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http断点续传简单实现(java)

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/* TTj] _R{n  
**SiteFileFetch.java 1iR\M4?Frf  
*/ >^9j>< Z  
package NetFox; !lEV^SQJs  
import java.io.*; }.|a0N 5  
import java.net.*; ZU B]qzmK  
?UflK  
E.:eO??g  
public class SiteFileFetch extends Thread { w].DLoz  
kp[&SKU c  
7]L}~  
SiteInfoBean siteInfoBean = null; //文件信息Bean UVi9}zr  
long[] nStartPos; //开始位置 :+_H%4+  
long[] nEndPos; //结束位置 Z] cFbl\ma  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]OKKR/:  
long nFileLength; //文件长度 J^` pE^S  
boolean bFirst = true; //是否第一次取文件 )0 6. dZq\  
boolean bStop = false; //停止标志 C;ha2UV0H  
File tmpFile; //文件下载的临时信息 O>rz+8T  
DataOutputStream output; //输出到文件的输出流 &JLKHwi/  
NODE`VFu  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ct*~\C6Ze  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?=iy 6q  
{ 7[kDc-  
siteInfoBean = bean; C\C*@9=&x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0""%@X]m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4yxf/X)  
if(tmpFile.exists ()) !&KE">3Qu  
{ 65 &+Fv  
bFirst = false; }VH` \g}  
read_nPos(); = "Lb5!  
} Jn?ZJZ  
else P6^\*xkMr  
{ ='eQh\T)  
nStartPos = new long[bean.getNSplitter()]; wjID*s[  
nEndPos = new long[bean.getNSplitter()]; 9WoTo ,q  
} J{uqbrJICr  
"el3mloR 8  
%kBrxf  
 +@Kq  
} jw2hB[WR  
S|RUc}(  
Jn0L_@  
public void run() Fok`-U  
{ SV2\vby}C  
//获得文件长度 ~ebm,3?  
//分割文件 1RQM-0W,  
//实例FileSplitterFetch  ,8p-EH  
//启动FileSplitterFetch线程 S^e e<%-  
//等待子线程返回 #{bT=:3a  
try{ +>mU4Fwp  
if(bFirst) Z79Y$d>G<E  
{ %. IW H9P7  
nFileLength = getFileSize(); Vc|QW  
if(nFileLength == -1) Mm"0Ip2"  
{ F*B^#AZg  
System.err.println("File Length is not known!"); G"<} s mB  
} ~|wh/]{b9  
else if(nFileLength == -2) Xdf;'|HO  
{ %8% 0l*n'  
System.err.println("File is not access!"); _32 o7}!x  
} !| GD8i  
else =WFG[~8  
{ #)%dG3)e  
for(int i=0;i<nStartPos.length;i++) 9qJ:h-?M  
{ Qo["K}Ty  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a,*|*Cv  
} 3 _DJ  
for(int i=0;i<nEndPos.length-1;i++) y=y#*yn&  
{ kvt"7;(  
nEndPos = nStartPos[i+1]; (TGG?V  
} [*=UH* :'N  
nEndPos[nEndPos.length-1] = nFileLength; h4M>k{  
} 0 s%{m<  
} 2 mvp|< "  
}cy<$=c#E_  
_3Q8R}  
//启动子线程 A}03s6^i;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `~W?a  
for(int i=0;i<nStartPos.length;i++) &>auW}r  
{ O`0A#h&No  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DVyxe}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :"oUnBY%  
nStartPos,nEndPos,i); tj!~7lo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ <pO<S  
fileSplitterFetch.start(); M*jn8OE  
} 1QuR7p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ba|76OBRJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $k3l[@;hE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 71yf+xL  
nEndPos = " + nFileLength); `>}e 5  
// fileSplitterFetch[nPos.length-1].start(); Z o5.Yse  
v/7iu*u  
F, p~O{ Q  
//等待子线程结束 dr7ry"5Zq  
//int count = 0; :j#Fq d[DF  
//是否结束while循环 .[:*bo3  
boolean breakWhile = false; FHu+dZ  
_Nq7_iT0  
>_?Waz %  
while(!bStop) (V+iJ_1g{  
{ +D+Rf,D  
write_nPos(); w=75?3c7F  
Utility.sleep(500); k<NEauQ  
breakWhile = true; z2A1h!Me  
7(= 09z  
K~>ESMZ5  
for(int i=0;i<nStartPos.length;i++) XFN4m #  
{ V\o& {7!  
if(!fileSplitterFetch.bDownOver) 0j|JyS:}G  
{ @460r  
breakWhile = false; Gl>_C@n0h  
break; !tofO|E5  
} ::rKW *?  
