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http断点续传简单实现(java)

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/* Z%N{Y x(  
**SiteFileFetch.java ><TuL7+  
*/ Od^y&$|_%`  
package NetFox; SBAq,F'  
import java.io.*; E6NkuBQ((  
import java.net.*; MQD UJ^I$  
hh{4r} |  
G! zV=p  
public class SiteFileFetch extends Thread { #v=hiL  
]"q)X{G(+  
Q68&CO(rE  
SiteInfoBean siteInfoBean = null; //文件信息Bean @mNf(&  
long[] nStartPos; //开始位置 /.aZXC$]  
long[] nEndPos; //结束位置 +AtZltM i  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a_L&*%;  
long nFileLength; //文件长度 f&js,NU"  
boolean bFirst = true; //是否第一次取文件 )2g\GRg6  
boolean bStop = false; //停止标志 ^%)'wDK  
File tmpFile; //文件下载的临时信息 6QLWF @  
DataOutputStream output; //输出到文件的输出流 }7IS:"tu  
hc"+6xc  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) H"WkyvqXb  
public SiteFileFetch(SiteInfoBean bean) throws IOException 82YTd(yB  
{ /$! / F@^  
siteInfoBean = bean; 6sRn_y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tt{,f1v0t  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p=coOWOQ  
if(tmpFile.exists ()) gv r "F  
{ +%7yJmMw  
bFirst = false; AGx]srl  
read_nPos(); a"b9h{h@  
} bguhx3s  
else B$ +YK%I  
{ Nw+0b4{  
nStartPos = new long[bean.getNSplitter()]; I$n 0aR6  
nEndPos = new long[bean.getNSplitter()]; zob^z@2  
} ^a[7qX_B  
aM9^V MOb  
\%KJ +PJ  
' 6Ybf  
} 1wW8D>f]K  
x9a*^l  
KX"?3#U#Fm  
public void run() t*.O >$[  
{ o`+6E q0w  
//获得文件长度 XK`>#*"V  
//分割文件 R."<he ;  
//实例FileSplitterFetch {[jcT>.3j  
//启动FileSplitterFetch线程 5H6m{ng  
//等待子线程返回 0F1 a  
try{  w+=>b  
if(bFirst) 54JZEc  
{ lV?rC z  
nFileLength = getFileSize(); W% YJ.%I  
if(nFileLength == -1) zQ(li9  
{ 4+:Q"  
System.err.println("File Length is not known!"); );kO2 7dg  
} aG%KiJ7KEN  
else if(nFileLength == -2) qy`@\)S/5  
{ QjWv?tm  
System.err.println("File is not access!"); ' aBX>M  
} z[M LMf[c  
else .6z#o{n  
{ U-QK   
for(int i=0;i<nStartPos.length;i++) %ErL L@e  
{ L Bb&av  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); qx18A  
} 8+k\0fmy  
for(int i=0;i<nEndPos.length-1;i++) !l?Go<^*L  
{ (Q o  
nEndPos = nStartPos[i+1]; [D[s^<RJs  
} h1z[ElEeoP  
nEndPos[nEndPos.length-1] = nFileLength; >DBaKLu\  
} ]ctUl #j  
} ]!d #2(  
Tsxl4ZK  
'VS!<  
//启动子线程 W#P)v{K  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IiHl"2+/  
for(int i=0;i<nStartPos.length;i++) beRpA;  
{ B[Fx2r`0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R(74Px,/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >)=FS.?]  
nStartPos,nEndPos,i); t4GG@`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i;s&;_0{  
fileSplitterFetch.start(); [c +[t3dz  
}  "9!ln  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M`-#6,m3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); X~*1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", U; JZN  
nEndPos = " + nFileLength);  \U(qv(T  
// fileSplitterFetch[nPos.length-1].start(); F-R4S^eV  
1#qyD3K  
D.kLx@Z  
//等待子线程结束 Ck%nNy29  
//int count = 0; 3 q^3znt  
//是否结束while循环 ^ b{0|:  
boolean breakWhile = false; J(ZYoJ  
&p8b4y_  
y))d[ 1E  
while(!bStop) 0UB)FK ,9  
{ %"r3{Hs  
write_nPos(); z4!TK ps  
Utility.sleep(500); ?x7zYE,6  
breakWhile = true; &W`."  
