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http断点续传简单实现(java)

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/* D"1ciO8^I]  
**SiteFileFetch.java UQW;!8J#R(  
*/ ` S85i*  
package NetFox; mg >oB/,'Z  
import java.io.*; qd{|"(9B  
import java.net.*; y ImriCT  
 2 H^9Qd  
\UB<'~z6!  
public class SiteFileFetch extends Thread { @Gn9x(?J  
B)^]V<l(w  
yMz@-B  
SiteInfoBean siteInfoBean = null; //文件信息Bean U7x}p^B9\N  
long[] nStartPos; //开始位置 "t_]Qu6  
long[] nEndPos; //结束位置 gn(n</\/O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ii|<:BW  
long nFileLength; //文件长度 <j,7Z>Rk\x  
boolean bFirst = true; //是否第一次取文件 :syR4A WM  
boolean bStop = false; //停止标志 =~aJ]T}(  
File tmpFile; //文件下载的临时信息 O4$: xjs  
DataOutputStream output; //输出到文件的输出流 m5d;lrk@&/  
`VBjH]$  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9@vY(k k  
public SiteFileFetch(SiteInfoBean bean) throws IOException SZwfYY!ft0  
{ UhEJznfi  
siteInfoBean = bean; +%gh?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VJr?` eY4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 54 }s:[O  
if(tmpFile.exists ()) XTeU 2I  
{ FP9ZOoog  
bFirst = false; _bMs~%?~/  
read_nPos(); {n1o)MZ]R  
} @69q// #B  
else Z.R^@@RqJ  
{ -@#AQ\  
nStartPos = new long[bean.getNSplitter()]; VJ1 `&  
nEndPos = new long[bean.getNSplitter()]; D %5 0  
} MCYrsgg}  
g" M1HxlV  
 d;CD~s  
i,bFe&7J  
} TUk1h\.q  
e@Mm4&f[p  
kF\ QO [  
public void run()  %gf8'Q  
{ f'%}{l: ss  
//获得文件长度 `,7BU??+u  
//分割文件 +F0M?,  
//实例FileSplitterFetch zR`]8E]  
//启动FileSplitterFetch线程 x3M`l|  
//等待子线程返回 i.byHz?/  
try{ ^AEg?[q  
if(bFirst) ZMx<:0ai  
{ 6SidH_&C  
nFileLength = getFileSize(); p$"*U[%l  
if(nFileLength == -1) 8Ipyr%l  
{ Y8CXin h  
System.err.println("File Length is not known!"); 2oq>tnYyV[  
} {(aJrSE<z  
else if(nFileLength == -2) 8}S|iM  
{ 8"S0E(,mu  
System.err.println("File is not access!"); Wxg|jP$~   
} N:&Gv'`  
else 0c`wJktWK  
{ S*\`LBl"nX  
for(int i=0;i<nStartPos.length;i++) Z&}94  
{ E7jv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i-/'F  
} (sPZ1Fr\o  
for(int i=0;i<nEndPos.length-1;i++) -EL"Sv?  
{ pWQ?pTh  
nEndPos = nStartPos[i+1]; (2a~gQGD  
} "2Ye\#BU6  
nEndPos[nEndPos.length-1] = nFileLength; X#Hs{J~@p  
} kszYbz"  
} Li7/pUq>}!  
LL:B H,[  
U :IQWlC  
//启动子线程 jdoI)J@9H  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; < Gu s9^_  
for(int i=0;i<nStartPos.length;i++) \9 ^w M>U  
{ UHxXa*HyI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), GadD*psD2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sM-k,0z  
nStartPos,nEndPos,i); ,>e<mphM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &{7%Vs TB  
fileSplitterFetch.start(); W}T$Z  
} *d)B4qG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;%Z)$+Z_)<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3 i>uKU1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LdRLKE<'e  
nEndPos = " + nFileLength); ="XxS|Mq3  
// fileSplitterFetch[nPos.length-1].start(); Q+#, VuM  
G:A` n;E0  
uS<&$J H  
//等待子线程结束 X\flx~  
//int count = 0; JZai{0se  
//是否结束while循环 9v/1>rziE  
boolean breakWhile = false; ON !1lS  
eLl ;M4d  
RX#:27:  
while(!bStop) 3ne=7Mj  
{ )kg^.tP  
write_nPos(); r_ Xk:  
Utility.sleep(500); )2:d8J\  
breakWhile = true;  fkYa  
y5oiH  
MF>?! !  
for(int i=0;i<nStartPos.length;i++) hGzj}t W8d  
{ 0naegy?,  
if(!fileSplitterFetch.bDownOver) l$z-'  
{ V<(cW'zA/  
breakWhile = false; M`S >Q2{  
break; 6&h,eQ!  
