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http断点续传简单实现(java)

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/* 0e./yPTT  
**SiteFileFetch.java 'iQ  
*/ y{ & k`H  
package NetFox; .<xzf4C  
import java.io.*; D$ X9xtT  
import java.net.*; 7  s+j)  
un*Ptc2%  
(pBPf  
public class SiteFileFetch extends Thread { jbQ N<`!  
-Iq W@|N  
V[9#+l~#  
SiteInfoBean siteInfoBean = null; //文件信息Bean * SAYli+@  
long[] nStartPos; //开始位置 bx!uHL=  
long[] nEndPos; //结束位置 4Vv~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u_kcuN\Sq  
long nFileLength; //文件长度 ceiUpWMu,  
boolean bFirst = true; //是否第一次取文件 kXj rc  
boolean bStop = false; //停止标志 ,E7+Z' ;  
File tmpFile; //文件下载的临时信息 (tZ#E L0  
DataOutputStream output; //输出到文件的输出流 l'yX_`*Iq  
:+ASZE.  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) U2Uf69R  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7CKpt.Sz6  
{ cZ8lRVaWW  
siteInfoBean = bean; |\HYq`!g%7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~Te9Lq|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); WUC-* (  
if(tmpFile.exists ()) 'eM90I%(  
{ ^Rel-=Z$B  
bFirst = false; ^{ Kj{M22  
read_nPos(); rTJ='<hIy  
} wEQ7=Gyx  
else M<Gr~RKmAn  
{ V)pn)no'V  
nStartPos = new long[bean.getNSplitter()]; #sHA!@ |  
nEndPos = new long[bean.getNSplitter()]; m7~<z>5$  
} 0LX"<~3j  
Sn o7Ru2  
@k< e]@r  
/ 7i>0J]  
} JPo.&5k  
33R1<dRk  
y#Cp Vm#!>  
public void run() UJ\[ ^/t  
{ {z^6V\O5  
//获得文件长度 }JP0q  
//分割文件 S\\3?[!p  
//实例FileSplitterFetch W^o* ^v  
//启动FileSplitterFetch线程 trl:\m  
//等待子线程返回 MU  }<-1  
try{ ywSV4ZtM  
if(bFirst) E$u9Jbe  
{ Y 6NoNc]h  
nFileLength = getFileSize(); UU7E+4O&  
if(nFileLength == -1) "-y 2En  
{ 96V@+I  
System.err.println("File Length is not known!"); ym\AVRO{  
} 8LI aN}  
else if(nFileLength == -2) dwH8Zg$B  
{ T9s$IS,  
System.err.println("File is not access!"); P M x`P B  
} g431+O0K1  
else \t pJ   
{ b 8vyJb,K  
for(int i=0;i<nStartPos.length;i++) -dj9(~?^  
{ ]q,5'[=~4h  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5hhiP2q  
} /*V:Lh  
for(int i=0;i<nEndPos.length-1;i++) 2s^9q9NS"  
{ gY],U4_:p  
nEndPos = nStartPos[i+1]; R*"31&3le4  
} OpNTyKbaD  
nEndPos[nEndPos.length-1] = nFileLength; |"K<   
} 1v<,nABuJ6  
} sIVVF#0}]  
cWNZ +Q8Y  
]JQ+*ZYUE  
//启动子线程 ;)6LX-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; T(GEFnt Y  
for(int i=0;i<nStartPos.length;i++) bF85T(G  
{ .=~-sj@k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qD/GYqvm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), t; 3n  
nStartPos,nEndPos,i); fXL&?~fS  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QU#u5sX A  
fileSplitterFetch.start(); iY|zv|;]=  
