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http断点续传简单实现(java)

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/* e :(7$jo  
**SiteFileFetch.java dwd5P7  
*/ z'=8U@P'#  
package NetFox; lyY\P6 X  
import java.io.*; U($bR|%D  
import java.net.*; LH7m >/LJr  
gD}lDK6N  
. V5Pr}"y  
public class SiteFileFetch extends Thread { <'n'>@  
)ry7a .39b  
US5 ]@!  
SiteInfoBean siteInfoBean = null; //文件信息Bean "DN0|%`M/  
long[] nStartPos; //开始位置 SlU?,)J}  
long[] nEndPos; //结束位置 d 8YP<"V&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MI^@p`s  
long nFileLength; //文件长度 tB S+?N  
boolean bFirst = true; //是否第一次取文件 BlwAD  
boolean bStop = false; //停止标志 +,7nsWV  
File tmpFile; //文件下载的临时信息 yx0wR  
DataOutputStream output; //输出到文件的输出流 PIk2mX/D_6  
in-|",O`Z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) tu5g> qb  
public SiteFileFetch(SiteInfoBean bean) throws IOException " pg5w  
{ ~e|RVY,  
siteInfoBean = bean; }W2FF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;Gc,-BDFw  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /g/]Q^  
if(tmpFile.exists ()) |/^ KFY"  
{ S2y_5XJ<D  
bFirst = false; tx` Z?K[  
read_nPos(); w)C/EHF  
} @c;XwU]2t  
else 0m2%ucKw  
{ m*bTELb  
nStartPos = new long[bean.getNSplitter()]; / thFs4  
nEndPos = new long[bean.getNSplitter()]; 1SAO6Wh  
} C{{RU7iqc&  
EM2=g9y  
,> Ya%;h2k  
A9 *P7  
} :.DZ~I  
2:5Go  
]|m?pt  
public void run() nXU`^<nA  
{ u[:-^H  
//获得文件长度 `T'[H/  
//分割文件 t=l@(%O 0_  
//实例FileSplitterFetch Wi U-syNh  
//启动FileSplitterFetch线程 0r_3:#Nn  
//等待子线程返回 (YV]T!q  
try{ qjr:(x/  
if(bFirst) scc+r  
{ 84f(BE  
nFileLength = getFileSize(); d/"%fpp^0G  
if(nFileLength == -1) XE#a#  
{ plNoI1st  
System.err.println("File Length is not known!"); 8}M-b6R V  
} MnL o{G]  
else if(nFileLength == -2) *x!j:/S`n  
{ B~ ?R 6  
System.err.println("File is not access!"); h5)4Z^n  
} t.rlC5 k  
else XY`{F.2h  
{ XWq`MwC9  
for(int i=0;i<nStartPos.length;i++) }H Ct=W`  
{ EpW89X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5'<J@3B  
} I]@QhCm0  
for(int i=0;i<nEndPos.length-1;i++) "lV bla4b  
{  .u3;  
nEndPos = nStartPos[i+1]; po! [Nd&"  
} u Vth&4dh9  
nEndPos[nEndPos.length-1] = nFileLength; QbJE+m5  
} }j)][{i*x  
} R+*-i+]Q#7  
R@df~  
uv|RpIve:  
//启动子线程 sB@9L L]&|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Nf5zQ@o_y  
for(int i=0;i<nStartPos.length;i++) i}L*PCP  
{ $x/VO\Z{-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A3Xfu$[u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <B Vx%  
nStartPos,nEndPos,i); Hg~8Td**  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >qy$W4  
fileSplitterFetch.start(); j'uzjs[  
} qV#,]mX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cy64xR BB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qef5eih  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M7fPaJKL  
nEndPos = " + nFileLength); IKrojK8-?  
