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http断点续传简单实现(java)

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/* 8iB}gHe9  
**SiteFileFetch.java daX$=n  
*/ PQ#zF&gL9t  
package NetFox; Z{MR#.I  
import java.io.*; 4P>4d +  
import java.net.*; 8B*XXFy\  
]ZbZ]  
mBQp#-1\  
public class SiteFileFetch extends Thread { Uyuvmt>  
(oUh:w.]Gw  
e2}5< 7  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4GL-3e  
long[] nStartPos; //开始位置 Y*KP1=Md  
long[] nEndPos; //结束位置 >U.f`24  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HRG2sv T4t  
long nFileLength; //文件长度 U#X6KRZ~g  
boolean bFirst = true; //是否第一次取文件 <Rno ;  
boolean bStop = false; //停止标志 wH<'*>/  
File tmpFile; //文件下载的临时信息 A_ftf 7,  
DataOutputStream output; //输出到文件的输出流 -(Z%?]+  
bMrR  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pO10L`|  
public SiteFileFetch(SiteInfoBean bean) throws IOException d~>d\K%v  
{ ,WA[HwY-  
siteInfoBean = bean; #C`IfP./  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m|c5X)}-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v)!C Dpw  
if(tmpFile.exists ()) PlX6,3F  
{ Wifr%&t{J  
bFirst = false; 2H]~X9,z2  
read_nPos(); HTa]T'  
} fl4z'8P"(  
else ij|+MX  
{ ; *@lH%u  
nStartPos = new long[bean.getNSplitter()]; NCKhrDd&  
nEndPos = new long[bean.getNSplitter()]; xc&&UKd  
} $lC*q  
H;=JqD8`  
p_Yx"nO7  
oA;> z  
} |_H{ B+.  
&l<~Xd#  
L+]|-L`S  
public void run() 9P)28\4  
{ W,53|9b@  
//获得文件长度 Wb;x eG  
//分割文件 [3~mil3rO  
//实例FileSplitterFetch 0c,)T1NG>  
//启动FileSplitterFetch线程 Vi5&%/Y  
//等待子线程返回 R|,F C'  
try{ %z_L}L  
if(bFirst) R oY"Haa  
{ vr$zYdV>  
nFileLength = getFileSize(); M#5*gWfq9  
if(nFileLength == -1) !ot$Q  
{ ?%]?#4bkc  
System.err.println("File Length is not known!"); mD]^a;U[X  
} Cbq|<p# #o  
else if(nFileLength == -2) Z4ZR]eD  
{ _ l$1@  
System.err.println("File is not access!"); pn._u`xMV  
} Fb^Ae6/i  
else $YPQi.  
{ x392uS$#  
for(int i=0;i<nStartPos.length;i++) <:YD.zAh|  
{ G^6\OOSy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D$vP&7pOr4  
} fN-y8  
for(int i=0;i<nEndPos.length-1;i++) XVRtfo  
{ V1 :aR3*!  
nEndPos = nStartPos[i+1]; B|zVq=l~  
} W4ygJL7 6  
nEndPos[nEndPos.length-1] = nFileLength; qbunP!  