} Z+gG.|"k  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '8k{\>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); '7Ad:em  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^R g=*L  
nEndPos = " + nFileLength); ^| b]E  
// fileSplitterFetch[nPos.length-1].start(); [!g$|   
iXF iFsb  
z: ;ZPSn  
//等待子线程结束 +qWrm |O]  
//int count = 0; ~PTqR2x  
//是否结束while循环 gv6}GE  
boolean breakWhile = false; @]{+9m8G@  
IIZu&iZo\  
wsfN \6e  
while(!bStop) |9fvj6?Y  
{ fGwRv% $^  
write_nPos(); _mEW]9Sp  
Utility.sleep(500); 0x N1Xm0d  
breakWhile = true; W[$GB_A)  
=DL |Q  
: \{>+!`w  
for(int i=0;i<nStartPos.length;i++) =7e|e6  
{ 4!q4WQ ;  
if(!fileSplitterFetch.bDownOver) .wdWs tQ  
{ !nm[ZrS P  
breakWhile = false; I^u$H&  
break; !,SGKLs.m  
} A"Prgf eT  
} Fm{/&U^  
if(breakWhile) 4s:S_Dw  
break; @|=JXSr!KY  
O<*l"fw3  
b`9J1p.;  
//count++; ,k9@%{4 l  
//if(count>4) ,m HQ  
// siteStop(); j;BMuLTm1  
} 7U3b YU~;  
@5[9iY  
Tc3~~X   
System.err.println("文件下载结束!"); J2KULXF  
} Au=9<WB%H  
catch(Exception e){e.printStackTrace ();} Q#h*C ZT  
} `U.VfQR:  
u%s@B1j  
v M lT  
//获得文件长度 g?9IS,Gp  
public long getFileSize() \ZOH3`vq  
{ l DWg%pI+  
int nFileLength = -1; ^xNs^wC.  
try{ ,A{'lu  
URL url = new URL(siteInfoBean.getSSiteURL()); *GGiSt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I,nW~;OV0  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?*nFz0cs^  
2 1LJ3rW_  
W1$<,4j@M  
int responseCode=httpConnection.getResponseCode(); HCCEIgCT  
if(responseCode>=400) &|'t>-de,  
{ lMQ_S"  
processErrorCode(responseCode); <*Ex6/j  
return -2; //-2 represent access is error |e%o  
} &A1~x!`  
>l>;"R9N  
}|Ao@UvH  
String sHeader; 4t]YHLBS  
_Yms]QEZ  
}+m")=1{  
for(int i=1;;i++) Sc?UjEs  
{ 2~wIHtd  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3j h: K   
//Utility.log(in.readLine()); #+Pk_?  
sHeader=httpConnection.getHeaderFieldKey(i); O} &%R:  
if(sHeader!=null) nZtP!^#  
{ q!OB?03n  
if(sHeader.equals("Content-Length")) ]zt77'J  
{ {\ P`-'C  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IQm[ ,Fh  
break; Twi7g3}/jB  
} r](%9Y  
} 7<Yf  
else L3@upb  
break; %77X/%.Y  
} $*k9e^{S  
} '=V!Y$tn  
catch(IOException e){e.printStackTrace ();} rD?G7l<~>_  
catch(Exception e){e.printStackTrace ();} q!y6 K*  
:|5 \XV)>  
Rn4Bl8z'>  
Utility.log(nFileLength); jMAZ4M  
?b,x;hIO  
jfOqE*frl!  
return nFileLength; KT9!R  
} *Bm7>g6  
C@ns`Eh8w  
zT< P_l  
//保存下载信息(文件指针位置) ~Q3y3,x  
private void write_nPos() CC~:z/4,N  
{ wr~Ydmsf  
try{ *?o`90HHP[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); c?/R=/H  
output.writeInt(nStartPos.length); |n/qJIE6  
for(int i=0;i<nStartPos.length;i++) !4 =]@eFk  
{ pVa9g)+z}  
// output.writeLong(nPos); ,SQ`, C _5  
output.writeLong(fileSplitterFetch.nStartPos); ]}za  
output.writeLong(fileSplitterFetch.nEndPos); JK/VIu&!  