// fileSplitterFetch[nPos.length-1].start(); Y1wH_!%b  
%ONU0xtqk  
J4]tT pu"K  
//等待子线程结束 !59,<N1Iu  
//int count = 0; Q<Q?#v7NX  
//是否结束while循环 0 wjL=]X1e  
boolean breakWhile = false; eemC;JV%  
5oe{i/#di  
F2>W{-H+  
while(!bStop) .~a.mT  
{ < ZG!w^  
write_nPos(); \nUJ)w  
Utility.sleep(500); >:bXw#w]  
breakWhile = true; TVZf@U  
+<T361eyY  
<CcSChCg  
for(int i=0;i<nStartPos.length;i++) s7(1|}jh  
{ v =_Ds<6n  
if(!fileSplitterFetch.bDownOver) en"\2+{Cg  
{ }U^iVq*  
breakWhile = false; Xf;_r+;  
break; mwMcAUD]2  
} ,`ba?O?*G  
} ?>1wZ  
if(breakWhile) 6T5\zInd  
break; #z61 I"kU  
2U`!0~pod  
^v&"{2  
//count++; Nh01NY;  
//if(count>4) rA|&G'  
// siteStop(); '};mBW4z  
} \Ez&?yb/  
'=+gwe M  
M4n0GWHLy  
System.err.println("文件下载结束!"); Cb6K!5[q]  
} U]&/F{3 im  
catch(Exception e){e.printStackTrace ();} Mn 8| K nh  
} 0Q~\1D 9g  
Gs>4/  
!<<wI'8  
//获得文件长度 Jsa;pG=3&  
public long getFileSize() \bies1TBB^  
{ 3T /_#=9TV  
int nFileLength = -1; ,T-xuNYC  
try{ 6s t^-L  
URL url = new URL(siteInfoBean.getSSiteURL()); !y862oKD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t9.| i H  
httpConnection.setRequestProperty("User-Agent","NetFox"); (+nnX7V?I  
w5vzj%6i  
DH"_.j  
int responseCode=httpConnection.getResponseCode(); 3fUiYI|&7  
if(responseCode>=400) ~ Zw37C9J  
{ y\n#`*5k  
processErrorCode(responseCode); "[sr0'g:  
return -2; //-2 represent access is error g^{a;=  
} )m I i.  
l\TL=8u2c  
Q yhu=_&  
String sHeader; T5-Yqz  
pI1g<pe  
!ZM*)6^  
for(int i=1;;i++) y~z&8XrH  
{ g77:92  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .dn#TtQv  
//Utility.log(in.readLine()); [M#(su0fv  
sHeader=httpConnection.getHeaderFieldKey(i); )=!|^M  
if(sHeader!=null) y,6KU$G  
{ >x]ir  
if(sHeader.equals("Content-Length")) ~"Su2{"8B  
{ L/)eNZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N+vsQ!Qz  
break; z2jS(N?J1  
} xxG>Leml  
} L=5Y^f'aU  
else xg4wtfAbS  
break; )Wk&c8|y  
} hbSKlb0d  
} Of-8n-  
catch(IOException e){e.printStackTrace ();} EgRuB@lw76  
catch(Exception e){e.printStackTrace ();} h(i_'P?  
8g?2( MT;  
s~A:*2\  
Utility.log(nFileLength); F5+!Gb En  
+1K= ]#a  
!FQS9SoO9  
return nFileLength; \1eWI  
} dFZh1*1  
z"*3p8N  
_y:a Pn  
//保存下载信息(文件指针位置) \okvL2:!  
private void write_nPos() Z ?ATWCa  
{ IH"_6s#$&  
try{ uM[[skc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9Qq%Fw_  
output.writeInt(nStartPos.length); Icx)+Mq  
for(int i=0;i<nStartPos.length;i++) ;,Os3  
{ "2:#bXM-  
// output.writeLong(nPos); q8& ^E.K  
output.writeLong(fileSplitterFetch.nStartPos); N_p^DP   
output.writeLong(fileSplitterFetch.nEndPos); 8\bZ?n#dn  
} Gb.}af#v  
output.close(); ^Yo2R  
} ")u)AQ  
catch(IOException e){e.printStackTrace ();} u&'&E   
catch(Exception e){e.printStackTrace ();} KcM+ 8W\  
} a fB?js6  
T^g i^{  
Q) iN_|  
//读取保存的下载信息(文件指针位置) GXR7Ug}k  
private void read_nPos() \,G19o}`Es  
{ '<h@h*R  
try{ -AXMT3p=1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]_hXg*?  