} -}*YfwK  
if(breakWhile) MXU8QVSY"  
break; 41`&/9:"_M  
4m$Xjj`vE  
"*aL(R  
//count++; dD8f`*"*=  
//if(count>4) HBnnIbEtF'  
// siteStop(); )[hQK_e]  
} 5S ?+03h~  
[S!_ubP5  
)o8]MWT\;  
System.err.println("文件下载结束!"); pO_L,~<  
} ({AqL#x`u  
catch(Exception e){e.printStackTrace ();} | sio:QP  
} =XT}&D6  
?KfV>.()  
u CNi&.  
//获得文件长度 5}t}Wc8  
public long getFileSize() (>\w8]  
{ ww"HV;i  
int nFileLength = -1; 7Z<ba^r}  
try{ kMLWF  
URL url = new URL(siteInfoBean.getSSiteURL()); hzjEO2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2aUy1*aM  
httpConnection.setRequestProperty("User-Agent","NetFox"); YAf`Fnmw  
x7]Yn'^'  
&*#- %<=1  
int responseCode=httpConnection.getResponseCode(); ! uyC$8V*l  
if(responseCode>=400) AGxG*KuZ  
{ #2023Zo]  
processErrorCode(responseCode); wfxg@<WR  
return -2; //-2 represent access is error Z>H y+Q4  
} dLMKfh/4Q  
2,X~a;+  
eD481r  
String sHeader; $NtbI:e{  
_*O^|QbM  
+5+?)8Ls  
for(int i=1;;i++) n^ AQ!wC  
{ 2& l~8,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); hs"=>(P)  
//Utility.log(in.readLine()); o4"7i 9+g  
sHeader=httpConnection.getHeaderFieldKey(i); M1/Rba Q  
if(sHeader!=null) q-fxs8+m|  
{ ( o_lH2  
if(sHeader.equals("Content-Length")) !5P\5WF~Y  
{ _JjR= m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); O:Fnxp5@  
break; 1c} %_Z/  
} A%pBvULH  
} #X(KW&;m  
else .;0?r9  
break; IE-c^'W=}m  
} jCMr[ G=  
} AVys`{*c  
catch(IOException e){e.printStackTrace ();} $i+ 1a0%n  
catch(Exception e){e.printStackTrace ();} ni@N/Z?!pA  
}0P5~]S<5A  
;U=RV&  
Utility.log(nFileLength); n%>c4*t  
2%'iTXF  
W~J>Srt  
return nFileLength; C[ ehw  
} I'h6!N"  
0P<bS?e<l  
Lii,L}  
//保存下载信息(文件指针位置) \lnpsf  
private void write_nPos() Ls#= R  
{ ]iyJ>fC  
try{ ESl-k2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u2SnL$A7  
output.writeInt(nStartPos.length); #l6L7u0~wC  
for(int i=0;i<nStartPos.length;i++) s^]F4'  
{ WvN!8*XFM  
// output.writeLong(nPos); y^#jM  
output.writeLong(fileSplitterFetch.nStartPos); 8#9 di  
output.writeLong(fileSplitterFetch.nEndPos); L)5YX-?  
} Jbud_.h9  
output.close(); J3oj}M*  
} DL5`A?/  
catch(IOException e){e.printStackTrace ();} <wt#m`Za  
catch(Exception e){e.printStackTrace ();} #4ZDY,>Xi#  
} t UJ m}+=>  
J1^6p*]GX  
R)AFaP |  
//读取保存的下载信息(文件指针位置) Ub%al D  
private void read_nPos() o!`.LL%  
{ !}D!_z,)u  
try{ GB1[`U%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); uM\(#jZ  
int nCount = input.readInt();  m/)Wn  
nStartPos = new long[nCount]; }vRs n-E@  
nEndPos = new long[nCount]; =gCv`SFW  
for(int i=0;i<nStartPos.length;i++) bY4~\cP.  
