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http断点续传简单实现(java)

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/* n-"(lWcp  
**SiteFileFetch.java W u C2 LM  
*/ }WowgY  
package NetFox; c-jE1y<  
import java.io.*; {PGiNY%q  
import java.net.*; u=6LPwiI  
Y)O88C  
ugu|?z*dI  
public class SiteFileFetch extends Thread { k)3b0T@b  
< )qJI'u|  
?&`PN<~2z  
SiteInfoBean siteInfoBean = null; //文件信息Bean <r>1W~bp.q  
long[] nStartPos; //开始位置 \CU-a`n  
long[] nEndPos; //结束位置 rSgOQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >g>L>{  
long nFileLength; //文件长度 T1-.+&<  
boolean bFirst = true; //是否第一次取文件 |e QwI&  
boolean bStop = false; //停止标志 KgH_-REN  
File tmpFile; //文件下载的临时信息 1 $m[# 3  
DataOutputStream output; //输出到文件的输出流 +L\Dh.Ir  
gmqL,H#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [PIh^ DhK  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5cF7w  
{ QmKEl|/{u  
siteInfoBean = bean; nk*T x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kEYkd@ {  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n8+_Uww  
if(tmpFile.exists ()) *^3&Y@  
{ JBI>D1`"  
bFirst = false; ^XgBkC~  
read_nPos(); gcA,u)z}R  
} kgb:<{pJ  
else {3* Ne /  
{ r`\6+Ntb.  
nStartPos = new long[bean.getNSplitter()]; d)WGI RUx  
nEndPos = new long[bean.getNSplitter()]; 1CR)1H  
} !hugn6  
f-BPT2U+  
O}-+o1  
Q,LDn%+;B*  
} ;u?L>(b  
g=na3^PL6  
(|2:^T+  
public void run() t" $#KP<  
{ ;%Zu[G`C  
//获得文件长度 Z#t}yC%^d  
//分割文件 ,$+ P  
//实例FileSplitterFetch &SW~4{n:  
//启动FileSplitterFetch线程 pwg\b  
//等待子线程返回 hnnVp_<]  
try{ " Ng%"Nz  
if(bFirst) oFi_ op  
{ [9C{\t  
nFileLength = getFileSize(); v.6K;TY.  
if(nFileLength == -1) 3Viz0I<%  
{ rqWD#FB=z  
System.err.println("File Length is not known!"); @@z5v bs'{  
} &?H`MCv t  
else if(nFileLength == -2) 8b:GyC5L  
{ n`X}&(O  
System.err.println("File is not access!"); S*NeS#!v  
} r>lo@e0G  
else c$8M}q:X  
{ *5KDu$'(e  
for(int i=0;i<nStartPos.length;i++) v ;nnr0;  
{ |/%X8\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S[e> 8  
} zi_0*znw  
for(int i=0;i<nEndPos.length-1;i++) AIG5a$}&  
{ gX~lYdA  
nEndPos = nStartPos[i+1]; qQwf#&  
} }vEMG-sxX  
nEndPos[nEndPos.length-1] = nFileLength; FL[,?RU?2  
} >aAsUL5W  
} tx$`1KA  
b?j\YX[e  
bo-lT-I  
//启动子线程 |Sv}/ P-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =eQ'^3a  
for(int i=0;i<nStartPos.length;i++) HE:]zH  
{ cKB1o0JsYJ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ckkm}|&m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ID~}pEQ  
nStartPos,nEndPos,i); HP,{/ $i:  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4C }#lW9  
fileSplitterFetch.start(); gn:&akg  
} /[I#3|  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J%IKdxa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); owzcc-g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !8*7{7  
nEndPos = " + nFileLength); }_oQg_-7e  
// fileSplitterFetch[nPos.length-1].start(); 5i-VnG  
.|i/ a%J  
ig^x%!;  
//等待子线程结束 r8Z.}<j  
//int count = 0; UmLBoy&*  
//是否结束while循环 EvptGM  
boolean breakWhile = false; : j`4nXm  
X`A+/{ H  
:{ Lihe~\  
while(!bStop) ^g=j`f[T  
{ I`nC\%g  
write_nPos(); >W6?!ue_  
Utility.sleep(500); skF}_  
breakWhile = true; fuT Bh6w&  
a(AYY<g  
/<k]mY cu  
for(int i=0;i<nStartPos.length;i++) m>f8RBp]'  
{ +ZR>ul-c  
if(!fileSplitterFetch.bDownOver) ojx2[a\  
{ ~{ucr#]C  
breakWhile = false; FK @Gd)(  
break; 1fTf+P  
} 6J <.i  
} ZU;nXqjc  
if(breakWhile) K$wxiGg8P  
break; > .K  
qb$M.-\ne  
$U"pdf  
//count++; W)AfXy  
//if(count>4) &hJQHlyJM0  
// siteStop(); _q}^#-  
} K.Y.K$NjP{  
]4B&8n!  
