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http断点续传简单实现(java)

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/* z&Aya*0v`  
**SiteFileFetch.java n>7aZ1Qa  
*/ y/kB`Z(Yj  
package NetFox; 0igB pHS  
import java.io.*; @rA V;D%  
import java.net.*; W/b)OlG"2  
La3rX  
k{=dV  
public class SiteFileFetch extends Thread { +S[3HX7H  
Z[ &d2'  
0w0{@\9  
SiteInfoBean siteInfoBean = null; //文件信息Bean $zU%?[J  
long[] nStartPos; //开始位置 e$2P/6k>  
long[] nEndPos; //结束位置 O1)\!=& .  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T ,jb%uPcE  
long nFileLength; //文件长度 sHMO9{[7H  
boolean bFirst = true; //是否第一次取文件 VumM`SH  
boolean bStop = false; //停止标志 k#u)+e.'  
File tmpFile; //文件下载的临时信息 D6|-nl  
DataOutputStream output; //输出到文件的输出流 0xO*8aKT  
n\V7^N  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) biBMd(6  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,hT.Ok={36  
{ k`A39ln7wu  
siteInfoBean = bean; -%gEND-AP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); eO(U):C2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); hqlQ-aytS  
if(tmpFile.exists ()) A0U9,M  
{ 2ZEGE+0  
bFirst = false; erbk (  
read_nPos(); \G7F/$g  
} =6O*AJ  
else -ucgET`  
{ 8D,*_p  
nStartPos = new long[bean.getNSplitter()]; D4{KU%Xp&  
nEndPos = new long[bean.getNSplitter()]; QxGcRlpLK  
} %[s%H)e)  
?FjnG_Uz`D  
Wz"H.hf  
PgGUs4[  
} -zn_d]NV  
5V\",PA W  
JAP(J~  
public void run() 3fB]uq+eD%  
{ (Nk[ys}%*  
//获得文件长度 v3FdlE  
//分割文件 AO]cnh C  
//实例FileSplitterFetch @2a!T03  
//启动FileSplitterFetch线程 *8m['$oyV  
//等待子线程返回 qk3|fW/-  
try{ DcdEt=\)h  
if(bFirst) Hh*?[-&r~  
{ xE]y*\  
nFileLength = getFileSize(); yz=X{p1  
if(nFileLength == -1) \q4r/SbgW  
{ ' |B3@9<  
System.err.println("File Length is not known!"); <F(2D<d{;)  
} N$IA~)  
else if(nFileLength == -2) *B}O  
{ 3 V>$H\H  
System.err.println("File is not access!"); H,5]w\R6\  
} kltW  
else *o4a<.hd2  
{ Uc'}y!R  
for(int i=0;i<nStartPos.length;i++) )RvX}y-  
{ g#^MO]pY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Iz#4!E|<  
} .(.<  
for(int i=0;i<nEndPos.length-1;i++) !|i #g$  
{ ;H.V-~:P)  
nEndPos = nStartPos[i+1];  Owi/e  
} ujS oWs  
nEndPos[nEndPos.length-1] = nFileLength; n=C"pH#  
} m,!SD Cq  
} i,a"5DR8  
Iia.`"S  
A;RV~!xx  
//启动子线程 ^bfZd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z[d13G;  
for(int i=0;i<nStartPos.length;i++) 'ScvteQ  
{ A)>#n)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )%MC*Z :^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  w:QO@  
nStartPos,nEndPos,i); i2  c|_B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^Y%_{   
fileSplitterFetch.start(); |g)>6+?]W  
} 9jqsEd-SW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @v2ko5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A$5M.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FA$32*v  
nEndPos = " + nFileLength); rf:H$\yw  
// fileSplitterFetch[nPos.length-1].start(); HOFxOBV  
kDWEgnXK,v  
7#%Pry  
//等待子线程结束 LlO8]b!P-^  
//int count = 0; @x+2b0 b  
//是否结束while循环 j;Z?q%M{6  
boolean breakWhile = false; T-6<qh  
m 0vW<  
0FI |7  
while(!bStop) -|KZOea  
{ PBCGC^0{  
write_nPos(); ix4]^  
Utility.sleep(500); SnQT1U%  
breakWhile = true; ybE 2N  
YnU)f@b#  
T!KwRxJ23  
for(int i=0;i<nStartPos.length;i++) HdI)Z<Krp  
{ 9%iQ~   
if(!fileSplitterFetch.bDownOver) N\ !  
