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http断点续传简单实现(java)

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/* .XkMk|t8  
**SiteFileFetch.java ^m/14MN|  
*/ NxVw!TsR  
package NetFox; a=XW[TY1  
import java.io.*; hk/! 'd  
import java.net.*; 1xU3#b&2tC  
6{ ,HiY  
En&5)c+js4  
public class SiteFileFetch extends Thread { k'$!(*]\b  
bln/1iS  
q~L^au8  
SiteInfoBean siteInfoBean = null; //文件信息Bean s/:Fwr4q#a  
long[] nStartPos; //开始位置 p'sc0@}_O  
long[] nEndPos; //结束位置 @$"L:1_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )HD`O~M>  
long nFileLength; //文件长度 `:O\dN>ON  
boolean bFirst = true; //是否第一次取文件 J(#mtj>v_  
boolean bStop = false; //停止标志 @\w,otT  
File tmpFile; //文件下载的临时信息 n6(i`{i  
DataOutputStream output; //输出到文件的输出流 }tPk@$  
m^_6:Q0F!8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) '!P"xBVAu  
public SiteFileFetch(SiteInfoBean bean) throws IOException YUQtMf9  
{ mR8W]'gl.L  
siteInfoBean = bean; z4@k$ L8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9'x)M?{8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {k5X*W  
if(tmpFile.exists ()) f'q 28lVf  
{ [+w3J#K  
bFirst = false; CSV;+,Vv  
read_nPos(); +,50q N:%[  
} {B*W\[ns  
else 0F#>CmD  
{ 4f~["[*ea  
nStartPos = new long[bean.getNSplitter()]; F?m?UQS'u  
nEndPos = new long[bean.getNSplitter()]; zq1mmFIO  
} hh~n#7w~IR  
FuX 8v  
dY" }\v6  
$|KaBx1  
} ;NV'W]  
L:M0pk{T  
V@d )?T  
public void run() PuxK?bwC  
{ k>E`s<3  
//获得文件长度 |3K)$.6~  
//分割文件 .$", *d  
//实例FileSplitterFetch x'Pi5NRE  
//启动FileSplitterFetch线程 JaWv]@9*  
//等待子线程返回 hJ5z/5aE;  
try{ 3`HnLD/  
if(bFirst) w(1Gi$Z(Q)  
{ VGw(6`|!  
nFileLength = getFileSize(); :)jJge&^p  
if(nFileLength == -1) ;Qi }{;+  
{ ~#}Dx :HH  
System.err.println("File Length is not known!"); <DH*~tLp2  
} i`)!X:j  
else if(nFileLength == -2) tvX>{-M  
{ G6K  <  
System.err.println("File is not access!"); [oc~iDx%W  
} <B /5J:o<  
else # x>ga  
{ %o?IsIys  
for(int i=0;i<nStartPos.length;i++) Pw@olG'Ah  
{ 5&CDHc7Oj  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); rZ_>`}O2  
}  Voh hQ  
for(int i=0;i<nEndPos.length-1;i++) 5)zn:$cz  
{ 4c~>ci,N?(  
nEndPos = nStartPos[i+1]; kqvow3u  
} W[NEe,.>  
nEndPos[nEndPos.length-1] = nFileLength; J NC  
} n,P5o_^:  
} Swtbl`,  
:9l51oE7  
\g-j9|0  
//启动子线程 p4VqV6LwD  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; LF*Q!  
for(int i=0;i<nStartPos.length;i++) |0bc$ZY:  
{ 2aw&F Z?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,/&Zw01dGN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }tST)=M`  
nStartPos,nEndPos,i); ^T4Ay=~{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;52'}%5  
fileSplitterFetch.start(); Jf:,y~mV  
} +rNkN:/L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H L<s@kEZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tn/T6C^)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <XQ.A3SG!  
nEndPos = " + nFileLength); HTz+K6&  
// fileSplitterFetch[nPos.length-1].start(); mnF}S5[9  
P\~{3U  
vxN0,l  
//等待子线程结束 Cd#E"dY6  
//int count = 0; ]_*S~'x  
//是否结束while循环 =lr)gj  
boolean breakWhile = false; ARh6V&Hi-  
w#G2-?aj  
KA]*ox6j;  
while(!bStop) yno('1B@  
{ E@QA".  
