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http断点续传简单实现(java)

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/* &66-0d+Sh  
**SiteFileFetch.java "#Qqwsw7  
*/ ;~CAHn|Fe  
package NetFox; ve|ig]$5g<  
import java.io.*; `!V=~"ve  
import java.net.*; J$Uj@M  
{ }Q!./5  
(v+nn1,  
public class SiteFileFetch extends Thread { 5 Yj qN  
k]K][[s`  
%Bn"/0,  
SiteInfoBean siteInfoBean = null; //文件信息Bean jrJ!A(<)  
long[] nStartPos; //开始位置 }TfZ7~o[  
long[] nEndPos; //结束位置 `=TV4h4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P_6JweN  
long nFileLength; //文件长度 L?:.8k`d  
boolean bFirst = true; //是否第一次取文件 cih[A2lp  
boolean bStop = false; //停止标志 Q"rQVO  
File tmpFile; //文件下载的临时信息 PWUS@I  
DataOutputStream output; //输出到文件的输出流 zmaf@T  
m3[R   
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T rK-XTev  
public SiteFileFetch(SiteInfoBean bean) throws IOException /&1FgSARK  
{ k;BXt:jDq  
siteInfoBean = bean; Z'=:Bo{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); PggjuPPh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [[ {L#  
if(tmpFile.exists ()) t,H=;U#  
{ jMFLd  
bFirst = false; G)5R iRcs  
read_nPos(); sKD sps^$  
} d7(g=JK<  
else uknX py))  
{ &gGh%:`B  
nStartPos = new long[bean.getNSplitter()]; 0G?*i_u\  
nEndPos = new long[bean.getNSplitter()]; +h*-9  
} EH1GdlhA  
iR(=< >  
:qlcN@_  
tAPn? d5  
} GS_+KR\  
tE=;V) %we  
)w/ #T  
public void run() 3(&f!<Uy  
{ <cig^B{nX  
//获得文件长度 _TLB1T^/4  
//分割文件 ArK%?*`5  
//实例FileSplitterFetch *BdKQ/Dk  
//启动FileSplitterFetch线程 f%ThS42  
//等待子线程返回 y@GqAN'DK[  
try{ L?h'^*F H}  
if(bFirst) }(MI}o}  
{ #^FDG1=  
nFileLength = getFileSize();  Q6qIx=c4  
if(nFileLength == -1) {"e)Jj_=  
{ V7~tIhuJH  
System.err.println("File Length is not known!"); =o_Ua^mr  
} ;YGCsLT<xt  
else if(nFileLength == -2) RV@'$`Q  
{ ,76xa%k(U|  
System.err.println("File is not access!"); L'A9TW2  
} kfc5ra>&  
else `|rF^~6(dR  
{ zv.R~lMtY  
for(int i=0;i<nStartPos.length;i++) $tm%=g^  
{ @}{lp'8FYi  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fGtYvl O-5  
} M0) q  
for(int i=0;i<nEndPos.length-1;i++) T5<851rH  
{ ue8"_N  
nEndPos = nStartPos[i+1]; PAYS~MnV@3  
} ctk~}( 1#  
nEndPos[nEndPos.length-1] = nFileLength; Sj(5xa[  
} ]0dj##5tJ  
} ]wxjd l  
azBYh*s=5{  
.dwy+BzS  
//启动子线程 e #!YdXSx  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GBg~NkC7.  
