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http断点续传简单实现(java)

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/* Zv]'9,cbk  
**SiteFileFetch.java m:}PVJ-"  
*/ v~8Cp C  
package NetFox; 6jw9p+.  
import java.io.*; 9sP;s^#t7U  
import java.net.*; #|PPkg%v<  
mpr_AL!ZO~  
G]]"J c  
public class SiteFileFetch extends Thread { G2$<Q+UYs?  
45.<eWH$*(  
"Jahc.I  
SiteInfoBean siteInfoBean = null; //文件信息Bean 18^#:=Z  
long[] nStartPos; //开始位置 ZLjEH7  
long[] nEndPos; //结束位置 sL Kk1A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^ps6\>=0cW  
long nFileLength; //文件长度 =K)[3mX X  
boolean bFirst = true; //是否第一次取文件 c,2OICj  
boolean bStop = false; //停止标志 >jU25"XI[  
File tmpFile; //文件下载的临时信息 zif&;)wV/  
DataOutputStream output; //输出到文件的输出流 ~dO+kD  
z @g%9 |U  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  /!#A'#Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException LR "=(  
{ v9\U2j  
siteInfoBean = bean; M(^_/ 1Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y Nc@K|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j.&Y'C7GOC  
if(tmpFile.exists ()) HNRAtRvnY  
{ XS}-@5TI  
bFirst = false; qzj.N$9]  
read_nPos(); 7|HIl=  
} 7lx" X0w*m  
else O#<F"e;$  
{ i]#"@xQ  
nStartPos = new long[bean.getNSplitter()]; qfkd Q/fP  
nEndPos = new long[bean.getNSplitter()]; |KR8=-!7  
} 1{ H=The  
?8do4gT+1  
?f$U8A4lp  
{Rdh4ZKh  
} ~<.{z]*O  
}4g$ aTc  
n $lVmQ6  
public void run() yH(3 m#  
{ X }`o9]y  
//获得文件长度 nC%<BatQ  
//分割文件 K'}I?H~P_  
//实例FileSplitterFetch <PFF\NE9  
//启动FileSplitterFetch线程 **\?-*c=U  
//等待子线程返回 i&1rf|  
try{ cyLl,OA  
if(bFirst) %)72glB  
{ E/hT/BOPK  
nFileLength = getFileSize(); {!j)j6(NY  
if(nFileLength == -1) bU/4KZ'-^  
{ }= wor~  
System.err.println("File Length is not known!"); 2FW"uYA;6  
} 6g\hQ\+Z}  
else if(nFileLength == -2) _s+G02/q1  
{ Qqi?DW1)-  
System.err.println("File is not access!"); Dpwqg3,  
} H+562W  
else h56Kmxxk  
{ =k*XGbU  
for(int i=0;i<nStartPos.length;i++) t-5K dLB  
{ bEB2q\|Je  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U{KnjoS  
} D66NF;7q  
for(int i=0;i<nEndPos.length-1;i++) uts>4r>+  
{ jU kxA7 }}  
nEndPos = nStartPos[i+1]; 0VrsbkS  
} L }3eZ-  
nEndPos[nEndPos.length-1] = nFileLength; @ze2'56F}  
} (c&%1bJ  
} +*w}H 0Z  
Fc8 0HK5R  
ZPY&q&R  
//启动子线程 h1"|$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ch3MwM5]  
for(int i=0;i<nStartPos.length;i++) V%)Tu{L  
{ .heU Ir,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }zS5o [OE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), dC8}Ttc}  
nStartPos,nEndPos,i); )#8g<]q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WF-jy7+  
fileSplitterFetch.start(); p!8phS#iP  
} gwsIzYV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n((A:b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'e*w8h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9gdK&/ulR  
nEndPos = " + nFileLength); AC'_#nPL#  
// fileSplitterFetch[nPos.length-1].start(); MoQ\~/Z|  
XXhN; -p  
3^nH>f-Y  
//等待子线程结束 /:Gy .  