write_nPos(); 6k])KlJ2;  
Utility.sleep(500); 4ax|Vb)D  
breakWhile = true;  W^g[L:s  
w,.qCpT$_  
=~FG&rk^  
for(int i=0;i<nStartPos.length;i++) (N~$x  
{ ^E>CGGS4  
if(!fileSplitterFetch.bDownOver) x.DzViP/  
{ ro| vh\y  
breakWhile = false; {^q)^<#JT  
break; z>vtEV))  
} +6W(z3($  
} }4c/YP"a'E  
if(breakWhile) 2BB<mv K4  
break; Ef7:y|?  
|qjZ38;6  
#I\Y= XCY  
//count++; Mpx/S<Z  
//if(count>4) z YDK $  
// siteStop(); eS!C3xC;J]  
} "/%89 HMD  
(L69{n  
&d$~6'x*  
System.err.println("文件下载结束!"); PjqeE,5  
} XYbyOM VI  
catch(Exception e){e.printStackTrace ();} ?{J!#`tfV  
} A[/I#Im7  
):6 -  
{E,SHh   
//获得文件长度 )3E,D~1e%  
public long getFileSize() cwtD@KC[B  
{ g@nk.aRw  
int nFileLength = -1; SX+RBVZU  
try{ #n})X,ip2  
URL url = new URL(siteInfoBean.getSSiteURL()); Sgj/s~j~1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )r!e2zc=Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); V 7<eQ0;m  
Px4/O~bLk  
/8CY0Ey  
int responseCode=httpConnection.getResponseCode(); *{/@uO  
if(responseCode>=400) F&@|M(  
{ ]A:( L9  
processErrorCode(responseCode); sB7" 0M  
return -2; //-2 represent access is error OeTu?d&N  
} ( )|3  
!L\'Mk/=A  
r+g jc?Ol  
String sHeader; $B _Nc*_e  
SPwPCI1?  
6$ e]i|e  
for(int i=1;;i++) (r F?If  
{ 8 $ ~3ra  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); jUY+3"?   
//Utility.log(in.readLine()); ( tn< VK.  
sHeader=httpConnection.getHeaderFieldKey(i); !$kR ;Q"/  
if(sHeader!=null) wJIB$3OT  
{ Ph)| j&]  
if(sHeader.equals("Content-Length")) 6v47 QW|'  
{ O-GxUHwW r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); %Y',|+Arx  
break; z}APR@?`n8  
} P/ aDd@j  
} t.=Oj  
else 5+L8\V9;  
break; :('I)C  
}  X4I]9 t\  
} xXOw:A'  
catch(IOException e){e.printStackTrace ();} XS/n>C  
catch(Exception e){e.printStackTrace ();} V*qY"[   
{8m1dEC^@Q  
_Y#Bm/*  
Utility.log(nFileLength); {%7<"  
~I$}#  
/2w@ K_Px6  
return nFileLength; qX@9N=g`#O  
} w6U @tW  
#O|lfl>}  
8ui=2k(  
//保存下载信息(文件指针位置) TG]}X\c+V|  
private void write_nPos() dQ6GhS ~  
{ Mo|yv[(K ,  
try{ jsWX 6(=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); YN^jm  
output.writeInt(nStartPos.length); on5 0+)uN  
for(int i=0;i<nStartPos.length;i++) J#@lV  
{ zPBfiK_hV  
// output.writeLong(nPos); .eTk=i[N-  
output.writeLong(fileSplitterFetch.nStartPos); okDJ(AIV+  
output.writeLong(fileSplitterFetch.nEndPos); wP`sXPSmIu  
} !aeNq82  
output.close(); PW^ 8;[\QP  
} ;IhPvff  
catch(IOException e){e.printStackTrace ();} 9HKf^+';n  
catch(Exception e){e.printStackTrace ();} 3kw}CaZ6  
} sRi%1r7  
\^s2W:c  
1*c>I@I;  
//读取保存的下载信息(文件指针位置) |Mlh;  
private void read_nPos() )k~1,  
{ <ge}9pU)o^  
try{ wT% "5:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A;t zRe  
int nCount = input.readInt(); uQ1jwYK`7  
nStartPos = new long[nCount]; -$L(y@%X^  
nEndPos = new long[nCount]; X 7&U3v  
for(int i=0;i<nStartPos.length;i++) L]>4Nd  
{ xN "wF-s4?  