{ 3d^zLL  
nStartPos = input.readLong(); sD,[,6(  
nEndPos = input.readLong(); HG2i^y  
} *<yKT$(+_  
input.close(); W_NQi  
} )SMS<J  
catch(IOException e){e.printStackTrace ();} %t&5o>1C  
catch(Exception e){e.printStackTrace ();} X&1R6 O  
} -'FzH?q:  
.u3!%{/v(c  
w z-9+VN6  
private void processErrorCode(int nErrorCode) 0f).F  
{ $= '_$wG 8  
System.err.println("Error Code : " + nErrorCode); KJ]:0'T  
} \Gh]$s p  
N@$g"w  
 o *2TH2  
//停止文件下载 sjpcz4|K  
public void siteStop() bE-{ U/;  
{ `B+P$K<X  
bStop = true; jg]_'^pVzr  
for(int i=0;i<nStartPos.length;i++) [:x^ffs  
fileSplitterFetch.splitterStop(); gdupG  
/ vI sX3v  
J G xuB*}  
} PiMW 29B^  
} PpPg ~ix*  
//负责部分文件的抓取 opQ%!["N  
**FileSplitterFetch.java  =,q,W$-  
*/ :yN;_bC!b%  
package NetFox; qEC -'sl<  
U^tr Z])  
cD&53FPXC  
import java.io.*; B w1ir  
import java.net.*; TFbMrIF  
eHCLENLmB  
jTbJL  
public class FileSplitterFetch extends Thread { _RT3Fk  
CQf!<  
nPp\IE}:  
String sURL; //File URL ^EGe%Fq*x]  
long nStartPos; //File Snippet Start Position P9~7GFas|  
long nEndPos; //File Snippet End Position =W(mZ#*vdY  
int nThreadID; //Thread's ID ^2L\Y2  
boolean bDownOver = false; //Downing is over 9Xb,Swo~  
boolean bStop = false; //Stop identical <]6])f,y\  
FileAccessI fileAccessI = null; //File Access interface ,E{z+:Es  
RF/I*5  
z;6 Tp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @^8tk3$ Y  
{ bmT_tNz  
this.sURL = sURL; X}.y-X#v5J  
this.nStartPos = nStart; ~y.{WuUD  
this.nEndPos = nEnd; (9r\YNK  
nThreadID = id; "oZ-W?IKE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h }&WBN  
} T8& kxp  
8RJXY:%  
1 "'t5?XW  
public void run() t|Cp<k]B  
{ uGIA4CUm  
while(nStartPos < nEndPos && !bStop) 1!,xB]v1Ri  
{ 3.M<ATe^  
:<ye:P1s  
%|L+~=  
try{ B#RwW,  
URL url = new URL(sURL); j(4BMk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); " N)dle,  
httpConnection.setRequestProperty("User-Agent","NetFox"); *oAv:8"iY  
String sProperty = "bytes="+nStartPos+"-"; P;o6rQf  
httpConnection.setRequestProperty("RANGE",sProperty); %~`8F\Hiu  
Utility.log(sProperty); D_oGhQYY4  
t sdkpt  
cd1M0z  
InputStream input = httpConnection.getInputStream(); C8qA+dri  
//logResponseHead(httpConnection); 5)fEs.r0U  
<[O8 {9j  
QXZjsa_|  
byte[] b = new byte[1024]; s`W\`w}  
int nRead; T#'+w@Q9{9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \ IJ\  
{ u_[^gS7  
nStartPos += fileAccessI.write(b,0,nRead); /QDlm>FM4  
//if(nThreadID == 1) 5$o]D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G8%Q$  
} f/t1@d!  
2P9gS[Ub  
&WN#HI."]  
