模拟Hibernate

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package com.kedou.bean;

public class StudentTest {

/**
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
Student s=new Student();
s.setId(12);
s.setName("zhangyuan");
s.setAge(23);
Session session=new Session();
session.save(s);


}

}
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package com.kedou.bean;

public class Student {
private int id;
private String name;
private int age;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}

}
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package com.kedou.bean;

import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.util.HashMap;
import java.util.Map;

public class Session {
String tableName = "_Student";
Map<String, String> cfs = new HashMap<String, String>();
String[] methodNames;

public Session() {
cfs.put("_id", "id");
cfs.put("_name", "name");
cfs.put("_age", "age");
methodNames = new String[cfs.size()];
}

public void save(Student s) throws Exception {

String sql = createSQL();
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(
"jdbc:mysql://localhost/hibernate", "root", "zhangyuan");
PreparedStatement ps = conn.prepareStatement(sql);
for(int i=0;i<methodNames.length;i++){
Method m=s.getClass().getMethod(methodNames[i]);
Class r=m.getReturnType();
System.out.println(m.getName()+"|"+r.getName());

if(r.getName().equals("java.lang.String")){
String returnValue=(String) m.invoke(s);
ps.setString(i+1, returnValue);
}
if(r.getName().equals("int")){
Integer returnValue=(Integer)m.invoke(s);
ps.setInt(i+1, returnValue);
}
}
System.out.println(sql);
ps.executeUpdate();
ps.close();
conn.close();

}
private String createSQL() {
String str1 = "";
String str2 = "";
int index = 0;
for (String s : cfs.keySet()) {
String v = cfs.get(s);
v = Character.toUpperCase(v.charAt(0)) + v.substring(1);
methodNames[index] = "get" + v;
str1 += s + ",";
index++;
}
str1 = str1.substring(0, str1.length() - 1);
for (int i = 0; i < cfs.size(); i++) {
str2 += "?,";

}
str2 = str2.substring(0, str2.length() - 1);
System.out.println(str1);
String sql="insert into " + tableName + "(" +str1 + ")" + "values ("
+ str2 +")";

return sql;
}

}