int nCount = input.readInt(); s5ILl wr  
nStartPos = new long[nCount]; F~3 &@TWi  
nEndPos = new long[nCount]; m@yx6[E#  
for(int i=0;i<nStartPos.length;i++) {sUc2vR  
{ 7 .xejz  
nStartPos = input.readLong(); ,%KMi-w]q,  
nEndPos = input.readLong(); YVO~0bX:  
} ah!fQLMH  
input.close(); /4 .]L~  
} _<jccQ  
catch(IOException e){e.printStackTrace ();} Mvk#$:8e  
catch(Exception e){e.printStackTrace ();} %p};Di[V  
} !^3j9<|@'  
Y|<1|wGG  
;_1 >nXh  
private void processErrorCode(int nErrorCode) [[Usrbf  
{ c#pVN](?  
System.err.println("Error Code : " + nErrorCode); gWy2E;"a  
} ScC!?rTW~7  
{\kDu#18Ld  
xKoNo^FF  
//停止文件下载 {6*{P!H  
public void siteStop() Of{'A  
{ w&}UgtEm  
bStop = true; 7P D D  
for(int i=0;i<nStartPos.length;i++) ^j'vM\^`ml  
fileSplitterFetch.splitterStop(); ntF#x.1Pm  
[~ |e:  
gR{.0e  
} q?oJ=]m"  
} g%d&>y?1r  
//负责部分文件的抓取 "Oy&6rrr  
**FileSplitterFetch.java dYhLk2  
*/ mWU*}-M  
package NetFox; Q$2^m(?;  
|)Sx"B)  
tA9(N>[ *  
import java.io.*; +,}CuF  
import java.net.*; >V3pYRA   
2 Xc,c*r  
i{ 2rQy+  
public class FileSplitterFetch extends Thread { ++0xa%:  
EB>rY  
?T:$:IHw  
String sURL; //File URL [>f4&yY  
long nStartPos; //File Snippet Start Position @0rwvyE=+3  
long nEndPos; //File Snippet End Position !O#NP!   
int nThreadID; //Thread's ID 9rQpKq:# E  
boolean bDownOver = false; //Downing is over [u`9R<>c"U  
boolean bStop = false; //Stop identical FZtILlw  
FileAccessI fileAccessI = null; //File Access interface cH$Sk  
_:9-x;0H2  
"zN]gz=OV>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )IZ~!N|-w  
{ [es-&X07<  
this.sURL = sURL; yO0 9NQ 5u  
this.nStartPos = nStart; s)|l-I  
this.nEndPos = nEnd; O:G-I$F|  
nThreadID = id; !yX4#J(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;hp?wb  
} ppM^&6x^  
'^.}5be&  
y'pX/5R0  
public void run() #oD * H:%*  
{ ^k}jPc6  
while(nStartPos < nEndPos && !bStop) }[I|oV5*+&  
{ ^<O:`c6_  
& pS5_x  
{!vz 6QDS  
try{ Fu !sw]6xx  
URL url = new URL(sURL); CI6qDh6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cX/ ["AM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Qws#v}xF  
String sProperty = "bytes="+nStartPos+"-"; k`Ifd:V.y  
httpConnection.setRequestProperty("RANGE",sProperty); G!IJ#|D:~  
Utility.log(sProperty); (1b%);L7  
R?[KK<sWWe  
c{t(),nAA  
InputStream input = httpConnection.getInputStream();  ~WG#Zci-  
//logResponseHead(httpConnection); p![CH  
Y+I`XeY  
ssC5YtF7X  
byte[] b = new byte[1024]; tmI2BBv  
int nRead; ocT.2/~d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) l~Sn`%PgA  
{ sGD b<  
nStartPos += fileAccessI.write(b,0,nRead); UZ+FV;<  
//if(nThreadID == 1) Bx32pY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JMq00_  
} f<0nj?  
