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http断点续传简单实现(java)

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/* 0~L 8yMM  
**SiteFileFetch.java r L|BkN  
*/ {^O/MMB\\%  
package NetFox; bFdg '_  
import java.io.*; w0%ex#lkm  
import java.net.*; (a4y1k t-  
8P y_Y>  
>U Ich  
public class SiteFileFetch extends Thread { q>lkLHS  
f%%En5e +  
)^@V*$D  
SiteInfoBean siteInfoBean = null; //文件信息Bean D'hr\C^  
long[] nStartPos; //开始位置 RuEnr7gi  
long[] nEndPos; //结束位置 dE!=a|Pl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 w I 7  
long nFileLength; //文件长度 `,]PM) iC  
boolean bFirst = true; //是否第一次取文件 0+`*8G)  
boolean bStop = false; //停止标志 Jt^JE{m9%  
File tmpFile; //文件下载的临时信息 <y/AEY1  
DataOutputStream output; //输出到文件的输出流 :qKY@-t7H  
E6\~/=X=%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) FrM~6A_  
public SiteFileFetch(SiteInfoBean bean) throws IOException TZ_'nB~  
{ >-WO w  
siteInfoBean = bean; >bP7}T  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wbKBwI5w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .Eyk?"^  
if(tmpFile.exists ()) \B +SzW  
{ o:\j/+]  
bFirst = false; <g1hdF0  
read_nPos(); 90k|u'ikOp  
} kF~e3A7C  
else &=O1Qg=K  
{ _( /lBf{|  
nStartPos = new long[bean.getNSplitter()]; Olh-(u:9+O  
nEndPos = new long[bean.getNSplitter()]; eC:Q)%$%l  
} ,+evP=(cX  
9uoj3Rh<  
Gl:T  
UC$+&&rO  
} "lb!m9F{  
Pu*UZcXY  
zg Ti Az  
public void run() vK~KeZ\,p=  
{ ;P#*R3   
//获得文件长度 [`dipLkr  
//分割文件 %+J*oFwQu  
//实例FileSplitterFetch -{mq\GvGn  
//启动FileSplitterFetch线程 T<GD!j(  
//等待子线程返回 !Hj)S](F  
try{ [)c|oh%  
if(bFirst) }f*S 9V  
{ 8Y'"=!3  
nFileLength = getFileSize(); Bq`kVfx  
if(nFileLength == -1) 6VE5C g  
{ K7Tell\`  
System.err.println("File Length is not known!"); fbkjK`_q  
} j"8N)la  
else if(nFileLength == -2) C{^@.8:  
{ Uwa1)Lwn  
System.err.println("File is not access!"); ^Z+D7Q  
} k]YGD  
else z*1K<w8  
{ *&MkkI#  
for(int i=0;i<nStartPos.length;i++) bd}SB-D  
{ X.|0E87  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =1Jo-!{{  
} l))IO`s=_  
for(int i=0;i<nEndPos.length-1;i++) !7?wd^C'f  
{ rNp#5[e  
nEndPos = nStartPos[i+1]; _gh7_P^H=d  
} Z8UM0B=i  
nEndPos[nEndPos.length-1] = nFileLength; gu&oCT  
} ?yK\L-ad  
} Y.#+Yh[  
`;@4f |N9  
:"]ei@  
//启动子线程 _r'M^=yx[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4y.[tk5  
for(int i=0;i<nStartPos.length;i++) rg.if"o  
{ q5PYc.E([  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Eq{TZV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "-%H</  
nStartPos,nEndPos,i); 9f`Pi:*+/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;wrgpP3  
fileSplitterFetch.start(); :_ox8xS4  
} 3R {y68-S  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6Tnzg`0I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9_{!nQC.g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", = ;d<Ikj  
nEndPos = " + nFileLength); ;0'v`ob'.?  
