execute,executeQuery和executeUpdate的区别

package javaTest;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
public class ConnDataBase {
public static void main(String[] args) {
execute();//增删改查
//		executeQuery();//excuteQuery 查
//		executeUpdate();//excuteUpdate 增删改
}
/**
* 获取连接
* @return 连接对象
*/
public static Connection getConnection(){
Connection con = null;
try {
Class.forName("oracle.jdbc.OracleDriver");//获取oracle驱动
con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:ORCL", "ssh1", "ssh1");///填入url，用户名，密码
}catch(Exception e){
e.printStackTrace();
}
return con;
}
/**
* 用executeUpdate执行增删改操作
*/
public static void executeUpdate(){
Connection con=null;
try {
con=getConnection();
String sql="insert into student(s#,sname,sage,ssex) values('7','哈7','27','男')";
//			String sql="delete from student where s#='7'";
//			String sql="update student set sname='呵7' where s#='7'";
Statement st=con.createStatement();//创建用于执行静态的statement对象
int count=st.executeUpdate(sql);//执行sql插入（删除、更新）语句，返回插入的行数
System.out.println("插入（删除、更新）"+count+"条数据");
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
/**
* 用executeUpdate执行查询操作
*/
public static void executeQuery(){
Connection con = null;
try {
con = getConnection();
String sql = "select * from Student";
Statement st = con.createStatement();
ResultSet rs = st.executeQuery(sql);
while (rs.next()) {
ResultSetMetaData rsmd = rs.getMetaData();//用于分析结果集的元数据接口
int columnCount = rsmd.getColumnCount();//列数
for(int i=0;i<columnCount;i++){
System.out.print(rs.getString(i+1)+" ");     	
}
System.out.println();
}
con.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 用execute执行增删改查操作
*/
public static void execute(){
Connection con = null;
try {
con = getConnection();
String sql = "select * from Student";
//			String sql="insert into student(s#,sname,sage,ssex) values('7','哈7','27','男')";
//			String sql="delete from student where s#='7'";
//			String sql="update student set sname='呵7' where s#='7'";
Statement st = con.createStatement();
boolean hasResultSet = st.execute(sql);
if(hasResultSet){
ResultSet rs=st.getResultSet();
while (rs.next()) {
ResultSetMetaData rsmd = rs.getMetaData();//用于分析结果集的元数据接口
int columnCount = rsmd.getColumnCount();//列数
for(int i=0;i<columnCount;i++){
System.out.print(rs.getString(i+1)+" ");     	
}
System.out.println();
}
}else{
int count=st.getUpdateCount();//受影响行数
System.out.println("插入（删除、更新）"+count+"条数据");
}
con.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}