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http断点续传简单实现(java)

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/* 6W3."};  
**SiteFileFetch.java =|dm#w_L"  
*/ oHp"\Z&  
package NetFox; /v| b]Ji  
import java.io.*; lw?C:-m  
import java.net.*; %[ *+  
(~! @Uz5  
e=IbEm{|  
public class SiteFileFetch extends Thread { _3O*"S=1  
nD>X?yz2  
:_2:Fh.}3~  
SiteInfoBean siteInfoBean = null; //文件信息Bean Dq9f Fe  
long[] nStartPos; //开始位置 hkV*UH{  
long[] nEndPos; //结束位置 o8IqO'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5p:2gsk  
long nFileLength; //文件长度 RdL5VAD  
boolean bFirst = true; //是否第一次取文件 (^sb('"  
boolean bStop = false; //停止标志 4ji'6JHPg  
File tmpFile; //文件下载的临时信息 ;05lwP* r]  
DataOutputStream output; //输出到文件的输出流 gbh/ `  
N1'Yo:_A  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  xB?!nd  
public SiteFileFetch(SiteInfoBean bean) throws IOException 30(e6T;   
{ -em3 #V  
siteInfoBean = bean; e8egxm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .L^;aL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eI|~neh  
if(tmpFile.exists ()) YnDaB px  
{ MrOtsX  
bFirst = false; ^L Xr4  
read_nPos(); V\FlKC   
} f`\J%9U_O  
else mUR[;;l  
{ &9.3-E47*  
nStartPos = new long[bean.getNSplitter()]; 5GPAt  
nEndPos = new long[bean.getNSplitter()]; Vhb~kI!x  
} b}u#MU  
66+]D4(k  
9)j"|5H  
KBI 1t$  
} <Nc9F['&#  
 :J)^gc  
3O2vY1Y2  
public void run() QV*la=j/  
{ 0TICv2l!  
//获得文件长度 ^{++h?cS)  
//分割文件 e(`r"RrQ  
//实例FileSplitterFetch 98_os2`  
//启动FileSplitterFetch线程  x}d5 Y  
//等待子线程返回 $[J\sokpY  
try{ YhAO  
if(bFirst) rEU1 VvE  
{ ;;U&mhz`  
nFileLength = getFileSize(); irjHPuhcG  
if(nFileLength == -1) akHQ&+[j  
{ |L-- j  
System.err.println("File Length is not known!"); I>-}ys`[  
} ?9 `T_,  
else if(nFileLength == -2) a<+Rw{  
{ ,p\*cHB9  
System.err.println("File is not access!"); ,pkzNe`F  
} `fVzY"Qv k  
else qPhVc9D#  
{ AO5a  
for(int i=0;i<nStartPos.length;i++) HJ!)&xT  
{ @OHNz!Lj:d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2elj@EB,M  
} F[.IF5_  
for(int i=0;i<nEndPos.length-1;i++) 2Y=Q%  
{ uHDUuK:Ur  
nEndPos = nStartPos[i+1]; m^)\P?M5|  
} 6e}T zc\@(  
nEndPos[nEndPos.length-1] = nFileLength; A?)(^  
} nRX<$OzTV  
} td#m>S  
+yHzp   
+,D82V7S  
//启动子线程 WCp[6g&%O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >S?7-2X  
for(int i=0;i<nStartPos.length;i++) kaDn= ={YM  
{ : R8+jO   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y92<(ziaX)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >4#\ U!  
nStartPos,nEndPos,i); u9+)jN<Yh  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mj9]M?]  