gXZC%S  
dT4?8:  
for(int i=0;i<nStartPos.length;i++) '`p#%I@  
{ x9bfH1  
if(!fileSplitterFetch.bDownOver) T?4MFx#  
{ $ jWe!]ASU  
breakWhile = false; 2 DJs '"8  
break; 7m~.V[l1  
} y2;uG2IS_g  
} yDg`9q.ckm  
if(breakWhile) eU&[^  
break; KC9_H>  
%JeT,{  
5MfbO3  
//count++; 5,cq-`  
//if(count>4) J.W0F #?  
// siteStop(); X,y0 J  
} cK%Sty'8+  
.|^L\L(!  
i2j_=X-  
System.err.println("文件下载结束!"); m^Qc9s#D  
} -f@~{rK.L  
catch(Exception e){e.printStackTrace ();} &\#If:  
} I(y:Td  
ShbW[*5  
V]dzKNFi  
//获得文件长度 Clr~:2g\  
public long getFileSize() _LU]5$\b  
{ = &jLwy  
int nFileLength = -1; o *)>aw  
try{ L}5nq@Uu)  
URL url = new URL(siteInfoBean.getSSiteURL()); Z`y%#B6x.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y> ElE-  
httpConnection.setRequestProperty("User-Agent","NetFox"); !LB#K?I  
Opx"'HC@G  
OPOL-2<wiy  
int responseCode=httpConnection.getResponseCode(); |(G^3+5Uwm  
if(responseCode>=400) HJWk%t<  
{ .Y|5i^i9{  
processErrorCode(responseCode); zO)A_s.6K  
return -2; //-2 represent access is error n`gW&5,,z  
} Mhp6,JL  
3]"RaI4Q0  
V<:scLm#OF  
String sHeader; *;@V5[^3I?  
+NWhvs  
k|Mj|pqA  
for(int i=1;;i++) z/Z 0cM#  
{ qp$Td<'Y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Qau\6p>^  
//Utility.log(in.readLine()); 3pg_`  
sHeader=httpConnection.getHeaderFieldKey(i); xc{$=>'G  
if(sHeader!=null) m%au* 0p  
{ LgFF+z  
if(sHeader.equals("Content-Length")) qM%l  
{ {WJ9!pA!lk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w6FtDl$  
break; P(AcDG6K  
} v d A 3  
} U?BuV  
else =E$Hq4I  
break; _voU^-  
} 21ng94mC  
} $bSnbU <  
catch(IOException e){e.printStackTrace ();} &(&5ao)5  
catch(Exception e){e.printStackTrace ();} o^HzE;L}  
)vWI{Q]r  
,xmL[Yk,  
Utility.log(nFileLength); h2~b%|Pv  
9?W!E_  
/WqiGkHV*  
return nFileLength; J; @g#h?  
