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http断点续传简单实现(java)

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/* &!CVF  
**SiteFileFetch.java SCcvU4`o  
*/ :0l+x 0l}  
package NetFox; o%?)};o  
import java.io.*; o0R?vnA=  
import java.net.*; LIcc0w3  
*<xu3){:c  
!l $d^y345  
public class SiteFileFetch extends Thread { Zt!#KSF7%  
S/`#6  
%b^4XTz  
SiteInfoBean siteInfoBean = null; //文件信息Bean ^L2d%d\5  
long[] nStartPos; //开始位置 #%;Uh  
long[] nEndPos; //结束位置 #BLHHK/[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;l*%IMB  
long nFileLength; //文件长度 ST?{H SCz  
boolean bFirst = true; //是否第一次取文件 RK!9(^Ja  
boolean bStop = false; //停止标志 f7_( C0d  
File tmpFile; //文件下载的临时信息 G+<XYkz*  
DataOutputStream output; //输出到文件的输出流 n|{K_! f  
^!\1q<@n  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) U*C^g}iA  
public SiteFileFetch(SiteInfoBean bean) throws IOException :|W=2( >  
{ xT+_JT65  
siteInfoBean = bean; ni?k' \\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \AwkK3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); unFRfec{  
if(tmpFile.exists ()) ;TJpD0  
{ UOZ+ &DL,L  
bFirst = false; \t!~s^Oox  
read_nPos(); vu+g65"  
} x &R9m,  
else v?VDASR2`  
{ A r!0GwE+  
nStartPos = new long[bean.getNSplitter()]; y u'-'{%  
nEndPos = new long[bean.getNSplitter()]; ZHNL ~=r}  
} 9`*ST(0/  
Y$ jX  
o`iA&  
|}4\Gm  
} V?M (exN  
BY~Tc5  
[Qnf]n\FJ  
public void run() Fx:38Ae  
{ }nlS&gew^  
//获得文件长度 g=t`3X#d  
//分割文件 ]6e(-v!U  
//实例FileSplitterFetch _Tj&gyS  
//启动FileSplitterFetch线程 -P}A26qB  
//等待子线程返回 FoetP`   
try{ !i"zM}  
if(bFirst) wyy 1M+  
{ Yj@ Sy  
nFileLength = getFileSize(); w-n}&f  
if(nFileLength == -1) 4k225~GQ:C  
{ 4 . 7X*1  
System.err.println("File Length is not known!"); 1d< b\P0  
} *6?mZ*GYY  
else if(nFileLength == -2) KUJLx  
{ N0p6xg~  
System.err.println("File is not access!"); -Rpra0o. C  
} 7W)W9=&BT  
else ;z4J)qw  
{ @:?[R&`  
for(int i=0;i<nStartPos.length;i++) 2K9X (th1  
{ gML8lu0)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >Hnm.?-AWl  
} ?b+Y])SJK  
for(int i=0;i<nEndPos.length-1;i++) _{jC?rzb  
{ un 5r9  
nEndPos = nStartPos[i+1]; U 3< 3T  
} j,.M!q]  
nEndPos[nEndPos.length-1] = nFileLength; Mc,|C)  
} tpGT~Y(  
} _8.TPB]no  
=6~  
r.e K;  
//启动子线程 ],weqs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~3.*b% ,  
for(int i=0;i<nStartPos.length;i++) KM;H '~PZi  
{  2 q4p-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `$/a-K}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  4v`/~a  
nStartPos,nEndPos,i); vQ}ZfP  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HF FG4'  
fileSplitterFetch.start(); +ALrHFG  
} `TPIc  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 44 u)F@)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PRU&y/zZmG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 486\a  
nEndPos = " + nFileLength); i3 eF_  
// fileSplitterFetch[nPos.length-1].start(); He=C\"  
M)#9Q=<  
}!_z\'u  
//等待子线程结束 3*<@PXpK&  
//int count = 0; Aars\   
//是否结束while循环 v ;\cM/&5  
boolean breakWhile = false; 8r(a wp  
``CM7|)>`  
8|zavH#P  
while(!bStop) q~}oU5  
{ U3N d\b'0  
write_nPos(); Hl}lxK,]  
Utility.sleep(500); #r#[&b  
breakWhile = true; "d)Yq Q  
![%wM Pp  
 oYN"L  
for(int i=0;i<nStartPos.length;i++) 1Of(O!  