Utility.log("Thread " + nThreadID + " is over!"); lhsd 39NM  
bDownOver = true; iM;7V*u  
//nPos = fileAccessI.write (b,0,nRead); WZq0$:I;R  
} IXYSZ)z  
catch(Exception e){e.printStackTrace ();} Fm(~Vt;%u  
} @vWf-\  
} nQ4s  
@!z9.o;  
VT1Nd  
//打印回应的头信息 J(+I`  
public void logResponseHead(HttpURLConnection con) LB}y,-vX>  
{ '<" eG!O  
for(int i=1;;i++) #g,JNJ}  
{ 'EFSr!+  
String header=con.getHeaderFieldKey(i); 23XSQHVx  
if(header!=null) 8s6~l.v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r8\"'4B1  
Utility.log(header+" : "+con.getHeaderField(header)); `9QvokD  
else C2RR(n=N^  
break; :7&#ej6  
} \ FW{&X9a  
} 0{bGVLp  
ssVO+ T  
Qhlgu!  
public void splitterStop() ,L ;ueAo  
{ 'V";"Ei  
bStop = true; j)IXe 0dMC  
} :#8#tLv  
~~eR,HYk  
Sc Uh -y_  
} /Po't(-x  
2Cd#~  
^c?2n  
/* w'[lIEP 2$  
**FileAccess.java ]$[J_f*x  
*//文件访问(定位,写) _^cDB1I ?  
package NetFox; 49b#$Xq  
import java.io.*; &|('z\k  
siveqz6h  
v;.7-9c*  
public class FileAccessI implements Serializable{ kL;sA'I:S  
]k~k6#),;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GtcY){7  
RandomAccessFile oSavedFile; VfAC&3 %M  
long nPos; bqEQP3t^  
~\A(xmW}  
uJ jm50R<  
public FileAccessI() throws IOException :wiQ^ea  
{ zbsdK  
this("",0);  y/t{*a  
} PLDg'4DMg  
3vx*gfr3  
^CZ!rOSv  
public FileAccessI(String sName,long nPos) throws IOException (jYHaTL6Y'  
{ S;#S3?G  
oSavedFile = new RandomAccessFile(sName,"rw"); ab ?   
this.nPos = nPos; +92/0  
oSavedFile.seek(nPos); v%O KOrJ  
} y\K r@;q0w  
H,`F%G#!`q  
$Llv6<B  
public synchronized int write(byte[] b,int nStart,int nLen) >p#`%S  
{ 6yk=4l\  
int n = -1; >)*'w!  
try{ \MBbZB9@  
oSavedFile.write(b,nStart,nLen); -V0_%Smc  
n = nLen; eJA$J=^R;  
} OE' ?3S  
catch(IOException e) }U3+xl6g  
{ sC >_ulkoa  
e.printStackTrace (); [ZC]O2'  
} Q^X  
|{ W4JFKJ  
l?pF?({  
return n; lM1~ K  
} cb!mV5M-g  
FsQeyh>  
{y)O ?9q  
} MCOiB <L6  
Qt`hUyL  
#HFB* >  
/* `)V1GR2 ES  
**SiteInfoBean.java -n&g**\w  
*/ e$]`  
package NetFox; K"u-nroHW  
wKOljE6d  
_: @~ bHd  
public class SiteInfoBean { yUV0{A-q{0  
F5UvD[i  
 8:=&=9%  
private String sSiteURL; //Site's URL pF kA,  
private String sFilePath; //Saved File's Path +UbSqp1BS  
private String sFileName; //Saved File's Name e ewhT ^  
private int nSplitter; //Count of Splited Downloading File Xi$( U8J_  
_M'WTe  
I\ e?v`e  
public SiteInfoBean() n@5Sp2p  
{//nSplitter的缺省值为5 8K+(CS>xvO  
//default value of nSplitter is 5 ldp x,  
this("","","",5); ql"&E{u?  