} -gzY ~a  
} mKh <M)Bz  
F VVpyB|  
xtN=?WjVe0  
//启动子线程 * SHQ[L4{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; B+pJWl8u  
for(int i=0;i<nStartPos.length;i++) Kd%>:E*  
{ l4LowV7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), U*R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uTq)Ets3  
nStartPos,nEndPos,i); &l| :1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ->0OqVQA  
fileSplitterFetch.start(); a=%QckR*  
} n~e#Y<IP\1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NW*qw q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  (r!d4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NU#rv%p  
nEndPos = " + nFileLength); j\^ u_D  
// fileSplitterFetch[nPos.length-1].start(); 1(ud(8?|  
=#Qm D=  
a#NP69  
//等待子线程结束 Jemb0Qv  
//int count = 0; Z^?YTykH  
//是否结束while循环 >RL|W}tI4  
boolean breakWhile = false; /U1 jCLR'  
xy.di9  
,TdL-a5  
while(!bStop) w*-1*XNA  
{ 1$^=M[v  
write_nPos(); puPYM"  
Utility.sleep(500); J@4,@+X  
breakWhile = true; HbUadPr  
`tjH#W`  
xSal=a;k  
for(int i=0;i<nStartPos.length;i++) ROfr  
{ wsg u# as|  
if(!fileSplitterFetch.bDownOver) cz6\qSh\,  
{ F87aIJ.pGN  
breakWhile = false; w]Fi:kV  
break; 4[$D3,A  
} fmv8)$W#U  
} GSh~j-C'  
if(breakWhile) zV<vwIUrr  
break; Dqu][~oQ  
LmA IvEr  
1X45~  
//count++; MG G c  
//if(count>4) e52y}'L  
// siteStop(); $sTvXf:g  
} 4CdST3  
|n_es)A  
^^m3 11=  
System.err.println("文件下载结束!"); k"V@9q;*  
}  #VA8a=t  
catch(Exception e){e.printStackTrace ();} *G,'V,?  
} z#|#Cq`VG  
ncy?w e  
uSRvc0R\  
//获得文件长度 'J=knjAT  
public long getFileSize() CaV>\E)  
{ UVIR P#  
int nFileLength = -1; +#/`4EnI  
try{ my|UlZ(qg  
URL url = new URL(siteInfoBean.getSSiteURL()); )U':NV2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fsxZQ=-PW  
httpConnection.setRequestProperty("User-Agent","NetFox"); bR*/d-v^  
jRv j:H9  
xqA XfJ.  
int responseCode=httpConnection.getResponseCode(); ~1`ZPLVG  
if(responseCode>=400) FlPPz  
{ 5Tt%<#4  
processErrorCode(responseCode); o3oAk10  
return -2; //-2 represent access is error YV 5kzq  
} t;~H6  
E{-W#}#  
fcC?1M[BP~  
String sHeader; "++q. y  
*k7vm%#ns  
; {P"~(S%  
for(int i=1;;i++) 1 =cFV'  
{ PilV5Gg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %N, P? ,U  
//Utility.log(in.readLine()); wv~?<DF  
sHeader=httpConnection.getHeaderFieldKey(i); yye( ^  
if(sHeader!=null) )ZI9n7  
{ r,` 59  
if(sHeader.equals("Content-Length")) tluyx  
{ '[6o(~ *  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @fVCGV?'  
break; {m&8Viq1  
} I'NE>!=Q  
} 2EdKxw3$]  
else ^6Std x_  
break; t#p*{S 3u  
} hjgxCSp  
} l*yh(3~}  
catch(IOException e){e.printStackTrace ();} V(Dn!Nz  
catch(Exception e){e.printStackTrace ();} >;;tX3(  
#n[1%8l,  
Yp_R+a^  
Utility.log(nFileLength); ppBIl6  
7JedS  
m#(tBfH[  
return nFileLength; e0#/3$\aSV  
} 2[*r9%W  
 VS:UVe  
cVR3_e{&H  
//保存下载信息(文件指针位置) OEkx}.w  
private void write_nPos() aC&ZV}8of  
{ l/JE}Eg(  
try{ zMXlLRC0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); l u^fKQ  
output.writeInt(nStartPos.length); 9J$8=UuxWG  
for(int i=0;i<nStartPos.length;i++) J01Y%W  
{ #e!4njdM  
// output.writeLong(nPos); ;I#S m;  
output.writeLong(fileSplitterFetch.nStartPos); x 7;Zwd  
output.writeLong(fileSplitterFetch.nEndPos); y,*>+xk,  
} bYKyR}e  
output.close(); f.o,VVYi  
} 7sQw&yUL)  
catch(IOException e){e.printStackTrace ();} B~0L'8WzW  
catch(Exception e){e.printStackTrace ();} \I"UW1)B  
} 5nGDt~a  
]vPa A  
Au6*hv3:  
//读取保存的下载信息(文件指针位置) n>w/T"  
private void read_nPos() r*'X]q|L+  
{ 6G<t1?_yD  
try{ ::xH C4tw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D{](5?$`|  
int nCount = input.readInt(); f|*vWHSM  
nStartPos = new long[nCount]; @R|Gz/  
nEndPos = new long[nCount]; +n ${6/  
for(int i=0;i<nStartPos.length;i++) T/_JXK>W  
{ 9\/T #EP  
nStartPos = input.readLong(); ,u^S(vxyz  
nEndPos = input.readLong(); V0gk8wD  
} s{-`y`JP  
input.close(); aN.t) DG}J  
} {ZS-]|Kx  
catch(IOException e){e.printStackTrace ();} L29,Y=n@  
catch(Exception e){e.printStackTrace ();} Vs1j9P|G  
} hm%'k~  
2>.2H  
R|%R-J]  
private void processErrorCode(int nErrorCode) Y=oj0(Q*  
{ z|Hc=AU8y  
System.err.println("Error Code : " + nErrorCode); .oJs"=h:m  
} \;?=h  
H(^O{JC]y!  
