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http断点续传简单实现(java)

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/*  !&Z,ev  
**SiteFileFetch.java 96.z\[0VZ  
*/ Hw"UJP  
package NetFox; H~P"uYKIZ  
import java.io.*; pM i w9}  
import java.net.*; -Jtx9P  
l^IPN 'O@  
{vJ)!'Eh  
public class SiteFileFetch extends Thread { _>moza  
7Z;w<b~  
s;0eD5b>x  
SiteInfoBean siteInfoBean = null; //文件信息Bean iC{~~W6  
long[] nStartPos; //开始位置 G{cTQH|  
long[] nEndPos; //结束位置 r_kw "9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kH43 T  
long nFileLength; //文件长度 ;Q]j"1c  
boolean bFirst = true; //是否第一次取文件 %YaUc{.%  
boolean bStop = false; //停止标志 ?"aj&,q+  
File tmpFile; //文件下载的临时信息 iZy`5  
DataOutputStream output; //输出到文件的输出流 /Lc= K<  
2z\4?HJy  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7Pc0|Z/  
public SiteFileFetch(SiteInfoBean bean) throws IOException w$5N6  
{ Vd{h|=J  
siteInfoBean = bean; #NVqS5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WR*|kh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Hh bf9)  
if(tmpFile.exists ()) ikGH:{  
{ $DfaW3bJ  
bFirst = false; J\%<.S>  
read_nPos(); V+dfV`*k  
} Ur626}  
else 4R U1tWQ%  
{ r]{fjw(~  
nStartPos = new long[bean.getNSplitter()]; S%ri/}qI[{  
nEndPos = new long[bean.getNSplitter()]; h]94\XQ>$  
} @HfWAFT  
RT45@   
O8+[ )+6^  
%(-YOTDr  
} -%=StWdb   
: {9|/a  
[hg|bpEG  
public void run() )Q\ZYCPOr  
{  afEp4(X~  
//获得文件长度 W7a s =+;X  
//分割文件 -?b@6U  
//实例FileSplitterFetch >EMgP1  
//启动FileSplitterFetch线程 1q!JpC^  
//等待子线程返回 c= 2e?  
try{ *x| <\_+  
if(bFirst) L!L/QG|wdf  
{ SPV'0* Z  
nFileLength = getFileSize(); er5}=cFZ  
if(nFileLength == -1)  =&fBmV  
{ F_~-o,\  
System.err.println("File Length is not known!"); 33kI#45s  
} Yf:utCvv  
else if(nFileLength == -2) Kfj*uzKB  
{ <LW|m7  
System.err.println("File is not access!"); $ Yz &x%Lb  
} HHZ!mYr  
else kXC.rgal  
{ bE>3D#V<  
for(int i=0;i<nStartPos.length;i++) ABV\:u  
{ ,l<-*yMD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z1+rz%  
} 1#qCD["8  
for(int i=0;i<nEndPos.length-1;i++) LM'` U-/e$  
{ +29;T0>a  
nEndPos = nStartPos[i+1]; fC3IxlG  
} s/[i>`g/9  
nEndPos[nEndPos.length-1] = nFileLength; ud:?~?j&w  
} U30)r+&  
} V8Q#%#)FHe  
5?kA)!|UB  
8{+~3@T  
//启动子线程 @sKAsn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pOI+  
for(int i=0;i<nStartPos.length;i++) `Ik}Xw  
{ 73~Mq7~8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }WGi9\9T&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UKK}$B  
nStartPos,nEndPos,i); M{kPEl&Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6sy%KO*A  
fileSplitterFetch.start(); o33{tUp'  
} +lha^){  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l3MbCBX2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); k7{fkl9|#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s*CKFEb#  