} }iE!( l  
output.close(); *%#Sa~iPo  
} zF([{5r[!)  
catch(IOException e){e.printStackTrace ();} q-lejVS(g  
catch(Exception e){e.printStackTrace ();} ?r}'0dW  
} YR? ujN  
bZKlQ<sI  
6]D%|R,Q#}  
//读取保存的下载信息(文件指针位置) h@H8oZ[  
private void read_nPos() iu$:_W_  
{ |ler\"Eu  
try{ ^F?}MY>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .m^L,;+2  
int nCount = input.readInt(); e%wzcn  
nStartPos = new long[nCount]; Fs}vI~}  
nEndPos = new long[nCount]; MKPw;@-  
for(int i=0;i<nStartPos.length;i++) d7 W[.M$]  
{ vhz[H  
nStartPos = input.readLong(); U%?  
nEndPos = input.readLong(); A{IJ](5.kd  
} `J v~.EF%  
input.close(); >[A7oH  
} .G~Y`0  
catch(IOException e){e.printStackTrace ();} _s%;GWj  
catch(Exception e){e.printStackTrace ();} [WXa]d5Y  
} x[dR5  
YK V?I   
Zai:?%^  
private void processErrorCode(int nErrorCode) Gp.XTz#=  
{ G< _<j}=  
System.err.println("Error Code : " + nErrorCode); Q&k1' nT5  
} -L6YLe%w  
=uil3:,[S  
&9ZrZ"]  
//停止文件下载 sPxDo?1x-  
public void siteStop() U{[ g"_+~  
{ "+{>"_KV  
bStop = true; 9ZVzIv(   
for(int i=0;i<nStartPos.length;i++) >bUxb-8  
fileSplitterFetch.splitterStop(); ,g~Iup  
Kwmtt  
m~;}8ObQE  
} R<eD)+  
} "WfVZBWG$  
//负责部分文件的抓取 5%#V>|@e#  
**FileSplitterFetch.java  nPRv.h  
*/ f[s|<U^  
package NetFox; gbvMS*KQz  
rFLm!J]  
,VYUQE>\  
import java.io.*; ^Q9;ro*;ck  
import java.net.*; ~^<1k-  
I8%Uyap{  
!$Whftg  
public class FileSplitterFetch extends Thread { ~e;2gm  
0tS < /G8  
j0q:i}/U,  
String sURL; //File URL  {Yc#XP  
long nStartPos; //File Snippet Start Position QMQ\y8E  
long nEndPos; //File Snippet End Position e{6I-5`|,#  
int nThreadID; //Thread's ID ygo4.  
boolean bDownOver = false; //Downing is over - xE%`X  
boolean bStop = false; //Stop identical 7mBH #Q)  
FileAccessI fileAccessI = null; //File Access interface g=)OcTd#  
E-v#G~  
AQU^7O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bZ-_Q  
{ HD~o]l=H  
this.sURL = sURL; L}hc|(:  
this.nStartPos = nStart; ODFCA. t  
this.nEndPos = nEnd; 5==hyIy  
nThreadID = id; DV!10NqUr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @ i*It Hk  
} pW,)yo4  
(O-.^VV  
$TZjSZ1w  
public void run() jnzOTS   
{ 9=5xt;mEs}  
while(nStartPos < nEndPos && !bStop) /!A?>#O&.  
{ f j:q>}V  
{W11+L{8  
O =gv2e  
try{ ]*v [6 +  
URL url = new URL(sURL); GC3WB4iY@U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  SCq:jI  
httpConnection.setRequestProperty("User-Agent","NetFox"); }v4T&/vt-  
String sProperty = "bytes="+nStartPos+"-"; <_>xkQbn2  
httpConnection.setRequestProperty("RANGE",sProperty); VOkSR6  
Utility.log(sProperty); Gv\:Agi  
I ]HP  
*/)O8`}2  
InputStream input = httpConnection.getInputStream(); )[np{eF.k  
//logResponseHead(httpConnection); {7Qj+e^  
yLgv<%8f  
oU)Hco"_k  
byte[] b = new byte[1024]; 5i1E 5@~  
int nRead; (,XbxDfM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VBq|j"o0"  
{ g 5@P  
nStartPos += fileAccessI.write(b,0,nRead); k esuM3  
//if(nThreadID == 1) C;\R 62'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6 6C_XT  
} 2kkqPBc_  
