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http断点续传简单实现(java)

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/* 0 yuW*z  
**SiteFileFetch.java 7BK0}sxO  
*/ M42 Ssn)  
package NetFox; K1\a#w  
import java.io.*;  @Z\,q's  
import java.net.*; ,!Z *5  
DRp~jW(\y  
smRE!f*q  
public class SiteFileFetch extends Thread { clL2k8VS  
]|zp0d=&o  
V )x$|!(  
SiteInfoBean siteInfoBean = null; //文件信息Bean D6>2s\:>vp  
long[] nStartPos; //开始位置 GVYBa_gx  
long[] nEndPos; //结束位置 \]2]/=2tLd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \Zqng  
long nFileLength; //文件长度 mpuq 9)6  
boolean bFirst = true; //是否第一次取文件 YaKeq5%y  
boolean bStop = false; //停止标志 :D%"EJ  
File tmpFile; //文件下载的临时信息 M<.d8?p )  
DataOutputStream output; //输出到文件的输出流 QS` PpyBkd  
G~2jUyv  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) B8V>NvE~o  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4E]l{"k<  
{ aWWU4xe  
siteInfoBean = bean; 3=FZ9>by  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); snf~}:&   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); toya fHf  
if(tmpFile.exists ()) v9w'!C)b  
{ AX;8^6.F3  
bFirst = false; (e!0]Io@  
read_nPos(); }Qip&IN  
} wsIW |@  
else wVicyiY]  
{ ;t<QTGJ  
nStartPos = new long[bean.getNSplitter()]; z(_Ss@ $  
nEndPos = new long[bean.getNSplitter()]; vY  }A  
} TZ(cu>  
K1r#8Q!t  
8S mCpg  
H:t$'kb`  
} K?B{rE Lp  
b\vKJ2  
!`g~F\l  
public void run() hyCh9YOu)  
{ [ sN EHf  
//获得文件长度 (@<lRA ^  
//分割文件 6r"eN%m  
//实例FileSplitterFetch wkA+j9.  
//启动FileSplitterFetch线程 !}v=N";c  
//等待子线程返回 Oiz ,w7LRh  
try{ Ljxz.2LGr  
if(bFirst) s%C)t6`9  
{ B_nVP  
nFileLength = getFileSize(); TcjEcMw,  
if(nFileLength == -1) Hfw q/Is  
{ ^)(bM$(`  
System.err.println("File Length is not known!"); ~P8tUhffK  
} T>}5:,N~  
else if(nFileLength == -2) 66/3|83Z  
{ Ghx3EVqnx"  
System.err.println("File is not access!"); E^ P,*s  
} q|o}+Vr  
else DoJ\ q+  
{ J&[@}$N  
for(int i=0;i<nStartPos.length;i++) !%^^\,  
{ +$C 4\$t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8jd;JPz@\  
} P `}zlml  
for(int i=0;i<nEndPos.length-1;i++) 10<x.8fSP  
{ -fwoTGlX  
nEndPos = nStartPos[i+1]; C${Vg{g7a  
} @R/07&lBR  
nEndPos[nEndPos.length-1] = nFileLength; {sihus#Q  
} QMa;Gy  
} k. MUdU^  
 tBq nf v  
pm*xb]8y  
//启动子线程 #MX'^RZ>2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;> _$`  
for(int i=0;i<nStartPos.length;i++) ORyE`h  
{ NO|KVZ~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F~%]6^$w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [Sr,h0h6  
nStartPos,nEndPos,i); 8YZbP5'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U=DmsnD,  
fileSplitterFetch.start(); A )^`?m3  
} GN ]cDik  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T&%ux=Jt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Kqp(%8mf  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G;v8$)Zj  
nEndPos = " + nFileLength); #33fGmd[  
// fileSplitterFetch[nPos.length-1].start(); r"``QmM  
%X4xv_o`f  
WF1px%  
//等待子线程结束 TD'L'm|2  
//int count = 0; aGJC1x  
//是否结束while循环 6l5:1|8b,!  
