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http断点续传简单实现(java)

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/* r,dxW5v.  
**SiteFileFetch.java S[M\com'  
*/ QfM*K.7Sl  
package NetFox; v]27+/a$c  
import java.io.*; ? 5 V-D8k  
import java.net.*; `24:Eg6r  
N,_ej@L8  
y/2U:H  
public class SiteFileFetch extends Thread { 'lNl><e-  
7f td2lv  
 yQ8H-a.  
SiteInfoBean siteInfoBean = null; //文件信息Bean k .l,>s`!  
long[] nStartPos; //开始位置 ,@ Cru=  
long[] nEndPos; //结束位置 $RSVN?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rQ$A|GJL  
long nFileLength; //文件长度 ?0Ca-T Rz  
boolean bFirst = true; //是否第一次取文件 f1>^kl3@P  
boolean bStop = false; //停止标志 M>k7 '@G  
File tmpFile; //文件下载的临时信息 w02HSQ  
DataOutputStream output; //输出到文件的输出流 (;h]'I@  
^ihXM]1{G  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 9tC8|~Q  
public SiteFileFetch(SiteInfoBean bean) throws IOException `ionMTZY  
{ ?-'Q-\j  
siteInfoBean = bean; osX23T~-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YKvFZH)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F]?$Q'U  
if(tmpFile.exists ()) w } 2|Do$5  
{ T}]Ao  
bFirst = false; U>x2'B v  
read_nPos(); .]H]H*wC  
} uf)W? `e~  
else Lou4M  
{ JnY3]  
nStartPos = new long[bean.getNSplitter()]; AQ 7e  
nEndPos = new long[bean.getNSplitter()]; ^! ZjK-$A<  
} cuk2\> Xl  
Nd!2 @?V4  
"x$S%:p  
)SUN+YV^  
} nZ7v9o9  
M7Hk54U +t  
;+b}@e  
public void run() JkxS1  
{ FvI`S>  
//获得文件长度 L kq>>?T=  
//分割文件 (Fgt#H(B  
//实例FileSplitterFetch Nyqm0C6m^  
//启动FileSplitterFetch线程 Dfhs@ z  
//等待子线程返回 |f?C*t',  
try{ *u{.K:.I  
if(bFirst) '/ &"  
{ :M[E-j;  
nFileLength = getFileSize(); 0RSa{iS*A  
if(nFileLength == -1) \]ODpi 2  
{ A^p $~e\)  
System.err.println("File Length is not known!"); wD,F=O  
} WNYLQ=;  
else if(nFileLength == -2) V_W=MWs&+  
{ (kuZS4Af  
System.err.println("File is not access!"); wbS++cF<  
} 610k#$  
else ^&rb I,D  
{ }t-r:R$,  
for(int i=0;i<nStartPos.length;i++) N~ozyIP,  
{ iRVLo~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %-'U9e KN  
} ? sewU9*  
for(int i=0;i<nEndPos.length-1;i++) L2h+[f  
{ 6~/H#8Kdn  
nEndPos = nStartPos[i+1]; P*T)/A%4  
} #EM'=Q%TO  
nEndPos[nEndPos.length-1] = nFileLength; #129 i2  
} v/haUPWF\  
} y14@9<~9  
pq&c]8H  
Go67VqJr  
//启动子线程 TnaIRJ\B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L wu;y@[  
for(int i=0;i<nStartPos.length;i++)  Fszk?0T  
{ B&$89]gs|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5Q}@Y3 i=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2$ rq  
nStartPos,nEndPos,i); d?P aZz{4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0Yjy  
fileSplitterFetch.start(); &4[iC/}  
} A{o{o++  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *sG<w%%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -/qrEKQ0U?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o<'gM]$  
nEndPos = " + nFileLength); ]/'] {*T1  
// fileSplitterFetch[nPos.length-1].start(); D_)vGvv3;.  