} B 6|=kl2C  
} bY]aADv\  
if(breakWhile) A.(Z0,S-i  
break; m[%&K W(  
X $J  
d+z8^$z"  
//count++; OCF= )#}qd  
//if(count>4) a^|mF# z  
// siteStop(); 0urQA_JC  
} o2&mhT  
, @(lYeD"  
z!?xz  
System.err.println("文件下载结束!"); $1/yc#w u  
} |"\A5v|1  
catch(Exception e){e.printStackTrace ();} h\:"k_u#  
} 7!z0)Ai_>=  
!~PV\DQN  
vr2tMD  
//获得文件长度 W!htCwnkF  
public long getFileSize() 2gukK8R$  
{ >~2oQ[ n  
int nFileLength = -1; 9Yd<_B#  
try{ Ptn0;GC  
URL url = new URL(siteInfoBean.getSSiteURL()); /_>S0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $xNZ.|al  
httpConnection.setRequestProperty("User-Agent","NetFox"); G4]T  
Qp]V~s(  
arRb q!mO  
int responseCode=httpConnection.getResponseCode(); ZC@Pfba[`  
if(responseCode>=400) <D!"<&N  
{ !-p5j3A4L  
processErrorCode(responseCode); >pUR>?t"  
return -2; //-2 represent access is error CKy' 8I9  
} 8)/d8@  
FL9 Dz4  
O_*%_S}F&  
String sHeader; 3Vs8"BFjz  
0.=dOz r  
N-y[2]J90  
for(int i=1;;i++) "V}WV!w  
{ UM3}7|  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &r do Mc;  
//Utility.log(in.readLine()); X8"4)IZ3  
sHeader=httpConnection.getHeaderFieldKey(i); Z`T]jm-3  
if(sHeader!=null) =YOq0  
{ 5$d>:" >  
if(sHeader.equals("Content-Length")) /&_$+Iun  
{ 2.qEy6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b<n*wH  
break; jH({Qc,97  
} fX2sjfk  
} #Ipi3  
else Vo"Wr>F  
break; 8,7^@[bzXx  
} Y;-$w|&P>  
} E{k$4  
catch(IOException e){e.printStackTrace ();} 9$$dSN\&  
catch(Exception e){e.printStackTrace ();} ]{s0/(EA  
TD!--l*gL  
SYkwM6  
Utility.log(nFileLength); s'b 4Me  
UQ c!"D  
FC@h6 \+a  
return nFileLength; ?(0=+o(`  
} qILb>#  
C3)*Mn3%P  
N:x--,2  
//保存下载信息(文件指针位置) [MhKR }a  
private void write_nPos() +saXN6  
{ ;-#2p^  
try{ %PM&`c98z7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "ngULpb{R  
output.writeInt(nStartPos.length); JlR$"GU  
for(int i=0;i<nStartPos.length;i++) ~@=(#tO.  
{ n+MWny  
// output.writeLong(nPos); =h0vdi%{  
output.writeLong(fileSplitterFetch.nStartPos); <-;/,uu  
output.writeLong(fileSplitterFetch.nEndPos); fG9 ;7KG  
} @ <(4J   
output.close(); $>Qq 7  
} g&z8t;@  
catch(IOException e){e.printStackTrace ();} E@,m +  
catch(Exception e){e.printStackTrace ();} N,W ?}  
} 'HKDGQl`  
u}3D'h  
GXC,p(vbE  
//读取保存的下载信息(文件指针位置) YLJ^R$pi  
private void read_nPos() ckGmwYP9  
{ 6S`0<Z;;/  
try{ cX7 O*5C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }D>#AFs6#  
int nCount = input.readInt(); o3]Lrzh  
nStartPos = new long[nCount]; f7YBhF  
nEndPos = new long[nCount]; h4Wt oE>i  
for(int i=0;i<nStartPos.length;i++) s@Dln Du .  