// fileSplitterFetch[nPos.length-1].start(); cK&oC$[r-  
wP*Z/}Uum+  
w3D_ c~  
//等待子线程结束 I "4B1g  
//int count = 0; _(foJRr  
//是否结束while循环 TZg7BLfy  
boolean breakWhile = false; ej+!|97M  
mZyTo/\0  
605|*(  
while(!bStop) .2xkf@OP  
{ m@ YL Z  
write_nPos(); iY-dM(_:]  
Utility.sleep(500); 9&cZIP   
breakWhile = true; gZ3!2T>  
z{\.3G  
4KCxhJq  
for(int i=0;i<nStartPos.length;i++) $]FWpr%)  
{ ?F/3]lsggT  
if(!fileSplitterFetch.bDownOver) il~,y8WTU{  
{ JN_# [S$  
breakWhile = false; s><co]  
break; uZ+<  
} P*>V6SK>b  
} W= !f  
if(breakWhile) /!hW6u5  
break; |w DCIHzQ  
q)*0G*  
jJ|;Nwm<[  
//count++; L6^h3*JyD  
//if(count>4) J}JnJV8|G  
// siteStop(); 5 S 1m&s5k  
} H|Ems}b  
x+pFu5,  
e\<I:7%Rg  
System.err.println("文件下载结束!"); C1=[\c~jw  
} nFqMS|EN  
catch(Exception e){e.printStackTrace ();} 5 F-Q&  
} x?3p3[y  
}49?Z3  
!duR7a  
//获得文件长度 `d8TA#|`  
public long getFileSize() )Ii=8etdv  
{ g=)@yZ3>v  
int nFileLength = -1; Z]tz<YSkG  
try{ b|NEU-oy  
URL url = new URL(siteInfoBean.getSSiteURL()); yC[}gHv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <6@Db$-  
httpConnection.setRequestProperty("User-Agent","NetFox"); >2a~hW|,  
LE;c+(CAU  
?g'l/xuRe  
int responseCode=httpConnection.getResponseCode(); { }z7N~  
if(responseCode>=400) x RfX:3  
{ tm$3ZzP4  
processErrorCode(responseCode); }sFHb[I &  
return -2; //-2 represent access is error Jps!,Mflc  
} <%5ny!]  
W/ERqVZR]  
r <U }lK  
String sHeader; PYZ8@G  
Q8_d]V=X:  
!59q@M ya[  
for(int i=1;;i++) W|:WAxJ*d  
{ d$!ibL#o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *`kh}  
//Utility.log(in.readLine()); uB\A8zC  
sHeader=httpConnection.getHeaderFieldKey(i); =_5-z|<  
if(sHeader!=null) |K]tJi4fz  
{ j9%=^ZoQj  
if(sHeader.equals("Content-Length")) .L}ar7  
{ JH 8^ZP:d'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c5JxKU_  
break; MD+Q_  
} #}.db?[Rv  
} i9d.Ls  
else Qk((H~I}  
break; bS*9eX=K  
} y@F{pr+dA  
} cG.4%Va@s_  
catch(IOException e){e.printStackTrace ();} GE|V^_|i  
catch(Exception e){e.printStackTrace ();} p?5zwdX+`  
,+ WDa%R  
_T1|_9b  
Utility.log(nFileLength); )gZ yW  
8q_nOGd  
d+8Sypv^4*  
return nFileLength; F8q|$[nH  
} _k&vW(O=:  
X4gs{kx}|  
kIyif7  
//保存下载信息(文件指针位置) |Gz(q4  
private void write_nPos() f mf(5  
{ }}<^f M  
try{ @PutUYz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L^dF )y?  
output.writeInt(nStartPos.length); :U=*@p4?  