nEndPos = " + nFileLength); 0HD1Ob^@  
// fileSplitterFetch[nPos.length-1].start(); 5,AQ~_,'\  
,f?#i%EF&  
0acY@_  
//等待子线程结束 N2&aU?`e  
//int count = 0; Y0B*.H Ae  
//是否结束while循环 C6"!'6 W  
boolean breakWhile = false; -N\{QX1Yd  
nv$  
)Elr8XLw  
while(!bStop) L7Oytdc<  
{ /#G"'U/  
write_nPos(); {t/!a0\HS  
Utility.sleep(500); ^/n[5@6H  
breakWhile = true; S ,(@Q~  
PYHm6'5BtB  
$PS5xD~@  
for(int i=0;i<nStartPos.length;i++) b"FsT  
{ ,t+ATaOF  
if(!fileSplitterFetch.bDownOver) r3j8[&B"  
{ Zc4hjg  
breakWhile = false; Ic=V:  
break; H+5]3>O-$  
} ^LU[{HZV  
} k13/yiv  
if(breakWhile) +~fu-%,k  
break; ?ha}&##  
: m5u=:t  
aq5<Ks`r  
//count++; E7eVg*Cvi  
//if(count>4) ygf qP  
// siteStop(); ;5|EpoM  
} &yA<R::o  
(x^|  
oNU* q.Q  
System.err.println("文件下载结束!"); ONGe/CEXT  
} mW-@-5Wda  
catch(Exception e){e.printStackTrace ();} Zj7XmkL  
} ; %Da {  
@E>^\!nH  
&\X;t|  
//获得文件长度 {H+?DMh  
public long getFileSize() BkZ%0rw%  
{ CXQ ?P  
int nFileLength = -1; 8S02 3  
try{ AX,Db%`l,  
URL url = new URL(siteInfoBean.getSSiteURL()); tJu<#h X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sMS`-,37u  
httpConnection.setRequestProperty("User-Agent","NetFox"); "G,*Z0V5  
|wb7`6g  
JZXc1R| 9  
int responseCode=httpConnection.getResponseCode(); Ksp;bfe  
if(responseCode>=400) " }ZD)7K  
{ .E}});l  
processErrorCode(responseCode); aXJe"IT.u  
return -2; //-2 represent access is error ~Op1NE  
} rka:.#!  
UA8!?r-cR  
3 #wj-  
String sHeader; ; p_X7N  
!xc7~D@om(  
0/gcSW b  
for(int i=1;;i++) ;Pa(nUE@  
{ Km nr }Lp9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K?tk&0  
//Utility.log(in.readLine()); /< :; ^B  
sHeader=httpConnection.getHeaderFieldKey(i); $K KaA{0-  
if(sHeader!=null) W^N"y &  
{ +i>q;=~  
if(sHeader.equals("Content-Length")) *@& "MZ/M  
{ 1wgu%$|d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Yq^y"rw  
break; LX fiSM{o  
} Ww(_EW  
} %pp+V1FH  
else ~?&ijhZ  
break; +n,BD C;  
} w?tKL0c  
} jwq"B$ap  
catch(IOException e){e.printStackTrace ();} HxMsH5;  
catch(Exception e){e.printStackTrace ();} .;:xx~G_Q  
:}JZKj!}M  
=e;wEf%`  
Utility.log(nFileLength); fEjW7 c  
LNZ#%R~r  
?},ItJ#>)q  
return nFileLength; uJOW%|ZN`  
} VL{#.;QQa  
^8m+*t  
m#nxw  
//保存下载信息(文件指针位置) 2 QmUg  
private void write_nPos() }SV3PdE  
{ v/czW\z  
try{ [KH?5 C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); DOerSh_0W  
output.writeInt(nStartPos.length); zFtGc  
for(int i=0;i<nStartPos.length;i++) OVyy}1Hx  
{ u,m-6@ il  
// output.writeLong(nPos); 1955(:I  
output.writeLong(fileSplitterFetch.nStartPos); 1,j9(m2  
output.writeLong(fileSplitterFetch.nEndPos); QP B"E W  
} ^PQV3\N  
output.close(); <yS"c5D6  
} +*J4q5;E[?  