mM'uRhO+  
System.err.println("文件下载结束!"); mZ g'  
} C6qGCzlG`  
catch(Exception e){e.printStackTrace ();} A+Kp ECP  
} HfEl TC:3f  
+o]J0Gu  
(gUVZeVFP  
//获得文件长度 = O|}R  
public long getFileSize() Yv3 P]6c.  
{ !$p E=~1C  
int nFileLength = -1; ft$!u-`  
try{ A]MX^eY  
URL url = new URL(siteInfoBean.getSSiteURL()); hX:yn:P~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sj&1I.@,>  
httpConnection.setRequestProperty("User-Agent","NetFox"); k{ulu  
& kQj)  
P"|-)d  
int responseCode=httpConnection.getResponseCode(); _e "  
if(responseCode>=400) '26 ,.1  
{ xmejoOF  
processErrorCode(responseCode); CUx-k|\  
return -2; //-2 represent access is error GQYB2{e>  
} 1-.(pA'  
i^)JxEPr w  
KB$Y8[  
String sHeader; mOJ-M@ME  
bUe6f,8,  
19i=kdH  
for(int i=1;;i++) 4$+/7I \  
{ _sQhDi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); or(P?Ro  
//Utility.log(in.readLine()); qmtH0I7)  
sHeader=httpConnection.getHeaderFieldKey(i); Y?%=6S  
if(sHeader!=null) f%yNq6l  
{ (8(P12l  
if(sHeader.equals("Content-Length")) ]+Z,HY@;-  
{ >6|Xvtf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sW&h?jdf  
break; jpZ 7p ;  
} |<#yXSi  
} hLaQ[9  
else F#z1 sl'  
break; \^dYmU  
} 0U! _o2]  
} {Hz;*1?$k  
catch(IOException e){e.printStackTrace ();} T3t w.yh  
catch(Exception e){e.printStackTrace ();} >:0^v'[  
=WK's8FB;8  
7!~)a  
Utility.log(nFileLength); u6 4{w,  
p+CK+m   
P}vk5o'  
return nFileLength; Ki(0s  
} IO"q4(&;P4  
G1:"Gxja  
ZeH=]G4Zv7  
//保存下载信息(文件指针位置) T+>W(w i  
private void write_nPos() @Py?.H   
{ w}U'>fj  
try{ WL;2&S/{@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a[J_H$6H!  
output.writeInt(nStartPos.length); `82^!7!  
for(int i=0;i<nStartPos.length;i++) "YN6o_*]  
{ LAuaowE\v  
// output.writeLong(nPos); %Lom#:L'  
output.writeLong(fileSplitterFetch.nStartPos); o`nJJ:Cxq-  
output.writeLong(fileSplitterFetch.nEndPos); ]3 76F7  
} H<   
output.close(); :` S\p[5  
} 1_> w|6;e  
catch(IOException e){e.printStackTrace ();} `~1#X  
catch(Exception e){e.printStackTrace ();} *LQt=~  
} e09QaY  
"sed{?  