for(int i=0;i<nStartPos.length;i++) ^)TZHc2a[  
{ T)MKhK9\Ab  
// output.writeLong(nPos); 29:] cL(5  
output.writeLong(fileSplitterFetch.nStartPos); V!u W\i/  
output.writeLong(fileSplitterFetch.nEndPos); #V@[<S2  
} ?g}G#j  
output.close(); m;'ebkq  
} L\a G.\  
catch(IOException e){e.printStackTrace ();} 1GE[*$vuq  
catch(Exception e){e.printStackTrace ();} W|4:3 c4  
} rytves%;C  
zt6GJ z1q  
]v=A}}kS  
//读取保存的下载信息(文件指针位置) XU_gvz  
private void read_nPos() h:xvnyaI  
{ 3VaL%+T$,  
try{ >4 VN1 ^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Qu|H_<8g  
int nCount = input.readInt(); ,N93H3(  
nStartPos = new long[nCount]; )\Am:?RH;  
nEndPos = new long[nCount]; %g:6QS|  
for(int i=0;i<nStartPos.length;i++) yw\Q>~$n[=  
{ Q WcQtM  
nStartPos = input.readLong(); }]<0!q &xB  
nEndPos = input.readLong(); S"H djEF7\  
} VYbH:4K@%  
input.close(); #x*\dL  
} TophV}@B`  
catch(IOException e){e.printStackTrace ();} 2{|Z?3FJ^  
catch(Exception e){e.printStackTrace ();} VkFMr8@|  
} {^8?fJ/L  
ia@ |+r  
%tB7 &%ut  
private void processErrorCode(int nErrorCode) Q<0X80w>  
{ OY Sq)!:  
System.err.println("Error Code : " + nErrorCode); C cPOK2  
} KT[ZOtu  
,<k%'a!B  
nr&bpA/  
//停止文件下载 r3  qKT  
public void siteStop() uP G\1  
{ bMn)lrsX  
bStop = true; u8.F_'`z  
for(int i=0;i<nStartPos.length;i++) ,BUrZA2\U$  
fileSplitterFetch.splitterStop(); > a;iX.K  
`*6|2  
<2N{oK.  
} IdqCk0lVD  
} JkhWLQ>o  
//负责部分文件的抓取 By waD?  
**FileSplitterFetch.java k3K*{"z  
*/ 'Lq+ONX5  
package NetFox; 1w~PHH`~  
`WIZY33V  
?VlGTMaS+  
import java.io.*; C~egF=w  
import java.net.*; vJxE F&X  
nNq<x^@83  
R2v9gz;W  
public class FileSplitterFetch extends Thread { FQJiLb._Z  
a*-9n-U@[k  
K[kK8i+(  
String sURL; //File URL 9dq"x[  
long nStartPos; //File Snippet Start Position 3m= _a  
long nEndPos; //File Snippet End Position b"WF]x|^  
int nThreadID; //Thread's ID WG A1XQ{  
boolean bDownOver = false; //Downing is over f`:GjA,J$  
boolean bStop = false; //Stop identical (>vyWd]  
FileAccessI fileAccessI = null; //File Access interface 1aQm r=,  
rCwE$5 b  
o3V\   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FY^2 Y  
{ :h5G|^  
this.sURL = sURL; tPl 4'tW_  
this.nStartPos = nStart; 0KnL{Cj   
this.nEndPos = nEnd; 2HtsSS#0Q  
nThreadID = id; ]L97k(:Ib  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f[1cN`|z  
} 4^uSW&`;/  
`Jk0jj6Z  
& ?xR  
public void run() j1KNgAo<4  
{ M#; ks9  
while(nStartPos < nEndPos && !bStop) H,]8[ qT<  
{ & y5"0mA  
#m,H1YH M  
y92R}e\M  
try{ Ez;Qo8  
URL url = new URL(sURL); z3y{0<3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h <e  
httpConnection.setRequestProperty("User-Agent","NetFox"); /kY9z~l  
String sProperty = "bytes="+nStartPos+"-"; HD^#"  
httpConnection.setRequestProperty("RANGE",sProperty); !{g<RS( c  
Utility.log(sProperty); wkM1tKhy/  
_;B wP  
eJ99W=  
InputStream input = httpConnection.getInputStream(); ;.V/ngaj  
//logResponseHead(httpConnection); r|EN5  
o5bp~.m<  
J-hJqR*;K  
byte[] b = new byte[1024]; S3\NB3@qC&  
int nRead; zbmC? 2$  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C3}:DIn"w  
{ #7 3pryXV  
nStartPos += fileAccessI.write(b,0,nRead);  !BsQJ_H  
//if(nThreadID == 1) !l9{R8m>eJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f`n4'dG  
} jc&k-d>=G  
5p (zhfuG  
=#2c r:1  
Utility.log("Thread " + nThreadID + " is over!"); #RBrii-,  
bDownOver = true; 6nZ]y&$G-k  
//nPos = fileAccessI.write (b,0,nRead); ~Q&J\'GQH  
} nF@**,C Q  
catch(Exception e){e.printStackTrace ();} s*k)h,\  
} {Rkd;`Q`!  
