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http断点续传简单实现(java)

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/* _c[Bjip  
**SiteFileFetch.java o|r8x_!+  
*/ gzV&S5A{_  
package NetFox; xLZJ[:gr  
import java.io.*; =t@8Y`9w  
import java.net.*; )Q:.1Hgl  
e u{  
L$T23*9XY  
public class SiteFileFetch extends Thread { Q}/2\Q=)j  
1a_R8j  
I[P43>F3  
SiteInfoBean siteInfoBean = null; //文件信息Bean WDr C  
long[] nStartPos; //开始位置 ~f:y^`+Q[  
long[] nEndPos; //结束位置 {lNvKm)w  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r .&<~x  
long nFileLength; //文件长度 q oA?  
boolean bFirst = true; //是否第一次取文件 o p{DPUO0  
boolean bStop = false; //停止标志 NoSq:e  
File tmpFile; //文件下载的临时信息 | DB7o+4  
DataOutputStream output; //输出到文件的输出流 i!AFXVX  
*/8b)I}yY  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) OD;-0Bj  
public SiteFileFetch(SiteInfoBean bean) throws IOException PIo8mf/  
{ $_ &Lp\  
siteInfoBean = bean; .k_> BD];  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Z{Si`GA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); H]zi>;D  
if(tmpFile.exists ()) 6R`q{}.  
{ DL*/hbG  
bFirst = false; KM'*+.I  
read_nPos(); VaV(+X  
} |IN{8  
else IF>dsAAI<  
{ #Qir%\*V  
nStartPos = new long[bean.getNSplitter()]; Ll2yJ .C4  
nEndPos = new long[bean.getNSplitter()]; q:iB}ch5R  
} Bsr; MVD  
Npr<{}ZE  
[m*E[0Hu  
PM(M c]6  
} |o6g{#1  
ET2^1X#j  
^/"[jq3F  
public void run() hN#A3FFo L  
{ bi:TX<K+  
//获得文件长度 Ne!0`^`~  
//分割文件 6}q8%[l|  
//实例FileSplitterFetch `jI$>{oa  
//启动FileSplitterFetch线程 +mgm39  
//等待子线程返回 G8sxg&bf{  
try{ ygN4%-[XA  
if(bFirst) W UN|,P`b  
{ #0:N$'SZ  
nFileLength = getFileSize(); gG?sLgL:  
if(nFileLength == -1) " A4.2  
{ d_ [l{  
System.err.println("File Length is not known!"); f+WN=-F\  
} per$%;5E"  
else if(nFileLength == -2) k Q Sx65  
{ R&v V! d  
System.err.println("File is not access!"); 2oO&8:`tv  
} ?FV>[&-h#I  
else Oh&k{DWE$  
{ )qq5WShMJ  
for(int i=0;i<nStartPos.length;i++) !e<D2><^  
{ .+.'TY--  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d?9b6k?  
} /Wx({N'h$  
for(int i=0;i<nEndPos.length-1;i++) Kw/7X[|'G  
{ BQOit.  
nEndPos = nStartPos[i+1]; P{2ue`w[  
} Z)Zc9SVC  
nEndPos[nEndPos.length-1] = nFileLength;  K}OY!|  
} j=],n8_i  
} i 6DcLE  
_ Vo35kA  
ru>c\X^|  
//启动子线程 #Yd 'Vve  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; bE6:pGr  
for(int i=0;i<nStartPos.length;i++) -zSkon2Y^  
{ 'zUWO_(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l(B(gPvU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ab@1JAgs  
nStartPos,nEndPos,i); VhfM j|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +[lv `tr  
fileSplitterFetch.start(); uE;bNs'  
} o<\u Hr3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rFJPeK7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DI )!x {"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", t ;-U  
nEndPos = " + nFileLength); X<8   
// fileSplitterFetch[nPos.length-1].start(); ';vL j1v  
_U<r@  
E3~Wyfd7  
//等待子线程结束 >[qoNy;  
//int count = 0; ?TLzOYJp  
//是否结束while循环 lx H3a :gm  
boolean breakWhile = false; [S:{$4&  
^C|N  
@dHQ}Ni  
while(!bStop) ]Jum(1Bo  
{ >"/Sa_w  
write_nPos(); C25EIIdRb  
Utility.sleep(500); vMHJgpd&j  
breakWhile = true; LJ{P93aq`^  
OMz_xm.UPi  
7jzd I!  