} gc(Gc vdB\  
3ARvSz@5  
Gk_%WY*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yg({g "  
{ m$<LO%<~p  
sSiteURL= sURL; \f| Hk*@  
sFilePath = sPath; DV+M;rs  
sFileName = sName; ?bFP'.  
this.nSplitter = nSpiltter; k1tJ$}  
5=/&[=  
/`(Kbwh   
} 0XouHU  
UNLmnj;-Q  
+;z^qn  
public String getSSiteURL() W P7RX|7  
{ dRw O t  
return sSiteURL; @z $,KUH  
} GX2aV6}  
48%-lkol)  
oh*Hzb  
public void setSSiteURL(String value) n>Cl;cN=  
{ cr GFU?8  
sSiteURL = value;  1B}q?8n  
} [/dGOl+  
& gF*p  
<Jt H/oN  
public String getSFilePath() Bmx+QO  
{ w2*.3I,~)B  
return sFilePath; [zXKS |  
} VnlgX\$}  
 )ph**g  
L1J \ C  
public void setSFilePath(String value) /V'^$enK!}  
{ 'Br:f_}  
sFilePath = value; y98 v  
} s|er+-'  
qHwHP 1  
'ec G:B`S  
public String getSFileName() (!b_o A8V  
{ w+A:]SU  
return sFileName; (EW<Ggi  
} [3$L}m  
HCBZ*Z-  
FHztF$Z  
public void setSFileName(String value) "i jpqI  
{ EY~b,MIL4  
sFileName = value; \9;SOAv  
} vjo@aY.x  
j^4KczJl  
zk6al$3R  
public int getNSplitter() )1CYs4lp  
{ )"( ojh  
return nSplitter; 8aDSRfv*  
} hz:^3F`>/&  
$'Pn(eZHGv  
q%H`/~AYM  
public void setNSplitter(int nCount) kg,t[Jl  
{ > L5fc".  
nSplitter = nCount; z+@ CzHCN  
} yH`4 sd  
} !-G'8a|7  
bx!uHL=  
4Vv~  
/* u_kcuN\Sq  
**Utility.java ceiUpWMu,  
*/ kXj rc  
package NetFox; ,E7+Z' ;  
(tZ#E L0  
01N]|F:  
public class Utility { a#i85su  
^pI&f{q  
v?AQ&'Fk  
public Utility() CMQlxX?  
{ !WTZ =|  
x" N{5  
g>k"R4  
} oAnNdo  
A/bxxB7w  
//线程睡眠 VV_Zrje  
public static void sleep(int nSecond) [G.4S5FX.]  
{ 0<g;g%   
try{ =D&xw2  
Thread.sleep(nSecond); 8 `\^wG$W  
} i|`b2msvd  
catch(Exception e) Sf_q;Ws  
{ _'eG   
e.printStackTrace (); |)%]MK$;  
} /6?A#%hc  
} ,s=jtK  
gzHMZ/31  
//日志 JPo.&5k  
public static void log(String sMsg) 33R1<dRk  
{ D)kh"cK*1  
System.err.println(sMsg); B/:+(|  
} %_kXC~hH_  
j|6@>T1  
A$6T)  
public static void log(int sMsg) X jJV  
{ tYe+7s  
System.err.println(sMsg); Z`FEB0$  
} uq/z.m  
} m7dpr$J  
`5HFRgL`.  
0n FEPMO  
/* V XE85  
**TestMethod.java \vH /bL  
*/ G<F+/Oi&DX  
package NetFox; >M}\_c=  
| c:E)S\  
R04%;p:k#  
public class TestMethod { k!&G ;6O-  
|igr3p5Fw  
Z$UPLg3=;_  
public TestMethod() bCV3h3<  
{ ///xx/weblogic60b2_win.exe >DFpL$oP  
try{ MC 8t"SB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *qX!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p"xti+2,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o {W4@:Ib  
fileFetch.start(); R*"31&3le4  
} Qkk3>{I  
catch(Exception e){e.printStackTrace ();}  +*W9*gl  
3 s@6pI  
^)JUl!5j]C  
} @ij8AGE:  
2H,^i,  
.Mn_T*F  
public static void main(String[] args) z~O#0Q !  
{ &-S;.}  
new TestMethod(); BLepCF38  
} 3SI~?&HU!/  
} +hUS sR&  
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