nStartPos = input.readLong(); w`Xg%*]}  
nEndPos = input.readLong(); ^BNp`x;;`  
} #NM JZ  
input.close(); x\]z j!  
} SJ[AiHR  
catch(IOException e){e.printStackTrace ();} 6`W|V+6|7  
catch(Exception e){e.printStackTrace ();} TU-c9"7M~  
} MA"#rOcP  
eaxfn]gV  
2:~cJk{  
private void processErrorCode(int nErrorCode) /=ACdJ  
{ \bRy(Z)  
System.err.println("Error Code : " + nErrorCode); 2YluJ:LN  
} ex0oAt^  
`{L{wJ:&a  
Z fqQ {_  
//停止文件下载 ' 3VqkQ4  
public void siteStop() PC0HH  
{ O(Td:Zdp  
bStop = true; OaNc9c"  
for(int i=0;i<nStartPos.length;i++) <vLdBfw&N  
fileSplitterFetch.splitterStop(); i :EO(`  
c _p[yS  
kU(kU2u%9  
} #!1IP~  
} Yg|"-  
//负责部分文件的抓取 BDp:9yau  
**FileSplitterFetch.java rFO_fIJno  
*/ 9nO(xJ"e4  
package NetFox; 'tut4SwC  
pMDH  
{70 Ou}*  
import java.io.*; ~K%k 0kT  
import java.net.*; Md?acWE*L  
c+wuC,  
WN1Jm:5YV  
public class FileSplitterFetch extends Thread { ]'6'<S  
K7S754m  
ysl8LK   
String sURL; //File URL cp|:8 [  
long nStartPos; //File Snippet Start Position n{z8Ao%  
long nEndPos; //File Snippet End Position iA&oLu[y3  
int nThreadID; //Thread's ID qz87iJp&  
boolean bDownOver = false; //Downing is over !6{J q]  
boolean bStop = false; //Stop identical j7,13,t1-  
FileAccessI fileAccessI = null; //File Access interface ' #KA+?@  
7\f{'KL  
gINwvzW{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "B~WcC  
{ _Ws#UL+Nq  
this.sURL = sURL; 4*H(sq  
this.nStartPos = nStart; tr5'dX4]  
this.nEndPos = nEnd; K:uQ#W.&  
nThreadID = id; f%L:<4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  c,.0d  
} l$=Gvb  
Xn PJC'  
=>e?l8`%  
public void run() 'Z59<Ya&x  
{ f>O54T .L.  