//int count = 0; $|@vmv0  
//是否结束while循环 7)Vbp--b#  
boolean breakWhile = false; lZ7 $DGe  
<xF]ca  
T)OR HJ&,  
while(!bStop) z6l'v~\  
{ *!JB^5(H  
write_nPos(); j)Ak:l%a  
Utility.sleep(500); d@1^U9sf  
breakWhile = true; v*qbzW`  
UOf\pG  
?>7-a~*A@  
for(int i=0;i<nStartPos.length;i++) +0z7}u\x  
{ NN=^4Xpc:  
if(!fileSplitterFetch.bDownOver) kE .4 #  
{ NU?<bIQ  
breakWhile = false; "O0xh_Nr  
break; !&hqj$>-}  
} Dol{y=(3e  
} Jy% ?"wn  
if(breakWhile) tE {M  
break; MjQju@  
{4,],0bjx/  
j}",+H v  
//count++; dd<l;4(  
//if(count>4) Ikf[K%NKn  
// siteStop(); 5|*`} ;/y  
} \>Rfa+  
T:Nk9t$W7@  
'UWkJ2:!  
System.err.println("文件下载结束!"); qf\W,SM  
} n`&D_AbQ  
catch(Exception e){e.printStackTrace ();} T9w=k)  
} E5)0YYjHZ  
} v:YSG  
[V:~j1{3  
//获得文件长度 )]FXUz|;  
public long getFileSize() \q1tT!]  
{ 6{ ]F#ig=  
int nFileLength = -1; dB[4NT  
try{ EG3,TuDH8  
URL url = new URL(siteInfoBean.getSSiteURL()); Rh|9F yN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `sT;\  
httpConnection.setRequestProperty("User-Agent","NetFox"); > d p/  
*$-X&.h[  
2I}pX9  
int responseCode=httpConnection.getResponseCode(); ;Go^)bN ;  
if(responseCode>=400) gtu<#h(  
{ }rfikm  
processErrorCode(responseCode); w=WF$)ZU  
return -2; //-2 represent access is error |*NZ^6`@  
} mXp#6'a  
z80P5^9  
"4\  
String sHeader; 8.B'O>\T  
196a~xNV  
gPMfn:a-8  
for(int i=1;;i++) HbA/~7  
{ vnvpb! @Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =eQB-Xe8Y  
//Utility.log(in.readLine()); Q*>)W{H&)  
sHeader=httpConnection.getHeaderFieldKey(i); ErK1j  
if(sHeader!=null) /_qq(,3  
{ 6(`N!]e*L  
if(sHeader.equals("Content-Length")) 'l.tV7  
{ js81@WX!c  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T(*,nJi~9  
break; C LaQE{  
} baII!ks  
}  80@\e  
else Th9V8Rg+E  
break; V )<>W_g  
} Yn ~fnI{  
} gE2(E0H  
catch(IOException e){e.printStackTrace ();} f $Agcy  
catch(Exception e){e.printStackTrace ();} H:~p5t  
^~[7])}g6  
TI7$J#  
Utility.log(nFileLength); DPzW,aIgv  
7_1 Iadb  
k-|g  
return nFileLength; Zt3sU_  
} pKc!sd C  
Og7yT{h_  
$?PI>9g!  
//保存下载信息(文件指针位置) jum"T\  
private void write_nPos() o&1mX  
{ lz0-5z+\  
try{ L[2qCxB'^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I_ZJnu<  
output.writeInt(nStartPos.length); _s^tL2Pc  
for(int i=0;i<nStartPos.length;i++) 71nZi`AR  
{ m0bxVV^DK!  
// output.writeLong(nPos); Mgw#4LU  
output.writeLong(fileSplitterFetch.nStartPos); oWY3dc  
output.writeLong(fileSplitterFetch.nEndPos); 7#E/Q~]'6  
} $vXY"-k  
output.close(); Z2]0brV  
} uQW)pD{_  
catch(IOException e){e.printStackTrace ();} daKZ*B|  
catch(Exception e){e.printStackTrace ();} -NwG' U~  
} CB#2XS>V  
\XB,)XDB  
b;QgL_w  
//读取保存的下载信息(文件指针位置) v"1&xe^4  
private void read_nPos() XE2Un1i}j1  
{ eV?%3h.   