boolean breakWhile = false; 'MEz|Z  
*AoR==:ya  
O4r0R1VQM  
while(!bStop) zm]aU`j  
{ /tP|b _7O  
write_nPos(); BGOuDKz9C  
Utility.sleep(500); v1BDP<qU2  
breakWhile = true; jT8#C=a7  
e\Y*F  
mz @T  
for(int i=0;i<nStartPos.length;i++) RIb4!!',c  
{ )-0kb~;|  
if(!fileSplitterFetch.bDownOver) B:gjAb}9T  
{ /4a._@1h[y  
breakWhile = false; JRSSn]pw  
break; 19O,a#{KHf  
} q#vQv 5  
} R A KFU  
if(breakWhile) .q `Hjmg<  
break; Xe<sJ. &Wf  
rM .|1(u  
u=/{cOJI6  
//count++; Y%PwktQm  
//if(count>4) &j4xgh9  
// siteStop(); a= DcZ_M  
} #0ETY\}ZD  
S{;sUGcu  
c0%"&a1]]V  
System.err.println("文件下载结束!"); f0X_fm_q  
} bn^{c  
catch(Exception e){e.printStackTrace ();} NWM8[dI  
} V n*  
3pv4B:0  
O-LO/*5MI  
//获得文件长度 ~-EOjX(X'E  
public long getFileSize() K[ (NTp$E  
{ 9cf:pXMi  
int nFileLength = -1; @!`Xl*l  
try{ }dp=?AFg  
URL url = new URL(siteInfoBean.getSSiteURL()); .WPV dwV4U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =R#Qx,  
httpConnection.setRequestProperty("User-Agent","NetFox"); pPcTrN'  
|/09<F:L[  
x$1]M DAGb  
int responseCode=httpConnection.getResponseCode(); 0BIy>wy:  
if(responseCode>=400) ;.TRWn#  
{ /9HVY %n  
processErrorCode(responseCode); k Mu8"Az  
return -2; //-2 represent access is error Q^ pmQ  
} B[V+ND'(  
+)y^ 'Qs  
{ jhr<  
String sHeader; VY~yg*  
k 9L? +PD  
U@-^C"R  
for(int i=1;;i++) vH#huZA?7  
{ g=;%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #=6E\&NC  
//Utility.log(in.readLine()); W}5xmz  
sHeader=httpConnection.getHeaderFieldKey(i); kL$!E9  
if(sHeader!=null) A<1hOSCz\  
{ n}'=yItVL1  
if(sHeader.equals("Content-Length")) c17_2 @N  
{ _tBTE%sO  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); S<4c r  
break; sC='_h  
} TMig-y*[  
} %KmiH ;U  
else u/M+u;  
break; pL{U `5S  
} BaSZ71>9]r  
} H`0|tepz  
catch(IOException e){e.printStackTrace ();} cFeXpj?GV  
catch(Exception e){e.printStackTrace ();} yls ^cyX  
d5oIH  
'=Rs/EDME  
Utility.log(nFileLength); Qk,I^1w?7  
ch0{+g&  
w)Q0_2p.  
return nFileLength; Vl:^>jTki  
} hnDBFQ{  
[/Rf\T(,jn  
cUA7#1\T=  
//保存下载信息(文件指针位置) 89o/F+_b  
private void write_nPos() Z@3i$8  
{ ynE)Xdh  
try{ kP-3"ACG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <Dwar>}  
output.writeInt(nStartPos.length); ;\=M; Zt  
for(int i=0;i<nStartPos.length;i++) [N/"5 [  
{ 4|CtRF<L  
// output.writeLong(nPos); %`r?c<P}  
output.writeLong(fileSplitterFetch.nStartPos); [/e<l&y  
output.writeLong(fileSplitterFetch.nEndPos); MBqt&_?K  
} JwAYG5W  
output.close(); ;i<|9{;  
} tE)suU5Y  
catch(IOException e){e.printStackTrace ();} prTw'~(B  
catch(Exception e){e.printStackTrace ();} P;Ga4Q.  
