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1 package com.xxyh.jdbc; 2 import java.lang.reflect.InvocationTargetException; 3 import java.lang.reflect.Method; 4 import java.sql.Connection; 5 import java.sql.PreparedStatement; 6 import java.sql.ResultSet; 7 import java.sql.ResultSetMetaData; 8 import java.sql.SQLException; 9 import com.xxyh.jdbc.domain.User; 10 public class ORMTest { 11 12 public static void main(String[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException { 13 User user = getUser("select id as Id, name as Name, birthday as Birthday, money as Money from user where id=1"); 14 System.out.println(user); 15 } 16 17 static User getUser(String sql) throws SQLException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { 18 Connection conn = null; 19 PreparedStatement ps = null; 20 ResultSet rs = null; 21 try { 22 conn = JdbcUtils.getConnection(); 23 ps = conn.prepareStatement(sql); 24 rs = ps.executeQuery(); 25 26 ResultSetMetaData rsmd = rs.getMetaData(); 27 int count = rsmd.getColumnCount(); 28 String[] colNames = new String[count]; 29 for (int i = 1; i <= count; i++) 30 colNames[i-1] = rsmd.getColumnLabel(i); 31 32 User user = null; 33 34 if (rs.next()) { 35 user = new User(); 36 for (int i = 0; i < colNames.length; i++) { 37 String colName = colNames[i]; 38 String methodName = "set" + colName; 39 Method[] methods = user.getClass().getMethods(); 40 for (Method method : methods) { 41 if (methodName.equals(method.getName())) { 42 method.invoke(user, rs.getObject(colName)); 43 } 44 } 45 } 46 } 47 return user; 48 } finally { 49 JdbcUtils.close(rs, ps, conn); 50 } 51 52 } 53 }
@Override public String toString() { return "[" + getId() + "," + getName() + "," + getBirthday() + "," + getMoney() + "]"; }
通过使用泛型提高程序的通用性，getObject方法与具体的类无关：
1 package com.xxyh.jdbc; 2 import java.lang.reflect.InvocationTargetException; 3 import java.lang.reflect.Method; 4 import java.sql.Connection; 5 import java.sql.PreparedStatement; 6 import java.sql.ResultSet; 7 import java.sql.ResultSetMetaData; 8 import java.sql.SQLException; 9 import com.xxyh.jdbc.domain.User; 10 public class ORMTest { 11 12 public static void main(String[] args) throws IllegalAccessException, IllegalArgumentException, InvocationTargetException, SQLException, InstantiationException { 13 User user = (User) getObject("select id as Id, name as Name, birthday as Birthday, money as Money from user where id=2",User.class); 14 System.out.println(user); 15 } 16 17 static Object getObject(String sql, Class<?> clazz) throws SQLException, IllegalAccessException, IllegalArgumentException, InvocationTargetException, InstantiationException { 18 Connection conn = null; 19 PreparedStatement ps = null; 20 ResultSet rs = null; 21 try { 22 conn = JdbcUtils.getConnection(); 23 ps = conn.prepareStatement(sql); 24 rs = ps.executeQuery(); 25 26 ResultSetMetaData rsmd = rs.getMetaData(); 27 int count = rsmd.getColumnCount(); 28 String[] colNames = new String[count]; 29 for (int i = 1; i <= count; i++) 30 colNames[i-1] = rsmd.getColumnLabel(i); 31 32 Object object = null; 33 Method[] methods = clazz.getMethods(); 34 if (rs.next()) { 35 object = clazz.newInstance();// 创建一个对象 36 for (int i = 0; i < colNames.length; i++) { 37 String colName = colNames[i]; 38 String methodName = "set" + colName; 39 for (Method method : methods) { 40 if (methodName.equals(method.getName())) { 41 method.invoke(object, rs.getObject(colName)); 42 } 43 } 44 } 45 } 46 return object; 47 } finally { 48 JdbcUtils.close(rs, ps, conn); 49 } 50 51 } 52 }
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原文地址：http://www.cnblogs.com/xiaoxiaoyihan/p/4390839.html