try{ :5~Dca_iU4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Sn-#Y(>]o0  
int nCount = input.readInt(); nN{DO:_o  
nStartPos = new long[nCount]; l\{Qnb(  
nEndPos = new long[nCount]; ZvF#J_%gE5  
for(int i=0;i<nStartPos.length;i++) yT/rH- j;5  
{ nr]=O`Mvh  
nStartPos = input.readLong(); @JlT*:Dz  
nEndPos = input.readLong(); i<Ms2^  
} [s^p P2  
input.close(); fh =R  
} \>:t={>;  
catch(IOException e){e.printStackTrace ();} Gk5'|s  
catch(Exception e){e.printStackTrace ();} j4i$2ZT'  
} {O _X/y~  
Bdh*[S\u@E  
bnfeZR1m_  
private void processErrorCode(int nErrorCode) q,fp DNo  
{ PNAvT$0LaZ  
System.err.println("Error Code : " + nErrorCode); my sXgS&S  
} xCL)<8[R,}  
l#cVQ_^"  
uO1^Q;F  
//停止文件下载 M{p6&eg  
public void siteStop() RbUir185Y  
{ 2+pw%#fe  
bStop = true; {@KLN<  
for(int i=0;i<nStartPos.length;i++) =Jl\^u%H(x  
fileSplitterFetch.splitterStop(); E~q3o*  
~*EipxhstJ  
Z%o.kd"  
} MMa`}wSs  
} 9Y2u/|!.3  
//负责部分文件的抓取 3SWDPy  
**FileSplitterFetch.java VT>-*  
*/ Q']'KU.  
package NetFox; '(r?($s  
rs4:jS$)  
KD#zsL)3  
import java.io.*; =X'EDw  
import java.net.*; N/-(~r[  
;Uch  
0e>?!Z E  
public class FileSplitterFetch extends Thread { <EyJ $$  
G{.=27  
~*h)`uM  
String sURL; //File URL 2FL_!;p;2E  
long nStartPos; //File Snippet Start Position mn1!A`$  
long nEndPos; //File Snippet End Position XH0{|#hwN  
int nThreadID; //Thread's ID q@1A2L\Om  
boolean bDownOver = false; //Downing is over Q >yj<DR  
boolean bStop = false; //Stop identical or ~@!  
FileAccessI fileAccessI = null; //File Access interface dG3?(}p+  
Wsd_RT}ww  
x?6^EB|@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cJT_Qfxx  
{ 2hntQ1[  
this.sURL = sURL; aG"  
this.nStartPos = nStart; 5-a^Frmg#"  
this.nEndPos = nEnd; L) _ VdB  
nThreadID = id; ]%7m+-h@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 oM n'{+(w  
} /jaO\t'q  
3Qv9=q|[b  
K:4 G(?w  
public void run() z,qNuv"W  
{ 4wS!g10}  
while(nStartPos < nEndPos && !bStop) /$8& r  
{ oPAc6ObOV~  
>&Ye(3w&  
K/(Z\lL  
try{ }&ew}'*9)  
URL url = new URL(sURL); +ZwTi!W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l9 rN!Q|  
httpConnection.setRequestProperty("User-Agent","NetFox"); 00W_XhJ  
String sProperty = "bytes="+nStartPos+"-"; %&O'>L  
httpConnection.setRequestProperty("RANGE",sProperty); dZJU>o'BG  
Utility.log(sProperty); 5',b~Pp  
"g!/^A!!  
TTxSl p2=;  
InputStream input = httpConnection.getInputStream(); :OaGdL   
//logResponseHead(httpConnection); =:RNpi,  
HBa6Y&)<  
Fw#wVs)@:  
byte[] b = new byte[1024]; (yeN> x}_  
int nRead; +zFEx%3^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) KC\W6|NtGj  
{ \y/0)NL\  
nStartPos += fileAccessI.write(b,0,nRead); 3A b_Z  
//if(nThreadID == 1) 7sJGB^vM  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p_sqw~)^%  
} BI6`@}%7>  
PPtJ/ }\  
X0m6<q  
Utility.log("Thread " + nThreadID + " is over!"); cmLI!"RLe  
bDownOver = true; |SsmVW$B|  
//nPos = fileAccessI.write (b,0,nRead); +m6acu)N.  