} Zo g']=  
X4 A<[&F/  
q U]gj@R  
//读取保存的下载信息(文件指针位置) -( f)6a+H  
private void read_nPos() MP!d4  
{ iZM+JqfU|D  
try{ hFH*B~*:#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !*oi!ysU;O  
int nCount = input.readInt(); QNpqdwu%h  
nStartPos = new long[nCount]; S/4^ d &Gr  
nEndPos = new long[nCount]; QWzB6H]  
for(int i=0;i<nStartPos.length;i++) ~v6OsH%vx  
{ @te!Jgu{  
nStartPos = input.readLong(); >_|O1H./4  
nEndPos = input.readLong(); EUN81F?  
} $shoasSuI  
input.close(); .6`9H 1  
} &(xH$htv1  
catch(IOException e){e.printStackTrace ();} (X?%^^e!  
catch(Exception e){e.printStackTrace ();} 4}4Pyjh  
} 0@H|n^Md#  
&NH$nY.r  
NiU2@zgl  
private void processErrorCode(int nErrorCode) ]%?YZn<{  
{ G>1eFBh }  
System.err.println("Error Code : " + nErrorCode); 1T-8K r  
} M#As0~y  
wPwXM!  
*=+td)S/1  
//停止文件下载 `Ye\p6v!+  
public void siteStop() <8d^^0  
{ UrYZ` J  
bStop = true; QlO0qbG[y  
for(int i=0;i<nStartPos.length;i++)  PYM(Xz$  
fileSplitterFetch.splitterStop(); vK _?<>  
a hR ^  
%l,,_:7{  
}  B[Zjfc  
} 4KH45|; 3  
//负责部分文件的抓取 ~%SH3$  
**FileSplitterFetch.java E#u l IgD  
*/ &?*V0luP)  
package NetFox; %jJ>x3$F  
9hOJvQ2U]  
fO0XA"=  
import java.io.*; +eFFSt  
import java.net.*; 2@%$;.  
<iH`rP#  
^OstR`U3  
public class FileSplitterFetch extends Thread { 2\7`/,U6  
:k.NbN$i\  
pO ml8SQf  
String sURL; //File URL %2XHNW  
long nStartPos; //File Snippet Start Position rld67'KcE  
long nEndPos; //File Snippet End Position `<\1[HJ\  
int nThreadID; //Thread's ID X&0 uI*r  
boolean bDownOver = false; //Downing is over @> E2?CV  
boolean bStop = false; //Stop identical 2ioQb`=  
FileAccessI fileAccessI = null; //File Access interface \Dd-Xn_b  
}T%}wdj  
4*e0 hWp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1rkE yh??  
{ B:!W$ <  
this.sURL = sURL; Z(Bp 0a  
this.nStartPos = nStart; V{^!BBQ  
this.nEndPos = nEnd; V??dYB(  
nThreadID = id; u"d~!j1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 89wU-Aggq  
} oE(7v7iY  
uoXAQ6k  
L7V G`h;  
public void run() = Wu *+paQ  
{ bZ|FnY}FB  
while(nStartPos < nEndPos && !bStop) UmQ?rS8d  
{ ,:Lb7bFv>  
[L:o`j  
K9OYri^TQ  
try{ xv&Q+HD  
URL url = new URL(sURL); .8P.)%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JvT"bZk( o  
httpConnection.setRequestProperty("User-Agent","NetFox"); "87ghj_}  
String sProperty = "bytes="+nStartPos+"-"; 2U; t(,dn'  
httpConnection.setRequestProperty("RANGE",sProperty); m<0&~rg   
Utility.log(sProperty); /C4^<k\  
<K8\n^i~c  
wyQzM6:,yX  
InputStream input = httpConnection.getInputStream(); *{y K 8  
//logResponseHead(httpConnection); {6~l$  
2EfF=Fm>  
#@"<:!?z  
byte[] b = new byte[1024]; AKRTBjG"  
int nRead; av$/Om :  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h3Q21D'f  
{ _ h": >  
nStartPos += fileAccessI.write(b,0,nRead); DBCK2PlJ  
//if(nThreadID == 1) S p^9& ^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l"2OP6d  
} IjR'Qou5  
RW}"2  
yRiP{$E  
Utility.log("Thread " + nThreadID + " is over!"); 5<ux6,E1{  
bDownOver = true; j'BMAn ?  
