException e) 'z};tIOKJk  
{ c8o2* C$  
e.printStackTrace (); -}>H3hr  
} > mP([]  
AD'c#CT  
hi ),PfAV  
return n; ]vCs9* |B  
} Gkdxw uRw  
:-+j,G9 t  
.7Itbp6=R  
} qi1#s,  
X'7MW? q@  
Q6PMRG}/o  
/* 3+vMi[YO  
**SiteInfoBean.java h& Ezhv2  
*/ <ZoMKUuB  
package NetFox; ^%33&<mB}  
6.3qux9  
#4& <d.aw'  
public class SiteInfoBean { -D_xA10  
jXyK[q&O&  
kl5Y{![/&f  
private String sSiteURL; //Site's URL RXhT{Ho(>  
private String sFilePath; //Saved File's Path d]^\qeG^p  
private String sFileName; //Saved File's Name B}d)e_uLj  
private int nSplitter; //Count of Splited Downloading File XiyL563gh  
,LDdL  
#4^D'r>pJ  
public SiteInfoBean() ~H626vT37  
{//nSplitter的缺省值为5 *iVv(xXgN  
//default value of nSplitter is 5 <TEDs4 C  
this("","","",5); 8H{9  
} 8-Z|$F"  
>td\PW~X  
<IQ}j^u-F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e[.JS6  
{ hJoh5DIE95  
sSiteURL= sURL; 4~0 @(3  
sFilePath = sPath; r 4+%9)  
sFileName = sName; -lI6!a^  
this.nSplitter = nSpiltter; 212  
YM +4:P2  
D^H4]7wG@  
} SrvC34<7  
ia%U;M  
'# J/e0o@  
public String getSSiteURL() yxy~N\ 0  
{ .$r7q[  
return sSiteURL; {&)E$ M  
} {9h`h08?z  
RV6|sN[x>  
@?[}\9dW  
public void setSSiteURL(String value) |\h<!xR  
{ }H9V$~}@-  
sSiteURL = value; $7&t`E)qY  
} M_#^zo "x  
S(5&%}QFQ  
f:/"OCig  
public String getSFilePath()  @@+BPLl  
{ )9V8&,  
return sFilePath; C,dRdEB>  
} @t,Y< )U  
?~rz'Pu~  
'<hg c  
public void setSFilePath(String value) fzjZiBK@  
{ [hKt4]R  
sFilePath = value; Znh) m  
} W0 N*c*k  
2[Bw+<YA`  
|&0Cuwt  
public String getSFileName() #9@UzfZAwT  
{ -f%J_`  
return sFileName; .Gnzu"lod  
} )ZDqj  
1H7 bPl|  
JcI~8;Z@Z~  
public void setSFileName(String value) Zl=IZ?F   
{ 'FmnlC1  
sFileName = value; 6kHb*L Je  
} #s|/5[i  
>I *uo.OF  
0D^c4[Y'l  
public int getNSplitter() JReJlDu  
{ 5,K*IH  
return nSplitter; vo]$[Cp|4  
} V=5v7Y3( j  
Qon>[<]B  
HT=-mwa_]  
public void setNSplitter(int nCount) 2)+ddel<Z  
{ bRK[u\,  
nSplitter = nCount; 0z=^_Fb  
} rn%q*_3-o  
} WRfhxl  
3^p;'7x  
]ZM-c~nL  
/* |j~{gfpSE  
**Utility.java h<IPV'1  
*/ )+ 12r6W  
package NetFox; `ouCQ]tKz  
Nd61ns(N  
e:zuP.R  
public class Utility { Q%^!j_#  
6Bn%7ZBv  
">"B  
public Utility() qgZN&7Nn:  
{ ~ZZJ/Cu  
hYU4%"X  
Y|N.R(sAs&  
} 8YwSaBwO  
p& +w  
//线程睡眠 Tn(c%ytN  
public static void sleep(int nSecond) iP+3)  
{ V75P@jv5J  
try{ *S{fyYyM  
Thread.sleep(nSecond); xBK is\b  
} /&g~*AL  
catch(Exception e) ]R8JBnA  
{ 7q|51rZz  
e.printStackTrace (); 8d*W7>rq  
} jp P'{mc  
} Wd/m]]W8Q  
r@]iy78 j  
//日志 .3< sv  
public static void log(String sMsg) ?D`h[ai  
{ 2vx1M6a)L  
System.err.println(sMsg); -@yu 9=DT  
} n>:|K0u"  
29AWg(9?aS  
LKe ~  
public static void log(int sMsg) t {RdqAF  
{ 8:)itYE  
System.err.println(sMsg); eJ tfQ@?  
} (b>B6W\&  
} x#,nR]C  
"qvJ-Y  
hTK6N  
/* M|uWSG  
**TestMethod.java 8S*W+l19f  
*/ %:hU:+G E  
package NetFox; v\b@;H`  
w@"l0gm+u[  
0z:BSdno  
public class TestMethod { e!JC5Al7  
c 6Z\ecH9  
3pk `&'  
public TestMethod() /5 6sPl 7}  
{ ///xx/weblogic60b2_win.exe ,CA3Q.y>|  
try{ ]\Q9j7}37+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %+e% RZ3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Or*e$uMIY  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i*-L_!cc:  
fileFetch.start(); H_<hZ UB  
} > lIQM3  
catch(Exception e){e.printStackTrace ();} ~k[q:$T  
=[T_`*s&  
La#otuw+?  
} STY\c5  
:r,o-D  
f+iM_MI  
public static void main(String[] args) ^t#W?rxp&  
{ +U];  
new TestMethod(); 9 9S-P}xd  
} `U[s d*C"  
} ?ta(`+"  
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