for(int i=0;i<nStartPos.length;i++) C srxi'Pe  
{ NpPuh9e{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j-$F@p_2F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `>1XL2  
nStartPos,nEndPos,i); \img   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'r 0kX||  
fileSplitterFetch.start(); NB^+Hcb$  
} ojva~mnFf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +`RQ ^9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3u,CI!  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _Jt  
nEndPos = " + nFileLength); Ea,L04K  
// fileSplitterFetch[nPos.length-1].start(); -xVp}RLT  
-Z(='A  
P$7i>(?(  
//等待子线程结束 )hy(0 D  
//int count = 0; w,)O*1't  
//是否结束while循环 d!P3<:+R[  
boolean breakWhile = false; 1-=ZIHW  
KkJrh@lk  
wJAJ /  
while(!bStop) *DUP$@}k  
{ =:"wU  
write_nPos(); gVscdg5  
Utility.sleep(500); :w,#RcW  
breakWhile = true; my]t[%Q{  
WeiDg,]e$b  
}mdk+IEt  
for(int i=0;i<nStartPos.length;i++) })F.Tjf*  
{ fw3P?_4;*  
if(!fileSplitterFetch.bDownOver) ) Vf!U"  
{ G4;5$YGG  
breakWhile = false; a\l?7Jr  
break; e0z(l/UB  
} 1=@csO_yn  
} 2 ":W^P  
if(breakWhile) 3 BQZ[%0@  
break; ?se\?q  
zB68%  
JYw_Z*L=m  
//count++; b4?]/Uy+/  
//if(count>4) ^:cc3wt'3[  
// siteStop(); I<+i87=  
} /?Y]wY  
|MMaaW^"  
;@<Rh^g]  
System.err.println("文件下载结束!"); rNN ,!  
} t9eEcq Mg  
catch(Exception e){e.printStackTrace ();} H.)Y*zK0.  
} % B^BN|r  
T B(K&3_D  
dJ(<zz+;b  
//获得文件长度 ]8+ D  
public long getFileSize() <L'6CBbP  
{ Q)[DSM  
int nFileLength = -1; qokCVI-\  
try{ ]tx/t^&/\u  
URL url = new URL(siteInfoBean.getSSiteURL()); YAP,#a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HD_ #-M  
httpConnection.setRequestProperty("User-Agent","NetFox"); : *8t,f~s^  
Y/<`C  
(Go1@;5I  
int responseCode=httpConnection.getResponseCode(); 3j7Na#<tL3  
if(responseCode>=400) @#QaaR;4  
{ `e[>S  
processErrorCode(responseCode); 7R7e3p,K  
return -2; //-2 represent access is error :*I=' M9B  
} 3C gmZ7[  
1:;S6{oQ  
1smKU9B2)  
String sHeader; BVzMgn;  
<~teD[1k"  
_Kwp8_kTr  
for(int i=1;;i++) ]|_UpP8EP  
{ =/e$Rp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +~n4</  
//Utility.log(in.readLine()); :|a$[g5  
sHeader=httpConnection.getHeaderFieldKey(i); cH:9@>'$a  
if(sHeader!=null) Qf($F,)K  
{ gwyX%9  
if(sHeader.equals("Content-Length")) - !QVM\t  
{ ;DgQ8"f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =Cc]ugl7-  
break; (91 YHhk{  
} "lRxatM  
} e'|IRhr  
else \C<'2KZR,  
break; {|B 2$1':  
} S| |OSxZ  
} $d*PY_  
catch(IOException e){e.printStackTrace ();} j8)rz  
catch(Exception e){e.printStackTrace ();} xnOd$]  
aQ*?L l  
| Di7 ,$c  
Utility.log(nFileLength); y>>)Yo&|  
*cP(3n3]R  
Aa+<4 R  
return nFileLength; kx,3[qe'S  
} 37 b6w6{D  
5t,X;  
i`}!<{k  
//保存下载信息(文件指针位置) WBWIHv{j  
private void write_nPos() 8?hZ5QvA(j  
{ 8?N![D\@  
try{ QlMv_|`9  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K=1prv2  
output.writeInt(nStartPos.length); s`en8%  
for(int i=0;i<nStartPos.length;i++) ]E $bK  
{ watTV\b  
// output.writeLong(nPos); Vg~10Q  
output.writeLong(fileSplitterFetch.nStartPos); '{w[).c.  