rpgr5>  
//停止文件下载 5dV Sir  
public void siteStop() ?/_8zpW  
{ 0,T'z,  
bStop = true; iI[Z|"a21  
for(int i=0;i<nStartPos.length;i++) >@yHa'*9S  
fileSplitterFetch.splitterStop(); 3&D;V;ON}_  
m[7i<'+S  
IeqJ>t:   
} IX7|_ci  
} -$(,&qyk  
//负责部分文件的抓取 ) #/@Jo2F  
**FileSplitterFetch.java ({ 7tp!@  
*/ DRo@gYDn  
package NetFox; |\ 1?CYx  
9E (VU.  
C^@.GA  
import java.io.*; .EC/[fM  
import java.net.*; xg}RpC!  
wl{Fx+<^3  
U}xQUFT|  
public class FileSplitterFetch extends Thread { ?"p:6%GFz  
=?`5n|A*  
a2dlz@)J  
String sURL; //File URL SWjOJjn  
long nStartPos; //File Snippet Start Position OQ$77]XtvL  
long nEndPos; //File Snippet End Position Jlw oSe:S  
int nThreadID; //Thread's ID wX6VapFboI  
boolean bDownOver = false; //Downing is over lD!o4ZAo  
boolean bStop = false; //Stop identical $X %GzrN  
FileAccessI fileAccessI = null; //File Access interface 1n! Jfs U  
APT'2 -I_  
AW8"@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P!C!E/Jf5  
{ x@F"ZiYD@O  
this.sURL = sURL; G 1{F_  
this.nStartPos = nStart; @L%9NqE`O  
this.nEndPos = nEnd; R|T_9/#)  
nThreadID = id; Gd)@PWK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 BJ3st  
} +igFIoHTM  
td@F%*  
R>"E Xq  
public void run() X[8m76/V  
{ E'=~<&  
while(nStartPos < nEndPos && !bStop) <^&NA<2  
{ kb?QQ\e  
fW Vd[zuD4  
VT1W#@`e-  
try{ Ox"4 y  
URL url = new URL(sURL); ?aInn:FE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +]Oq{v:e  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q)}sX6TB  
String sProperty = "bytes="+nStartPos+"-"; W'\{8&:!  