!L3\B_#  
wi-F@})f#  
Utility.log("Thread " + nThreadID + " is over!"); ]rS:# LK  
bDownOver = true; WvN{f*  
//nPos = fileAccessI.write (b,0,nRead); i1JVvNMQ,  
} 0?Bv zfb  
catch(Exception e){e.printStackTrace ();} {g7~e {2  
} OSY.$$IO  
} _uq[D`=  
:x[SV^fw[  
X0 ^~`g  
//打印回应的头信息 EN/r{Cm$B  
public void logResponseHead(HttpURLConnection con) mhW*rH*m  
{ }Hy4^2B  
for(int i=1;;i++) /*1p|c^  
{ #t<  
String header=con.getHeaderFieldKey(i); r0/aw  
if(header!=null) )F'r-I%Hi  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 77H"=  
Utility.log(header+" : "+con.getHeaderField(header)); :um]a70  
else .X\9vVJ  
break; z]HaE|j}S  
} 1{-yF :A  
} bR'UhPs-8;  
K:q|M?_  
Y|nC_7&Bv  
public void splitterStop() r?2J   
{ ` #; "  
bStop = true; &j?+%Y1n@  
} S~hoAl"xb/  
l}_6 _g>6  
oxNQNJ!X  
} ,lDOo+eE%:  
&2sfu0K  
?)O!(=6%'  
/* 0)]?@"j  
**FileAccess.java {NUI8AL46A  
*//文件访问(定位,写) ["WWaCcx  
package NetFox; U28frRa  
import java.io.*; "_ H 9]}Q  
tLzb*U8'1w  
:$Xvq-#$|  
public class FileAccessI implements Serializable{ Vb,'VN%   
x(7Q5Uk\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 td5! S]  
RandomAccessFile oSavedFile; ows 3%  
long nPos; (>C$8)v  
|ngv{g  
{F ',e~}s  
public FileAccessI() throws IOException #CRd@k ?  
{ ymb{rKkN3  
this("",0); m[qW)N:w  
} x5R|,bY  
_sK{qQxvM=  
pEq }b+-  
public FileAccessI(String sName,long nPos) throws IOException in7h^6?I  
{ 2" u,f  
oSavedFile = new RandomAccessFile(sName,"rw"); PW+B&7{  
this.nPos = nPos; 0]xp"xOwW  
oSavedFile.seek(nPos); |ITh2m  
} f~:wI9  
gMsB1|  
Z '~Ie~  
public synchronized int write(byte[] b,int nStart,int nLen) j:7AVnt  
{ u;9a/RI  
int n = -1; (*Z:ByA  
try{ ?T)M z q}  
oSavedFile.write(b,nStart,nLen); X16vvsjw5  
n = nLen; l#TE$d^ym  
} "t%Jj89a\  
catch(IOException e) F^CR$L& K  
{ t!\B6!Fo  
e.printStackTrace (); &3 *#h  
} Gq-~z mg  
(,D:6(R7t  
Xi0fX$-,  
return n; g(dReC  
} ;)q"X>FMZe  
-8yN6 0|  
hv*XuT/  
} r7FpR!  
"R]wPF5u  
'"T9y=9]s  
/* 8cGoo u6  
**SiteInfoBean.java Ey)ey-'\  
*/ D2I|Z  
package NetFox; 0UhJ I  
%D3Asw/5a  
Jwpc8MQ  
public class SiteInfoBean { %+oqAY m+s  
Hu+GN3`sx^  
O9rA3qv B  
private String sSiteURL; //Site's URL sGx3O i   
private String sFilePath; //Saved File's Path 5 zz">-Q !  
private String sFileName; //Saved File's Name >qZl s'  
private int nSplitter; //Count of Splited Downloading File 3)y=}jw  
06z+xxCo  
a SMoee@!  
public SiteInfoBean() c7D{^$L9 v  
{//nSplitter的缺省值为5 z9E*1B+  
//default value of nSplitter is 5 <R?S  
this("","","",5); zKT4j1 h  
} [qU`}S2  
J,J6bfR/  
CA5T3J@vAQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a n0n8l  
{ $'<FPbUtD}  
sSiteURL= sURL; }Fsr"RER@{  
sFilePath = sPath; T+oOlug  
sFileName = sName; B!U;a=ia  
this.nSplitter = nSpiltter; 5A+@xhRf  
*T~b ox  
1024L;  
} e.fxB  
&+3RsIl W  
H5*#=It  
public String getSSiteURL() 5_1\{lP  
{ biV NZdA  
return sSiteURL; FKUo^F?z  
} Bj GfUQ  
q:=jv6T#  
Dus!Ki~8(t  
public void setSSiteURL(String value)  ozKS<<  
{ Mh MXn;VKj  
sSiteURL = value; fL*+[v4  
} }<zbx*!  