{ 6]iU-k0b  
if(!fileSplitterFetch.bDownOver) Kzn1ct{65!  
{ uZL]mwkj]  
breakWhile = false; inU5eronuj  
break; k( Sda>-  
} F:m6Mf7L  
} 9HJYrzf{%  
if(breakWhile) J+t51B(a  
break; HVus\s\&y%  
b3%x&H<j  
Pp } Z"  
//count++; 3g4=as4w  
//if(count>4) )'m;a_r`  
// siteStop(); ow \EL  
} KfjWZ4{v  
#; !@Pf  
48 wt  
System.err.println("文件下载结束!"); he~8V.$  
} ^>E>\uz0v  
catch(Exception e){e.printStackTrace ();} `n>|rd  
} fof}I:vO  
bIGcszWr  
kKlNhP(  
//获得文件长度 _p8u &TZ  
public long getFileSize() eHvUgDt  
{ P-B5-Nz  
int nFileLength = -1; 0JtM|Mg  
try{ BeFyx"NBg  
URL url = new URL(siteInfoBean.getSSiteURL()); f5F-h0HF`[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B0yJ9U= Fj  
httpConnection.setRequestProperty("User-Agent","NetFox"); eikZ~!@  
<B>qE a_I  
+- qk\sQ  
int responseCode=httpConnection.getResponseCode(); WD\Yx~o  
if(responseCode>=400) e'uC:O.u  
{ W#U|;@"  
processErrorCode(responseCode); 0p.MH~mx  
return -2; //-2 represent access is error :=*G7ZyW$  
} Wi=zu[[qc  
q`mxN!1[  
_'w:Sx?d7  
String sHeader;  d;>G  
!4Zy$69R  
}&+,y<>   
for(int i=1;;i++) #C } +  
{ dBA&NW07  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); FR6 W-L  
//Utility.log(in.readLine()); g"" 1\rc=  
sHeader=httpConnection.getHeaderFieldKey(i); 7~J>Ga  
if(sHeader!=null) .aO6Y+Y  
{ rZwSo]gp  
if(sHeader.equals("Content-Length")) >{ {ds--  
{ P7W|e~]Yq  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'qEw]l  
break;  Ps.xY;Y  
} !S&/Zp  
} _R(ZvsOZ  
else 9 Vq   
break; ,j>FC j>  
} Z[VrRT,\c  
} !GvT{  
catch(IOException e){e.printStackTrace ();} 6 8n ;#-X  
catch(Exception e){e.printStackTrace ();} ;39a`  
2He R1m<  
W=EcbH9/.)  
Utility.log(nFileLength); IT=y+  
|APOTQV  
zQ:nL*X'Z"  
return nFileLength; JE{ cZ<NNH  
} msCz\8Xd  
g&$5!ifgi  
[4C_iaE  
//保存下载信息(文件指针位置) (rJ-S"^u  
private void write_nPos() =Bc{0p*  
{ bxPa|s?  
try{ sF)$<[w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); QZ(O2!Mg  
output.writeInt(nStartPos.length); >pZ _  
for(int i=0;i<nStartPos.length;i++) :9L}jz  
{ ; Yc\O:Qq  
// output.writeLong(nPos); ^m D$#  
output.writeLong(fileSplitterFetch.nStartPos); mpD.x5jm<  
output.writeLong(fileSplitterFetch.nEndPos); 4J`-&05O  
}  ~}p k^FA  
output.close(); !7~4`D c6U  
} Fv,c8f  
catch(IOException e){e.printStackTrace ();} c]VK%zl  
catch(Exception e){e.printStackTrace ();} 9wc\~5{li  
} >Giw\|:f(  
3,i`FqQa  
i@P= *lLD  
//读取保存的下载信息(文件指针位置) GCQOjqiR  
private void read_nPos() jJYCGK$=  
{ N1g;e?T ':  
try{ qooTRqc#,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); MW^FY4V1m  
int nCount = input.readInt(); S9[Up}`  
nStartPos = new long[nCount]; tculG|/  
nEndPos = new long[nCount]; S+6YD0  
for(int i=0;i<nStartPos.length;i++) &{WEtaXaa  
{ 2>x[_  
nStartPos = input.readLong(); Z$Ps_Ik  
nEndPos = input.readLong(); v(O@~8(I  
} v(sS$2J|}  
input.close(); T|oDJ]\J  
} ;$!0pxL)s  
catch(IOException e){e.printStackTrace ();} `ALQSo~l  
catch(Exception e){e.printStackTrace ();} )"P.n-aF  
} 1Ogtzf  
EG=U](8T  
hZe9Y?)  