{ B6=?Qp/f  
nStartPos = input.readLong(); v%:VV*MxF  
nEndPos = input.readLong(); V'hb 4}@  
} $vrkxn  
input.close(); c+ D <  
} wXjidOd $  
catch(IOException e){e.printStackTrace ();} \?SvO  
catch(Exception e){e.printStackTrace ();} e,N}z  
} is }>+&_  
]Hp>~Zvbb  
G/*;h,NbNr  
private void processErrorCode(int nErrorCode) DA1?M'N  
{ B*Q9g r  
System.err.println("Error Code : " + nErrorCode); e:%|.$4OG  
} H2H`7 +I,  
*Nm$b+  
Mg #yl\v  
//停止文件下载 I4W@t4bZ  
public void siteStop() !O,Sq/=.  
{ o]E L=j  
bStop = true; vJLGy]  
for(int i=0;i<nStartPos.length;i++) c {/J.  
fileSplitterFetch.splitterStop(); > vdmN]  
>H^#!eaqw  
e2f+Fv 9  
} v3#,Z!  
} 8Qo'[+4;  
//负责部分文件的抓取 6<EGH*GQ$  
**FileSplitterFetch.java q`,%L1c4  
*/ [Ur\^wS  
package NetFox; Y{D%v  
~w a6S?  
Z:dp/M}  
import java.io.*; P#O2MiG  
import java.net.*; f(Y_<%  
/a'1 W/^2  
N0H=;CIQ  
public class FileSplitterFetch extends Thread { V"m S$MN  
&\1n=y  
#l ZK_N|1x  
String sURL; //File URL N+'j on}U  
long nStartPos; //File Snippet Start Position _ Ao$)Gu)  
long nEndPos; //File Snippet End Position "$XX4w M  
int nThreadID; //Thread's ID V:$+$"|  
boolean bDownOver = false; //Downing is over s bj/d~$N  
boolean bStop = false; //Stop identical H T|DT  
FileAccessI fileAccessI = null; //File Access interface Keozn*fzI  
tLBtE!J$[  
} vmRm*8z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )\|+G5#`  
{ ]QhTxrF"  
this.sURL = sURL; W7^[W.  
this.nStartPos = nStart; 5BJ E  
this.nEndPos = nEnd; -~mgct5  
nThreadID = id; )V\@N*L`ik  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TWzLJ63*  
} 1h&`mqY)L.  
? 3=G'Ip5n  
%WgN+A0  
public void run() b~J)LXj]w  
{ &}r"Z?f)  
while(nStartPos < nEndPos && !bStop) 27EK +$  
{ @eJCr)#}  
<.Ws; HN}  
1Y|a:){G  
try{ j-":>}oW2.  
URL url = new URL(sURL); ` y\)X C7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hW~.F  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ttt'X<9  
String sProperty = "bytes="+nStartPos+"-"; uMJ \  
httpConnection.setRequestProperty("RANGE",sProperty); /]_t->  
Utility.log(sProperty); Ot2o=^Ng  
} o%^ Mu B  
 Y !?'[t  
InputStream input = httpConnection.getInputStream(); W6&vyOc  
//logResponseHead(httpConnection); Ks-$:~?5":  
b6bs .  
flsejj$  
byte[] b = new byte[1024]; 9af.t  
int nRead; )S caT1I  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {_QdB;VwH  
{ !y= R)k  
nStartPos += fileAccessI.write(b,0,nRead); ;V xRaj?  