for(int i=0;i<nStartPos.length;i++) EyK F5TP0  
{ Ia%S=xU{=  
if(!fileSplitterFetch.bDownOver) "BvAiT{u  
{ 3[UB3F 4K  
breakWhile = false; i2y E-sgF  
break; p_:bt7 B  
} ` JZ`j7f  
} 6|@\\\l  
if(breakWhile) 1:j[p=Q&  
break; U(~d^9/#  
nvOJY6)$V  
sVNM#,  
//count++; I$Ra*r  
//if(count>4) ?H0"*8C?Y  
// siteStop(); 5bHS|<  
} gY/p\kwsj  
tYzpL   
2l.qINyz  
System.err.println("文件下载结束!"); IPa)+ ZQ  
} qHf8z;lc  
catch(Exception e){e.printStackTrace ();} y7@q]~%  
} |qq7vx  
Js0hlWu  
"74Rn"d5  
//获得文件长度 Kd|@  
public long getFileSize() @ rG=>??k  
{ @@pI>~#zh  
int nFileLength = -1; &~&nJr  
try{ ?(2^lH~6h  
URL url = new URL(siteInfoBean.getSSiteURL()); Q G8X{'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T@?uA*J  
httpConnection.setRequestProperty("User-Agent","NetFox"); _@_w6Rh  
'g#EBy  
H"vy[/UcR  
int responseCode=httpConnection.getResponseCode(); 6_zyPh  
if(responseCode>=400) YkJnZ_k/P  
{ %1UdG6&J_  
processErrorCode(responseCode); RKtU@MX49  
return -2; //-2 represent access is error %kXg|9Bx!  
} Y| 2Gj(*8  
5m\T~[`%  
nm{J  
String sHeader; ;+NU;f/WM  
fZNWJo# `.  
NzAMX+L  
for(int i=1;;i++) VPI;{0kh  
{ 0~GtK8^B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Sft+Gb6  
//Utility.log(in.readLine()); r zO5 3\  
sHeader=httpConnection.getHeaderFieldKey(i); V'm4DR#M  
if(sHeader!=null)  }0f"SWO>  
{ s+7#TdhA  
if(sHeader.equals("Content-Length")) u~7 ,v  
{ F\BD7W  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p`mNy o'  
break; tO8<N'TD  
} /5&' U!:+  
} SMIr@*R  
else u0?,CQPL  
break; t(Sjo8, b  
} :J~sz)n4  
} D)){"Q!b  
catch(IOException e){e.printStackTrace ();} uNXKUJ V0  
catch(Exception e){e.printStackTrace ();} R\ZyS )~l  
_I A{I  
e)): U  
Utility.log(nFileLength); d7i 0'R  
W,-fnJk  
kr{eC/Q"  
return nFileLength; J{qpGRQNa  
} m)oGeD( !  
G~FAChI8![  
sUTfY|<7|  
//保存下载信息(文件指针位置) *-lw2M9V  
private void write_nPos() "&{sE RYY  
{ am(jmf::  
try{ ]<g`rR7}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t/Y)%N  
output.writeInt(nStartPos.length); Ow f:Kife  
for(int i=0;i<nStartPos.length;i++) (sN;B)  
{ 'rSP@  
// output.writeLong(nPos); JV_V2L1Ut  
output.writeLong(fileSplitterFetch.nStartPos); c@<vFoq  
output.writeLong(fileSplitterFetch.nEndPos); _X"G(  
} Y2 QX9RN  
output.close(); 04}" n  
} )D>= \ Me  
catch(IOException e){e.printStackTrace ();} *wNO3tP't  
catch(Exception e){e.printStackTrace ();} Di>B:=  
} /+g)J0u  
Lcow2 SbH  
C'oNGOEd  
//读取保存的下载信息(文件指针位置) , 3p$Z  
private void read_nPos() o@j)clf  
{ ;:#g\|(<+  
try{ % >}{SS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \9 5O  
int nCount = input.readInt(); Qs1e0LwA9  
nStartPos = new long[nCount]; lq*{2M{[  
nEndPos = new long[nCount]; EI!e0 V1!  
