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http断点续传简单实现(java)

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/* Ag4Ga?&8ec  
**SiteFileFetch.java |*c\6 :  
*/ o|;eMO-  
package NetFox; =Wk/q_.  
import java.io.*; ^g-t#O lD?  
import java.net.*; zIm_7\e  
 c(V=.+J  
N>pmhskN?  
public class SiteFileFetch extends Thread { H1%[\X?=  
g;!@DVF$  
Ph+X{|  
SiteInfoBean siteInfoBean = null; //文件信息Bean z(` }:t  
long[] nStartPos; //开始位置 bA<AG*  
long[] nEndPos; //结束位置 \aVY>1`  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z'oiyXEE3  
long nFileLength; //文件长度 b~r{J5x@  
boolean bFirst = true; //是否第一次取文件 W\qLZuQ  
boolean bStop = false; //停止标志 G]mWaA  
File tmpFile; //文件下载的临时信息 ImV]}M~_  
DataOutputStream output; //输出到文件的输出流 h#m:Y~GoF  
$# !UGY  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .Y(lB=pV  
public SiteFileFetch(SiteInfoBean bean) throws IOException RE>ks[  
{ %t~SOkx  
siteInfoBean = bean; O%JsUKV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EwD3d0udL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `kNi*I^  
if(tmpFile.exists ())  Vp] D  
{ "rx^M*"  
bFirst = false; FJf~vAQ  
read_nPos(); phgexAq  
} 6vgBqn[  
else *|k;a]HT  
{ >^yc=mM(g3  
nStartPos = new long[bean.getNSplitter()]; /j' B\,  
nEndPos = new long[bean.getNSplitter()]; F?8BS*r_  
} @ 2!C^}d3F  
.;HIEj zq  
J}(6>iuQY?  
;;?vgrz  
} ```d:f  
C1T=O  
a4T~\\,dZ>  
public void run() 4N~+G `  
{ iIsEQh  
//获得文件长度 I%9bPQ  
//分割文件 3T|Y}  
//实例FileSplitterFetch x*h?%egB!p  
//启动FileSplitterFetch线程 #`La|a.-  
//等待子线程返回 os1?6 z~  
try{ WgA`kT  
if(bFirst) ^Ue0mC7m  
{ H\fcY p6  
nFileLength = getFileSize(); JAlU%n?R  
if(nFileLength == -1) U~*c#U"bh  
{ iUIy,Y  
System.err.println("File Length is not known!"); pd4cg?K  
} g@@&sB-A"  
else if(nFileLength == -2) 6x_ T@  
{ g/8.W  
System.err.println("File is not access!"); P3iA(3I24<  
} hojHbmm4  
else =n-z;/NL  
{ )?w&oIj5  
for(int i=0;i<nStartPos.length;i++) 4E=0qbt8  
{ K1T1@ j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #>8T*B  
} y(bsCsV&  
for(int i=0;i<nEndPos.length-1;i++) O)`fvpVU  
{ CQdBf3q  
nEndPos = nStartPos[i+1]; x*.Ye 5Jb  
} j2|XD Of  
nEndPos[nEndPos.length-1] = nFileLength; "~u_\STn <  
}  ~~PgF"v  
} :GQ UM6  
N-[n\}'  
'_B_&is  
//启动子线程 >']+OrQH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6W5d7`A  
for(int i=0;i<nStartPos.length;i++) 9Z&?R++?  
{ KNy`Lj)VPY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ajW[eyX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nV'3sUvR#  
nStartPos,nEndPos,i); [#p&D~Du&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FbveI4  
fileSplitterFetch.start(); /H')~!Yz  
} 2Ok?@ZdjA{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mc?';dEG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a`#S|'oatC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0pD W _  
nEndPos = " + nFileLength); 1h2H1gy5I3  
// fileSplitterFetch[nPos.length-1].start(); Qh\YR\O  
m$,,YKhh  
Rab#7Q16Q8  
//等待子线程结束 '9qn*H`'  
//int count = 0; 2G?$X?  