while(nStartPos < nEndPos && !bStop) <3)|44.o&  
{ k+f1sV[4}  
t[/\KG8  
y~x#pC*w  
try{ |1lf(\T_  
URL url = new URL(sURL); $vW^n4!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F:M/z#:~  
httpConnection.setRequestProperty("User-Agent","NetFox"); fJvr+4i4k  
String sProperty = "bytes="+nStartPos+"-"; - *r[  
httpConnection.setRequestProperty("RANGE",sProperty); HE@-uh  
Utility.log(sProperty); $]nVr(OZ_  
avmcGyL  
]&' jP  
InputStream input = httpConnection.getInputStream(); O(WEgz  
//logResponseHead(httpConnection); mn(/E/  
FLK"|*A  
?ISI[hoc  
byte[] b = new byte[1024]; "k/;`eAP  
int nRead; =!(S<];  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W;q#ZD(;  
{ %N7gT*B:  
nStartPos += fileAccessI.write(b,0,nRead); eSJAPU(D  
//if(nThreadID == 1) -<]\l3E&J  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Av@& hD\  
} ;tXB46  
>c}:   
q|R+x7x  
Utility.log("Thread " + nThreadID + " is over!");  ^8b~ZX  
bDownOver = true; ! Zno[R  
//nPos = fileAccessI.write (b,0,nRead); QjehDwt|  
} F19;RaP+  
catch(Exception e){e.printStackTrace ();} %uh R'8"  
} l}dj{s  
} A>4l/  
+GRxHuW,  
K3a>^g  
//打印回应的头信息 L-`(!j  
public void logResponseHead(HttpURLConnection con) Q -M rH   
{ 7ytm .lU  
for(int i=1;;i++) .L~fFns/  
{ [t {vYo  
String header=con.getHeaderFieldKey(i); _e;N'DZ  
if(header!=null) O\LjtMF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mipi]*ZfXE  
Utility.log(header+" : "+con.getHeaderField(header)); @QvfN>T  
else /;zZnF\ e  
break; 37%`P \O;s  
} >|v=Ba6R0  
} p Z0=  
t^`<*H  
luJ{Iq  
public void splitterStop() We[<BJ o4  
{ |3s.;w K  
bStop = true; *K]>}  
} eUX@9eML  
C}x4#bNK  
.a ~s_E  
} 2q2p=H>&  
e@='Q H  
Z}]:x `fXd  
/* pA*D/P-  
**FileAccess.java zfk'>_'  
*//文件访问(定位,写) =4YbVA+(  
package NetFox; j:3A;r\  
import java.io.*; ]$*$0  
HY*l4QK  
XMjI}SPG  
public class FileAccessI implements Serializable{ p=:7 atE  
d)`nxnbMeM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Yt\E/*%  
RandomAccessFile oSavedFile; n,C D4Nv  
long nPos; l=Lmr  
-0=}|$H.  
FCsyKdM  
public FileAccessI() throws IOException wxdh?sQ  
{ ,apd3X%g  
this("",0); tXssejiE%  
} $K=K?BV[  
$#6 Fnhh}  
/ig^7+#  
public FileAccessI(String sName,long nPos) throws IOException u!=]zW%  
{ >=.ch5h3J)  
oSavedFile = new RandomAccessFile(sName,"rw"); ?K= gg<  
this.nPos = nPos; GM34-GH+  
oSavedFile.seek(nPos); *Y| lO  
} eukX#0/^  
nOA ,x  
{|8:U}<#h  
public synchronized int write(byte[] b,int nStart,int nLen) 5Ws:Ei{R  
{ 842Mydom  
int n = -1; E9~&f^f  
try{ m? \#vw$  
oSavedFile.write(b,nStart,nLen); Y/?DSo4G  
n = nLen; (hD X4;4  
} jgZX ~D  
catch(IOException e) :Su5  
{ OF<[Nh\.  
e.printStackTrace (); -y7l?N5F>  
} ex;Y n{4  
DYy@t^sC  
LaAgoarN  
return n; .HH,l  
} S4@117z5  
~|$) 1  
MSxU>FX0  
} xc3Ov9`8%  
%j 9vX$Hj  
W#oEF/G  
/* ;DT"S{"7  
**SiteInfoBean.java HbJadOK  
*/ 8yJk81 gY  
package NetFox; ;n:H6cp  
|r<.R>  
$w2[5|^S  
public class SiteInfoBean { juve9HaW  
Z(Ls#hp  
Px^<2Q%Fs  
private String sSiteURL; //Site's URL Yc|-sEK/  
private String sFilePath; //Saved File's Path A61-AwvF8-  
private String sFileName; //Saved File's Name *`\4j*$^  
private int nSplitter; //Count of Splited Downloading File 0*]<RM  
<9MQ  
n]6w)wE (  
public SiteInfoBean() gvwCoCbb  
{//nSplitter的缺省值为5 U3VsMV*Y  
//default value of nSplitter is 5 N?`GZ+5  
this("","","",5); //4p1^%  
} `"bRjC"f]  
do :RPZ!  