} Y6<"_  
93I.Wp_{  
>Z%qkU/  
//保存下载信息(文件指针位置) .$&_fUY  
private void write_nPos() )/uu~9SFd  
{ v:.`~h/b  
try{ U4PnQ K,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -hv<8bC~4  
output.writeInt(nStartPos.length); sUl/9VKl  
for(int i=0;i<nStartPos.length;i++) 3jx5Lou)&  
{ Z'/sZ3Q}  
// output.writeLong(nPos); RC{|:@]8  
output.writeLong(fileSplitterFetch.nStartPos); y*K]z  
output.writeLong(fileSplitterFetch.nEndPos); .zDm{_'  
} |Iq#Q3w  
output.close();  3"B$M  
} oW7\T !f  
catch(IOException e){e.printStackTrace ();} &4]~s:F  
catch(Exception e){e.printStackTrace ();} lJ y\Ky(*  
} A\xvzs.d  
8<#S:O4kA  
oY;=$8y<q  
//读取保存的下载信息(文件指针位置) ?-.Qv1hs6p  
private void read_nPos() $ /Rr|<  
{ L`"B;a&  
try{ aJ;6!WFW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t^ax:6;"|  
int nCount = input.readInt(); ZV,1IaO  
nStartPos = new long[nCount]; %v)m&VUi%  
nEndPos = new long[nCount]; Fke_ms=I^  
for(int i=0;i<nStartPos.length;i++) vdS)EIt  
{ y*6-?@  
nStartPos = input.readLong(); *.g@6IkAQ  
nEndPos = input.readLong(); %p wpRD@  
} \9FWH}|  
input.close(); Y\cQ "9  
} 8y$c\Eu(mF  
catch(IOException e){e.printStackTrace ();} HzuB.B<  
catch(Exception e){e.printStackTrace ();} 83~9Xb=!\  
} O\;R (  
.LQvjK[N  
@ckOLtxE>  
private void processErrorCode(int nErrorCode) v J `'x  
{ 2p6`@8*34  
System.err.println("Error Code : " + nErrorCode); Wa{()Cz  
} @20~R/vh  
&i/QFO7y}  
cwK+{*ZH/  
//停止文件下载 ;`p!/9il  
public void siteStop() dF (m!P/R  
{ Lc0yLm  
bStop = true; xW hi>  
for(int i=0;i<nStartPos.length;i++) a d,0*(</  
fileSplitterFetch.splitterStop(); t93iU?Z  
wfE%` 1  
Z{#;my*X|  
} PR{y84$  
} 3jaY\(`%h  
//负责部分文件的抓取 =5 zx]N1r  
**FileSplitterFetch.java 6X1_NbC  
*/ ,sn/FT^; q  
package NetFox; +[2X@J  
OvFWX%uY  
hp:8e@  
import java.io.*; |izf|*e  
import java.net.*; LEM^8G]O  
ptcG:  
;?-`n4B&  
public class FileSplitterFetch extends Thread { VOmWRy"L  
JE[+  
1Vden.H*CI  
String sURL; //File URL ]n/fB|tE  
long nStartPos; //File Snippet Start Position l>H G|ol  
long nEndPos; //File Snippet End Position 4t Z. T9d  
int nThreadID; //Thread's ID Wd0$t    
boolean bDownOver = false; //Downing is over #!h +K"wX  
boolean bStop = false; //Stop identical [+j39d.Q  
FileAccessI fileAccessI = null; //File Access interface pbM"tr_A{  
s3., N|  
L.]mC !  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9F*],#ng  
{ |ULwUi-r  
this.sURL = sURL; 1zz.`.R2U  
this.nStartPos = nStart; 1!;}#m7v  
this.nEndPos = nEnd; #"Wh$x%  
nThreadID = id; fUJ\W"qya  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pPezy:  
} l}Fa-9_'  
#9Fe,  
OP-%t\sj>  
public void run() JN{xh0*  
{ _tGR:E  
while(nStartPos < nEndPos && !bStop) N]p|c3D  
{ <;?&<qMo,P  
aD5G0d?u  
N%2UL&w#B  
try{ Ya_4[vR<  
URL url = new URL(sURL); "eH~/6A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c/c%-=  
httpConnection.setRequestProperty("User-Agent","NetFox"); te+5@k#t  
String sProperty = "bytes="+nStartPos+"-"; CCX!>k]  
httpConnection.setRequestProperty("RANGE",sProperty); a%wK[yVp  
Utility.log(sProperty); {]a 6o[}u  
h0N*hx   
d\cwUXf J  
InputStream input = httpConnection.getInputStream(); ,0~/ Cn  
//logResponseHead(httpConnection); M~G1ZB  
SwDUg}M~  
`tCOe  
byte[] b = new byte[1024]; ^1%gQ@P  
int nRead; M?UlC   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p2=Sbb  
{ 1qs~[7{C1  
nStartPos += fileAccessI.write(b,0,nRead); UJ0Dy ` f  
//if(nThreadID == 1) Qbc62qFu!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L-ZJ[#D  
} o6} +5  
0shNwV1zF  
wFW2m  
Utility.log("Thread " + nThreadID + " is over!"); J)l]<##  
bDownOver = true; `P`n qn  
//nPos = fileAccessI.write (b,0,nRead); VH{SE7  
} y %k`  
catch(Exception e){e.printStackTrace ();} >e4  
} {d;eZt `  
} ,]N!I%SI  
SZ9xj^"g  
`;^%t  
//打印回应的头信息 @UO=)PxN3  
public void logResponseHead(HttpURLConnection con) Z {ntF  
{ Cf_Ik  
for(int i=1;;i++) PAe2 hJ  
{ zN\~v  
String header=con.getHeaderFieldKey(i); C/P,W>8  
if(header!=null) {C%/>e2-%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N_vVEIO9  
Utility.log(header+" : "+con.getHeaderField(header)); 7eh|5e$@  
else mf26AIlkQ  
break; 5k`[a93T  
} F_SkS?dB  
} tVhY=X{N?  