for(int i=0;i<nStartPos.length;i++) f.Feo  
{ 8-uRn38  
nStartPos = input.readLong(); Y>i5ubR~  
nEndPos = input.readLong(); b@?pofZ`k  
} vzPuk|q3  
input.close(); z(JDLd  
} e A'1  
catch(IOException e){e.printStackTrace ();} p"k[ac{  
catch(Exception e){e.printStackTrace ();} `S+B-I0  
} @teNT"  
G.y~*5?#  
.!Qo+(  
private void processErrorCode(int nErrorCode) +#=l{_Z,ZJ  
{ $Q'S8TU  
System.err.println("Error Code : " + nErrorCode); p|,3X*-ynx  
} N&K`bmtD  
w$%1j+%&  
TF7~eyLg  
//停止文件下载 REc+@;B  
public void siteStop() R}J}Q b  
{ %IhUQ6  
bStop = true; *!- J"h  
for(int i=0;i<nStartPos.length;i++) 9W+RUh^W  
fileSplitterFetch.splitterStop(); KE*8Y4#9  
7,:$, bL  
pxgVYr.  
} j$mCU?  
} lOJ3_8  
//负责部分文件的抓取 f' 28s*n  
**FileSplitterFetch.java QxS=W2iN  
*/ Qqn9nO9  
package NetFox; q{E44 eQ7F  
Pt^SlX^MM  
zEN3N n.8  
import java.io.*; w(-h!d51+  
import java.net.*; 1Bhd-  
q[Ed6FM$~  
c3]X#Qa#m$  
public class FileSplitterFetch extends Thread { 1p }:K`#{  
[t}\8^y  
\Uh$%#}.  
String sURL; //File URL ##_Jz5P  
long nStartPos; //File Snippet Start Position gt Vnn]Jh  
long nEndPos; //File Snippet End Position RwyRPc _  
int nThreadID; //Thread's ID x-%4-)  
boolean bDownOver = false; //Downing is over | g[iK1  
boolean bStop = false; //Stop identical gSn9L)k(O  
FileAccessI fileAccessI = null; //File Access interface U,e'vS{  
lw j,8  
M*n@djL$\~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _&xi})E^O]  
{ lU&[){  
this.sURL = sURL; KYN{Dh]-}  
this.nStartPos = nStart; r< ~pSj  
this.nEndPos = nEnd; '7;b+Vbl#  
nThreadID = id; ZA{T0:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <]e0TU?bk  
} 3d81]!n  
6xq/  
jSc!"Trl]  
public void run() bxR6@  
{ BfOQ/k))  
while(nStartPos < nEndPos && !bStop) H)VzPe#{  
{ 7 S 6@[-E  
&upM,Jsr*  
c4i%9E+Af  
try{ 6! .nj3$*  
URL url = new URL(sURL); >A_:q yGk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1 |T{RY5  
httpConnection.setRequestProperty("User-Agent","NetFox"); {Z!x]}{M  
String sProperty = "bytes="+nStartPos+"-"; uzgQ_  
httpConnection.setRequestProperty("RANGE",sProperty); M|DVFC  
Utility.log(sProperty); ;FfDi*S7  
3 jR I@  
K0xka[x=(  
InputStream input = httpConnection.getInputStream(); YggeKN  
//logResponseHead(httpConnection); &'KJh+jJ  
4M,Q{G|e  
Z(c3GmY  
byte[] b = new byte[1024]; -{O>'9'1A  
int nRead; JVxGS{Z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lo< t5~GQ  
{ }fT5(+ Wo  
nStartPos += fileAccessI.write(b,0,nRead); :plN<8  
//if(nThreadID == 1) 4Fs5@@>X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RM|2PG1m  
} l>){cI/D#  
'^10sf`"  
YDxEWK<  
Utility.log("Thread " + nThreadID + " is over!"); 1r?hRJ:'  
bDownOver = true; 0+dc  
//nPos = fileAccessI.write (b,0,nRead); J<;@RK,c_  
} d":GsI?3  
catch(Exception e){e.printStackTrace ();} U_[<,JE  
} 1=U NA :t<  
} 68 \73L=  
hI>vz"J  
DElrY)3O.  