{ /}m*|cG/  
breakWhile = false; D\-\U E/  
break; o#,^7ln  
} yvoz 3_!  
} 7\,9Gcv1  
if(breakWhile) bC1G5`v_D  
break; iI";m0Ny  
Gw$5<%sB  
~<n.5q%Z  
//count++; )B0%"0?`8  
//if(count>4) >!xyA;  
// siteStop(); ~;#}aQYo  
} mA+:)?e5~  
()l3X.t,$  
~BmA!BZV`  
System.err.println("文件下载结束!");  Q}L?o  
} yW= +6@A4  
catch(Exception e){e.printStackTrace ();} C$1W+(  
} ]>VG}e~b  
>- \bLr  
")STB8kQ  
//获得文件长度 nwUz}em?O  
public long getFileSize() q_h (D/g  
{ Bso#+v5  
int nFileLength = -1; A,cXN1V  
try{ qGV_oa74  
URL url = new URL(siteInfoBean.getSSiteURL()); V>`ANZ4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Fds 11 /c7  
httpConnection.setRequestProperty("User-Agent","NetFox"); =oq8SL?bJ*  
lt&(S)  
SULFAf<  
int responseCode=httpConnection.getResponseCode(); daI_@kY"  
if(responseCode>=400) P8,Ps+  
{ 4>>=TJ!M  
processErrorCode(responseCode); 2.Qz"YDh =  
return -2; //-2 represent access is error ?zf3Fn2y  
} zR^Gy"  
i9DD)Y<  
M>]A! W=  
String sHeader; \MOwp@|y  
j,+]tHC-  
*c94'Tcl  
for(int i=1;;i++) *kl  :/#  
{ $}gM JG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k_=yb^6[U  
//Utility.log(in.readLine()); Ptv'.<-  
sHeader=httpConnection.getHeaderFieldKey(i); T+F]hv'  
if(sHeader!=null)  Qw}1q!89  
{ TB! I  
if(sHeader.equals("Content-Length")) -$Hu $Y}>  
{ wgS,U }/i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F#sm^%_2  
break; SXm%X(JU  
} RDp  
} (O5Yd 6u  
else *{DTxEy  
break; W8^m-B&  
} zl|z4j'Irc  
} yijP  
catch(IOException e){e.printStackTrace ();} ro{!X,_$,  
catch(Exception e){e.printStackTrace ();} +1!iwmch>  
Kf[d@ L  
rR> X<  
Utility.log(nFileLength);  S=(O6+U  
o[Jzx2A<  
Go)$LC0Mi  
return nFileLength; ^es]jng`  
} "%gsGtS  
eyCZ[SC  
h^yqrDyJ  
//保存下载信息(文件指针位置) `GCoi ?n7  
private void write_nPos() "tzu.V-  
{ 9Rnypzds  
try{ }aVZ\PDg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3 !@  
output.writeInt(nStartPos.length); "d_wu#fO)  
for(int i=0;i<nStartPos.length;i++) YNEwX$)M,B  
{ JNfL jfE)<  
// output.writeLong(nPos); ) CP  
output.writeLong(fileSplitterFetch.nStartPos); cQU;PH]  
output.writeLong(fileSplitterFetch.nEndPos); -Z"4W  
} N]A# ecm  
output.close(); (jM0YtrD  
} [>O!~  
catch(IOException e){e.printStackTrace ();} ?l0Qi  
catch(Exception e){e.printStackTrace ();} YA4D?'  