private void processErrorCode(int nErrorCode) -xH3}K%  
{  q _;#EV  
System.err.println("Error Code : " + nErrorCode); z}VCiS0  
} bw#\"uJ  
rA_r$X  
hoPh#? G  
//停止文件下载 ^=cX L  
public void siteStop() nM$-L.dG  
{ K}S=f\Q]  
bStop = true; %HZ!s `w_  
for(int i=0;i<nStartPos.length;i++) qP%[ nY  
fileSplitterFetch.splitterStop(); -Xgup,}?  
giddM2'  
@yPI$"Ma  
} %%O_:@9x,  
} 79lG~BGE  
//负责部分文件的抓取 !Nhq)i  
**FileSplitterFetch.java oB}rd9  
*/ W9SEYkg  
package NetFox; FRE${~Xd  
? v@q&  
a)L=+Z  
import java.io.*; E[_-s  
import java.net.*; $J:~jY/J  
dI8y}EbE~  
TlBu3z'P  
public class FileSplitterFetch extends Thread { z?_5fte`  
}xzbg  
Vuo 8[h>  
String sURL; //File URL }JWk?  
long nStartPos; //File Snippet Start Position O~g0R6M6e  
long nEndPos; //File Snippet End Position h@ ?BA<'S  
int nThreadID; //Thread's ID G Q+g.{c  
boolean bDownOver = false; //Downing is over T/l2B1  
boolean bStop = false; //Stop identical [+$o`0q;N?  
FileAccessI fileAccessI = null; //File Access interface !g-19at  
.7GAGMNS  
d`+cNKf  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O/Wc@Ln  
{ v:] AS:  
this.sURL = sURL; )wY bcH  
this.nStartPos = nStart; A|U_$!cLZ  
this.nEndPos = nEnd; HPR*:t  
nThreadID = id; E :Y *;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ijj]_V{,  
} lFL iW  
BK:S:  
7e-l`]  
public void run() H0B"?81  
{ nMHs5'_y  
while(nStartPos < nEndPos && !bStop) M9b_Q  
{ ^m:?6y_uw  
Ge;plD-f  
_,4f z(  
try{ 4RqOg1  
URL url = new URL(sURL); u{ .UZTn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ' RjFWHAp  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^25[%aJI  
String sProperty = "bytes="+nStartPos+"-"; ^4yFLqrC  
httpConnection.setRequestProperty("RANGE",sProperty); k w!1]N  
Utility.log(sProperty); %h%^i   
)LwB  
{ O*maE"  
InputStream input = httpConnection.getInputStream(); @`ttyI^1f  
//logResponseHead(httpConnection); h&vq}  
%!HmtpS  
)S|}de/a2  
byte[] b = new byte[1024]; Gu:aSb  
int nRead; 'qhA4W9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P$\vD^  
{ V< @]Iv  
nStartPos += fileAccessI.write(b,0,nRead); &k?Mt #J  
//if(nThreadID == 1) Rd5r~iT  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SA|f1R2uS  
} #{l+I( M  
l 49)Cv/  
,bCPO` 45  
Utility.log("Thread " + nThreadID + " is over!"); @qH<4`y.^  
bDownOver = true; lV^sVN Z]  
//nPos = fileAccessI.write (b,0,nRead); J+LFzl07q  
} /9WR>NUAO  
catch(Exception e){e.printStackTrace ();} ^=wG#!#V"1  
} - iS\3P.  