output.writeLong(fileSplitterFetch.nEndPos); k=4C"   
} l5nm.i<M  
output.close(); zF@[S  
} qVW3oj<2  
catch(IOException e){e.printStackTrace ();} WK5B8u*<  
catch(Exception e){e.printStackTrace ();} lhX4 MB"  
} >dJ[1s]  
4_-L1WH  
LP'~7FG  
//读取保存的下载信息(文件指针位置) RiZ)#0  
private void read_nPos() 22/"0=2g  
{ c_T+T/O  
try{ DQ@M?~1hp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EXsVZg"#  
int nCount = input.readInt(); 'cqY-64CJZ  
nStartPos = new long[nCount]; SLz;5%CPV  
nEndPos = new long[nCount]; &2nICAN[  
for(int i=0;i<nStartPos.length;i++) L[^.pO  
{ sI6I5  
nStartPos = input.readLong(); 7+;.Q  
nEndPos = input.readLong(); M8R/a[ -A  
} "R\D:Olb#  
input.close(); 8g {;o 7  
} 'p[*2J"K4  
catch(IOException e){e.printStackTrace ();} <v!jS=T  
catch(Exception e){e.printStackTrace ();}  7LB%7~{<  
} jx}7/  
XAN.Plk  
{:#c1d2@8  
private void processErrorCode(int nErrorCode) s"5nfl  
{ p fR~?jYzm  
System.err.println("Error Code : " + nErrorCode); Lvrflx*Q  
} 2 sj: &][R  
mU]pK5  
RivhEc1h%  
//停止文件下载 ?{P$|:ha  
public void siteStop() 'Ck:=V%}g  
{ FX!Qd&kl1  
bStop = true; m@']%X*(,  
for(int i=0;i<nStartPos.length;i++) ?<rZ9$  
fileSplitterFetch.splitterStop(); T$sm}=  
a ?\:,5=  
H43d[@h  
} Z<*"sFpAO  
} /9,y+"0SQz  
//负责部分文件的抓取 J!}\v=Rn  
**FileSplitterFetch.java :`>tCYy;  
*/ d@tf+_Ih  
package NetFox; +6x}yc:yd  
SkmKf~v  
*zMt/d*<&  
import java.io.*; Jp c %i8  
import java.net.*; Jl1\*1"  
n5#QQk2  
hj\A-Yf  
public class FileSplitterFetch extends Thread { bYmk5fpRG  
pgs<Mo$\%B  
T7-yZSw -m  
String sURL; //File URL Dw>)\\n{Kl  
long nStartPos; //File Snippet Start Position SW5n?Qj3-  
long nEndPos; //File Snippet End Position >[&ser  
int nThreadID; //Thread's ID d)0|Q  
boolean bDownOver = false; //Downing is over )%<,JD  
boolean bStop = false; //Stop identical gD;T"^S+  
FileAccessI fileAccessI = null; //File Access interface bM2x (E\O  
96S$Y~G# &  
!K+hXQE1  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1h#/8 X  
{ HA0F'k  
this.sURL = sURL; 7j HrLsB  
this.nStartPos = nStart; :9e4(7~ona  
this.nEndPos = nEnd; ?mF:L"i  
nThreadID = id; @NL37C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1!yd(p=cL  
} )3O#T$h  
1]Cd fj6@  
z "z  
public void run() Mf !S'\  
{ f@q.kD21  
while(nStartPos < nEndPos && !bStop) o2;Eti  
{ i'10qWz  
Hy -)yR  
~Ye nH  
try{ TRJTJM_k  
URL url = new URL(sURL); M`7[hr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,Vl2U"   
httpConnection.setRequestProperty("User-Agent","NetFox"); )L7[;(gQ  
String sProperty = "bytes="+nStartPos+"-"; @ 'c(q=K;  
httpConnection.setRequestProperty("RANGE",sProperty); 2jlz#Sk  
Utility.log(sProperty); ;$8ptB.  
-d thY(8  
h6bvUI+|h  
InputStream input = httpConnection.getInputStream(); "a(e2H2&T4  
//logResponseHead(httpConnection); (zxL!ZR<  
N<<O(r  
q(csZ\e=  
byte[] b = new byte[1024]; RCi8{~rIvS  
int nRead; 4"\x#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @BPQ >  
{ O S#RCN*  
nStartPos += fileAccessI.write(b,0,nRead);  w%::~]  
//if(nThreadID == 1) Aar]eY\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ThkCKM  
} &gW<v\6,  
kd_! S[  
!T2{xmHKv$  
Utility.log("Thread " + nThreadID + " is over!"); $5\!ws<cZ  
bDownOver = true; {=,G>p  
//nPos = fileAccessI.write (b,0,nRead); ! &cfX/y8  
} [k75+#'  
catch(Exception e){e.printStackTrace ();} =M9R~J!  