//打印回应的头信息 Q /zlU@  
public void logResponseHead(HttpURLConnection con) ;eY.4/*R  
{ !> 2kH  
for(int i=1;;i++) Wb{0UkApJ  
{ hb ="J349  
String header=con.getHeaderFieldKey(i); =`pH2SJT  
if(header!=null) z&KrG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 3LW_qX  
Utility.log(header+" : "+con.getHeaderField(header)); 0aM&+j\q}  
else ^I y'G44  
break; 6 @A'N(I=O  
} Mv?$zV"`#  
} w Sd|-e  
A}3dx!?7j  
l' mdj!{&  
public void splitterStop() `p'682xI  
{ @ Cd#\D|  
bStop = true; }5]2tH${  
} KBOp}MEz  
!*G%vOa  
N5d)&a 7?  
} gzd<D}2F~  
QCAoL.v  
aDZ,9}  
/* C116 c"  
**FileAccess.java f Hd|tl  
*//文件访问(定位,写) VS jt|F)t  
package NetFox; (|9t+KP  
import java.io.*; G$mAyK:  
N3(.7mxo  
J~.`  
public class FileAccessI implements Serializable{ v2l*n  
F87/p  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K;Fs5|gFU  
RandomAccessFile oSavedFile; lW|`8ykp  
long nPos; W+Q^u7K  
SxI-pH'  
Ms 3Sri  
public FileAccessI() throws IOException u*=8s5Q[  
{ 572{DC&T  
this("",0); [nASMKK0  
} m gE r+  
).3riR  
^_gH}~l+U  
public FileAccessI(String sName,long nPos) throws IOException e);`hNLih  
{ Z^!% b  
oSavedFile = new RandomAccessFile(sName,"rw"); 6o d^+>U  
this.nPos = nPos; Y*/e;mG.  
oSavedFile.seek(nPos); LU $=j  
} %jJ|4\  
$a'}7Q_  
RJ1 @ a  
public synchronized int write(byte[] b,int nStart,int nLen) Dbu>rESz  
{ SA?lDRF  
int n = -1; PH$C."Vv  
try{ U'aJCM  
oSavedFile.write(b,nStart,nLen); VVJIJ9L&C  
n = nLen; 9? y&/D5O  
} cq0-D d9^&  
catch(IOException e) ryNe=9p  
{ 5=&ME(fmV  
e.printStackTrace (); c!ieN9^+  
} +"1fr  
.XT]\'vW  
-v! ;  
return n; Ye S5%?Fk  
} qV0GpVJZU?  
G=/^]E  
Ggry,3X3  
} =P%?{7  
;pj,U!{%s\  
-}u1ZEND  
/* " GY3sam  
**SiteInfoBean.java !bs5w_@  
*/ mw&'@M_(7  
package NetFox; {T-=&%||  
x[=,$;o+  
3Cgv($xl&  
public class SiteInfoBean { "5204I  
a<J< Oc!  
iPdS>e e  
private String sSiteURL; //Site's URL lAR1gHhJ  
private String sFilePath; //Saved File's Path Kr?<7vMT5  
private String sFileName; //Saved File's Name ~BiLzT1,  
private int nSplitter; //Count of Splited Downloading File Gz52^O :  
U+R9bn   
vnWt8?)]^  
public SiteInfoBean() (8baa.ge  
{//nSplitter的缺省值为5 EU7nS3K)O~  
//default value of nSplitter is 5 RN&6z"|jR  
this("","","",5); EM(%|#  
} /dO*t4$@?  
%l?*w~x  
+%H=+fJ2}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x_t$*  
{ ^ WF_IH&  
sSiteURL= sURL; aJ@lT&.  
sFilePath = sPath; fr'DV/T  
sFileName = sName; $xCJ5M4  
this.nSplitter = nSpiltter; CaV@<T  
+p[O|[z  
+/ {lz8^,  
} <0;G4fE7[H  
d3\KUR^  
BiDyr  
public String getSSiteURL() |ZC'a!  