} riDb !oC  
ISGw}#}]?  
<rBW6o7  
//打印回应的头信息  r{;NGQYs  
public void logResponseHead(HttpURLConnection con) #7]Jz.S  
{ zmo2uUEd  
for(int i=1;;i++) Ys.GBSlHG  
{ 3^P;mQ$p1  
String header=con.getHeaderFieldKey(i); 2=?3MXcjy  
if(header!=null) 0=&S?J#!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %e[E@H7  
Utility.log(header+" : "+con.getHeaderField(header)); .$s']' =  
else j3&q?1  
break; 5BA:^4zr?  
} F=Xb_Gd`  
} ^W sgAyCB  
aEzf*a|fSV  
B.=n U  
public void splitterStop() Zb_A(mnzh  
{ |*48J1:1y  
bStop = true; }bRn&)e  
} P84YriLo  
ts<\n-f  
8Vz!zYl  
} GH':Yk  
Cgln@Rz  
%7 -(c  
/* )n"0:"Ou  
**FileAccess.java =p5]r:9W  
*//文件访问(定位,写) f?ycZ  
package NetFox; Z^Um\f   
import java.io.*; /pkN=OBR  
:LB*l5\  
O*/%z r  
public class FileAccessI implements Serializable{ ELV~ ayp5  
_QHk&-Lp  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &x B^  
RandomAccessFile oSavedFile; $Tv~ *|a  
long nPos; !YpH\wUyvP  
Y,L[0%  
]#DCO8Vk  
public FileAccessI() throws IOException vN v'%;L  
{ Q }^Ip7T  
this("",0); LmyaC2  
} T~$Eh6 D  
:FU?vh$)  
MCTJ^g"D  
public FileAccessI(String sName,long nPos) throws IOException G6{'|CV  
{ FZ%h7Oe  
oSavedFile = new RandomAccessFile(sName,"rw"); \15'~ ]d  
this.nPos = nPos; 4".I*ij  
oSavedFile.seek(nPos); Rs{8vV  
} &c "!Y)%G  
%Iflf]l  
DazoY&AWE  
public synchronized int write(byte[] b,int nStart,int nLen) z &P1C,n)  
{ yogL8V-^4  
int n = -1; %^E 7Iqc  
try{ \"RCJadK  
oSavedFile.write(b,nStart,nLen); 2vX!j!_  
n = nLen; >iFi~)i_4y  
} Nd61ns(N  
catch(IOException e) JAP4Vwj%j  
{ y,vrMWDy  
e.printStackTrace (); {,zn#hU.R  
} fs%l j_t  
C: <TJ  
>r5s>A[YC  
return n; Tn(c%ytN  
} f|-%.,  
*S{fyYyM  
&{H LYxh   
} 0N4+6k|  
|;(0]  
!Di*y$`}b  
/* qr_:zXsob_  
**SiteInfoBean.java Y SD|#0  
*/ cr<ty"3\  
package NetFox; n>:|K0u"  
dSw%Qv*y  
-mAi7[omh  
public class SiteInfoBean { n6s[q- td  
sj\kp ni  
p}O[A`  
private String sSiteURL; //Site's URL [ nG@ 3n  
private String sFilePath; //Saved File's Path 8S*W+l19f  
private String sFileName; //Saved File's Name f<v:Tg.[  
private int nSplitter; //Count of Splited Downloading File ?PST.+l  
"Zq)y_1  
5>*~1}0T  
public SiteInfoBean() /5 6sPl 7}  
{//nSplitter的缺省值为5 P gK> Z,  
//default value of nSplitter is 5 Y;OqdO  
this("","","",5); i*-L_!cc:  
} ~k[q:$T  
>,s.!vpK  
1feS/l$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) dyMj=e  
{ 'k(aZ"  
sSiteURL= sURL; 9 9S-P}xd  
sFilePath = sPath; xD3Y-d9  
sFileName = sName; oD>j2 6Q  
this.nSplitter = nSpiltter; J_ S]jE{  
-^+!:0';  
#Kd^t =k  