catch(IOException e){e.printStackTrace ();} 0'hxw3#  
catch(Exception e){e.printStackTrace ();} OkZ!ZS h  
} psC7I E<v  
I{zE73  
yU|ji?)e  
//读取保存的下载信息(文件指针位置) ?X'* p<`  
private void read_nPos() ?i~/gjp  
{ }BJ1#<  
try{ 5Mr;6 ]I<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {_Qxe1^g  
int nCount = input.readInt(); / D ]B  
nStartPos = new long[nCount]; 2]9<%-=S  
nEndPos = new long[nCount]; U_- K6:tr  
for(int i=0;i<nStartPos.length;i++) kkBU<L2  
{ 2Nkn C>9(\  
nStartPos = input.readLong(); @'*#]YU8  
nEndPos = input.readLong(); CLfb`rF  
} !)3s <{k#  
input.close(); cf'}*$[S  
} 8uxFXQ  
catch(IOException e){e.printStackTrace ();} 5{q/z^]  
catch(Exception e){e.printStackTrace ();} WdqK/s<jM  
} j#,M@CE  
LH#LBjOZk  
l :Nxl  
private void processErrorCode(int nErrorCode) z8|9WZ:  
{ O{#Cddt:r  
System.err.println("Error Code : " + nErrorCode);  #U52\3G  
} X-$td~r  
eH955[fVd4  
Sqf.#}u<=  
//停止文件下载 KN:dm!A  
public void siteStop() :EwA$`/  
{ F[=lA"F^  
bStop = true; yl<$yd0Zdu  
for(int i=0;i<nStartPos.length;i++) }AW)R&m  
fileSplitterFetch.splitterStop(); 3c^=<i %  
j{R|]SjW2H  
|/^aL j^u  
} % `T5a<  
} M3@fc,Ch  
//负责部分文件的抓取 8.Ef5-m  
**FileSplitterFetch.java ?gwbg*  
*/ 6r=)V$K <  
package NetFox; %]0U60  
#}7m'F  
b*F~%K^i$  
import java.io.*; ~|{)h^]@  
import java.net.*; sLa)~To  
*rz(}(r  
L*01l"5  
public class FileSplitterFetch extends Thread { l;}7A,u  
,beR:60)  
,DuZMGg  
String sURL; //File URL s<_LcQbt{  
long nStartPos; //File Snippet Start Position ,XG|oo -  
long nEndPos; //File Snippet End Position M(zY[O  
int nThreadID; //Thread's ID qb> r\bc  
boolean bDownOver = false; //Downing is over DgT.Lku?  
boolean bStop = false; //Stop identical $;i$k2n:  
FileAccessI fileAccessI = null; //File Access interface 60%~+oHi~  
T:%wX9W  
PnIvk]"Ab  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FP9<E93br  
{ g~hk-nXL.  
this.sURL = sURL; 8+|V!q   
this.nStartPos = nStart; q\t>D _lU  
this.nEndPos = nEnd; *DC Nu{6  
nThreadID = id; FR,#s^kF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sx<+ *Trl  
} <<On*#80w  
0S:!Gv +  
|z|)r"*\4  
public void run() \v3> Eo[  
{ ~q?"w:@;x  
while(nStartPos < nEndPos && !bStop) _Kl{50}]  
{ Na 9l#  
$ l sRg:J  
.V 3X#t  
try{ zHoO?tGf  
URL url = new URL(sURL); {iIg 4PzrU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #D LT-G0  
httpConnection.setRequestProperty("User-Agent","NetFox"); h[je_^5  
String sProperty = "bytes="+nStartPos+"-"; B,vHn2W  
httpConnection.setRequestProperty("RANGE",sProperty); yp2'KES>  
Utility.log(sProperty); TQ\wHJ  
y)^CDe2xU  
/>^`*e_  
InputStream input = httpConnection.getInputStream(); m wEVEx24  
//logResponseHead(httpConnection); N<Z)b!o%u  
1Q&WoJLfR  
9Ajgfy>  
byte[] b = new byte[1024]; $Y 4ch ko  
int nRead; FQ|LA[~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n?e@):  
{ o eJC  
nStartPos += fileAccessI.write(b,0,nRead); %<J(lC9,C  
//if(nThreadID == 1) Kjn&  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \B>[je-d  
} ? W2I1HEy  
FM"GK '  
AY/-j$5+?  