+S WtHj7e  
]Ljb&*IEj  
public String getSFilePath() {< EPm&q  
{ Ze <)B *  
return sFilePath; iNc!z A4  
} Yr>0Qg],  
b1;h6AeL  
-/2B fIq  
public void setSFilePath(String value) @$iZ9x6t  
{ = 5[%%Lf  
sFilePath = value; nw_s :  
} 0f@9y  
6)BPDfU,  
o2cc3`*8d  
public String getSFileName() 7!wc'~;  
{ P- +]4\  
return sFileName; R x(yn  
} ;G[0%z+*  
;WAa4r>  
,.h@tN<C  
public void setSFileName(String value) EwmNgmYq  
{ I9m9`4BK  
sFileName = value; /;{L~f=et)  
} u-tD_UIck  
sVGQSJJ5  
0 /9 C=v  
public int getNSplitter() #c":y5:  
{ +25=u|#4r  
return nSplitter; \98N8p;,I  
} Djdd|Z+*{  
v??$z#1F3  
"Q:h[)a  
public void setNSplitter(int nCount) z`.<dNg  
{ '$eJATtC  
nSplitter = nCount; {> 8?6m-  
} Z/!awf>  
} xR8.1T?8  
c{ +bY .J  
8vtembna4  
/* ,LP^v'[V7  
**Utility.java \Rb:t}  
*/ ^do6?e`?-  
package NetFox; p w5{=bD  
k2tSgJW  
Od ^Sr4C  
public class Utility { -Sn'${2  
LAY:R{vI  
X;2LK!x;y  
public Utility() fms(_Q:R?  
{ QleVW  
ly35n`  
aC%Q.+-t  
} Jgg<u#  
l5~O}`gfh  
//线程睡眠 ml Cg&fnDB  
public static void sleep(int nSecond) 1e7I2g  
{ ek U%^R<  
try{ (9kR'kr  
Thread.sleep(nSecond); 3Pgokj   
} >\3\&[#"  
catch(Exception e) Ok|Dh;1_  
{ VIN0kRQ#  
e.printStackTrace (); bar=^V)  
} 8ZqLG a]  
} 3Zl:rYD?  
 I8`$a  
//日志 n\V7^N  
public static void log(String sMsg) /nuz_y\J  
{ ,hT.Ok={36  
System.err.println(sMsg); k`A39ln7wu  
} -%gEND-AP  
eO(U):C2  
f$n5$hJlQ  
public static void log(int sMsg) Pqw<nyC.  
{ ^6R(K'E}  
System.err.println(sMsg); U*E)y7MY  
} \G7F/$g  
} =6O*AJ  
-ucgET`  
>T c\~l  
/* s;=C&N5g  
**TestMethod.java -u4")V>  
*/ +4 Pes  
package NetFox; {7c'%e  
#^Pab^Y3r-  
EpyMc+.Ze'  
public class TestMethod { mo] l_'  
s,8zj<dUv  
tl\<:8pI"  
public TestMethod() ah_ >:x  
{ ///xx/weblogic60b2_win.exe m4m|?  
try{ %>_6&A{K,d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h.F=Fhx/1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); k4hk* 0Jq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +xU({/  
fileFetch.start(); l"1D' Hk  
} Ox&G  [  
catch(Exception e){e.printStackTrace ();} D>@NYqMF  
5oSp/M  
FKu8R%9xn%  
} ed}#S~4q  
Y&8,f|{R  
VN`fZ5*d~  
public static void main(String[] args) rQ_@q_B.  
{ 8.8t$  
new TestMethod(); # Q,EL73;  
} X<Z(,B  
} 3X11Gl  
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