} * j%x  
mH'~pR>t  
 8b2 =n  
//读取保存的下载信息(文件指针位置) Q5+1'mzAB  
private void read_nPos() hy5[ L`B  
{ <1D|TrP  
try{ ]%' AZ`8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Qd[_W^QI  
int nCount = input.readInt(); BNu >/zGpB  
nStartPos = new long[nCount]; 0ns\:2)cEB  
nEndPos = new long[nCount]; }Y~Dk]*  
for(int i=0;i<nStartPos.length;i++) Lnr9*dm6q  
{ Iux3f+H  
nStartPos = input.readLong();  )(G9[DG  
nEndPos = input.readLong(); HC%Hbc~S_Q  
} .A2$C|a*  
input.close(); =&WIa#!=  
} Ttluh *  
catch(IOException e){e.printStackTrace ();} 8D='N`cN+  
catch(Exception e){e.printStackTrace ();} Jj"{C]  
} {>f"&I<xw  
1@F-t94I  
ju"z  
private void processErrorCode(int nErrorCode) uzy5rA==  
{ 9P?0D  
System.err.println("Error Code : " + nErrorCode); pM?;QG;jA  
} 8QrpNSj4  
3 jZMXEG)  
k?+ 7%A]  
//停止文件下载 l|P"^;*zq  
public void siteStop() Yj/afn(Jt  
{ 'NEl`v*<P  
bStop = true; u^" I3u8$  
for(int i=0;i<nStartPos.length;i++) \Z[1m[{  
fileSplitterFetch.splitterStop(); pHV^K v#  
r;#"j%z  
!6!)H8rX  
} _fHC+lwN  
} B/twak\  
//负责部分文件的抓取 sdFHr4  
**FileSplitterFetch.java `H+"7SO  
*/ yqT!A  
package NetFox; j / 5  
tn]nl!_@  
U'fP  
import java.io.*; {q-&!l|  
import java.net.*; J2bvHxb Rd  
j#l=%H  
t#k]K]  
public class FileSplitterFetch extends Thread { z*\_+u~u  
7o E0;'  
2}hJe+#v  
String sURL; //File URL A3jxjQ  
long nStartPos; //File Snippet Start Position Pe`(9&iT.  
long nEndPos; //File Snippet End Position C8U3+ s  
int nThreadID; //Thread's ID sg2;"E@  
boolean bDownOver = false; //Downing is over i}-uK,^  
boolean bStop = false; //Stop identical AI|vL4*Xd  
FileAccessI fileAccessI = null; //File Access interface "4N&T#  
1[%3kY-h  
?:(y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =8AT[.Hh  
{ &@0~]\,D7  
this.sURL = sURL; n5:uG'L\  
this.nStartPos = nStart; 5S~ H[>A"  
this.nEndPos = nEnd; I652Fcj  
nThreadID = id; ^/f~\ #R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7EJ2 On  
} PTQ#8(_,  
Ds9)e&yYrb  
`2lS@  
public void run() n6/Ous  
{ WyN ;lId  
while(nStartPos < nEndPos && !bStop) 0dch OUj  
{ Z(mUU]  
\ TV  
Rs%`6et}\  
try{ LgqQr6y"  
URL url = new URL(sURL); hlzB cz*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]3KeAJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); }A)\bffH  
String sProperty = "bytes="+nStartPos+"-"; 3BFOZV+  
httpConnection.setRequestProperty("RANGE",sProperty); 9/ <3mF@E  
Utility.log(sProperty); h0{X$&:  
dSM\:/t  
F.9}jd{  
InputStream input = httpConnection.getInputStream(); hZ&KE78?  
//logResponseHead(httpConnection); Pfd1[~,  
FuhmLm'p  
0=Z[6Q@:  
byte[] b = new byte[1024]; YF%gs{  
int nRead; >!963>DR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n;g'?z=hy  
{ 5ZCu6 A  
nStartPos += fileAccessI.write(b,0,nRead); CIudtY(:  
//if(nThreadID == 1) NR4+&d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8wU$kK  
} p.DQ|?  