OpwZTy}1}  
t[6g9e$  
public void splitterStop() S?{|qlpy  
{ Sa&~\!0t  
bStop = true; ,i2%FW  
} qj71 rj  
Ru?Ue4W^b  
Av*R(d=`  
} .P=uR8  
9?*BN\E5S  
'aB0abr|  
/* o} #nf$v(  
**FileAccess.java S.+)">buH  
*//文件访问(定位,写) V*l0| ,9  
package NetFox; 4/{Io &|  
import java.io.*; ~'WvIA (  
ufdC'2cp8  
DA oOs}D  
public class FileAccessI implements Serializable{ B{ NKDkDH  
FhB^E$r%  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Vgs( feGs  
RandomAccessFile oSavedFile; JF*JF Ob  
long nPos; F9e$2J)C  
W%09.bF  
]lF'o&v]  
public FileAccessI() throws IOException "F+ 9xf&r  
{ Jkt L|u:k  
this("",0); H ^Xw<Z=  
} DYH-5yX7  
Z*kGWL  
\n850PS  
public FileAccessI(String sName,long nPos) throws IOException @A6\v+ih  
{ n@BE*I<"  
oSavedFile = new RandomAccessFile(sName,"rw"); +1p>:cih  
this.nPos = nPos; 9`^VuC'  
oSavedFile.seek(nPos); ?B %y)K  
} -8tWc]c |4  
zQ {g~x  
nJ4h9`[>V  
public synchronized int write(byte[] b,int nStart,int nLen) 4j!MjlG$  
{ ?9i7+Y"  
int n = -1; $B4}('&4FQ  
try{ `QR2!W70o3  
oSavedFile.write(b,nStart,nLen); N_L&!%s  
n = nLen; Bh*~I_Ta>  
} wC BL1[~C  
catch(IOException e) UTUIL D  
{ }se)=7d8 Z  
e.printStackTrace (); dv%gmUUf}k  
} ~GfcI:Zz&  
<uL?7P  
'oTcx Jx  
return n; NV;5T3  
} y wk;  
Qd!;CoOmZs  
,I=Cl mR  
} $X9Ban]  
(k M\R|  
Xr M[8a  
/* KLq u[{y.'  
**SiteInfoBean.java ;sNyN#  
*/ iTD}gC  
package NetFox; P1 (8foZA  
> Q@*o  
(eJr-xZ/  
public class SiteInfoBean { $t 1]w]}d  
SlZL%C;  
`+B+RQl}[  
private String sSiteURL; //Site's URL 9;Wz;p  
private String sFilePath; //Saved File's Path qB]z"Hfq,  
private String sFileName; //Saved File's Name dWD,iO_"@  
private int nSplitter; //Count of Splited Downloading File h1K 3A5  
6FSw_[)  
.2 UUU\/5  
public SiteInfoBean() ~A8lvuw3  
{//nSplitter的缺省值为5 vG\]xM'u  
//default value of nSplitter is 5 w}NgFrL  
this("","","",5); A i9*w?C  
} K;6K!6J:[  
tb/u@}")  
FPMhHHM  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4,s: G.g  
{ 'cw0FpQ;  
sSiteURL= sURL; ~uC4>+dk  
sFilePath = sPath; /l+x&xYD  
sFileName = sName; l,*Q?q  
this.nSplitter = nSpiltter; H gNUr5p  
< q; ]  
; tvB{s_  
} /gy;~eB01  
(:+IS W  
h,140pW  
public String getSSiteURL() 4C01=,6ye  
{ -ZQ3^'f:0J  
return sSiteURL; &%qD Som3  
} )r?i^D&4  
o,\%c" mC  
V]k!]  