Bpv"qU7  
//读取保存的下载信息(文件指针位置) gH0Rd WX  
private void read_nPos() [@0Hmd7  
{ EE*FvI`  
try{ )H{OqZZYD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;pG5zRe  
int nCount = input.readInt(); *s?C\)x  
nStartPos = new long[nCount]; yS4nB04`=  
nEndPos = new long[nCount]; hmI> 7@&  
for(int i=0;i<nStartPos.length;i++) %V92q0XW  
{ uCj)7>}v{M  
nStartPos = input.readLong(); 2,p= %  
nEndPos = input.readLong(); @1V?94T1  
} BLb'7`t  
input.close(); Ju_(,M-Vgr  
} b7HT<$Wg  
catch(IOException e){e.printStackTrace ();} UZo[]$"Q`  
catch(Exception e){e.printStackTrace ();} 8< z   
} @"afEMd  
\o5/, C  
*a` _,Q{x  
private void processErrorCode(int nErrorCode) 3*e )D/lm  
{ 21hTun"W  
System.err.println("Error Code : " + nErrorCode); pZ 7KWk4  
} j^ttTq|l  
hne}G._b  
~'LoIv20j)  
//停止文件下载 l>pnY%(A  
public void siteStop() =j8g6#'u  
{ uy([>8uu  
bStop = true; ,9W!cD+0  
for(int i=0;i<nStartPos.length;i++) .19_EQ>+  
fileSplitterFetch.splitterStop(); =!=DISPo  
D;Y2yc[v  
sbV_h;<  
} g8]$BhRIfr  
} 4qyPjAG  
//负责部分文件的抓取 L]=LY  
**FileSplitterFetch.java N._^\FRyn  
*/ "S psSQ  
package NetFox; 6}:(m#+  
VQbKrnX  
r: ,"k:C  
import java.io.*; FwDEYG  
import java.net.*; !lI1jb"  
<\L=F8[  
L F!S`|FF  
public class FileSplitterFetch extends Thread { ;RW5XnVx  
dDqT#N?Y  
Z`ZML+;~6  
String sURL; //File URL XpdjWLO]C<  
long nStartPos; //File Snippet Start Position V""3#Tw   
long nEndPos; //File Snippet End Position SKJ'6*6  
int nThreadID; //Thread's ID xsg55`  
boolean bDownOver = false; //Downing is over "Wy!,RH  
boolean bStop = false; //Stop identical K?=g IC:  
FileAccessI fileAccessI = null; //File Access interface 1fV\84m^  
oi%IHX(`  
?IR+OCAA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException LHq*E`  
{ t=n@<1d  
this.sURL = sURL; f4^\iZ{`G  
this.nStartPos = nStart; {QT:1U \.  
this.nEndPos = nEnd; s+a#x(7{  
nThreadID = id; tS[@?qP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1pTQMf a  
} w=ZK=@  
5- "aK~@+  
j`-9.  
public void run() 67wq8|  
{ kQ.3J.Q5  
while(nStartPos < nEndPos && !bStop) !D 9V9p  
{ +P=I4-?eX  
qhNYQ/uS  
/z4n?&tM  
try{ 3EyVoS6D  
URL url = new URL(sURL); m"vWu0/#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); uD4$<rSHb  
httpConnection.setRequestProperty("User-Agent","NetFox"); :BUr8%l  
String sProperty = "bytes="+nStartPos+"-"; ExSy/^4f  
httpConnection.setRequestProperty("RANGE",sProperty); _@sSVh$+  
Utility.log(sProperty); 27UnH: =  
%kiPE<<x  
7/FF}d  
InputStream input = httpConnection.getInputStream(); :qvaI,  
//logResponseHead(httpConnection); 8o,"G}Hjk  
zl$z>z)  
ksQw|>K  
byte[] b = new byte[1024]; S oB6F9  
int nRead; :Q>{Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x-SYfvYY  
{ I(+%`{Wv  
nStartPos += fileAccessI.write(b,0,nRead); 3E;<aCG?  