>)>f~>  
gq=t7b  
Utility.log("Thread " + nThreadID + " is over!"); *1|7%*!8  
bDownOver = true; ACszx\[K3  
//nPos = fileAccessI.write (b,0,nRead); =pH2V^<<#  
} VYk:c`E  
catch(Exception e){e.printStackTrace ();} J9^NHU  
} #Hw|P  
} ':*H#}Br-#  
i8]EIXbMX  
gabfb#  
//打印回应的头信息 8z=# 0+0  
public void logResponseHead(HttpURLConnection con) tsXKhS;/w  
{ + G@N  
for(int i=1;;i++) zl0{lV  
{ Ak'=l;  
String header=con.getHeaderFieldKey(i); _imuyt".+  
if(header!=null) { bj!]j  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #<{v~sVp&  
Utility.log(header+" : "+con.getHeaderField(header)); o Pe|Gfv\G  
else x#1 Fi$.  
break; c~ss^[qx|  
}  RD$:.   
} %OQdUH4x  
X9x`i  
W06aj ~7Z  
public void splitterStop() ?cU,%<r  
{ |]\zlH"w  
bStop = true; fY<#KM6X  
} 7;>|9k  
t7=D$ua  
CPz<iU  
} N J3;[qJ  
gZ@+62  
-/f$s1  
/* ,\4]uZ<  
**FileAccess.java 2 bc&sU)X  
*//文件访问(定位,写) (0-Ol9[  
package NetFox; ( t&RFzE?G  
import java.io.*; Q}BMvR 9w  
VjQ&A#   
<jh4P!\&j  
public class FileAccessI implements Serializable{ ^<I(  
qBEp |V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z.VKG1e}  
RandomAccessFile oSavedFile; -Vn#Ab_C  
long nPos; YT(N][V  
t.P@Ba^  
DbGS]k<$  
public FileAccessI() throws IOException zWY988fX0  
{ >kXscbRL7  
this("",0); fU>l:BzJ K  
} Xa[k=qFo  
_ *f>UW*,  
cBxGGggB  
public FileAccessI(String sName,long nPos) throws IOException \n<! ld  
{ 3h7RQ:lUi  
oSavedFile = new RandomAccessFile(sName,"rw"); Y'U1=w~E  
this.nPos = nPos; jTa\I&s,A  
oSavedFile.seek(nPos); "i0>>@NR'  
} {&5lZ<nu8A  
T$;S   
__=53]jGE  
public synchronized int write(byte[] b,int nStart,int nLen) Ht[$s40P  
{ H4g8 1V=  
int n = -1; ~P3b5 -  
try{ o[Ffa# sE  
oSavedFile.write(b,nStart,nLen); u)oAQ<w  
n = nLen;  ?eS;Yc  
} 4=Th<,<  
catch(IOException e) J"aw 1  
{ $Q*R/MY  
e.printStackTrace (); m23"xnRB  
} $nt&'Xnv  
^KhJBM/Z  
r=Xo;d*TE  
return n; 2uj .*  
} qPDNDkjDD  
|Y3w6!$  
78l);/E{v  
} HVa9b;  
o `YBz~2  
@2E52$zu  
/* s#^0[ Rt  
**SiteInfoBean.java !)bZ.1o  
*/ ?lC>E[  
package NetFox; d6n_Hpxw^  
UFj H8jSBx  
wV )\M]@  
public class SiteInfoBean { 71{Q#%5U~  
(OiV IH  
"z9C@T  
private String sSiteURL; //Site's URL 6{6hz 8  
private String sFilePath; //Saved File's Path 'V]C.`9c  
private String sFileName; //Saved File's Name KElEGW  
private int nSplitter; //Count of Splited Downloading File L-9fo-  
]Thke 4  
t4oD> =,92  
public SiteInfoBean() rl}<&aPH  
{//nSplitter的缺省值为5 x,C8):\t`B  
//default value of nSplitter is 5 LK}g<!o(  
this("","","",5); %`i*SF(gV  
} 8\s#law  
SJ]6_4=y*  
P!79{8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (_ G>dP_  
{ ,:mL\ZED  
sSiteURL= sURL; `,}7LfY  
sFilePath = sPath; ^BA I/WP  
sFileName = sName; s4fO4.bnm  
this.nSplitter = nSpiltter; RJD{l+  
G2|jS@L#  
r;{$x  
} rt^~ I \V  
BL&AZv/T  
]W;6gmV  
public String getSSiteURL() YYpC!)  