//nPos = fileAccessI.write (b,0,nRead); ##EYH1P]  
} hYM@?/(q  
catch(Exception e){e.printStackTrace ();} d\ ~QBr?  
} dVFf.  
} ODC8D>ZYl  
tX"Th'Qi  
yZ7,QsEsN  
//打印回应的头信息 HfvTxaK  
public void logResponseHead(HttpURLConnection con) Ie4hhW  
{ S}ECW,K  
for(int i=1;;i++) ]f_6 '|5 A  
{ 9> g,  
String header=con.getHeaderFieldKey(i); 'I /aboDB  
if(header!=null) stk9Ah  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y;AL'vm9  
Utility.log(header+" : "+con.getHeaderField(header)); H03jDM8Q  
else D*YM[sN`  
break; 8kIR y   
} =n' 4?W@  
} ^-[?#]  
bLd#xXl  
X0M1(BJgGo  
public void splitterStop() SJ};TEA  
{ C,pJ`:P  
bStop = true; '^FGc  
} lME)?LOI  
/M*a,o  
@;H,gEH^  
} p$x{yz3  
" $ew~;z  
wlEo"BA  
/* IW% |G  
**FileAccess.java S.d^T](  
*//文件访问(定位,写) \0H's{uek  
package NetFox; j`*#v  
import java.io.*; ,57`D'  
!DI{:I_h(  
`/MvQ/  
public class FileAccessI implements Serializable{ =l0Jb#d  
}QsZ:J.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2d {y M(=(  
RandomAccessFile oSavedFile; {|yob4N  
long nPos; fz3 lV  
~35U]s@v  
yin'vgQ  
public FileAccessI() throws IOException ?l$Nf@-  
{ 7zv1 wb  
this("",0); ]+m/;&0  
} jOyvDY9\  
j $TwL;  
]d]JXt?)i  
public FileAccessI(String sName,long nPos) throws IOException UEzb^(8>  
{ , E$@=1)  
oSavedFile = new RandomAccessFile(sName,"rw"); !QT'L,_  
this.nPos = nPos; 2"d!(J6}K  
oSavedFile.seek(nPos); u]ZqOJXxu  
} KV*xApb9y  
v (2GX  
DS%\SrC  
public synchronized int write(byte[] b,int nStart,int nLen) /De^  
{ 2AVa(  
int n = -1; ?^EXTU85`"  
try{ f5GdZ_  
oSavedFile.write(b,nStart,nLen); >Z;jY*  
n = nLen; *\o/q[  
} 1<h>B:  
catch(IOException e) Vm|Y$ C  
{ {" 4e+y  
e.printStackTrace (); p*8-W(u)  
} \6 93kQ  
q;:6_Qr  
;kJu$U  
return n; 3J=Y9 }  
} dna6QV>A  
Bs M uQ|!  
NcAp_q? 4  
} k3t78Qg  
~WpGf,  
n3`&zY  
/* SgEBh  
**SiteInfoBean.java tL+OCLF;  
*/ :~ A%#  
package NetFox; wO>L#"X^v  
:SsUdIX;P  
7E @+  
public class SiteInfoBean { p<v.Q   
i#%a-I:M  
wfjc/u9W6R  
private String sSiteURL; //Site's URL }BmS )J q  
private String sFilePath; //Saved File's Path U5]pi+r  
private String sFileName; //Saved File's Name t nS+5F  
private int nSplitter; //Count of Splited Downloading File _7D_72  
4TwQO$C  
2nFy`|aA%  
public SiteInfoBean() Y= 7%+WyD  
{//nSplitter的缺省值为5 P(>(K{v  
//default value of nSplitter is 5 iHp\o=#  
this("","","",5); Z.wA@ ~e  
} M@thI%lR  
9F^;!  