public void setSSiteURL(String value) a2=wJhk  
{ mu"]B]  
sSiteURL = value; .j}u'!LKul  
} A$XjzTR  
nQ$N(2<Fe  
U%k e 5uwP  
public String getSFilePath() mZ/B:)_  
{ Z(as@gj H  
return sFilePath; }lpcbm  
} i;)g0}x`  
0BaL!^>  
j{U-=[$'  
public void setSFilePath(String value) Go`omh b  
{ o4~ft!>  
sFilePath = value; oSa FmP  
} 34;c00  
lmmyDg1R  
[7I|8  
public String getSFileName() )&dhE^ O  
{ d}l^yln  
return sFileName; !+hX$_RT  
} VpV w:Rh>  
huKz["]z[  
p*npY"}v  
public void setSFileName(String value) 3gabk/  
{ TJ; v}HSo  
sFileName = value; \o % ES  
} r`B+ KQ4  
t91CxZQ^s  
*|E@ 81s#  
public int getNSplitter() [qZ4+xF,,  
{ HqF8:z?v  
return nSplitter; X!2|_  
} oTa! F;I  
8OFrW.>[  
ZcWl{e4  
public void setNSplitter(int nCount) Y}?@Pm drz  
{ n/|/Womr  
nSplitter = nCount; epG;=\f}m`  
} R3@iN &  
} = oh6;Ojt  
XdS<51 C  
~IqT >  
/* njq-iU  
**Utility.java X4k/7EA  
*/ F_r eBPx  
package NetFox; i@I%$!cB  
ix#  
KdR&OBm  
public class Utility { <.v6w*+{/  
n9J>yud|  
[KE4wz+s{  
public Utility() BuvBSLC~  
{ u?J(l)gd  
g8x8u|  
\)#3S $L~  
} &qpA<F@7  
3+$O#>  
//线程睡眠 )xK!i.  
public static void sleep(int nSecond) n=>Gu9`  
{ 785iY865  
try{ r9t{/})A  
Thread.sleep(nSecond); =|#-Rm^YB  
} PA=BNKlH  
catch(Exception e) *7vPU:Q[  
{ 6,h<0j{  
e.printStackTrace (); jF5JpyOc  
} &%bX&;ECzf  
} tQ|I$5jNJ  
Y~:7l5C  
//日志 kL3=7t^ 1  
public static void log(String sMsg) .o8Gi*PEY  
{ Sh*P^i.]+  
System.err.println(sMsg); ^\6UTnS.  
} TSk6Q'L\v  
l )4OV>  
Uy_= #&jg  
public static void log(int sMsg) 2~4C5@SxL  
{ P>kx{^  
System.err.println(sMsg); 4HHf3j!5  
} k^]~NP  
} ;i:7E#@  
' #mC4\<W8  
lt4UNJ3w  
/* BxqCV%9o  
**TestMethod.java xV6j6k  
*/ hf-S6PEsM  
package NetFox; ,]Ma ,2  
dkLR Q   
*,pqpD>  
public class TestMethod { `Qhh{  
k$2Y)  
6GN'rVr!Z  
public TestMethod() ;uDFd04w [  
{ ///xx/weblogic60b2_win.exe +W1rm$Q  
try{ k8JPu"R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 9e5UTJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); PA/6l"-`3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); b1OB'P8  
fileFetch.start(); DNy)\+[  
} <f6Oj`{f4  
catch(Exception e){e.printStackTrace ();} *Tlv'E.M  
72 6y/o  
8xX{y#  
} 2P=;r:cx  
HHYcFoJwYN  
+x2xQ8#|~~  
public static void main(String[] args) P:v y  
{ O+N-x8W{  
new TestMethod(); <gy'@w?  
} 6>Cubb>  
} t|m3b~Oyv  
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