//是否结束while循环 Vu}806kB  
boolean breakWhile = false; 7Yuk  
@7-=zt+f  
[4p=X=B  
while(!bStop) (Akd8}nf~  
{ `)6>nPr7P  
write_nPos(); ?cJY B)  
Utility.sleep(500); ~z5@V5 z  
breakWhile = true; F) ?o,  
\/!ZA[D|E\  
<yZP|_  
for(int i=0;i<nStartPos.length;i++) <"?*zx&  
{ qU#$2  
if(!fileSplitterFetch.bDownOver) GR<c=   
{ AM'gnP>  
breakWhile = false; ! ao6e  
break; ~ FGe ~  
} 5:UyUB  
} Km,*)X.-5  
if(breakWhile) W2`.RF^  
break; Zd[OWF  
nTs/Q  V  
i2*d+?Er  
//count++; V$(/0mQV(  
//if(count>4) ,;%yf?  
// siteStop(); i X%[YQ |  
} [EgW/\35  
g5y;?fqJ  
UFe(4]^  
System.err.println("文件下载结束!"); [Eu];  
} #|Oj]bd(=  
catch(Exception e){e.printStackTrace ();} nd:E9:  
} 4}i*cB `  
H-(q#?:  
P/MM UmO  
//获得文件长度 ]*3:DU  
public long getFileSize() sK&,):"]R  
{ X"j>=DEX  
int nFileLength = -1; JS!*2*Wr  
try{ SauH>  
URL url = new URL(siteInfoBean.getSSiteURL()); dv , C6t2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?g3 ]~;#  
httpConnection.setRequestProperty("User-Agent","NetFox"); P? (vW&B  
3;-^YG  
(bv,02  
int responseCode=httpConnection.getResponseCode(); hL!QLiF:  
if(responseCode>=400) L,?/'!xV  
{ tiYOMA  
processErrorCode(responseCode); A2NF<ZsD  
return -2; //-2 represent access is error -f?Ah  
} ^,TTwLy- t  
b{M}5~e=B  
<'+ %\  
String sHeader; +{$QAjW(/  
H-I{-Fm  
~zF2`.  
for(int i=1;;i++) , ECLqs%  
{ oq$w4D0Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (e9fm|n!)|  
//Utility.log(in.readLine()); +?[BU<X6u  
sHeader=httpConnection.getHeaderFieldKey(i); f8'MP9Lv  
if(sHeader!=null) .et ^4V3  
{ KzphNHd  
if(sHeader.equals("Content-Length")) ``u:lL  
{ DI1(`y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); __I/F6{ 9V  
break; ^:u?ye;  
} *5OCqU+g  
} Cqx v"NN  
else +@<KC  
break; JYm7@gx  
} ghAi{@s$)  
} Hx2En:^Gf  
catch(IOException e){e.printStackTrace ();} I%"'*7 U  
catch(Exception e){e.printStackTrace ();} eEl.. y  
T5|c$doQ  
a}gk T]  
Utility.log(nFileLength); 8;8c"'Mn  
q'G,!];qL  
\NK-L."[  
return nFileLength; Y]N,.pv=  
} hat>kXm2K  
`uo, __y  
;AIc?Cg  
//保存下载信息(文件指针位置) y&oNv xG-  
private void write_nPos() tmJgm5v  
{ c|AtBgvf  
try{ WKl+{e  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TWd;EnNM  
output.writeInt(nStartPos.length); g=l:cVr8y  
for(int i=0;i<nStartPos.length;i++) XiQkrZ  
{ QTmZ( >z  
// output.writeLong(nPos); yz\c5  
output.writeLong(fileSplitterFetch.nStartPos); !kL> ,O>/  
output.writeLong(fileSplitterFetch.nEndPos); < g|Z}Y  
} 2p!"p`b~  
output.close(); W^\d^)  
} `t (D!  