b`_w])Y@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &VBd~4|p  
{ f2,1<^{  
sSiteURL= sURL; P=5NKg  
sFilePath = sPath; V >,Z-&.%  
sFileName = sName; o_Si mJFK  
this.nSplitter = nSpiltter; ?K@t0a   
I=Oy-  
SxjCwX">  
} . /p|?pu  
do-c1;M  
+} mk>e/  
public String getSSiteURL() K+T .o6+  
{ i%#$*  
return sSiteURL; =_[Z W  
} n tP|\E  
- ~4+w  
SjdZyJa  
public void setSSiteURL(String value) R1-k3;v^  
{ J@9}`y=K  
sSiteURL = value; ~^vC,]hU  
} -K[782Q  
p[2GkP  
jvVi%k  
public String getSFilePath() b8f+,2Tk  
{ htPqT,L  
return sFilePath; ^I]{7$6^  
} L "<B;u5pM  
a9~"3y  
:h:@o h_=  
public void setSFilePath(String value) (XH2Sy  
{ IB|]fzy  
sFilePath = value; 9B +wYJp  
} +/?iCmW  
s~},y]YV  
E-1"+p  
public String getSFileName() ^UA(HthY  
{ ]Fb0Az  
return sFileName; %TrF0{NR90  
} $gMCR b,  
%So] 3;'  
XV'fW~j\  
public void setSFileName(String value) yW.COWL=)  
{ L<(VG{)Z  
sFileName = value; Zwe[_z!*D  
} k*-NsNPw$  
x:t<ZG&Xwg  
Ewo*yY>  
public int getNSplitter() (3*UPZv  
{ &2EBk=X  
return nSplitter; nE y]`  
} tk/`%Q  
*(cU]NUH_  
YYRT.U'  
public void setNSplitter(int nCount) $gp!w8h  
{ ^t'3rft  
nSplitter = nCount; &k T"oK  
} F3ZxhkF  
} J -Qh/d%]  
i9UI,b%X  
LNQSb4  
/* wUi(3g|A  
**Utility.java ?kt=z4h9(  
*/ | W#~F&{]  
package NetFox; OYf{?-QD  
~_!ts{[E  
Xz;b,C&*t  
public class Utility { .F0]6#(  
#B\=Aa`*  
JatHSW7j9  
public Utility() ^Y^"'"  
{ c!&Qj  
s0{ NsK>  
!W1eUY  
} Xy#V Q{!  
JZ`L%  
//线程睡眠 N_C_O$j  
public static void sleep(int nSecond) xKp0r1}  
{ |0{ i9 .=  
try{ Kla:e[{  
Thread.sleep(nSecond); um8AdiK  
} R9. HD?H@  
catch(Exception e) U  5`y  
{ @~jxG%y86  
e.printStackTrace (); ~uPk  
} )LswSV  
} ~Sy-ga J  
I{dl%z73  
//日志 i=QqB0  
public static void log(String sMsg) +Z? [M1g  
{ 6b:DJ  
System.err.println(sMsg); ~HP LV  
} eX<K5K.B  
wsg//Ec]  
FU@uH U5fd  
public static void log(int sMsg) Wp*sP Z  
{ R'EW7}&  
System.err.println(sMsg); U($^E}I2(  
} L? ;/cO^  
} ,0T)Oc|HL/  
o_ yRn16  
xQz#i-v  
/* "2h5m4  
**TestMethod.java A9BxwQU#  
*/ @;9()ad  
package NetFox; xbC~ C~#  
Zd>ZY,-5  
!cCg/  
public class TestMethod { ^`&HWp  
|t\KsW  
ci7~KewJ*  
public TestMethod() _hoAW8i  
{ ///xx/weblogic60b2_win.exe 0]a15  
try{ u ~71l)LA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'P/taEi=R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); a!.!2a&t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); spiDm:Xe  
fileFetch.start(); P $h;SK  
} -fM1$/]  
catch(Exception e){e.printStackTrace ();} }W "(c YN_  
h}6b&m  
y@9Y,ZR*  
} H!JWc'(<$  
EHWv3sR-  
DN|vz}s  
public static void main(String[] args) -I vL+}K  
{ $i&\\QNn  
new TestMethod(); eH=c|m]!P  
} \|!gPc%s  
} S 1ibw\'  
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