} +Kg3qS"  
catch(Exception e){e.printStackTrace ();} %t-}dC&  
} *5'l"YQ@1  
} w >#.id[k  
y{qKb:~wv  
x8h=3e$  
//打印回应的头信息 <d hBO  
public void logResponseHead(HttpURLConnection con) xHwcP21  
{ Il s^t  
for(int i=1;;i++) )RwO2H  
{ (<5&<JC{  
String header=con.getHeaderFieldKey(i); Yh;A  
if(header!=null) \E:l E/y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;ZLfb n3\  
Utility.log(header+" : "+con.getHeaderField(header)); H Ff9^  
else =Cr F(wVO"  
break; A v%'#1w<"  
} @$d_JwI  
} q0]Z` <w  
4EEXt<c.  
/H[!v:U  
public void splitterStop() ,n+~S^r  
{ +QVe -  
bStop = true; -qndBS  
} %L;'C v  
0_-NE4SM/  
qc`UDD5  
} < {dV=  
-7l)mk  
xu0pY(n^r  
/* T $;N8x[  
**FileAccess.java 8a4&}^|  
*//文件访问(定位,写) 0xg6  
package NetFox; E; Z1HF R  
import java.io.*; vy330SQPo  
UKxeN[fv  
-( ,iwF b  
public class FileAccessI implements Serializable{ t{)J#8:g  
x?B8b-*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^iq$zHbc0u  
RandomAccessFile oSavedFile; {n>W8sN<  
long nPos; HN tl>H  
SLG3u;Ab  
d4zqLD$A  
public FileAccessI() throws IOException PXYo@^ 3  
{ 0Bpix|mq  
this("",0); _n+./ B  
} ^g56:j~?  
\!4sd2Yi  
W=T}hA#`  
public FileAccessI(String sName,long nPos) throws IOException xc+h Fx  
{ J<{@D9r9<~  
oSavedFile = new RandomAccessFile(sName,"rw"); -Fj:^q:@u  
this.nPos = nPos; Qm\VZ<6/5  
oSavedFile.seek(nPos); )0:@T)G  
} jreY'y:  
c*g(R.!  
~\z\f} w  
public synchronized int write(byte[] b,int nStart,int nLen) OW12m{  
{ .Lk2S "+  
int n = -1; qeyBZ8BG  
try{ *?`:=  
oSavedFile.write(b,nStart,nLen); u&>o1!c*P  
n = nLen; y^oSVj  
} @edi6b1W  
catch(IOException e) J !:ss  
{ AdtAc$@xK  
e.printStackTrace (); WBA0! g98  
} ;Vad| -  
j/R  
Q b5AQf30  
return n; #n'tpp~O  
} $e! i4pM  
(,E.1j]ji  
TWC^M{e  
} ^AUmIyf_  
`bGAc&,&  
m#'2 3  
/* SLc6 ]?  
**SiteInfoBean.java /R< Q~G|\  
*/ :G|Jcl=r  
package NetFox; Aov=qLWJ  
~h;c3#wuc  
~<pGiW'w5  
public class SiteInfoBean { AR?J[e  
zb}:wUR  
ztG_::QtG]  
private String sSiteURL; //Site's URL ,2)LH 'Xx  
private String sFilePath; //Saved File's Path Frt_X%  
private String sFileName; //Saved File's Name !V.'~xj  
private int nSplitter; //Count of Splited Downloading File p3*}!ez4  
& h9ji[  
-O_5OT4  
public SiteInfoBean() =F ZvtcCa  
{//nSplitter的缺省值为5 itM6S$  
//default value of nSplitter is 5 ]7ROCJ;  
this("","","",5); im_W0tGvF  
} p~28?lYv  
@R?S-*o  
NrTQ}_3)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fAfsKO*  
{ U]fE(mpI9  
sSiteURL= sURL; TE0hV w0c  
sFilePath = sPath; |-I[{"6q$@  
sFileName = sName; JPgV7+{b[  
this.nSplitter = nSpiltter; A%u-6"  
-ny[Lh^b  
7,_N9Q]rB  
} /+Xv( B  
b IcLMG s  
9xC,i )  
public String getSSiteURL() u Y/Q]N T  
{ VVvV]rU~  
return sSiteURL; Rw*l#cr=.  
