Java反射实现类似Hibernate的通用增删改查
package com.zsw.util.service;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.lang.reflect.*;
import java.sql.*;
public class DBCommonFunction<T> {
private T ts;
public T getTs() {
return ts;
}
public void setTs(T ts) {
this.ts = ts;
}
public DBCommonFunction(T ts) {
this.ts = ts;
}
public void getClasses() {
Object object = ts.getClass();
System.out.println(getTs().getClass().getName());
try {
Class s = Class.forName(getTs().getClass().getName());
object = s.newInstance(); // 利用T类型 创建一个新的实例
System.out.println((T) object);
} catch (Exception e) {
e.printStackTrace();
}
}
// 获得T的参数并赋值
public void getParam() {
try {
Class s = Class.forName(getTs().getClass().getName());
Object o = s.newInstance();
for (Field f : o.getClass().getDeclaredFields()) {
if (f.getType().getSimpleName().equals("String")) {
f.set(o, 2 + "");
} else {
f.set(o, 1);
}
System.out.println(f);
}
System.out.println((T) o);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 获取表名
*/
private String getTblName() {
return getTs().getClass().getSimpleName() + "s";
}
/**
* 获取表中的字段
*/
@SuppressWarnings("finally")
private String getPram() {
String pram = "";
try {
Class s = Class.forName(getTs().getClass().getName());
Object o = s.newInstance();
Field[] fs = o.getClass().getDeclaredFields();
for (int i = 1; i < fs.length; i++) {
Field f = fs[i];
if (fs.length - 1 == i)
pram += f.getName();
else
pram += f.getName() + ",";
}
} catch (Exception e) {
e.printStackTrace();
} finally {
return pram;
}
}
/**
* 获取传递进的类型的值
*/
private String getValues(T t) {
Field[] fs = t.getClass().getDeclaredFields();
String ret = "";
try {
Class.forName(t.getClass().getName());
for (int i = 1; i < fs.length; i++) {
if (fs.length - 1 == i)
if (fs[i].getType().getSimpleName().equals("String")) {
ret += "'"+fs[i].get(t).toString()+"'";
} else {
ret += fs[i].get(t);
}
else {
if (fs[i].getType().getSimpleName().equals("String")) {
ret += "'"+fs[i].get(t)+"',";
} else {
ret += fs[i].get(t)+",";
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
return ret;
}
}
public List<T> findAll(){
List<T> list = new ArrayList<T>();
Connection conn = PageService.getConn();
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
pstmt = conn.prepareStatement("select * from "+getTblName());
rs = pstmt.executeQuery();
while (rs.next()) {
Class s = Class.forName(getTs().getClass().getName());
Object o = s.newInstance();
for (Field f : o.getClass().getDeclaredFields()) {
f.set(o,rs.getObject(f.getName()));
}
list.add((T)o);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
return list;
}
}
/**
* 通用的添加
*/
public boolean Add(T t) {
String sql = "insert into " + getTblName() + " (" + getPram()
+ ") values (" + getValues(t) + ")";
Connection conn = PageService.getConn();
PreparedStatement pstmt = null;
int count = 0;
try {
pstmt = conn.prepareStatement(sql);
count = pstmt.executeUpdate();
} catch (Exception e) {
e.printStackTrace();
} finally{
try {
pstmt.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
return count > 0?true:false;
}
}