httpConnection.setRequestProperty("RANGE",sProperty); cLH|;  
Utility.log(sProperty); Bv $;yR  
tw8@&8"  
[R j=k)aBm  
InputStream input = httpConnection.getInputStream(); <CL0@?*i9  
//logResponseHead(httpConnection); @]Ye36v0#L  
hu-fwBK  
byM/LE7)  
byte[] b = new byte[1024]; rUkiwqr~E  
int nRead; Y%$57,Bu n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EA 4a Z6%  
{ m,3?*0BMp=  
nStartPos += fileAccessI.write(b,0,nRead); >9D=PnHnD  
//if(nThreadID == 1) 1Y410-.3w{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g2 uc+p  
} x%ZjGDFm  
"sz)~Q'W5  
dL>0"UN}-  
Utility.log("Thread " + nThreadID + " is over!"); z3b8  
bDownOver = true; }io9Hk>|  
//nPos = fileAccessI.write (b,0,nRead); |b'fp1</  
} n{pS+u z  
catch(Exception e){e.printStackTrace ();} ~130"WQ;  
} !3K6ew>Sf  
} O qDLb  
x+(h#+F  
Z>Nr"7k  
//打印回应的头信息 De[!^/f;T  
public void logResponseHead(HttpURLConnection con) y";{k+  
{ pi? q<p%  
for(int i=1;;i++) 8^;[c  
{ )`Tny]M  
String header=con.getHeaderFieldKey(i); .:c^G[CQ^9  
if(header!=null) 7|3Z+#|T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ):eX*  
Utility.log(header+" : "+con.getHeaderField(header)); in-/  
else 8ON$M=Ze$  
break; Oh<[8S7]C  
} RNuOwZ1m  
} ;Gxp'y  
H$Fz{[[u  
IuTZ2~  
public void splitterStop() cS,(HLO91  
{ H"d.yZM0  
bStop = true; zt!mx{l'  
} .@.,D% 7<  
?<,9X06dP  
?3Wh. %n  
} -yOrNir}W  
.hlr)gF&)  
VB*$lx X  
/* zl46E~"]x  
**FileAccess.java y[S 5  
*//文件访问(定位,写) UDV,co  
package NetFox; 2(LS<HqP[  
import java.io.*; NFPW#-TF  
@! ^c@  
MuYr?1<q  
public class FileAccessI implements Serializable{ =ji p* E^  
,JRYG<O_T  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -]\%a=]  
RandomAccessFile oSavedFile; L.lmbxn  
long nPos; R3wK@D  
X!,P] G  
!Pt|Hk dr  
public FileAccessI() throws IOException }S3m wp<Y  
{ ^-PlTmT  
this("",0); (w?@qs!  
} ^~|P[}  
gSK (BP|  
+60zJ 4  
public FileAccessI(String sName,long nPos) throws IOException a3ve%b  
{ Skl1%`  
oSavedFile = new RandomAccessFile(sName,"rw"); '@RlKMnN  
this.nPos = nPos; / O6n[qj|  
oSavedFile.seek(nPos); z}yntY]n  
} c*K-?n9YMz  
-ZH]i}$  
3zY"9KUN  
public synchronized int write(byte[] b,int nStart,int nLen) ?s#DD,  
{ "P.7FD  
int n = -1; {w}PV5<  
try{ ,\4@Ao  
oSavedFile.write(b,nStart,nLen); \TkBV?W  
n = nLen; pNr3u  
} I5>HB;Q  
catch(IOException e) W}+Q!T=  
{ ]K?z|&N|HK  
e.printStackTrace (); 4vPQuk!  
} a*6x^R;)  
+Vt@~Z4K  
O*rKV2\  
return n; rPkV=9ull,  
} bV|:MW <Wv  
<_8\}!  
y _>HQs,:  
} ;2@MPx  
{-J/ <a@  
Wk$[;>NU3  
/* tx Lo =  
**SiteInfoBean.java KnbT2  
*/ _;W}_p}q{  
package NetFox; m*  |3  
2sjV*\Udf  
'y}l9alF  
public class SiteInfoBean { xKEHN gen  
tn+i5Eso  
*5sr\b4#S  
private String sSiteURL; //Site's URL 1Jc-hrN-  
private String sFilePath; //Saved File's Path g&O%qX-  
private String sFileName; //Saved File's Name 5R?iTB1,  
private int nSplitter; //Count of Splited Downloading File 20d[\P(.  
