????????

???????????????+??-??*??/??=??++??--??+=??-=??==??!=??&&??||??!??&??^??~??>=??<=??>??< …..

???????????е??????????????”????????????”??=??==??!=??????????е??????????????

????String???????+??+=???????

?????????????

???????????κ???????????String???????+??????????????????????????????String???????String????

???????????+????????κε????

????demo??

int i = 1;
int j = 2;
System.out.println("result:" + i + j);//result:12
System.out.println("i == j : " + i == j);// ×
System.out.println("i == j : " + (i == j));// √

????????????????????????(?????)??????????????(?????)????????????κγ??????????????????(?????????????????)???????????????????????????????????????????????????????洢????????

????????????????????????????????????????????????

????a = b;//b??????????a???????a??b???е???????????????????????κ????

????????????????????????????????

?????????????????????????????????????????????????????????????

?????????????????????е?????????

????demo??ObjectRefrenceTest.java

packagejavabase.flowcontrol;
publicclassObjectRefrenceTest{
/**
*?????????
*/
publicstaticvoidmain(String[]args){
Rowidrowid=newRowid();
rowid.rowid="LIYIHUIZHANYUANYING";
TiptopERPtopprod=newTiptopERP();
TiptopERPtoptest=newTiptopERP();
topprod.seesionId=0;
topprod.DBType="Oracle";
topprod.rowid=rowid;
toptest=topprod;//?????
System.out.println("Before:");
System.out.println("topprod:"+topprod.seesionId+topprod.DBType+topprod.rowid.rowid);
System.out.println("toptest:"+toptest.seesionId+toptest.DBType+toptest.rowid.rowid);
System.out.println("Afterchangetopprodobject:");
//toptest.DBType="Informix";
topprod.DBType="Informix";
topprod.rowid.rowid="5201314131413141314";//????????topprod.rowid???????????
System.out.println("topprod:"+topprod.seesionId+topprod.DBType+topprod.rowid.rowid);
System.out.println("toptest:"+toptest.seesionId+toptest.DBType+toptest.rowid.rowid);
System.out.println("-----------------------------");
TiptopERPerp=newTiptopERP();
TiptopERPmrpII=newTiptopERP();
erp.seesionId=2;
erp.DBType="DB2";
erp.rowid=rowid;//????????????rowid???????????erp.rowid
mrpII.seesionId=erp.seesionId;//??????????int???????
mrpII.DBType=erp.DBType;//??????????String???????
mrpII.rowid=erp.rowid;
System.out.println("Before:");
System.out.println("erp:"+erp.seesionId+erp.DBType+erp.rowid.rowid);
System.out.println("mrpII:"+mrpII.seesionId+mrpII.DBType+mrpII.rowid.rowid);
System.out.println("Afterchangrowid:");
erp.rowid.rowid="LIYIHUIZHANYUANYING";//????????erp.rowid???????????
System.out.println("erp:"+erp.seesionId+erp.DBType+erp.rowid.rowid);
System.out.println("mrpII:"+mrpII.seesionId+mrpII.DBType+mrpII.rowid.rowid);
System.out.println("Afterchangeerpobject:");
erp.seesionId=1;
erp.DBType="Mysql";
erp.rowid.rowid="5201314131413141314";//????????erp.rowid???????????
System.out.println("erp:"+erp.seesionId+erp.DBType+erp.rowid.rowid);
System.out.println("mrpII:"+mrpII.seesionId+mrpII.DBType+mrpII.rowid.rowid);
}
}
classTiptopERP{
intseesionId;//????????????
StringDBType;//String????
Rowidrowid;//??????
}
classRowid{
Stringrowid;
}
/*??????:
Before:
topprod:0OracleLIYIHUIZHANYUANYING
toptest:0OracleLIYIHUIZHANYUANYING
Afterchangetopprodobject:
topprod:0Informix5201314131413141314//rowid??????
toptest:0Informix5201314131413141314//rowid??????
-----------------------------
Before:
erp:2DB25201314131413141314//rowid??????
mrpII:2DB25201314131413141314//rowid??????
Afterchangrowid:
erp:2DB2LIYIHUIZHANYUANYING//rowid??????
mrpII:2DB2LIYIHUIZHANYUANYING//rowid??????
Afterchangeerpobject:
erp:1Mysql5201314131413141314//rowid??????
mrpII:2DB25201314131413141314//rowid??????
*/