//if(nThreadID == 1) i"WYcF |  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wI$ a1H  
} Z!)~?<gcq:  
pk :P;\  
\84t\jKR  
Utility.log("Thread " + nThreadID + " is over!"); <kak9 6A  
bDownOver = true; JE=t e(a  
//nPos = fileAccessI.write (b,0,nRead); zx3gz7>k;  
} =dmr ,WE  
catch(Exception e){e.printStackTrace ();} *MP.YI:h  
} bGPE0}b  
} E>!=~ 7.  
e-nA>v  
fpD$%.y'J  
//打印回应的头信息 $ik*!om5  
public void logResponseHead(HttpURLConnection con) Fx9-A8oIR  
{ S<tw5!tJ  
for(int i=1;;i++) /wV|;D^ )  
{ \N,ox(f?gW  
String header=con.getHeaderFieldKey(i); 9)Fx;GxL  
if(header!=null) tt"<1 z@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NRi5 Vp2=  
Utility.log(header+" : "+con.getHeaderField(header)); c-a,__c?hx  
else a=iupXre9  
break; b/wpk~qi  
} |9CikLX)7  
}  I//=C6  
g.lTNQm$u  
*'%V}R[>  
public void splitterStop() ^*K=wE}AG  
{ OtG\Uw8  
bStop = true; *g/klK  
} =[6^NR(  
a`xq h2P  
#B `?}a=  
} ;_o]$hV|  
ekM? ' 9ez  
YuXJT*  
/* T(b9b,ov)  
**FileAccess.java x:Y9z_)O  
*//文件访问(定位,写) ;G[V:.o-  
package NetFox; 4,9$udiGY  
import java.io.*; 6Sr]<I +:  
fab'\|Y   
*FlPGBjJ  
public class FileAccessI implements Serializable{ +iVEA(0&$  
p"g|]@m  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !?2)a pM  
RandomAccessFile oSavedFile; hAGHb+:  
long nPos; _?{7%(C  
x9_mlZ  
bc)>h!'Y  
public FileAccessI() throws IOException 2hh8G5IaQ  
{ iOE. .xA:  
this("",0); @:lM|2:  
} nM,:f)z  
O'y8q[2KE  
i+_LKHQN  
public FileAccessI(String sName,long nPos) throws IOException SQKhht`M  
{ @<.@ X*#I  
oSavedFile = new RandomAccessFile(sName,"rw"); Gw M:f/eV  
this.nPos = nPos; (3#PKfY+  
oSavedFile.seek(nPos); 5KCB^`|b>t  
} nxLuzf4U5  
QV;o9j  
D /eH~  
public synchronized int write(byte[] b,int nStart,int nLen) 9!FX *}dC  
{ !jCgTo y  
int n = -1; K1& QAXyP  
try{ 1!#85SMx  
oSavedFile.write(b,nStart,nLen); %y1!'R:ZW  
n = nLen; jc^QWK*q  
} Lb*KEF%s  
catch(IOException e) ^ Ltho`  
{ -yqsJGY  
e.printStackTrace (); >I5:@6 Z  
} B9v>="F  
T1LYJ]5  
80xr zv  
return n; _z\/{  
} /d`"WK,  
^^y eC|~N:  
fgLjF,Y  
} \}jMC  
_fAgp_)  
Z8$}Rpo  
/* n 8cA8<  
**SiteInfoBean.java v2T2/y%  
*/ lCi{v.  