catch(IOException e){e.printStackTrace ();} +f NvNbtA  
catch(Exception e){e.printStackTrace ();} Jblj^n?Bm  
} wRtZ `o  
,v9f~qh  
<>Y?v C  
//读取保存的下载信息(文件指针位置) &dR=?bz-A  
private void read_nPos() iv&v8;B  
{ q,%:h`t\  
try{ ?_g1*@pA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hhI)' $  
int nCount = input.readInt(); A],ooiq<  
nStartPos = new long[nCount]; }uY!(4Rw  
nEndPos = new long[nCount]; 4 !#a3=_  
for(int i=0;i<nStartPos.length;i++) p$E8Bn%[  
{ } JiSmi6o  
nStartPos = input.readLong(); qO@@8/l  
nEndPos = input.readLong(); bKDA!R2  
} ][;G=oCT  
input.close(); Kw5Lhc1V  
} 57,dw-|xi  
catch(IOException e){e.printStackTrace ();} a%vrt)Gx  
catch(Exception e){e.printStackTrace ();} ]N{0:Va@D  
} Anm=*;*M`  
%|"g/2sF[G  
sJG5/w  
private void processErrorCode(int nErrorCode) NbRn*nb/T  
{ *G5c|Y  
System.err.println("Error Code : " + nErrorCode); )C hqATKg  
} Ts$@s^S]  
E=]4ctK  
[KJ q  
//停止文件下载 q,>?QBct*  
public void siteStop() Vz=auM1xZ  
{ eH%RNtP`  
bStop = true; TX [%(ft  
for(int i=0;i<nStartPos.length;i++) q MYe{{r  
fileSplitterFetch.splitterStop(); 8, "yNq  
Q{g;J`Z)p  
Tr&M~Lgb)  
} 2aN<w'pA  
} U/l?>lOD\  
//负责部分文件的抓取 BX+.0M  
**FileSplitterFetch.java _-TA{21)  
*/ @A<PkpNL  
package NetFox; tw=oH9c80  
l fZ04M{2  
,XkGe   
import java.io.*; 5ETip'<KT6  
import java.net.*; @`36ku  
4qi[r)G  
_aWl]I){5  
public class FileSplitterFetch extends Thread { ;)AfB#:d  
0\9K3  
5ExDB6Bx@y  
String sURL; //File URL Px FWJ?=  
long nStartPos; //File Snippet Start Position ~]C%/gEh  
long nEndPos; //File Snippet End Position *J|(jdu7  
int nThreadID; //Thread's ID <[:o !$  
boolean bDownOver = false; //Downing is over ?:{sH#ua  
boolean bStop = false; //Stop identical RDqFL.-S  
FileAccessI fileAccessI = null; //File Access interface . #lsic8]  
:Y,BdU  
/Ci*Az P  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Kf tgOG f  
{ 8T)&`dM6P~  
this.sURL = sURL; T:]L/wCj  
this.nStartPos = nStart; BQH}6ueZ  
this.nEndPos = nEnd; F[ ajOb8  
nThreadID = id; "XgmuSQ!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _5 ^I.5Z3  
} 'B5^P  
?S$i?\Qh  
l:#-d.z#  
public void run() XQ%4L-rhN  
{ YKmsQ(q`N  
while(nStartPos < nEndPos && !bStop) %WTEv?I{Ga  
{ d[p;T\?"  
L|-98]8>  
Q6gt+FKU9  
try{ s~I6SA&i  
URL url = new URL(sURL); bHLT}x/Gw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G;NF5`*4mc  
httpConnection.setRequestProperty("User-Agent","NetFox"); dovZ#D@Q  
String sProperty = "bytes="+nStartPos+"-"; DGW+>\G  
httpConnection.setRequestProperty("RANGE",sProperty); &8.NT~"Gg  
Utility.log(sProperty); 05yZad*  
)SryDRT  
xv{O^Ie+S  
InputStream input = httpConnection.getInputStream(); Yim<>. !  