Sb>;k(;`:  
.1 .n{4z>:  
public SiteInfoBean() 0vQ@n7  
{//nSplitter的缺省值为5 GfD!Z3  
//default value of nSplitter is 5 pY!@w0.  
this("","","",5); v)!Rir5  
} nORm7sa9  
XB UO  
 r75,mX  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {6~v oVkj  
{ c_x6FoE;L  
sSiteURL= sURL; F'*y2FC  
sFilePath = sPath; ;gTdiwfgZ=  
sFileName = sName; <tMiI)0%  
this.nSplitter = nSpiltter; #q9jFW8  
zPWG^  
K SDo)7`  
} ^F5[2<O/!  
aRdk^|}  
r^n%PH <  
public String getSSiteURL() ]Hc `<P  
{ k+'Rh'>  
return sSiteURL; YDyOhv  
} .d^8w97  
&sh %]o8  
}ARWR.7Cc  
public void setSSiteURL(String value) #n]js7  
{ uNxR#S  
sSiteURL = value; xV}E3Yj2#  
} \,!FL))yC  
29z+<?K{  
-@Mr!!t?N  
public String getSFilePath() fBR,Oneo  
{ lV]hjt-L 2  
return sFilePath; lJpD>\$}@R  
} ~zi6wu(3  
8TD:~ee  
 ;iy]mPd  
public void setSFilePath(String value) 73A1+2  
{ l6:k|hrm;  
sFilePath = value; %L=ro qz  
} _' Xt  
R4 ;^R  
u^s{r`/  
public String getSFileName() =&U JFu  
{ NYM$0v`0YK  
return sFileName; $fPf/yQmC  
} ,6~c0]/  
_]E"hr6a  
K8XXO"  
public void setSFileName(String value) ;}#tm9S;  
{ 8O qG{jmG  
sFileName = value; n AQB  
} <@.f#  
U`ey7   
,oT?-PC$z  
public int getNSplitter() LUna stA^  
{ Vx;f/CH3!  
return nSplitter; MIub^ $<C  
} .!\y<9  
1RY}mq  
_FeLSk.  
public void setNSplitter(int nCount)  4>uz'j<  
{ oil s;*q  
nSplitter = nCount; ) 2wof(  
} xop9*Z$  
} &dp(CH<De  
1u:OzyJy  
# 5v 2`|)  
/* >(ku*  
**Utility.java T?N' k=   
*/ "(F>?pq  
package NetFox; 8wp)aGTcU  
/i"vEI  
,+3l9FuQ  
public class Utility { KRd.Ubs -  
lRi-?I| ~9  
)a .w4dH  
public Utility() {# ;e{v  
{  e-sMU  
_ M8Q%  
!`hiXDk*2  
}  gG1%.q  
>M<rr!|  
//线程睡眠 Q1mz~r  
public static void sleep(int nSecond) d!{,[8&  
{ &[`p qX  
try{ Vl5}m  
Thread.sleep(nSecond); 9w[7X"#n  
} lsCD%P  
catch(Exception e) wA|m/SZx  
{ 0R\lm<&  
e.printStackTrace (); k?0yH$)'t  
} .n[!3X|d  
} kLU$8L  
XE[~! >'  
//日志 {wih)XNY  
public static void log(String sMsg) =>-:o:Cu{  
{ j +\I4oFN  
System.err.println(sMsg); ?w`uv9NUJ8  
} EjV,&7o)  
iIA5ylf{E  
dms R>Q  
public static void log(int sMsg) ..UmbJJ.u  
{ tu#VZAPW@  
System.err.println(sMsg); ),v[.9!}:  
} wQgW9546  
} j#$ R.  
vQ2kL`@  
AYeA)jk  
/* 51W\%aB  
**TestMethod.java &s->,-,  
*/ 2>l4$G 0  
package NetFox; dX-{75o5P  
{1li3K&0s  
" |[w.`  
public class TestMethod { F<Js"z+  
cW4:eh  
0(VAmb%{  
public TestMethod() GKu@8Ol-wu  
{ ///xx/weblogic60b2_win.exe &Ey5 H?U!  
try{ -'QvUHL|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ac 0C,*|^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?wt%e;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @(Wx(3JR?}  
fileFetch.start(); @G+Hrd6  
} r" d/ 9  
catch(Exception e){e.printStackTrace ();} [wWip1OR  
coT|t T  
w&jyijk(  
} =hxj B*")  
;XNe:g.CR  
+[:"$?J  
public static void main(String[] args) Qz2Y w `  
{ !4\`g?  
new TestMethod(); Eq c&iS~  
} TCYjj:/  
} -lV]((I&  
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