~8G<Nw4*\  
L3- tD67oa  
Utility.log("Thread " + nThreadID + " is over!"); o$DJL11E  
bDownOver = true; oLp:Z=  
//nPos = fileAccessI.write (b,0,nRead); X`k[ J6  
} u)fmXoQ  
catch(Exception e){e.printStackTrace ();} !]k$a  
} K r&HT,>B  
} i3} ^j?jA2  
]gQ4qu5  
5:H9B  
//打印回应的头信息 ?pv}~>  
public void logResponseHead(HttpURLConnection con) DHV#PLbN$  
{ fw1g;;E  
for(int i=1;;i++) L_YVe(dT  
{ K}U}h>N  
String header=con.getHeaderFieldKey(i); bh1WD_  
if(header!=null) W@x UR-}51  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @"#W\m8  
Utility.log(header+" : "+con.getHeaderField(header)); 6"W~%FSJX  
else 43Yav+G(+  
break; 'L2M  W  
} }$ Am;%?p  
} :d<;h:^_  
Dyj5a($9"{  
\5_7!.  
public void splitterStop() &@xixbg  
{ U/oncC5  
bStop = true; mu/O\'5  
} ArUGa(; f  
WoiK _Ud  
Hs+VA$$*  
} "oYyeT ,?  
)[>b7K$f  
8 ]N+V:  
/* B{SzC=4f}  
**FileAccess.java RYaf{i`  
*//文件访问(定位,写) 8JUUK(&Z  
package NetFox; V(Ps6jR"BS  
import java.io.*; rQbL86+  
t,.MtU>K@  
n@xDFa  
public class FileAccessI implements Serializable{ j#b?P=|l  
:hG?} [-2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'Z+~G  
RandomAccessFile oSavedFile; z2&SZ.mk  
long nPos; +?~'K&@  
u4=j!Zb8}  
e1X*}OI  
public FileAccessI() throws IOException z1ltc{~Z  
{ }06  
this("",0); M ,8r{[2  
} H85HL-{  
x(z[S$6Y\  
~3.1. 'A  
public FileAccessI(String sName,long nPos) throws IOException I#kK! m1Q  
{ *Ri?mEv hF  
oSavedFile = new RandomAccessFile(sName,"rw"); 0EYK3<k9!  
this.nPos = nPos; S ; x;FU  
oSavedFile.seek(nPos); dm&F1NkT  
} 9LGJ-gL  
0!rU,74I=  
H'$g!Pg  
public synchronized int write(byte[] b,int nStart,int nLen)  XGEAcN  
{ !p1OBS|  
int n = -1; h@T}WZv  
try{ 7{ :| )  
oSavedFile.write(b,nStart,nLen); RR><so%  
n = nLen; J56+eC(  
} B3'qmi<  
catch(IOException e) uRQm.8b  
{ u7&r'rZ1_!  
e.printStackTrace (); U6 "U^  
} tgDmHxB]0  
9/RbfV[)  
SM5i3EcFYP  
return n; UcDJ%vI  
} [K[tL|EK  
~<3qsA..  
4em7PmT  
} vfJ}t#%UH  
 pFGK-J  
k'wF+>  
/* S'HM|&  
**SiteInfoBean.java O9]j$,i  
*/ _$By c(.c  
package NetFox; Wy,DA^\ef  
"TKf" zc  
zGu(y@o  
public class SiteInfoBean { gqJ&Q t#f  
%FQMB  
%lV&QQa  
private String sSiteURL; //Site's URL %L{H_;z  
private String sFilePath; //Saved File's Path j_\sdH*r  
private String sFileName; //Saved File's Name 'bkecC  
private int nSplitter; //Count of Splited Downloading File {SW104nb&#  
|,5b[Y"Dt  
4-=>># P  
public SiteInfoBean() \w^iSK-  
{//nSplitter的缺省值为5 t-lWvxXe  
//default value of nSplitter is 5 %$I\\q q>{  
this("","","",5); 7C ABM  
} }3Pz{{B&+O  
;'dw`)~jQ  
X(1nAeQ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s'ntf  
{ T.!GEUQ  
sSiteURL= sURL; N- ?U2V  
sFilePath = sPath; 3`J?as@^8  
sFileName = sName; hyL3fkMJ,  
this.nSplitter = nSpiltter; n w @cAv  
|v}"UW(y  
,m!j2H}8  
} R* E/E  
H]Q Z4(  
._=Pa)T  
public String getSSiteURL() 6 EE7<&  
{ [Zl  
return sSiteURL; Et%s,zeA{2  
} x'; 6  
<[?oP[ j  
9C$b^wHd  
public void setSSiteURL(String value) OAR1u}  
{ _+%-WFS|  
sSiteURL = value; xg'z_W  
} ME1lQ7E4B  
"4H&wHhT!  