} 0l/7JH_@V  
} ? * r  
.tHjGx  
`z.sWF|f!O  
//打印回应的头信息 >DbG )0|  
public void logResponseHead(HttpURLConnection con) 2^"! p;WQ  
{ kw} E0uY  
for(int i=1;;i++) j+S&5C/{  
{  *M$mAy<  
String header=con.getHeaderFieldKey(i); ^hr # 1  
if(header!=null) Ui-Y `  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4=`1C-v?q  
Utility.log(header+" : "+con.getHeaderField(header)); X$G:3uoN  
else r\}?HS06  
break; etUfdZ  
} Pa#Jwo  
} X}5"ZLa7l  
Yakrsi/jV}  
XH0o8\.  
public void splitterStop() y|i(~  
{ r_FI5f  
bStop = true; u~ VXe  
}  Hyenn  
q&O9W?E8dG  
8G2QI4  
} M+^ NF\  
8zcS h/  
f`K#=_Kq7  
/* `:R9M+ OX  
**FileAccess.java ,_/\pX0  
*//文件访问(定位,写) O2yD{i#l*#  
package NetFox; wDSwcNS  
import java.io.*; v-^<,|vm2f  
VKw.g@BY  
XR p60i6f  
public class FileAccessI implements Serializable{ lqgR4  !  
2^75|Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 TKbfZw  
RandomAccessFile oSavedFile; Tr4\ `a-i  
long nPos; Yt{Z+.;9OI  
5\O&pz@D  
{5HQ=&  
public FileAccessI() throws IOException g z uWhQo  
{ "pcr-?L  
this("",0); :8hXkQ  
} &j/,8 Z*  
&~x|w6M]J  
1}SON4U  
public FileAccessI(String sName,long nPos) throws IOException Snn4RB<(  
{ 3u 7A(  
oSavedFile = new RandomAccessFile(sName,"rw"); j|qdf3^f  
this.nPos = nPos; U#sv.r/L}3  
oSavedFile.seek(nPos); 69Z`mR  
} 7l09  
^^24a_+2  
{zc*yV\  
public synchronized int write(byte[] b,int nStart,int nLen) 0F6@aQ\y3  
{ |Q@(<'8=  
int n = -1; ftRdK>a D  
try{ =Lb(N61  
oSavedFile.write(b,nStart,nLen); /UY'E<wBx  
n = nLen; BT^=p  
} V\Y, 4&bI  
catch(IOException e) UF\k0oLz  
{ EM1HwapD  
e.printStackTrace (); D8xE"6T>  
} Fo5UG2E&  
ACFEM9 [=  
F9(jx#J~t  
return n; !}c\u  
} a*_&[  
O-pH~E  
|5q,%9_  
} D vN0h(?  
paYS< 8In  
G9#3 |B-?  
/* vXSA_" 0t  
**SiteInfoBean.java QW_v\GHx  
*/ mq(K_  
package NetFox; "jq6FT)O  
Sht3\cJ8  
G=CP17&h6  
public class SiteInfoBean { !c0x^,iE  
.<YfnW5/K  
3RD+;^}q 3  
private String sSiteURL; //Site's URL {A%&D^o)  
private String sFilePath; //Saved File's Path u@+^lRGFh  
private String sFileName; //Saved File's Name hOs~/bM  
private int nSplitter; //Count of Splited Downloading File .)1u0 (?  
