利用反射机制模拟Hibernate的Session

package com.quan.hibernate.model;

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

/**
 * Session的模拟
 */
public class create {

	String url = "jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=hibernate";
	String user = "sa";
	String password = "123";
	
	String tableName = "_Student";
	Map<String,String> cfs = new HashMap<String, String>();
	
	String[] methodNames;
	
	public create() {
		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.microsoft.jdbc.sqlserver.SQLServerDriver");
		Connection conn = DriverManager.getConnection(url, user, password);
		PreparedStatement ps = conn.prepareStatement(sql);
		
		for(int i = 0; i<methodNames.length;i++) {
	          Method m = s.getClass().getMethod(methodNames[i]);
	          Class r= m.getReturnType();
	          if(r.getName() == "java.lang.String") {
	        	  String returnValue = (String)m.invoke(s);
	        	  ps.setString(i+1, returnValue);
	          }
	          if(r.getName() == "int") {
	        	  Integer returnValue = (Integer)m.invoke(s);
	        	  ps.setInt(i+1, returnValue);
	          }
		}
		
		/*for(int i = 0; i<cfs.size(); i++) {
			ps.setXXX(s.getXXX);
		}*/
		
		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 + ",";
		}
		str1 = str1.substring(0, str1.length()-1);
		
		for(int i = 0; i<cfs.size();i++) {
			str2 += "?,";
		}
		str2 = str2.substring(0, str2.length()-1);
		
		String sql = "insert into "+tableName+"("+str1+")"+"valses ("+str2+")";
		
		return sql;
	}
}

 

评论

1 楼 lufei_vs 2010-02-01  

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