Utility.log("Thread " + nThreadID + " is over!"); Fe& n,  
bDownOver = true; 9u7n/o&8v6  
//nPos = fileAccessI.write (b,0,nRead); 8A8xY446)  
} V:G}=~+=  
catch(Exception e){e.printStackTrace ();} JM+sHHs  
} xH`j7qK.  
} $~G0#JL  
kf^-m/  
|Y8Mk2,s  
//打印回应的头信息 1YIux,2\  
public void logResponseHead(HttpURLConnection con) LF9aw4:>Ou  
{ g3|Y$/J7P  
for(int i=1;;i++) ^E<~zO=Z  
{ )0 n29  
String header=con.getHeaderFieldKey(i); #}t 1   
if(header!=null) # McK46B z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (ju aDn)  
Utility.log(header+" : "+con.getHeaderField(header)); q]iKz%|Z/  
else 9-a2L JI  
break; im4e!gRE  
} ^Z-. [Y  
} $ gr6  
0XR;5kd%  
W p7@  
public void splitterStop() P$(WdVG  
{ D,GPn%Wqi  
bStop = true; <r7qq$  
} e"o6C\c  
L.T gJv43  
?HEtrX,q  
} p;n3`aVh  
XC7Ty'#"KX  
l?@MUsg+  
/* +9 16ZPk  
**FileAccess.java qUEd E`B  
*//文件访问(定位,写) iJdrY 6qd  
package NetFox; JI+KS  
import java.io.*; ^:cb $9F  
B{OW}D$P#  
_>jrlIfc  
public class FileAccessI implements Serializable{ ;9p#xW6  
=q"w2b&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [$1: &!(!  
RandomAccessFile oSavedFile; U!a!|s>  
long nPos; [U%ym{be ^  
je- , S>U  
@Hspg^  
public FileAccessI() throws IOException HIPcZ!p  
{ IFC%%I t5,  
this("",0); 0.J1!RIK/  
} {FV,j.D  
dJ%wVY0z=  
^ Hz  
public FileAccessI(String sName,long nPos) throws IOException h \D_  
{ &prdlh=UE  
oSavedFile = new RandomAccessFile(sName,"rw"); V 5e\%  
this.nPos = nPos; teq^xTUF[  
oSavedFile.seek(nPos); cotxo?)Zv  
} =2.tu*!C  
PmPyb>HK=P  
b!4N)t>gl  
public synchronized int write(byte[] b,int nStart,int nLen) 2d5}`>  
{ #sz]PZ\  
int n = -1; 2A*X Hvwb  
try{ )Y&MIJ7>@  
oSavedFile.write(b,nStart,nLen); ]^yV`Z8  
n = nLen; #Dj"W8'zh  
} ?Kx6Sf<i  
catch(IOException e)  95.qAFB1  
{ c W81  
e.printStackTrace (); R/ ALR  
} z9k*1:  
b"ol\&1 #  
r,`Z.A  
return n; y'J:?!S,Yu  
} X[GIOPDx  
VZT6;1TD$8  
1&X}1  
} u#a%(  
A0cM(w{7_  
38V $<w  
/* ^3Z7dIUww  
**SiteInfoBean.java $ 7U Dz  
*/ UC8vR>e\  
package NetFox; Whv]88w{  
HpB!a,R6B  
7>nhIp))  
public class SiteInfoBean { +8LM~voB  
,~?A,9?%:  
ttK,((=@  
private String sSiteURL; //Site's URL M(n<Iu4^_  
private String sFilePath; //Saved File's Path fnVW/23  
private String sFileName; //Saved File's Name $l#v/(uFa  
private int nSplitter; //Count of Splited Downloading File ( GFgt_  
+G*"jI8W  
a za o`z  
public SiteInfoBean() d u.HSXK  
{//nSplitter的缺省值为5 Zw;$(="  
//default value of nSplitter is 5 O{lIs_1.Z  
this("","","",5); 8yHq7=  
} qiG]nCq  
mV6#!_"  
a(PjcQ4dY  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) eP V-yy  
{ G*kE~s9R  
sSiteURL= sURL; bWGyLo,  
sFilePath = sPath; 6@"Vqm|HD  
sFileName = sName; lTa1pp Zw  
this.nSplitter = nSpiltter; Zij"/gx\  
*0=fT}&!  