T:&+#0<  
N.`]D)57  
//等待子线程结束 @&W?e?O ~G  
//int count = 0; C(P$,;6  
//是否结束while循环 ~<U3KB  
boolean breakWhile = false; t}FMBG o[  
{LeEnh-  
 k WtUj  
while(!bStop) >dl!Ep  
{ N9ufTlq s  
write_nPos(); y b G)=0  
Utility.sleep(500); i=a LC*@  
breakWhile = true; @6!JW(,]\  
<<1oc{i  
=KZ4:d5  
for(int i=0;i<nStartPos.length;i++) Vel;t<1  
{ u@E M,o  
if(!fileSplitterFetch.bDownOver) {EUH#':  
{ IXN4?=)I  
breakWhile = false; M5V1j(URE  
break; g3XAs@  
} A!kyga6F5  
} D+3Y.r 9  
if(breakWhile) aVYUk7_<  
break; <X |h *  
bH{aI:9Fb  
c" 7pf T  
//count++; gsp 7N  
//if(count>4) OQQ9R?Ll{  
// siteStop(); k#(cZ  
} QA(,K}z~^S  
^IpiNY/%Q  
1#<E]<='t  
System.err.println("文件下载结束!"); }(K6 YL  
} hI8C XG  
catch(Exception e){e.printStackTrace ();} /<$"c"UQ  
} d"UW38K{  
,no:6&#  
WL Lv a<{  
//获得文件长度 eNFUjDm  
public long getFileSize() ODEXQl}R  
{ 2>k)=hl:  
int nFileLength = -1;  ^gyp- !  
try{ y^\#bpq&\  
URL url = new URL(siteInfoBean.getSSiteURL()); @RIEO%S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Cpcd`y=IN  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0AKwZ' &H  
E3skC%}  
=.hDf<U  
int responseCode=httpConnection.getResponseCode(); 1}E@lOc  
if(responseCode>=400) A*~1Uz\t  
{ {UBQ?7.jE  
processErrorCode(responseCode); Bedjw =B  
return -2; //-2 represent access is error ]P$DAi   
} }Xi#x*-D  
?ljod6  
Ne7{{1  
String sHeader; ;x^,t@ xge  
<WJ0St  
}%ThnFFBw  
for(int i=1;;i++) eF^"{a3b  
{ I JY5wP1"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i q:Q$z&  
//Utility.log(in.readLine()); ^u!Tyb8Dk  
sHeader=httpConnection.getHeaderFieldKey(i); PAU+C_P  
if(sHeader!=null) @a\SR'8  
{ vCSB8R  
if(sHeader.equals("Content-Length")) FT>~ES]cQd  
{ aX)./  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); JvL'gJ$70  
break; D!a5#+\C  
} q{/Jw"e  
} vfUfrk@D~  
else Gc!8v}[7J  
break; <]^;/2 .B  
} :V~*vLvR  
} c dbSv=r  
catch(IOException e){e.printStackTrace ();} wrYQ=u#Z  
catch(Exception e){e.printStackTrace ();} rDX'oP:  
v-fi9$#^  
o`mIi  
Utility.log(nFileLength); iv+jv2ZF%  
d5"EvT  
Q@wq }vc!  
return nFileLength; P`dHR;Y0  
} Jav2A6a  
RIEv*2_O  
pEj^x[b`^  
//保存下载信息(文件指针位置) pptM &Y  
private void write_nPos() 6//FZ:q  
{ 7E3SvC|M  
try{ qf`xH"$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); p <=%  
output.writeInt(nStartPos.length); !NLvo_[Y  
for(int i=0;i<nStartPos.length;i++) 0nn]]B@l  
{ yCCw<?  
// output.writeLong(nPos); TUUE(sLA  
output.writeLong(fileSplitterFetch.nStartPos); NS4'IR=;E!  