} +aV>$Y  
E q.?Ga  
ewk62 {  
//打印回应的头信息 >"S'R9t  
public void logResponseHead(HttpURLConnection con) 0%+TU4Xx  
{ l0b Y  
for(int i=1;;i++) xk}YeNVj  
{ /"Om-DK%  
String header=con.getHeaderFieldKey(i); VzMoWD;  
if(header!=null) Kig.hHj@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~^IS{1  
Utility.log(header+" : "+con.getHeaderField(header)); ^owEB%  
else >\$qF  
break; e0*',  
} \p.Byso,  
} ID5?x8o#k  
6$b"tdP  
W9Bl'e  
public void splitterStop() ;vF8V`f   
{ v)+wr[Qs  
bStop = true; lb&tAl"D  
} W==HV0n  
gV!Eotq  
Sy'/%[+goJ  
} f| 3`8JU  
VE6T&fz`  
us4.-L  
/* )"jG)c^1*  
**FileAccess.java <2ffcBv  
*//文件访问(定位,写) U{LDtn%@h6  
package NetFox; n@5pS3qZ  
import java.io.*; @|%t<{y^I  
N*lq)@smq  
[lQp4xgxi  
public class FileAccessI implements Serializable{ g 6>R yjN  
?qw&H /R  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q uv`~qn  
RandomAccessFile oSavedFile; x7l)i!/$  
long nPos; H<%7aOwO2  
NV*aHci  
v.cB3/$ z  
public FileAccessI() throws IOException :{LVS nG  
{ 5 & -fX:/  
this("",0); _"a(vfl#  
} @p|[7'  
{.H}+@0  
68Wm=j.m  
public FileAccessI(String sName,long nPos) throws IOException vV#Jl) A  
{ Trbgg  
oSavedFile = new RandomAccessFile(sName,"rw"); t{!}^{ "5  
this.nPos = nPos; - CT?JB  
oSavedFile.seek(nPos); ]Vl * !,(i  
} ;{q7rsE  
,, ]y 8P  
A:p7\Kp;5}  
public synchronized int write(byte[] b,int nStart,int nLen) R7x4v  
{ u+[ZWhKUp  
int n = -1; = Yh>5A  
try{ n|SsV  
oSavedFile.write(b,nStart,nLen); f Nm Sx  
n = nLen; 8Th|'  
} L;fhJ~ r  
catch(IOException e) b,KQG|k  
{ Nypa,_9}  
e.printStackTrace ();  7I^(v Q  
} ,Ztj  
?%;7k'0"  
 Cj_cu  
return n; 3UslVj1u  
} -AD3Pd|Y[  
>Ah [uM  
}4#%0x`w  
} +7^%fX;3pW  
r<UZ\d -  
_9Iz'-LgB  
/* Wl;F]_|*(  
**SiteInfoBean.java tP"C >#LO  
*/ dL |D  
package NetFox; qI^6}PB  
-PB m@}*  
&h`s:Y  
public class SiteInfoBean { !-U5d9!  
3RXq/E  
x`WP*a7Fk]  
private String sSiteURL; //Site's URL ",w@_}z:  
private String sFilePath; //Saved File's Path C6M|A3^T  
private String sFileName; //Saved File's Name M// q7SHh  
private int nSplitter; //Count of Splited Downloading File V~+Oil6sa  
w;&J._J  
=n cu# T]  
public SiteInfoBean() #i%it  
{//nSplitter的缺省值为5 -,uTAk0+@  
//default value of nSplitter is 5 2h IM!wQ  
this("","","",5); 7!]$XGz[  
} 8uP,#D<wZ  
mHM38T9C%  
#@w8wCj  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Dwj!B;AZ_  
{ Xjw> Qws  
sSiteURL= sURL; dPc*!xrq  
sFilePath = sPath; 2RFYnDN  
sFileName = sName; 3%bCv_6B  
this.nSplitter = nSpiltter; g j8rrd |  
YiJnh47  
E/v.+m  
} <1YINkRz  
tSaLR90Y6  
$5yH(Z[[  
public String getSSiteURL() |L}zB,  
{ ,)TtI~6Q  
return sSiteURL; ]P;uQ!  