{}gL*2:EW$  
*IF ~ab2  
public SiteInfoBean() $RHw6*COG  
{//nSplitter的缺省值为5 7C_U:x  
//default value of nSplitter is 5 Dr(;A>?qG  
this("","","",5); Ra^c5hP:.E  
} ycEp,V;[Z  
:9q|<[Y^  
LW/> %  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ' ~z`kah  
{ 1-<?EOYaE  
sSiteURL= sURL; !wKNYe  
sFilePath = sPath; jd "YaZOQ  
sFileName = sName; :; La V  
this.nSplitter = nSpiltter; !>+m46A  
p^p1{%=  
hu}uc&N)iE  
} &t'P>6)  
ymR AQVv  
)U0I|dx  
public String getSSiteURL() 5l(@p7_+  
{ 7E?60^Tve  
return sSiteURL; -:Juxh  
} D*_. 4I  
/R( .7N  
\ 9sJ`,T?  
public void setSSiteURL(String value) NjdDImz.;s  
{ hsQ*ozv[)  
sSiteURL = value; {t:*Xu  
} MQy,[y7I  
EIg:@o&Jj  
k^s7s{  
public String getSFilePath() & ##JZ  
{ Z^KWYe'w  
return sFilePath; YPw=iF]  
} %T;VS-f  
|+<o(Q(  
[W dxMU  
public void setSFilePath(String value) c.>OpsF  
{ S6_dmTV*  
sFilePath = value; 0nR_I^  
} <4;L& 3  
8lCo\T5"  
vv`53 Pbw)  
public String getSFileName() ;jlI>;C;V  
{ 2e({%P@2?  
return sFileName; #,!/Cnqis  
} !Pd)  
u 1Wixjd|  
H~0B5Hl!F  
public void setSFileName(String value) t-]~^s  
{ xp\6,Jyh  
sFileName = value; h<!!r  
} !\\1#:*_W  
3Z%jx#  
WxtB:7J  
public int getNSplitter() K#y CZ2  
{ WtMDHfwqu\  
return nSplitter; d#I; e  
} 8Urj;KkD  
S;nlC  
^Uik{x  
public void setNSplitter(int nCount) C33RXt$X  
{ ZM57(D  
nSplitter = nCount; 0!1cHB/c  
} ;PMy9H  
} 7q#R,\  
n3s  
U {9yfy  
/* 88DMD"$B  
**Utility.java gy5R"_MU  
*/ &Z7NF|  
package NetFox; !Bhs8eGr3  
bp P3#~ K  
-{$L`{|G  
public class Utility { 9t&m\J >8;  
Qf}}/k|)k  
g'.(te |  
public Utility() -&np/tEu&  
{ (.g?|c  
OX{2@+f#  
^4a|gc  
} h)X"<a++N  
X`k#/~+0  
//线程睡眠 OkQtM nq  
public static void sleep(int nSecond) oUN;u*  
{ 1@^*tffL:  
try{ a0&R! E;  
Thread.sleep(nSecond); b5^-q c6X  
} ;k,#o!>  
catch(Exception e) IvB)d}p  
{ 5VE9DTE  
e.printStackTrace (); A_|X54}w&  
} Twk,R. O  
} \U HI%1^  
xG,L*3c{o  
//日志 OH`|aqN  
public static void log(String sMsg) zj#8@gbh+  
{ c7 O$< F  
System.err.println(sMsg); U#(#U0s*-  
} %I%OHs  
\7 *"M y*  
qW9~S0sl  
public static void log(int sMsg) B>e},!  
{ ?&@a{-  
System.err.println(sMsg); '2S?4Z  
} >s>{+6e  
} Uc]sWcR  
`& ]H`KNa  
OUtMel_  
/* <;zcz[~  
**TestMethod.java Uk0 0lPG.U  
*/ %j;mDR9 5  
package NetFox; K,f- w2!  
VNxhv!w  
Y i`wj^  
public class TestMethod { aHSl_[  
*nV*WU S3  
$ I|K<slV  
public TestMethod() d0G d5%  
{ ///xx/weblogic60b2_win.exe T1YbF/M'  
try{ 7\EY&KI"0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^eCMATE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?0'db  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )L$)qfQ~x  
fileFetch.start(); >~rytg]f  
} A=\:b^\  
catch(Exception e){e.printStackTrace ();} C dTE~O<)  
&u9@FFBT8  
n]v,cfn/=<  
} *ZV=4[#bT  
+o}mV.&1,  
]Jx_bs~g  
public static void main(String[] args) =g$>]AE  
{ }/.GB5Ej  
new TestMethod(); [> LL  
} sx@ %3j  
} }\ hz@G<  
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