//logResponseHead(httpConnection); 7 >iU1zy  
[/s&K{+c  
3pf[M{dG  
byte[] b = new byte[1024]; @%k}FL=:t(  
int nRead; HK\~Qnq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~qe%Yq  
{ \^I>Q _LU  
nStartPos += fileAccessI.write(b,0,nRead); -7J|l  
//if(nThreadID == 1) ^7zu<lX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }Sy=My89r  
} n  -(  
Hbv6_H  
qW:HNEiir  
Utility.log("Thread " + nThreadID + " is over!"); kmzH'wktt  
bDownOver = true; 6T 8!xyi-+  
//nPos = fileAccessI.write (b,0,nRead); DCqY|4Qc  
} -*5Rnx|Y{  
catch(Exception e){e.printStackTrace ();} T\~x.aH`^  
} bR@p<;G|  
} =X.LA%Sf=u  
Z{&cuo.@<]  
T~Q JO0  
//打印回应的头信息 24 1*!  
public void logResponseHead(HttpURLConnection con) @(r /dZc  
{  hI9  
for(int i=1;;i++) __mF ?m  
{ =UyLk-P w  
String header=con.getHeaderFieldKey(i); jw-0M1B  
if(header!=null) PkI:*\R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 87hq{tTs]  
Utility.log(header+" : "+con.getHeaderField(header)); &0f5:M{P  
else McB[|PmC  
break; {G?N E  
} 9tF9T\jW  
} #o1=:PQaC  
 : ]C~gc  
RKPO#qju\F  
public void splitterStop() %iV^S !e  
{ boDt`2=  
bStop = true; %^RN#_ro(3  
} ]_N|L|]M  
ER,1(1]N  
vWAL^?HUP  
} I`NjqyTW  
#g6.Glz3  
U&O: _>~  
/* e7wSOs  
**FileAccess.java P.gb 1$7<  
*//文件访问(定位,写) ]U"94S U:)  
package NetFox; Gea\,{E9xA  
import java.io.*; 13taFV dU  
$ X q!L  
Ub6jxib  
public class FileAccessI implements Serializable{ iLSr*` o  
(o`{uj{!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6j ~#[  
RandomAccessFile oSavedFile; 21"1NJzP  
long nPos; eJg8,7WC  
%c4Hse#Y  
p5G?N(l  
public FileAccessI() throws IOException `V##Y  
{ .V,@k7U,V  
this("",0); FSND>\>  
} p, #o<W  
P&f7@MOV.P  
J{Q|mD=  
public FileAccessI(String sName,long nPos) throws IOException #\=FO>  
{ % >=!p  
oSavedFile = new RandomAccessFile(sName,"rw"); B {>7-0  
this.nPos = nPos; ZHa"isl$e  
oSavedFile.seek(nPos); <Y}R#o1Z  
} E>K!Vrh-L  
V:joFRH9  
{;2PL^i  
public synchronized int write(byte[] b,int nStart,int nLen) -f DnA4;  
{ hIT+gnhh  
int n = -1; >7 ="8  
try{ i{`:(F5*  
oSavedFile.write(b,nStart,nLen); v/_  
n = nLen; wRVUu)  
} uA< n  
catch(IOException e) ez| )ph7  
{ ]9^sa-8  
e.printStackTrace (); ueUuJxq)  
} }~L.qG  
E 7{U |\  
H*}y^ )x  
return n; ~A\GT$  
} ;0Tx-8l  
uLV#SQ=bZN  
`x*Pof!Io  
} YuO.yh_  
tS6qWtE  
\2h!aRWR  
/* F1yqxWHeo  
**SiteInfoBean.java a^I\ /&aw'  
*/ aht[4(XH5  
package NetFox; cz8T  
p^w;kN  
lN Yt`xp  
public class SiteInfoBean { JJN.ugT}1  
M<v%CawS  
t7aefV&_,  
private String sSiteURL; //Site's URL HMNLa*CL'  
private String sFilePath; //Saved File's Path 2fL;-\!y(  
private String sFileName; //Saved File's Name H*PSR  
private int nSplitter; //Count of Splited Downloading File Y^wW2-,m  
8)_XJ"9)G  
bE !GJZ  
public SiteInfoBean() _z|65H  
{//nSplitter的缺省值为5 JkbQyn  
//default value of nSplitter is 5 (,0(   
this("","","",5); GBPo8L"9  
} FOE4>zE  
;@oN s-  
YIG~MP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xqu}cz  
{ K  &N  
sSiteURL= sURL; (5-FVp fb  
sFilePath = sPath; 3EPv"f^V  
sFileName = sName; ]>5/PD,wWy  
this.nSplitter = nSpiltter; sYI-5D]  
H&-zZc4\  
X}Ai -D  
} s Z].8.  