fileSplitterFetch.start(); .=c@ps  
} L;KLmxy#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9@*4^Ks p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -OfAl~ 4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UB% ;P-RD  
nEndPos = " + nFileLength); \OK}DhY#  
// fileSplitterFetch[nPos.length-1].start(); PKs$Q=Ol<|  
({!*&DVu  
|txzIc.#  
//等待子线程结束 '_g*I  
//int count = 0; `]Vn[^?D  
//是否结束while循环 $,T3vX]<  
boolean breakWhile = false; i\MW'b  
m :]F &s  
er!+QD,EM  
while(!bStop) #P1 ;*m  
{ YeF'r.Y  
write_nPos(); .+^o{b  
Utility.sleep(500); ]d&;QZ#w  
breakWhile = true; 3v<9 Z9O  
rO1.8KKJ  
N=:xyv  
for(int i=0;i<nStartPos.length;i++) u)ZZ/|  
{ ['0^gN$:e  
if(!fileSplitterFetch.bDownOver) } x'o`GuUf  
{  +!wkTrV  
breakWhile = false;  uQW d1>  
break; jg3['hTJT  
}  R"PO@v  
} 9Mv4=k^7|4  
if(breakWhile) q{)Q ?E  
break; %E2C4UbY  
.>( qZEF  
E95VR?nUg  
//count++; ?Ye%k  
//if(count>4) ]O+Nl5*  
// siteStop(); sF#t{x/sW  
} It^_?oiK  
/3~}= b  
sZU Ao&  
System.err.println("文件下载结束!"); tLx8}@X"  
} h6(L22Hn  
catch(Exception e){e.printStackTrace ();} v8A{ q  
} QOF'SEq"k  
E __A1j*gd  
N{zou?+  
//获得文件长度 E`uK7 2j  
public long getFileSize() /s`xPxvt  
{ <NMOs"NB  
int nFileLength = -1; UgLJV2M6  
try{ mHC36ba  
URL url = new URL(siteInfoBean.getSSiteURL()); GJuU?h#:/{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RjX#pb  
httpConnection.setRequestProperty("User-Agent","NetFox"); DZ|/#- k  
N" oJ3-~  
h$fC/Juit  
int responseCode=httpConnection.getResponseCode(); |n&EbOmgf  
if(responseCode>=400) ^kj%Ekt7  
{ ,1e@Y~eZ  
processErrorCode(responseCode); >(a/K2$*1  
return -2; //-2 represent access is error HLM"dmI   
} = G3A}  
y|Zj M  
2c<phmiK  
String sHeader; C/pu]%n@4  
^kpu9H  
&]/.=J  
for(int i=1;;i++) <3Hu(Jx<O  
{ iD9hqiX&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MMUw+jM4  
//Utility.log(in.readLine()); #Y<b'7yJ  
sHeader=httpConnection.getHeaderFieldKey(i); b ~FmX  
if(sHeader!=null) aD3Q-a[  
{ 5($ '@u  
if(sHeader.equals("Content-Length")) N DV_/BI  
{ S>p>$m, Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DnPV Tp(>  
break; cj/FqU"  
} nyB~C7zR  
} "A9 c]  
else cb~m==G  
break; \>-%OcYlM  
} U z6XQskX  
} mCx6$jz  
catch(IOException e){e.printStackTrace ();} O k~\  
catch(Exception e){e.printStackTrace ();} zHCz[jlrMq  
U=bZy,FT$  
7e&%R4{b  
Utility.log(nFileLength); v<Ux+-  
[t`QV2um  
_/!IjB:(70  
return nFileLength; c8jq.y v  
} u5FlT3hY.  