output.writeLong(fileSplitterFetch.nEndPos); r`R~{;oT  
} 2HGD{;6>v{  
output.close(); G7A bhb,  
} N@*wi"Q  
catch(IOException e){e.printStackTrace ();} V<2fPDZ  
catch(Exception e){e.printStackTrace ();} w;@25= |  
} /rxltF3  
JkDPuTXD  
#;LMtDaL  
//读取保存的下载信息(文件指针位置) xGEmrE<;  
private void read_nPos() ^ ]qV8  
{ 2\63&C^  
try{ 3zTE4pHzu+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fj-pNl6Gf  
int nCount = input.readInt(); kq%gY  
nStartPos = new long[nCount]; P%@rH@^Y  
nEndPos = new long[nCount]; =Xy`"i{`(  
for(int i=0;i<nStartPos.length;i++) Z1$];Q\cX  
{ XMEK5Z9Dd  
nStartPos = input.readLong();  Q A)9  
nEndPos = input.readLong(); {jM<t  
} *e3L4 7"G  
input.close(); g"]<J &  
} n!ZP?]FR  
catch(IOException e){e.printStackTrace ();} '"w}gx  
catch(Exception e){e.printStackTrace ();} c@9Z&2)  
} $FQcDo|[  
7<1fKrN?GF  
Km9}^*Mo%  
private void processErrorCode(int nErrorCode) f']sU/c=  
{ w,![;wG  
System.err.println("Error Code : " + nErrorCode); P,/13tZ#3  
} } }f_  
M*O(+EM  
IQw %|^  
//停止文件下载 *hZ~i{c,7  
public void siteStop() ;Lsjh#  
{ >{ECyh;  
bStop = true; &7($kj  
for(int i=0;i<nStartPos.length;i++) r2SJp@f  
fileSplitterFetch.splitterStop(); w.D4dv_H  
o9 i#N  
Qb?y@>-[  
} /~Zc}o,J  
} OgKWgvy  
//负责部分文件的抓取 <+\k&W&Y|y  
**FileSplitterFetch.java ~TG39*m  
*/ ] ^; b  
package NetFox; B9LSxB  
]M~8 @K  
mNx,L+ 3  
import java.io.*; *9dV/TT~f[  
import java.net.*; gp$EXJ=  
}$|%/Y  
3q#"i&  
public class FileSplitterFetch extends Thread { m)@Q_{=6M  
Mr=}B6`  
N a. nA  
String sURL; //File URL KP=D! l&q  
long nStartPos; //File Snippet Start Position 6; 5)/q  
long nEndPos; //File Snippet End Position n9kd2[s|  
int nThreadID; //Thread's ID Gg}5$||^C  
boolean bDownOver = false; //Downing is over 7MO  
boolean bStop = false; //Stop identical gH i~nEH  
FileAccessI fileAccessI = null; //File Access interface m3xz=9Ve  
QT1:> k  
l5=u3r9WYC  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6%ZHP?  
{ H_?;h-Y]  
this.sURL = sURL; 1UW s_|X!  
this.nStartPos = nStart; uX<+hG.n}  
this.nEndPos = nEnd; h4Xc Kv+  
nThreadID = id; N 8:"&WM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ezcS[r  
} VLh%XoQx[  
<`c25ih.4  
v9E+(4I9_  
public void run() $yDW.pt  
{ |.b%rVu  
while(nStartPos < nEndPos && !bStop) rDIhpT)a  
{ E\R raPkQT  
Z!wD~C"D73  
<#xrrRhm}  
try{ R=\v3m  
URL url = new URL(sURL); ]`zjRRd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M8 iEVJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); >.J'L5 x$  
String sProperty = "bytes="+nStartPos+"-"; n 5~=qQK2  
httpConnection.setRequestProperty("RANGE",sProperty); CgVh\4,a  
Utility.log(sProperty); <\, & :<  
*nYB o\@g  
K4j@j}zK9I  
InputStream input = httpConnection.getInputStream(); +jq 2pFQ  
//logResponseHead(httpConnection); gI)w^7Gi  
<K.Bq]  
ra]!4Kd'  
byte[] b = new byte[1024]; iD%qy/I/  
int nRead; cy1\u2x_`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) MxY50 ^}(  
{ tCZpfZ@+=  
nStartPos += fileAccessI.write(b,0,nRead); 4)c+t"h  
//if(nThreadID == 1) IIq"e~"Vs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ')C|`(hs   
} LKqRvPnh  
cJP'ShnCh  
`aO.=:O_  
Utility.log("Thread " + nThreadID + " is over!"); <9@&oN+T  