<try%p|f  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /ab K/8ZQ  
{ E`sapk  
sSiteURL= sURL; e2VL/>y`  
sFilePath = sPath; l#J>It\  
sFileName = sName; $D2Ain1  
this.nSplitter = nSpiltter; * (XgUJ q+  
c+\Gd}IJq  
QKL]O*  
} QVA!z##  
HjE Tinm"  
J[_?>YJ  
public String getSSiteURL() 4=#QN  
{ E!(`275s  
return sSiteURL; 'KN!m| z  
} X  f'  
@)M.u3{\  
)9;kzp/  
public void setSSiteURL(String value) 2Xk1A S  
{ z<C~DH  
sSiteURL = value; Vv* 5{_  
} rnt$BB[g  
OkO@BWL  
H603L|4  
public String getSFilePath() 8)Bn?6.  
{ ROI$;B(  
return sFilePath; 4tN~UMw?  
} "MVN /Gl  
DQHGq_unP  
T=)L5Vuq<  
public void setSFilePath(String value) #7E&16Fk  
{ H6+st`{  
sFilePath = value; BRQ5  
} )F9V=PJE  
uma9yIk  
F\$}8,9  
public String getSFileName() C8%nBa /  
{ $F==n4)  
return sFileName; s13 d*  
} rH9|JEz  
{Ac3/UM/  
h: (l+jr  
public void setSFileName(String value) kv`3Y0R-"  
{ R|^t~h-  
sFileName = value; MJk:s[o  
} ^<H#dkECG  
<MDFf nj  
c9TkIe  
public int getNSplitter() >5YYij5Aj  
{ s!zr>N"  
return nSplitter; 1,sO =p)Yg  
} _KlPbyLU  
)Z`viT  
.~/;v~bL  
public void setNSplitter(int nCount) }N=zn7W  
{ I5AjEp  
nSplitter = nCount; jq]\oY8y  
} ]{l O  
} ;Q%19f3,6  
ckkM)|kK  
p RfHbPV?  
/* Wn)A/Z ^r  
**Utility.java .m % x-i  
*/ 6(Rq R  
package NetFox; n$VPh/  
enO=-#  
Vf* B1Zb  
public class Utility { ]4pC\0c  
Y K62#;  
kKTED1MW&W  
public Utility() ;?[+vf")  
{ E?W!.hbA  
bu!<0AP"N+  
[ZpG+VAJ8  
} a~+WL  
z K]%qv]  
//线程睡眠 +vY`?k`  
public static void sleep(int nSecond) K LM^O$=  
{ I2!&="7@  
try{ pPqbD}p  
Thread.sleep(nSecond); hB1iSm  
} 5nlyb,"^g  
catch(Exception e) "Kf~`0P  
{ AZm)$@e)  
e.printStackTrace (); +/ d8d  
} E~U|v'GCd  
} ZtZV:re=  
a[OLS+zf!P  
//日志 A&|(%  
public static void log(String sMsg) kT3;%D^  
{ iY`7\/H!L  
System.err.println(sMsg); =(uy':Dbn*  
} 1 jd=R7  
9U%}"uE  
BJ;cF"Kp  
public static void log(int sMsg) T%xL=STJNy  
{ # SOj4W  
System.err.println(sMsg); bSKV|z/x  
} HGMH g  
} <. ]&FPJ  
GoGgw]h>x  
N1zrfn-VU  
/* LWR &(p.%  
**TestMethod.java -|UX}t*  
*/ {ca^yHgGy  
package NetFox; o".O#^3H%  
~]s"PV:|  
s~'C'B?  
public class TestMethod {  l3 Bc g  
iK23`@&% _  
ymJw{&^am  
public TestMethod() \^Q)`Lqp:g  
{ ///xx/weblogic60b2_win.exe 246!\zf  
try{ mLdyt-1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3^Q U4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1T^L) %&p_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); " ~hjB  
fileFetch.start(); H s 3*OhK\  
} "!eT  
catch(Exception e){e.printStackTrace ();} v[=E f  
]qT r4`.  
Q ?<9  
} !q1^X% a  
9O_N iu0  
QE6-(/  
public static void main(String[] args) --hnv/AjI  
{ ?a_q!,8:  
new TestMethod(); DFH6.0UW  
} (9lx5  
} > %*X2'^  
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