} +X&b  
/,m!S RJ  
v?en-,{A  
public String getSSiteURL() uw,p\:D&  
{ xesZ 7{ o  
return sSiteURL; slWO\AYiO  
} e;ej/)no`  
mz kv/  
FJl_2  
public void setSSiteURL(String value) \uT y\KA  
{ ++)3*+N+  
sSiteURL = value; 7@*l2edXm+  
} C_~hX G  
gZLzE*NZ  
xOAA1#   
public String getSFilePath() 4$^\s5K  
{ 8vL2<VT;  
return sFilePath; h &R1"  
} B"rfR_B2M#  
S[zX@3eZV  
E"l/r4*f@  
public void setSFilePath(String value) 6~@S,i1  
{ @ppT;9<d  
sFilePath = value; yaD_c;  
} 8UahoNrSt  
>.)m|,  
<@puWm[p  
public String getSFileName() f1_b``M  
{ ZWH9E.uj  
return sFileName; L~PBD?l  
} %Ct^{k~1  
S);SfNh%CL  
1"4Pan  
public void setSFileName(String value) UHh7x%$n  
{ } qf=5v  
sFileName = value; vTdJe  
} g$N/pg2>cT  
e2 X\ll  
nbECEQ:|B  
public int getNSplitter() =>kE`"{!  
{ 1YrIcovi-  
return nSplitter; <V~B8C!)  
} 'fGB#uBt  
Q2L>P<87T  
+[R,wsG  
public void setNSplitter(int nCount) Ww[Xqmg  
{ m/T3Um  
nSplitter = nCount; 5>e#SW  
} nbMxQOD k  
} 7%Q?BH7{  
+' lj\_n  
Z?);^m|T  
/* oE H""Bd  
**Utility.java D\ ;(BB  
*/ 5C|Y-G  
package NetFox; qq,#bRe  
UBm L:Qv  
;Eer  
public class Utility { ,DZoE~  
OABMIgX  
FoNkISzW  
public Utility() Bo#,)%80  
{ WCdl 25L#  
J_|LG rt})  
n?[JPG2X  
} zFba("E Z  
:]rb}1nLB  
//线程睡眠 XY h)59oM%  
public static void sleep(int nSecond) dKk#j@[n"  
{ W0 n?S "  
try{ i!a. 6Gq  
Thread.sleep(nSecond); ].Sz2vI  
} $1E'0M`  
catch(Exception e) JH|]B|3  
{ lM |}K-2  
e.printStackTrace (); +v.<Fw2k#  
} ++=f7y u  
} 28! ke  
q?* z<)#  
//日志 Ct<]('Hm(  
public static void log(String sMsg) ]wZlJK`K  
{ V"Sa9P{y"  
System.err.println(sMsg); ?]AF? 0/  
} +7KRoF|  
=`KA@~XH4  
1VR|z  
public static void log(int sMsg) hjgB[ &U>  
{ KbSE=3  
System.err.println(sMsg); \:m1{+l  
} 11((b  
} Due@ '  
Xmm) z  
! }>CEE  
/* 8-PHW,1@a3  
**TestMethod.java sW,JnR  
*/ W8_$]}G8E  
package NetFox; kRb  %:*  
_M) G  
`oU|U!|  
public class TestMethod { |[Rlg`TQ;*  
eev-";c  
bgYUsc*uR  
public TestMethod() l86gs6>  
{ ///xx/weblogic60b2_win.exe %X BMi ~  
try{ Miz?t*|{[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +^DDWVp  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); p/U{*i ]t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !$hi:3{U ,  
fileFetch.start(); x']Fe7nv  
} 4Ql9VM%y  
catch(Exception e){e.printStackTrace ();} X`fb\}~R(  
2e9.U/9  
S J2l6  
}  b]gVZ-  
kMx)G]  
ALQ-aXJ  
public static void main(String[] args) bd\%K`JQ{  
{ }P'c8$  
new TestMethod(); s o1hC  
} 1\a.o[g3e  
} Ms#rvn!J  
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