bDownOver = true; "0|BoG  
//nPos = fileAccessI.write (b,0,nRead); m9#}X_&x  
} 5Xwk*@t2a  
catch(Exception e){e.printStackTrace ();} 3%XG@OgP  
} ^pJ0nY# c  
} *Jb_=j*)  
|.j^G2x  
b\1+kB/8  
//打印回应的头信息 n<{aPLQ  
public void logResponseHead(HttpURLConnection con) {hxW,mmA  
{ M} O[`Fx{W  
for(int i=1;;i++) +->\79<#V(  
{ Dp!;7e s|  
String header=con.getHeaderFieldKey(i); yrO?Np  
if(header!=null) Jf_]Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); c`-YIz)W  
Utility.log(header+" : "+con.getHeaderField(header)); ha_@Yqgh  
else PPN q:,  
break; L<0=giE  
} (.PmDBW  
} dF$KrwDK  
+d=~LQ}*  
7. %f01/i  
public void splitterStop() -<O JqB  
{ )j\r,9<K+5  
bStop = true; 9#u}^t  
} {U(Bfe^a,  
w]n 4KR4  
]X*YAPv  
} 9^oo-,Su_  
GL/  KB  
/a%*u6z@  
/* 9QX4R<"wUg  
**FileAccess.java l#Yx TY  
*//文件访问(定位,写) DK)u)?!  
package NetFox; Fl<(m  
import java.io.*; K~USK?Q%  
_=uviMuE  
%=BtOM_2  
public class FileAccessI implements Serializable{ . /Y&\<  
m+H%g"Zj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :#Ty^-"]1  
RandomAccessFile oSavedFile; *h2`^Z  
long nPos; hPcS, p{%  
1c'79YU  
n-d:O\]  
public FileAccessI() throws IOException NNgK:YibD  
{ @Eo4U]-  
this("",0); kr#I{gF  
} ~fBex_.o*  
gTnS[  
oK)[p!D?0{  
public FileAccessI(String sName,long nPos) throws IOException &%6NQWW  
{ Q ]/B/  
oSavedFile = new RandomAccessFile(sName,"rw"); ,pn ) >  
this.nPos = nPos; 9MT3T?IS  
oSavedFile.seek(nPos); 3#9uEDdE  
} RXM}hqeG  
^=k {~  
A&NqQ V,  
public synchronized int write(byte[] b,int nStart,int nLen) 6>s=Ci ZB  
{ pOKeEW<q  
int n = -1; 1ADv?+j)A/  
try{ ^L ]B5,} -  
oSavedFile.write(b,nStart,nLen); N^lAG"Jao[  
n = nLen; wajZqC2yg  
} 4x(F&0  
catch(IOException e) p/N62G  
{ +SyUWoM  
e.printStackTrace (); b]w[*<f?  
} 0:. 6rp  
/V#7=,,  
#J\s%60pt  
return n; dKb ^x^  
} Gh'X.?3   
n%*tMr9s  
XwtAF3oz  
} RYH)AS4w'  
X>}@EHT  
bGu([VB  
/* 6i| ~7md,  
**SiteInfoBean.java 4Ppop  
*/ &; s<dDQK  
package NetFox; SAy{YOLtl  
s0 47"Q  
LaclC]yLU  
public class SiteInfoBean { %uua_&#)  
lr0M<5d=p  
zXjw nep  
private String sSiteURL; //Site's URL AxEc^Cof  
private String sFilePath; //Saved File's Path rEmwKZF'  
private String sFileName; //Saved File's Name Si]X rub  
private int nSplitter; //Count of Splited Downloading File <}cZi4l'  
$D}"k!H  
G~(& 3  
public SiteInfoBean() aV#h5s  
{//nSplitter的缺省值为5 \ZsP]};*  
//default value of nSplitter is 5 2 ^oGwx @  
this("","","",5); @C=m?7O98  
} L$kgK# T  
gX_SKy  
]hL:33  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a}dw9wU!:  
{ L@?e:*h  
sSiteURL= sURL; 12-EDg/1  
sFilePath = sPath; }Bi@?Sb  
sFileName = sName; B>,A(X&  
this.nSplitter = nSpiltter; \qB6TiB/  
"Vx6 #u@}  
Mb1wYh  
} PV(4$I}  
5/,Qz>QE[  
_-RyHgX  
public String getSSiteURL() 8RU.}PD  
{ n>S2}y  
return sSiteURL; bM^7g  
} ~3d*b8  
g8'~e{= (  
`6}Yqh))  
public void setSSiteURL(String value) 5#2jq<D  
{ "O``7HA}  
sSiteURL = value; v1h.pbz`w  
} DL1 +c`d  
l|7O)  
Wt:~S/l  
public String getSFilePath() +<{m45  
{ %i595Ij-]  
return sFilePath; %jT w  
} Cdmy.gx^  
:]-$dEu&  
KGD'mByt"  
public void setSFilePath(String value) [[X+P 0`r  
{ %mu>-hac  
sFilePath = value; '-.wFB;  
} zIm-X,~I$  
h 1*FPsc  
5VZjDg?  