?67Y-\}  
9sYMSc~Bm  
public String getSSiteURL() z7fp#>uw  
{ I 7{T  
return sSiteURL; #Lh;CSS  
} *XIF)Q=<>  
kaVxT_  
iv J@=pd)B  
public void setSSiteURL(String value) |v 3T!  
{ vdc\R?  
sSiteURL = value; ek*rp`y]  
} *`5.|{<j{  
A P?R"%  
D2Kp|F;  
public String getSFilePath() tEvut=k'  
{ *0Skd  
return sFilePath; 12b(A+M   
} r@H /kD  
"#2a8#  
nFHUy9q  
public void setSFilePath(String value) ^ B fC  
{ )q8pk2  
sFilePath = value; K0|FY=#2y  
} 2*laAB  
#A JDWelD  
3u+T~g0^  
public String getSFileName() U:0mp"  
{ V^bwXr4f  
return sFileName; 6 ob@[ @  
} p>v$FiV2N  
Nk? ^1n$  
g}k`o!q  
public void setSFileName(String value) 6]WAUK%h  
{ |\pj;XU  
sFileName = value; h+g_rvIG*  
} t%/&c::(6  
JcsHt;  
Z&+ g;(g  
public int getNSplitter() /[ 5gX^A  
{ On9A U:\  
return nSplitter; 6*78cg Io  
} FXG]LoP  
"c%0P"u  
FrfM3x6UM  
public void setNSplitter(int nCount) gwuI-d^  
{ d;Ym=YHJtn  
nSplitter = nCount; :^6y7&o[  
} c_$=-Khk  
} %rL.|q9  
aFX=C >M  
'T*&'RQr  
/*  dVtG/0  
**Utility.java pZ.ecZe/  
*/ qd ~BnR$=  
package NetFox; ;#W2|'HD  
5}l[>lF  
u5`u>.!  
public class Utility { Q%`@0#"]Sv  
t6 "%3#s  
r= `Jn6@  
public Utility() Cn34b_Sbd  
{ |.: q  
^eY!U%.  
v!~fs)cdE|  
} MS~(D.@ZS  
!GjQPAW  
//线程睡眠 'x#~'v*  
public static void sleep(int nSecond) :'X&bn  
{ >C>.\  
try{ ? =Z?6fw  
Thread.sleep(nSecond); C`hU]  
}  ~d.Y&b  
catch(Exception e) {3mRq"e  
{ EHJ.T~X  
e.printStackTrace (); ( Y[Q,  
} #jvtUS\  
} hR?{3d#x2  
Mq156TL  
//日志 hn G Z=  
public static void log(String sMsg) e'NJnPO  
{ ~w+c8c8pW  
System.err.println(sMsg); AlaW=leTe  
} cA?W7D  
AofKw  
SwGx?U  
public static void log(int sMsg) Mk 6(UXY  
{ Qz1E 2yJ  
System.err.println(sMsg); pI\]6U  
}  ?(1 y  
} `g=J%p  
|mfvr *7  
6P l<'3&  
/* MAR'y8I  
**TestMethod.java Gx/Oi)&/  
*/ ASA,{w]  
package NetFox; m.rmM`  
+Mb.:_7'  
Rh{f5-  
public class TestMethod { eF$x1|  
& '`g#N  
F v2-(  
public TestMethod() "%w u2%i  
{ ///xx/weblogic60b2_win.exe +{.WQA}z\  
try{ P/eeC"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BL }\D;+t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )qw&%sO +  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CY5Z{qiX  
fileFetch.start(); ITI)soa~  
} A}9`S6@@  
catch(Exception e){e.printStackTrace ();} xJ]\+ 50  
U?Zq6_M&  
}o(-=lF  
} PJ%C N(0  
4xje$/_d  
WSB 0~+  
public static void main(String[] args) sY&IquK^  
{ B~ GbF*j  
new TestMethod(); .*Y  
} *i%.;Z"  
} %5n_ p^xp  
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