{ T% GR{mp  
return sSiteURL; <Sr:pm  
} B}nT>Ub  
&dPUd ~&EL  
Yxy!&hPLv:  
public void setSSiteURL(String value) 9oIfSr,y  
{ Sk:x.oOZ  
sSiteURL = value; :|8!w  
} Apj[z2nr  
I5)$M{#a  
B" _Xst  
public String getSFilePath() X#Ob^E%J  
{ Qsw.429t  
return sFilePath; VCVKh  
} %g^:0me`  
}t:* w  
cY Qm8TR<  
public void setSFilePath(String value) /E3~z0  
{ 'y5H%I!  
sFilePath = value; (&u'S+  
} C\Z5%2<Z  
 [aG   
OsW*@v(  
public String getSFileName() 8 &v)Vi-  
{ &O#1*y Z  
return sFileName; )?I*zc  
} f$5\ b[O  
qA[cF$CIl)  
< 2fy(9y  
public void setSFileName(String value) =**Q\ Sl  
{ %%#bTyF  
sFileName = value; ;.<HpDfG_  
} 24 .'+3  
Jz*A!Li  
cj^hwtx   
public int getNSplitter() u{w,y.l1h  
{ 0x<G\ l4  
return nSplitter; Q5l+-  
} %eh.@8GL`  
]826kpq_  
j<6+p r  
public void setNSplitter(int nCount) |j{]6Nu  
{ g[HuIn/  
nSplitter = nCount; ^go3F{; 4i  
} oad /xbp@/  
} $e{[fm x  
7G7"Zule*j  
pe>?m^gz[  
/* Jw>na _FJ  
**Utility.java 2kk; z0f  
*/ O OXP1L  
package NetFox; -%Ce  
=d iGuI B  
rg=Ym.  
public class Utility { K`j:F>b  
$~j9{*]5  
IxG7eX!  
public Utility() )/Gi-::  
{ O<$j}?2  
=q|//*t2  
:Rnwyj])  
} n ywC]T  
ep0dT3&  
//线程睡眠 <r(D\rmD  
public static void sleep(int nSecond) :6&#u.\u  
{ ]"?<y s  
try{ /1D.Ud^  
Thread.sleep(nSecond); i)Q d>(v  
} G'';VoW=   
catch(Exception e) 0P{8s  
{ .>~er?-  
e.printStackTrace (); NxDVU?@p*  
} 3lEP:Jp  
} aR'~=t&;z1  
ori[[~OyB  
//日志 ImD&~^-_<  
public static void log(String sMsg) 'NCx<0*  
{ VR%*8=  
System.err.println(sMsg); ,rF!o_7  
} G:wO1f6  
3OY(L`  
&}|`h8JA]K  
public static void log(int sMsg) @?;)x&<8?3  
{ JoZzX{eu"  
System.err.println(sMsg); :Bu)cy#/[  
} _meW9)B  
} sY?wQ:  
rx@i .+  
!, rF(pz  
/* D~|q^Ms,%  
**TestMethod.java 5*Qzw[[=  
*/ Y7 K2@257  
package NetFox; k7L4~W  
rz2,42H]  
${}9/(x/^  
public class TestMethod { 2- (}=N  
 B@*!>R  
:#{0yno)H  
public TestMethod() Iz;^D!  
{ ///xx/weblogic60b2_win.exe Q`Q"p  
try{ `*`ZgTV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #l.s> B4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OECVExb@eH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yu > ;m.e_  
fileFetch.start(); J!dv"Ww"  
} 6+"gk(  
catch(Exception e){e.printStackTrace ();} -w8?Ur1x:  
j~>J?w9<O  
& .#dZ}J  
} h?} S|>9  
T &bB8tQk  
hd[t&?{=  
public static void main(String[] args) Fg'{K%t4  
{ \" m&WFm  
new TestMethod(); \OWxf[  
} x{GFCy7  
} tw.z5  
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