package NetFox; mU'<:gL+  
RNg?o [S  
96=<phcwN[  
public class SiteInfoBean { gI+8J.AG=  
FG?Mc'r&  
la!]Y-s)'4  
private String sSiteURL; //Site's URL 8@3K, [Mo  
private String sFilePath; //Saved File's Path sI ,!+  
private String sFileName; //Saved File's Name ~9X^3.nI  
private int nSplitter; //Count of Splited Downloading File @AyteHK  
\Mf>X\}  
PEMkx"h +  
public SiteInfoBean() 9 {4yC9Oz>  
{//nSplitter的缺省值为5 O-iE0t  
//default value of nSplitter is 5 4{VO:(geZ  
this("","","",5); /y$Omc^  
} hor7~u+  
d} >Po%r:  
bIQ,=EA1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x4_IUIgh  
{ qJ ey&_  
sSiteURL= sURL; }@DCcf$<  
sFilePath = sPath; ) SV.|  
sFileName = sName; j=\h|^gA  
this.nSplitter = nSpiltter; WI8}_){ d  
1? >P3C  
SzULy >e  
} ou,[0B3n0  
oXPA<ef o  
m</m9h8  
public String getSSiteURL() i FI74COam  
{ #]#9Xq  
return sSiteURL; x*7@b8J  
} Q>niJ'7WF  
( ?FH`<  
[%W'd9`>  
public void setSSiteURL(String value) Ufr@j` *  
{ pR0[qsQM  
sSiteURL = value; ,Oo`*'a[o7  
} NvK9L.K  
0K!3Ny9(  
eJDZ| $  
public String getSFilePath() z^Hc'oVXj:  
{ WQ|:TLQ  
return sFilePath; J^!;$Hkd  
} ;vx5 =^7P  
OL'Ito  
P.~UU S  
public void setSFilePath(String value) | dQ>)_  
{ W4$o\yA]  
sFilePath = value; (d9~z  
} ' jciX]g  
MK< y$B{}  
('J/Ww<  
public String getSFileName() WM bkKC.{J  
{ /:|vJ|dJ  
return sFileName; >P6"-x,["  
} awLvLkQb{  
a~o <>H  
XF`2*:7  
public void setSFileName(String value) )f8>kz(  
{ h]7_ N,  
sFileName = value; c:Ua\$)u3,  
} h>Kx  
,EqQU|  
*v<f#hB"  
public int getNSplitter() kk4 |4  
{ #G9 W65f  
return nSplitter; sz7*x{E  
} kc'$4 J4Tw  
! j~wAdHk  
DP_b9o \5  
public void setNSplitter(int nCount) Iix,}kzss  
{ r&=ulg  
nSplitter = nCount; Bfb~<rs[  
} ct+F\:e  
} $QbJT`,mr  
q~{) {t;  
c r=Q39{  
/* gC7!cn  
**Utility.java `Fqth^RK?p  
*/ RB>=#03  
package NetFox; K)SWM3r  
#*A'<Zm  
/<[0o]  
public class Utility { >a3m!`lq  
q~`hn(S  
Z[O hZ 9  
public Utility() eqtZU\GI>  
{ s.1F=u9a  
7w )?s@CD  
d<c29Y  
} Omd;  
ss^a=?~  
//线程睡眠 t FU4%c7V  
public static void sleep(int nSecond) k@xinK%O{  
{ EKc<|e,F  
try{ .jRI $vm  
Thread.sleep(nSecond); =<\22d5L  
} R~<N*En~  
catch(Exception e) :>-zT[Lcn  
{ XQ1]F{?/H  
e.printStackTrace (); 18$d-[hX  
} ]w*"KG!(  
} q@.>eB'92P  
IIk_!VzT  
//日志 VuLb9Kn  
public static void log(String sMsg) \zd[A~!  
{ u%-]-:c  
System.err.println(sMsg); pl8b&bLzi  
} hs6pp/h>  
M+"6VtZH  
#p+iwW-  
public static void log(int sMsg) HDm]njF%qQ  
{ 2gWR2 H@  
System.err.println(sMsg); wd:Yy  
} ~[H8R|j "  
} h!tpi`8\z  
e;i 6C%DB  
T;M ;c. U  
/* Om.%K>V  
**TestMethod.java /gAT@Vx  
*/ ^f[6NYS?  
package NetFox; P9!awLM-  
he|Q (?  
D:`Q\za  
public class TestMethod { Mi]^wCF  
$(}rTm  
w_"d&eYdg0  
public TestMethod() `2>p#`  
{ ///xx/weblogic60b2_win.exe f )Lcs  
try{ o Mz{j:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ry95a%&/s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NuOA'e+i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3a:Hx| Yg  
fileFetch.start(); 8Z !%rS  
} ,ye}p 1M  
catch(Exception e){e.printStackTrace ();} 8T+9 fh]I  
c5p,~z_Dtu  
{@X>!]  
} j$ T12  
AojL4H|  
y\v#qFVOZ  
public static void main(String[] args) Y:CX RU6eD  
{ l8~(bq1  
new TestMethod(); izSX  
} I`{3I-E  
} 9!Av sC9  
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