= 8%+$vX  
bx<7@  
//保存下载信息(文件指针位置) /P|jHK|{  
private void write_nPos() FeFH_  
{ #VEHyz6P  
try{ I2'UC) 0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _sCpyu  
output.writeInt(nStartPos.length); -.E<~(fad  
for(int i=0;i<nStartPos.length;i++) hw&R .F  
{ *l^%7W rk  
// output.writeLong(nPos); 4<&`\<jZ  
output.writeLong(fileSplitterFetch.nStartPos); qcfLA~y  
output.writeLong(fileSplitterFetch.nEndPos); _ #+~#U%5n  
} Kq';[Yc  
output.close(); s0"1W"7vh  
} !(Y23w*  
catch(IOException e){e.printStackTrace ();} 9_ GR\\  
catch(Exception e){e.printStackTrace ();} cv["Ps#;`W  
} aNCIh@m~  
Ol24A^  
,tL<?6_  
//读取保存的下载信息(文件指针位置) [?hc.COE  
private void read_nPos() o3l_&?^  
{ #SRGVa`x  
try{ ZOG6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]f q.r  
int nCount = input.readInt(); j{9sn,<:  
nStartPos = new long[nCount]; /wL}+  
nEndPos = new long[nCount]; \6xVIQ& 0  
for(int i=0;i<nStartPos.length;i++) v7/qJ9l  
{ PQ|kE`'  
nStartPos = input.readLong(); }ya9 +?I  
nEndPos = input.readLong(); pRj1b^F5y  
} D[)g-_3f6<  
input.close(); Dw^d!%Ala  
} GRb"jF>ut  
catch(IOException e){e.printStackTrace ();} o84!$2P+w  
catch(Exception e){e.printStackTrace ();} ;p#)z/zZ  
} MI@id  
T)]5k3{  
Pz1pEyuL  
private void processErrorCode(int nErrorCode) 2, ` =i  
{ Jx@3zl  
System.err.println("Error Code : " + nErrorCode); .4~n|d>z  
} \0m[Ch}~ey  
70L{u+wIy  
-lm\~VZT3  
//停止文件下载 0p_/eWww-  
public void siteStop() nj~1y ')  
{ C_Y^<  
bStop = true; ^~2GhveBV  
for(int i=0;i<nStartPos.length;i++) nmVL%66K  
fileSplitterFetch.splitterStop(); { CkxUec  
<w.W[ak  
?*a:f"vQ  
} @U(D&_H,K  
} J]~LmSh  
//负责部分文件的抓取 R$=UJ}>  
**FileSplitterFetch.java n=n!Hn  
*/ EOjo>w>  
package NetFox; k9.2*+vvg  
|jniI(  
[|\~-6"7N|  
import java.io.*; 8|`4D 'Ln  
import java.net.*; qde.;Yv9  
)G0a72  
iU\WV  
public class FileSplitterFetch extends Thread { %J?;@ G)r  
|?SK.1pW  
:~pPB#)nk  
String sURL; //File URL m0W5Ogk  
long nStartPos; //File Snippet Start Position 1+PLj[;jJ:  
long nEndPos; //File Snippet End Position <DCrYt!1}c  
int nThreadID; //Thread's ID 37Z:WJ?  
boolean bDownOver = false; //Downing is over Y6/'gg'&5  
boolean bStop = false; //Stop identical S\ ~Wpf  
FileAccessI fileAccessI = null; //File Access interface TDdFuO'}  
U&|=dH]-  
GM{m(Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^Pf FW  
{ [Zk|s9  
this.sURL = sURL; PWOV~ `^;  
this.nStartPos = nStart; e7ixi^Q  
this.nEndPos = nEnd; G@anY=D\EB  
nThreadID = id; )%U&z>^P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9Nglt3J[  
} 6)kF!/J  
b/ h,qv  
:Q=Jn?Gjb  
public void run() 1GVJ3VXt  
{ 74rz~ZM 5  
while(nStartPos < nEndPos && !bStop) e;R5A6|  
{ Jeyy Z=  
/+ vl({vV  
7$+n"Cfm  
try{ TGGeTtk=  
URL url = new URL(sURL); j8!fzJG  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [L8Bgw1  
httpConnection.setRequestProperty("User-Agent","NetFox"); _K>cB<+d  
String sProperty = "bytes="+nStartPos+"-"; K>9]I97g'  
httpConnection.setRequestProperty("RANGE",sProperty); 7M<Ae D%  
Utility.log(sProperty); xCD|UC46?X  
[XjJsk,  
<*~vZT i(  
InputStream input = httpConnection.getInputStream(); Q i#%&Jz>f  
//logResponseHead(httpConnection); R 28v5  
{n=)<w  
|_8- 3  
byte[] b = new byte[1024]; iV[g.sP-  
int nRead; !9DqW&8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ' D+h_*H  
{ d>eVR  
nStartPos += fileAccessI.write(b,0,nRead); CeoK@y=o  
//if(nThreadID == 1) "d>{hP  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F_U3+J>  
} `UL #g![J  
"?hEGJ;m"  
bWo-( qxq  
Utility.log("Thread " + nThreadID + " is over!"); 2c@R!*  
bDownOver = true; 5b R;R{:x  
//nPos = fileAccessI.write (b,0,nRead); f@Rn&&-  
} :f?\ mVS+  
catch(Exception e){e.printStackTrace ();} mdR:XuRD"t  
} .@Z qCH  
} ~xpU<Pd*  
hV])\t=yf  
G0Smss=K  
//打印回应的头信息 E8u :Fg s  
public void logResponseHead(HttpURLConnection con) }9 N, +*  
{ \1hbCv$Hf  
for(int i=1;;i++) u{yENZ^P  
{ [ /w{,+U  
String header=con.getHeaderFieldKey(i); cHs@1R/-s  
if(header!=null) $R%xeih1fz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pHEhB9_A!  