public String getSFileName() 7DZTQUb"  
{ w&5/Zh[~~L  
return sFileName; ntZ~m  
} "[.ne)/MC  
F 3s?&T)[G  
Mt=R*M}D0  
public void setSFileName(String value) r>O|L%xpv  
{ \OY}GRKt  
sFileName = value; /?U!y?t&@  
} 2lo:a{}j  
%I0}4$  
&Sa~/!M  
public int getNSplitter() e[8UH=`|  
{ <]'|$8&jY  
return nSplitter; V)h y0_  
} c 6q/X*  
#Wk5E2t  
z37Z %^  
public void setNSplitter(int nCount) UKj`_a6  
{ *uU4^E(  
nSplitter = nCount; y;QQ| =,  
} ^cn@?k((A  
} #a'r_K=ch)  
@ZG>mP1Vo  
Zw24f1iY  
/* t\%%d)d9  
**Utility.java * :S~C  
*/ `2e_ L  
package NetFox; L;lk.~V4T  
32^#RlSu8  
@,e8t BL  
public class Utility { }*Zo6{B-  
- wWRm  
bw5T2wYZ  
public Utility() U(Z!J6{c  
{ XWXr0>!,?  
I=odMw7Hj  
7>&1nBh. f  
} AqqHD=Yp  
yW`e |!  
//线程睡眠 R{`gR"*  
public static void sleep(int nSecond) =x#&\ui  
{ dm& /K 4c  
try{ 3HKxYvc C  
Thread.sleep(nSecond); WGMb8 /{$P  
} s`1^*Dl%+  
catch(Exception e) /=/ HB  
{ t)'dF*L  
e.printStackTrace (); .pW o>`"  
} nALnB1  
} qRl/Sl#F  
4m\([EO  
//日志 DJ|BM+  
public static void log(String sMsg) OfJd/D  
{ jzMg'z/@J  
System.err.println(sMsg); `)2[ST  
} oLw|uU-|  
mw"}8y  
+4HlRGH  
public static void log(int sMsg) O]bKNA.5  
{ &~ y{'zoL  
System.err.println(sMsg); *v&*% B  
} }H2#H7!H  
} l?<q YjI  
+`Fb_m)f  
P9s_2KOF  
/* 'e85s%ru  
**TestMethod.java q<EEb  
*/ gb(#DbI  
package NetFox; Bj8<@~bX:L  
Ih3$  
6%UY1Q.?  
public class TestMethod { \ j:AR4  
xG w?'\  
& +]x;K  
public TestMethod() 0$QIfT)  
{ ///xx/weblogic60b2_win.exe Uuz?8/w}#  
try{ ? oc+ 1e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); dk8y>uLr_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qCQu^S' iD  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I{EIHD<  
fileFetch.start(); ?b"Vj+1:x  
} m/{Y]D{2  
catch(Exception e){e.printStackTrace ();} ,ex]$fQ'  
,jTPg/r  
BCBUb  
} #fN/LO  
L^)qe^%3  
 C/  
public static void main(String[] args) zhjJ>d%w  
{ zWtj|%ts  
new TestMethod(); 9cz)f\  
} zuMO1s  
} @.1Qs`pt  
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