3ZU`}  
public String getSFilePath() Z~~{!C+G  
{ +e%9P%[+  
return sFilePath; Tm_AoZH  
} xqO'FQO%  
RERum  
zVZZdG~8  
public void setSFilePath(String value) hv}rA,Yd  
{ #wNksh/J^  
sFilePath = value; q*Yh_IT.I  
} AASw^A3p  
z* YkD"]B  
AR]y p{NS  
public String getSFileName() II)\rVP5  
{ PLKp<kg  
return sFileName; IBf&'/ 8\  
} rv&(yA  
S$+vRX7  
,4jkTQ*@2  
public void setSFileName(String value) wZh&w<l'  
{ %(Nu"3|$K=  
sFileName = value; ._~_OVU  
} (X,Ua+{  
za1MSR  
vO%n~l=  
public int getNSplitter() p8oOm>B96n  
{ .rD@Q{e50  
return nSplitter; jB:$+k|~.  
} *&+e2itmp  
5iz]3]}%  
IBcCbNs!  
public void setNSplitter(int nCount) ~{0:`)2FQ  
{ a:Y6yg%1>  
nSplitter = nCount; \kvd;T#t6  
} rm;'/l8Y-E  
} VThcG( NF  
uo_Y"QiKEH  
L|qQZ=  
/* Tw)nFr8oF]  
**Utility.java `Ff3H$_*  
*/ KIC5U50J  
package NetFox; ~_QZiuq&  
UQaLhK v:  
~urIA/  
public class Utility { 2#kR1rJP  
dd@^e)VZB  
93XTumpV  
public Utility() &v Lz{  
{ ,icgne1j  
mFjX  
,fpu@@2  
} e ,/I}W  
u&/q7EBfP  
//线程睡眠 l{>fma]7  
public static void sleep(int nSecond) Uy5IvG;O+  
{ =zDU!< U  
try{ @ JZ I  
Thread.sleep(nSecond); ?FVX &{{V  
} w>p0ldi  
catch(Exception e) @v ss:'l  
{ \6-x~%xK  
e.printStackTrace (); -GD_xk  
} AMG}'P:  
} ^I~2t|}  
|Up+Kc:z/n  
//日志 3xxQL,FV  
public static void log(String sMsg) pzbR.L}'D  
{ 8V>j-C  
System.err.println(sMsg); .mn`/4  
} NKvBNf|D  
dFS>uIT7X  
+(x^5~QX  
public static void log(int sMsg) !jN}n)FSq  
{ <|c n Qj*  
System.err.println(sMsg); mM!'~{r[-  
} jGl8y!aM  
} U s86.@|  
}&I\a  
]>E*s3h  
/* PUV)w\!&is  
**TestMethod.java uM h[Ht^.  
*/ V%8?f,  
package NetFox; NZdjS9  
J 05@SG':  
a|SgGtBtT4  
public class TestMethod { .+MJ' bW  
<+o-{{E[  
jl;_lcO  
public TestMethod() rL3<r  
{ ///xx/weblogic60b2_win.exe mEfI2P)#|  
try{ /vll*}}  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1 0lvhzU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5ppOG_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'MRvH lCM  
fileFetch.start(); $}_N379&  
} G# gUd'=M  
catch(Exception e){e.printStackTrace ();} f]`#BE)V  
 n0F.Um  
FRd!UqMXY  
} (+6 8s9XS7  
C93BK)$}  
Xf!@uS6<X  
public static void main(String[] args) J( JsfU4  
{ G3'>KMa.  
new TestMethod(); ?YWfoH4mS  
} , (dg]7  
} bO 2>ced  
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