} %PRG;kR  
# ` Q3Z}C  
n+QUT   
public void setSSiteURL(String value) t~U:Ea[gd  
{ 8n+&tBq1  
sSiteURL = value; HY0q!.qog  
} |5oK04<  
N[~{'i  
/j/,@,lw7z  
public String getSFilePath() *oopdGue  
{ 0zQ"5e?qy  
return sFilePath; ;\ ^'}S|3Z  
} q,`"Z)97  
Yv<' QC  
K2$ fKju  
public void setSFilePath(String value) Fa<>2KkOr  
{ 4<}!+X7m  
sFilePath = value; uu ahR  
} hgIqr^N9  
;;e\"%}@=q  
KZy2c6XO;  
public String getSFileName() g_X-.3=2K  
{ XJg8-)T#  
return sFileName; CD]hi,B_J  
} sZe$?k|  
Lzmdy0!'  
9 5bi W  
public void setSFileName(String value) loRT+u$&  
{ mm}y/dO~}  
sFileName = value; bfo..f-0/Y  
} U*sjv6*T  
UWU(6J|Fk  
gu?e%]X3  
public int getNSplitter() Nq]8p =e  
{ ba5,?FVI~  
return nSplitter; W X"iDz.  
} h/oRWl0r  
OBb m?`[  
Z9 z!YaOL  
public void setNSplitter(int nCount) BF^dNgn+%K  
{ 8^IV`P~2M  
nSplitter = nCount; Ibf~gr(j  
} 5Zf^cou  
} G)|Xj70  
Eep~3U  
oW}nr<G{<  
/* yMG(FAyu  
**Utility.java }K .Rv(m  
*/ is~"yE7  
package NetFox; ]& 8c 45c  
dU}Cb?]7s  
1Kjqs)p^  
public class Utility { QhhL_vP  
#B!| sXC  
U g:  
public Utility() SFu]*II;{  
{ ,`Keqfx  
&Fiesi!tET  
{EfA#{x  
} J&2 J6Eq  
!>:SPt l  
//线程睡眠 XF&_**0n  
public static void sleep(int nSecond) +>&i]x(b  
{ bm*.*A]  
try{ XS}-@5TI  
Thread.sleep(nSecond); uTdx`>M,O  
} r|63T%q!  
catch(Exception e) "S]G+/I|iw  
{ {#.<hPXn  
e.printStackTrace (); XDYQV.Bv  
} zfD@/kU  
} lak,lDt]  
ew \WV "  
//日志 /1v:eoF;  
public static void log(String sMsg) "38L ,PW0Z  
{ VFrp7;z43  
System.err.println(sMsg); d5>EvK U  
} v.&c1hKHb  
z~-(nyaBS  
q@G}Hjn  
public static void log(int sMsg) xnC:?d  
{ gg/ts]$  
System.err.println(sMsg); **\?-*c=U  
} MgP&9  
} [8<0Q_?,  
a/v]E]=qI  
f|=u{6  
/*  m^\&v0  
**TestMethod.java BoQ%QV69%  
*/ ;"2VU"  
package NetFox; I94-#*~I  
(Hmm^MV)  
diNAT`|?#  
public class TestMethod { }$'XV.  
]bAVOKm-  
h56Kmxxk  
public TestMethod() obGhO  
{ ///xx/weblogic60b2_win.exe [K@(,/$  
try{ lX-i<0`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,>01Cs=t8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %-]a[qf3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u(fZ^  
fileFetch.start(); gkX7,J-0  
} mlCBstt{  
catch(Exception e){e.printStackTrace ();} (t\U5-w  
6uv~.-T<l  
-$kIVh  
} 5]GgjQ  
ZPY&q&R  
7AS_Aw1L  
public static void main(String[] args) {=\Fc`74  
{ L,.AY?)+7  
new TestMethod(); qo$ls\[X  
} *7-rm  
} jV9oTH-  
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