Nc G,0K  
} KotPV  
+90u!r^v  
@PYW|*VS  
public String getSSiteURL() E)KB@f<g*  
{ f:_=5e +  
return sSiteURL; #^5a\XJb  
} DY)D(f/&3  
n?y'c^  
^c/mj9M#C  
public void setSSiteURL(String value) B1|?RfCe  
{ Wr]O  
sSiteURL = value; l_^T&xq8  
} L@7Qs6G2u  
oHxGbvQc  
v*&Uk '4E  
public String getSFilePath() T&?w"T2y  
{ $-m@KB  
return sFilePath; w@87]/4Rq  
} _aVJ$N.  
/)sDnJ1r  
* eA{[  
public void setSFilePath(String value) Gh2#-~|cB  
{ zx ct(  
sFilePath = value; ~RcNZ\2y  
} VT'0DQ!NIq  
o^6jyb!j  
MzG5u<D  
public String getSFileName() 1v;'d1Hg;  
{ $8jaapNm@  
return sFileName; d/l,C4p  
} :lgHL3yl  
2K3MAd{  
J cP~-cp  
public void setSFileName(String value) 7 rH'1U  
{ 0Xp nbB~~I  
sFileName = value; %_>Tcm=  
} 1#/6r :  
g+e:@@ug  
[6O04"6K  
public int getNSplitter() @XeEpDn]  
{ DNmb[  
return nSplitter; $"/UK3|d  
} DLU[<! C  
VK9Q?nu  
5(423"(y  
public void setNSplitter(int nCount) Ud$Q0m&  
{ ])eOa%  
nSplitter = nCount; U9x4j_.q  
} D`en%Lf!m  
} |pBMrN+is  
5f8"j$Az  
+Dd"41  
/* xtOx|FkYcl  
**Utility.java n;%y  
*/ 6*sw,sU[y  
package NetFox; 3QIdN  
P= e4lF.  
'c#IMlv  
public class Utility { ,E%1Uq"  
9e]'OKL+  
o\&~CW~@~  
public Utility() expxp#S  
{ q1STRYb   
aQga3;S!  
%?Rs*-F.~1  
} 4e}{$s$Xx  
*vb^N0P  
//线程睡眠 n|6?J_{<b>  
public static void sleep(int nSecond) 'm[6v}  
{ f?Z|>3.2  
try{ %Mh Q  
Thread.sleep(nSecond); <3lUV7!  
}  '6O|H  
catch(Exception e) {>/)5 AGs  
{ &2Q*1YXj  
e.printStackTrace (); b"Zq0M0 l  
} s_xV-C#q@  
} #Gd7M3  
B=r0?%DX"1  
//日志 TiQ^}5~M  
public static void log(String sMsg) GYd]5`ri  
{ EA6t36|TX  
System.err.println(sMsg); +GYS26  
} W+.{4 K  
inZi3@h)T  
jM]d'E?ZLA  
public static void log(int sMsg) ALfiR(!  
{ 3^XVQS***  
System.err.println(sMsg); t=Jm|wJnUA  
} 3|zgDA  
} ,7<DGI_y  
5Q|sta!  
c8<xFvYG  
/* *!Y- !  
**TestMethod.java b_|u<  
*/ {M [~E|@D  
package NetFox; ^Z#@3 =  
:&9TW]*g  
Ge^Qar  
public class TestMethod { 1+a@k  
&Xv1[nByU  
]rnXNn;  
public TestMethod() I(n }<)eF  
{ ///xx/weblogic60b2_win.exe p-,Iio+  
try{ 0aogBg_@K  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ck$M(^)l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); )km7tA 0a  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (8G$(MK  
fileFetch.start(); h8jB=e, H  
} 'y.JcS!|  
catch(Exception e){e.printStackTrace ();} ab@=cL~^  
{OCJ(^8i  
qU-!7=}7  
} 3b@VY'P  
:Jk33 N4y0  
7TpRCq#  
public static void main(String[] args) (N0sE"_~I5  
{ O#:&*Mv  
new TestMethod(); bK4&=#Zh  
}  &{ZSE^  
} 4jGLAor|  
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