{ sJLOz>  
return sSiteURL; Erw1y,mF  
} X):7#x@uy  
1 ^|#QMT  
xf&[QG+Ef  
public void setSSiteURL(String value) d.? }>jl  
{ Q/g!h}>(.  
sSiteURL = value; m""+ $  
} lpXGsK H2  
hJ(vDv%  
<|l}@\iRX  
public String getSFilePath() 'Q=;I  
{ h/n(  
return sFilePath; fG1iq<~  
} # >k|^*\  
X\`']\l  
IL|Q-e}Ol  
public void setSFilePath(String value) Lf(( zk:pt  
{ 3RaW\cWzg  
sFilePath = value; Z3JUYEAS  
} J$}]p  
eN<L)a:J_  
6FzB-],  
public String getSFileName() / <)Vd  
{ kqCsEtm]  
return sFileName; lWYp  
} 7?yS>(VmT  
0g[ %)C  
/K|(O^nw  
public void setSFileName(String value) @Fc:9a@  
{ %>$<s<y  
sFileName = value; U> lf-iI2B  
} 2]vTedSOl  
&IN%2c  
|'z8>1  
public int getNSplitter() jh/,G5RM9  
{ @$jV"Y  
return nSplitter; a qEZhMy  
} 8;?4rrS  
!hq2AY&H)  
%_W4\  
public void setNSplitter(int nCount) DURWE,W>  
{ yn mjIQ  
nSplitter = nCount; -  ]wT  
}  p?f\/  
} [uU!\xe  
AY5iTbL1  
Y5tyFi#w[  
/* <kFLwF?PM'  
**Utility.java [eD0L7 1[  
*/ =|-= 4.b+|  
package NetFox; l^&#9d  
B,\VLX  
t}eyfflZ  
public class Utility { %]Z4b;W[Y  
'{AB{)1  
.yy-jf/  
public Utility() ?C[?dg{n  
{  E4eX fu  
14 & KE3`  
@#4-4.6I<x  
} 2yK">xYY@  
]^C 8Oh<  
//线程睡眠 ??"_o3  
public static void sleep(int nSecond) YHEn{z7  
{ i#V(oSx  
try{ tq59w  
Thread.sleep(nSecond); W+&5G(z~  
} d AcSG  
catch(Exception e) I5M\PK/  
{ KzVi:Hm  
e.printStackTrace (); E@ :9|5  
} U=bx30brh%  
} >S I'Q7k  
M,fL(b;2  
//日志 n.+'9Fj  
public static void log(String sMsg) rk8pL[|  
{ N; }$!sNIm  
System.err.println(sMsg); ZwDL  
} >IIq_6Z#  
To*+Z3Wd  
S[K5ofV  
public static void log(int sMsg) /i"hViCrlG  
{ &q>8D'  
System.err.println(sMsg); e\C-a4[C8P  
} dQ8RrD=$&  
} U:TkO=/>:  
{T-\BTh&Q  
_uO$=4Sd  
/* kumV|$Y?kA  
**TestMethod.java fc+-/!v  
*/ -LiGO#U  
package NetFox; ]u5TvI,C  
OV]xo8a;  
|E >h*Y  
public class TestMethod { Rv&"h_"t  
'o IE:#b  
hH`x*:Qja  
public TestMethod() VwI  
{ ///xx/weblogic60b2_win.exe {c*$i^T  
try{ kD#n/R Bgf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9;L4\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jOV6 %  
SiteFileFetch fileFetch = new SiteFileFetch(bean); G0 EXgq8  
fileFetch.start(); 1)= H2n4)  
} dCoP qKy  
catch(Exception e){e.printStackTrace ();} :Tpf8  
ytY\&m  
Ln# o:"E  
} Sl8+A+  
BHY-fb@R]H  
M Z"V\6T]  
public static void main(String[] args) 6 >)fNCe`  
{ aA4RC0'  
new TestMethod(); t5E$u(&+'B  
} SPV+ O{  
} PaSwfjOnqr  
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