//if(nThreadID == 1) %F]:nk`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7niI65  
}  -to3I  
"XKd#ncP  
kj!mgu#T  
Utility.log("Thread " + nThreadID + " is over!"); TL([hR _  
bDownOver = true; 3@mW/l>X  
//nPos = fileAccessI.write (b,0,nRead); d0-T\\U  
} iuEQ?fp  
catch(Exception e){e.printStackTrace ();} rq^VOK|L  
} mA6Nmq%{ F  
} incUa;  
iIU>:)i  
$%5!CD1)  
//打印回应的头信息 DZV U!J  
public void logResponseHead(HttpURLConnection con) oqy}?<SQ  
{ Q5tx\GE  
for(int i=1;;i++) e`Tssa+  
{ <O]B'Wc [  
String header=con.getHeaderFieldKey(i); =kn-F T  
if(header!=null) \>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /@]@Tz@'  
Utility.log(header+" : "+con.getHeaderField(header)); P6;Cohfh  
else p}h9>R  
break; rTM0[2N  
} YMn_9s7<  
} ;r3|EA35  
\_3#%%z  
A]OVmw  
public void splitterStop() xu* dPG)v  
{ "$|ne[b2  
bStop = true; /w:~!3Aj0+  
} SgY\h{{sP  
q@Sj$  
yx/.4DW1Ua  
} 2R`}}4<Z  
s%t =*+L\  
9E]7Etfw  
/* NU!B|l  
**FileAccess.java O:W4W=K  
*//文件访问(定位,写) d# q8-  
package NetFox; &BQ%df<y\  
import java.io.*; LArfX,x3i  
TS;?>J-  
`r.  
public class FileAccessI implements Serializable{ Mt+gg F.  
\FjY;rqfKe  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3ypf_]<  
RandomAccessFile oSavedFile; firiYL"=44  
long nPos; Be2yS]U  
BI 0 A0  
Qb&gKQtt@  
public FileAccessI() throws IOException F[==vte|  
{ +v"%@lC};  
this("",0); q<w Q/m  
} 1<3!   
= j S  
!gFUC<4bu  
public FileAccessI(String sName,long nPos) throws IOException kIYV%O   
{ 2^=.jML[  
oSavedFile = new RandomAccessFile(sName,"rw"); nAW`G'V#  
this.nPos = nPos; ]LZ,>v  
oSavedFile.seek(nPos); I xE }v%&  
} ~QE-$;  
:*s+X$x,<  
kK$*,]iCp  
public synchronized int write(byte[] b,int nStart,int nLen) y,=TB#  
{ D``>1IA]  
int n = -1; O,?aVgY  
try{ - WK  
oSavedFile.write(b,nStart,nLen); g'1ASMuR  
n = nLen; \9s x_T  
} RaLc}F)9   
catch(IOException e) 6T{SRN{  
{ z+%74O"c  
e.printStackTrace (); 2Jc9}|,  
} RT+_e  
5mB'\xGO2  
z7um9g  
return n; $|r p5D6  
} !x1ivP  
s+XDtO  
hZNA I  
} APT /z0X>  
2x dN0S  
f/RDo4  
/* "N*i!h  
**SiteInfoBean.java ad[oor/7|  
*/ V-TWC@Y"  
package NetFox; ]~-vU{  
,Frdi>7 ~  
)m[dfeqd +  
public class SiteInfoBean { "=\@ a=  
5RhP^:i@C  
D!CuE7}  
private String sSiteURL; //Site's URL 1rQKHC:|  
private String sFilePath; //Saved File's Path S K7b]J>  
private String sFileName; //Saved File's Name 'or8CGr^p  
private int nSplitter; //Count of Splited Downloading File !`EhVV8u-_  
C#4/~+  
caC( KK#<  
public SiteInfoBean() [p[C45d=<  
{//nSplitter的缺省值为5 gtV*`g  
//default value of nSplitter is 5 3&z.m/  
this("","","",5); rE&+fSBD  
} >*cg K}!@  
JW-!m8  
5D%gDw+"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A%c)=(,  
{ qmM%MPv  
sSiteURL= sURL; wx%TQ!  
sFilePath = sPath; ;l>C[6]  
sFileName = sName; W^AY:#eX~Q  
this.nSplitter = nSpiltter; \w+a Q?e_  
nH % 1lD?:  
y OLqIvN  
} BbdJR]N/!h  
&i%1\ o  
"ZLujpZcG  
public String getSSiteURL() +1 j+%&).  