Utility.log(header+" : "+con.getHeaderField(header)); YA O, rh  
else Wo2TU!  
break; 8i=J(5=  
} 2ixg ix  
} }BS.OK?  
:XEP:8  
t&^9o $  
public void splitterStop() ]tL9y<  
{ nellN}jYsM  
bStop = true; ehl) {Dd^  
} -$J\BkI  
#"fBF/Q  
N%%2!Z#  
} ;ajCnSmR  
'{p/F $  
j1%o+#df  
/* d76k1-m\o  
**FileAccess.java l9"0Wu@_x  
*//文件访问(定位,写) 3~}G~ t  
package NetFox; pw" !iG}  
import java.io.*; M.))UKSF  
mufi>}  
Ikql  
public class FileAccessI implements Serializable{ j+"i$ln+s  
^EWkJW,Yc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :#1{c^i%3  
RandomAccessFile oSavedFile; z$$ E7i  
long nPos; >Lx,<sE  
q  9lz  
KSnU;B6w>  
public FileAccessI() throws IOException J^8(h R  
{ :0x,%V74_!  
this("",0); A94ZG:   
} '=K [3%U  
bhDV U(%I6  
ma[%,u`  
public FileAccessI(String sName,long nPos) throws IOException O*xC}$OOn  
{ u9My.u@-*%  
oSavedFile = new RandomAccessFile(sName,"rw"); A(G%9'T  
this.nPos = nPos; h3D~?Iom  
oSavedFile.seek(nPos); \fIGMoy!  
} AVf'"~?  
UjxEbk5>^  
. >[d:0  
public synchronized int write(byte[] b,int nStart,int nLen) cih@: =Qy  
{ |VxEW U/  
int n = -1; VI7f}  
try{ )Kkw$aQI"d  
oSavedFile.write(b,nStart,nLen); Z&9MtpC+N3  
n = nLen; 1$T;u~vg  
} k=1([x  
catch(IOException e)  al/Mgo  
{ 9o5W\.A7[D  
e.printStackTrace (); %Z9&zmO  
} .'N:]G@!  
([SrIG>X  
\^a(B{   
return n; "} =RPc%9  
} 2u9O+]EP  
n "?It  
 uyBmGS2  
} XCr\Y`,Z@  
gv)F`uRWA  
mOgsO  
/* &AM<H}>  
**SiteInfoBean.java 7R9.g6j  
*/ qNb|6/DG  
package NetFox; f d~a\5%e  
+@*}_%^l"  
P7ktr?V0a  
public class SiteInfoBean { 9D@ $Y54  
ML@-@BaN  
0qP&hybL[(  
private String sSiteURL; //Site's URL OiBDI3,|+  
private String sFilePath; //Saved File's Path ms9zp?M  
private String sFileName; //Saved File's Name !_EL{/ko  
private int nSplitter; //Count of Splited Downloading File W,<L/ZKJ  
4Ufx,]  
?4>uGaU\  
public SiteInfoBean() #=@H-ZuD7  
{//nSplitter的缺省值为5 + / s2;G  
//default value of nSplitter is 5 qYpuo D   
this("","","",5); M]9oSi  
} I#lvaoeN  
b^ wWg  
R-odc,P=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L(Ww6oj  
{ O`Ht|@[6  
sSiteURL= sURL; CUJP"u>8M  
sFilePath = sPath; :eIPPh|\  
sFileName = sName; &XG k  
this.nSplitter = nSpiltter; kkWqP20q  
w&&uk[Gh/a  
S}fU2Wi  
} QY14N{]T\p  
6x18g(KbP  
P$l-p'U-  
public String getSSiteURL() C-25\  
{ )gM3,gSS  
return sSiteURL; WKVoqp}  
} jvfVB'Tmr  
m ,B,dqT  
b _Q:v&  