} 7[:9vY  
Jk|c!,!  
]E88zWDY`  
public void setSSiteURL(String value) ,~gY'Ql  
{ 5FnWlFc  
sSiteURL = value; 4W~pAruwr  
} x\!Qe\lE  
N/Z3 EF_  
+%8c8]2  
public String getSFilePath() goeWZO  
{ $TL~SVHj;{  
return sFilePath; G1vWHa7n;f  
} *8fnxWR   
Ezm ~SY  
93[c^sc9*a  
public void setSFilePath(String value) bJ]g2C7`36  
{ 8,#v7ns}#  
sFilePath = value; }f<.07  
} ;c_X ^"d  
%s%v|HDs  
U"A]b(54  
public String getSFileName() 4_8%ZaQ\.?  
{ x;l\#x/<  
return sFileName; Lcf =)GL  
} M$ `b$il  
9@#Z6[=R,  
Z'>Xn^  
public void setSFileName(String value) ( N~[sf?&  
{ #]oVVf_  
sFileName = value; k;R*mg*K  
} c</d1xT  
{%'(IJ|5z  
dOqn0Z  
public int getNSplitter() ^UZEdR;  
{ <K%qaf  
return nSplitter; ync2X{9D  
} .%h.b6^  
T/V8&'^i  
E#`=xg  
public void setNSplitter(int nCount) bBc<yaN  
{ _y#t[|}w  
nSplitter = nCount; ><viJ$i  
} D%N^iJC,9  
} G%  
E5UI  
PCH&eTKN  
/* 8xs[{?|:  
**Utility.java 3<1Uq3Pa  
*/ DKAqQ?fS  
package NetFox; ( YF`#v6  
H2l/9+  
E'?yI' ~=  
public class Utility { "GEJ9_a[  
Lo\+T+n  
2K'3ry)[y  
public Utility() 2i;G3"\  
{ ^]3Y11sI  
>c*}Do{lG  
1hw1AJ}(F  
} 5e~\o}]  
a ?/GEfd  
//线程睡眠 %Wkvo-rOq  
public static void sleep(int nSecond) .$y}}/{j?[  
{ qvy~b  
try{ Jiyt,D*wX  
Thread.sleep(nSecond); tI0d!8K  
} iY1%"x  
catch(Exception e) Fd*)1FQKT  
{ L}*:,&Y/  
e.printStackTrace (); "rOe J~4 X  
} o7)<pfif  
} 2`tdH|Z`  
?2zVWZ  
//日志 I *YO  
public static void log(String sMsg) 9>\P]:  
{ 47.c  
System.err.println(sMsg); =T;>$&qs  
} !'o5X]s  
55MrsiW  
&^3KF0\Q  
public static void log(int sMsg) YjN2 ,Xi  
{ / PDe<p  
System.err.println(sMsg); 8\+kfK  
} P,r9  <  
} 23 j{bK  
*{8<4CVv  
eL3HX _2(  
/* dznHR6x  
**TestMethod.java 83~ Gu[  
*/ 20750G  
package NetFox; KKP}fN  
eIBHAdU+g/  
JRt^YX  
public class TestMethod { ~WXT0-,  
hfT HP  
0`.3`Mk   
public TestMethod() qD=o;:~Km  
{ ///xx/weblogic60b2_win.exe p?(w !O  
try{ /cHd&i,>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0vOt. LC/S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); AoB~ZWq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); M:x?I_JG8  
fileFetch.start(); 8}9|hT;  
} R|aA6} /I  
catch(Exception e){e.printStackTrace ();} {* S8n09v  
np3$bqm  
4|*b{Ni  
} R\k= CoJJ  
par| j]  
i(R&Q;{E^  
public static void main(String[] args) "8MG[$Y  
{ dYEF,\Z'  
new TestMethod(); .2?tx OKh  
} *lHI\5  
} Q- ( [3%  
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