{ njN]0l{p  
return sSiteURL; /l@h[}g+d-  
} 2>!? EIE7  
EU"J'?  
Y94/tjt  
public void setSSiteURL(String value) &33.mdBH  
{ nlkQ'XGAI  
sSiteURL = value; eq#x~O4  
} wz(D }N5  
~M4@hG!  
uepL"%.@7|  
public String getSFilePath() ,dO$R.h  
{ )mbRG9P  
return sFilePath; XU19+mW=P  
} :u$+lq  
XTOZ]H*^  
x3++JG  
public void setSFilePath(String value) bR;Zc  
{ +)gXU Vwd  
sFilePath = value; gYy9N=f+  
} /P3s.-sL  
Pqm)OZE?  
}lzN)e  
public String getSFileName() ]9}T)D f'  
{ `bF] O"  
return sFileName; OnKPD=<  
} AZTn!hrU  
_p`@/[(|  
^,M&PP6  
public void setSFileName(String value) &G"r>,HU  
{ &RP}w%I1  
sFileName = value; \1p5$0z  
} q T pvz  
{UR&Y  
J|BZ{T}d  
public int getNSplitter() VF<C#I  
{ 6(X5n5C  
return nSplitter; >.-$?2  
} t9Nu4yl  
* (4TasQu  
Y/1,%8n  
public void setNSplitter(int nCount) &PAgab2$  
{ %VCfcM}5I  
nSplitter = nCount; 1xkU;no  
} 2%DleR'i  
} gxku3<S  
EdPN=  
F|DKp[<]8  
/* ]U,K]y[Bj  
**Utility.java oe5.tkc  
*/ h1 D#,  
package NetFox; (BA2   
gAY%VFBP0  
dTV:/QM  
public class Utility { K~#wvUb  
`=0J:  
~',}]_'oR-  
public Utility() I'[hvp  
{ z]YP  
-*K!JC-  
`>q|_w \e  
} B~u_zZE  
s\`Vr;R:|  
//线程睡眠 |;-,(509  
public static void sleep(int nSecond) jbHk  
{ v^lR]9;  
try{ ` tkd1M  
Thread.sleep(nSecond); WR*|kh  
} Hh bf9)  
catch(Exception e) ikGH:{  
{ yMNLsR~rh  
e.printStackTrace (); ,Dz2cR6  
} x,Cc$C~YP  
} 4R U1tWQ%  
8O]U&A@  
//日志 4nhe *ip  
public static void log(String sMsg) #&1Y!kbdd  
{ LaE;{jY  
System.err.println(sMsg); mF>CH]k3  
} FNDLqf!j  
sQA{[l!aj  
Zw5\{Z0  
public static void log(int sMsg) LC/w".oq?  
{ ;!@\|E  
System.err.println(sMsg); t#y   
} (/_Q r2KfC  
} P#H#@:/3  
gKZ{O  
|<.b:e\4  
/* {/BEO=8q2  
**TestMethod.java R0<ka[+  
*/ n;"4`6L~  
package NetFox; z#!xqIg0  
7[-jr;v  
v.1= TBh  
public class TestMethod { xLZQ\2q  
lxK_+fj q  
yvxC/Jo4  
public TestMethod() \2<2&=h?  
{ ///xx/weblogic60b2_win.exe ISr~JQr  
try{ r1FE$R~C=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F.=u Jdl.!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LeW.uh3.  
SiteFileFetch fileFetch = new SiteFileFetch(bean); e![Q1!r  
fileFetch.start(); lq@Vb{Z  
} {K'SOh H4?  
catch(Exception e){e.printStackTrace ();} 8mA6l0  
F$ .j|C1a  
$U jSP  
} ,l<-*yMD  
F!>K8q  
1#qCD["8  
public static void main(String[] args) LM'` U-/e$  
{ +29;T0>a  
new TestMethod(); T , =ga  
} Za!c=(5  
} DuvP3(K  
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