public void setSSiteURL(String value) C\.mv|aW~  
{ n =SY66  
sSiteURL = value; -^A=U7  
} _`RzPIS^  
%Xm3m0nsv{  
VrG4wLpLs  
public String getSFilePath() 8R !3}kx  
{ !r=^aa(\  
return sFilePath; X`xI~&t_  
} MYVUOd,  
bpe8 `b(#  
b1X.#pz7F  
public void setSFilePath(String value) nq'vq] ]  
{  ?gZJ v  
sFilePath = value; a2:Tu  
} RX]x3-  
G`!ff  
_W@SCV)yH  
public String getSFileName() 7lP3\7wD@9  
{ 3,`.$   
return sFileName; ,.# SEv5  
} JGmW>mH  
M :m-iX  
[,GXA)j  
public void setSFileName(String value) p)  x.Y  
{ b0\'JZ  
sFileName = value; 8mjP2  
} H<$.AC\zn  
~&E|;\G  
7Pt*V@DHS  
public int getNSplitter() 7e,<$PH  
{ #xWC(*Ggp  
return nSplitter; $Cu/!GA4.>  
} *q5'~)W<  
]mU,y$IQ  
0 O{Y Vk`  
public void setNSplitter(int nCount) OtopA)  
{ ?nm:e.S+?  
nSplitter = nCount; !U02>X   
}  KR  
} )G(6=l*  
nMU#g])y)  
IB wqu w+  
/* 0m5Q;|mH  
**Utility.java K#"@nVWJ.m  
*/ eO,  
package NetFox; /)8 0@  
] =Js5  
//--r5Q  
public class Utility { {$iJYS\  
(xU+Y1*g"%  
{Y5h*BD>  
public Utility() my#qmI  
{ Isq3YY  
9Ao0$|@b  
{GF>HHQb  
} ^qpa[6D6x  
vOYcS$,^X%  
//线程睡眠 .js4)$W^  
public static void sleep(int nSecond) -;$+`<%  
{ UQ|zSalv,  
try{ F"a^`E&  
Thread.sleep(nSecond); PVO9KWv**  
} *$(=I6b  
catch(Exception e) p71% -nV  
{ ?o0#h  
e.printStackTrace (); dRZor gar  
} < %Qw dEO  
} >qA5   
i_GE9A=h  
//日志 VmQ7M4j*  
public static void log(String sMsg) f{e*R#+&  
{ ADX}  
System.err.println(sMsg); XA])<dZ  
} 3&*0n^g  
rL URP2~  
;U<) $5  
public static void log(int sMsg) f5a%/1?  
{ /x_C  
System.err.println(sMsg); DT&[W<oN  
} |D^Q}uT  
} K. G#[  
Y=G *[G#  
}wR)p  
/* BO\l>\)Ir  
**TestMethod.java :Puv8[1i  
*/ "sFdrXJ  
package NetFox; +!POKr  
6,G^iv6H  
7>{edNy!,  
public class TestMethod { kyJv,!};  
wrG*1+r  
3Gn2@`GC  
public TestMethod() 9BANCW"  
{ ///xx/weblogic60b2_win.exe HkvCQH  
try{ ~E^EF{h   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gx[#@ (  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); KHr8\qLH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1jmhh !,  
fileFetch.start(); @6*<Xs =  
} y<F$@  
catch(Exception e){e.printStackTrace ();} }sy3M rb  
LWbWj ^  
MC#bo{Bq3-  
} 9r1pdG_C@  
E08AZOY&g  
c%~'[W04\  
public static void main(String[] args) {yyg=AMz  
{ C>68$wd>  
new TestMethod(); ](_(1  
} ,h/0:?R KW  
} cb%w,yXw  
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