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如何在java中利用cglib动态生成一个实体bean？很多新手对此不是很清楚，为了帮助大家解决这个难题，下面小编将为大家详细讲解，有这方面需求的人可以来学习下，希望你能有所收获。
<dependency> <groupId>commons-beanutils</groupId> <artifactId>commons-beanutils</artifactId> <version>1.9.3</version> </dependency> <dependency> <groupId>cglib</groupId> <artifactId>cglib-nodep</artifactId> <version>3.2.4</version> </dependency>
package com.dym.entity;
import net.sf.cglib.beans.BeanGenerator;
import org.apache.commons.collections.map.MultiValueMap;
import java.lang.reflect.*;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
/**
* @author: zhaoxu
* @description:
*/
public class DynamicBeanEntity {
Object dynamicBean;
Class clazz;
public DynamicBeanEntity(Map dynAttrMap) {
this.dynamicBean = generateBean(dynAttrMap);
clazz = dynamicBean.getClass();
}
/**
* 获取所有属性值
*
* @return
* @throws IllegalAccessException
*/
public Map<String, Object> getValues() throws IllegalAccessException {
Map<String, Object> fieldValuesMap = new HashMap(16);
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
field.setAccessible(true);
Object fieldValue = field.get(dynamicBean);
fieldValuesMap.put(field.getName().split("\\$cglib_prop_")[1], fieldValue);
}
return fieldValuesMap;
}
/**
* 获取动态bean所有方法信息
*
* @return
*/
public MultiValueMap getMethods() {
MultiValueMap map = new MultiValueMap();
Method[] methods = clazz.getMethods();
for (Method method : methods) {
Type[] genericParameterTypes = method.getGenericParameterTypes();
if (genericParameterTypes.length > 0) {
for (Type type : genericParameterTypes) {
map.put(method.getName(), type);
}
} else {
map.put(method.getName(), null);
}
}
return map;
}
/**
* 执行某个方法
*
* @param methodName
* @param parameters
* @return
* @throws InvocationTargetException
* @throws IllegalAccessException
* @throws NoSuchMethodException
*/
public Object executeMethod(String methodName, Object... parameters) throws InvocationTargetException, IllegalAccessException, NoSuchMethodException {
ArrayList<Class> paramTypeList = new ArrayList();
for (Object paramType : parameters) {
paramTypeList.add(paramType.getClass());
}
Class[] classArray = new Class[paramTypeList.size()];
Method method = clazz.getMethod(methodName, paramTypeList.toArray(classArray));
Object invoke = method.invoke(dynamicBean, parameters);
return invoke;
}
/**
* 设置属性值
*
* @param property
* @param value
* @throws NoSuchFieldException
* @throws IllegalAccessException
*/
public void setValue(String property, Object value) throws NoSuchFieldException, IllegalAccessException {
Field declaredField = clazz.getDeclaredField("$cglib_prop_" + property);
declaredField.setAccessible(true);
declaredField.set(dynamicBean, value);
}
/**
* 获取属性值
*
* @param property
* @return
* @throws NoSuchFieldException
* @throws IllegalAccessException
*/
public Object getValue(String property) throws NoSuchFieldException, IllegalAccessException {
Field declaredField = clazz.getDeclaredField("$cglib_prop_" + property);
declaredField.setAccessible(true);
Object value = declaredField.get(dynamicBean);
return value;
}
public Object getEntity() {
return this.dynamicBean;
}
/**
* 利用cglib的BeanGenerator创建对象
*
* @param dynAttrMap
* @return
*/
private Object generateBean(Map dynAttrMap) {
BeanGenerator generator = new BeanGenerator();
Iterator iterator = dynAttrMap.keySet().iterator();
while (iterator.hasNext()) {
String key = iterator.next().toString();
generator.addProperty(key, (Class) dynAttrMap.get(key));
}
return generator.create();
}
}package com.dym.attr;
import com.dym.entity.DynamicBeanEntity;
import org.apache.commons.collections.map.MultiValueMap;
import java.lang.reflect.InvocationTargetException;
import java.util.HashMap;
import java.util.Map;
/**
* @author: zhaoxu
* @description:
*/
public class test {
public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException, NoSuchMethodException, InvocationTargetException {
// 设置属性们，默认16
HashMap propertyMap = new HashMap(16);
propertyMap.put("name", String.class);
propertyMap.put("age", Integer.class);
propertyMap.put("height", Double.class);
// 生成动态 Entity
DynamicBeanEntity bean = new DynamicBeanEntity(propertyMap);
//设置属性值
bean.setValue("name", "zx");
bean.setValue("age", 22);
bean.setValue("height", 175.0);
//获取属性值
Map<String, Object> values = bean.getValues();
//获取可执行的方法
MultiValueMap methods = bean.getMethods();
//执行某个方法
bean.executeMethod("setAge", 23);
System.out.println("动态bean的age属性："+bean.getValue("age"));
}
}package com.dym.test;
import com.dym.util.DBUtil;
import com.dym.util.DynmicEntity;
import org.springframework.stereotype.Component;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
/**
* @author: zhaoxu
* @description:
*/
@Component
public class test {
public static void main(String[] args) {
ArrayList<DynmicEntity> beans = new ArrayList<>();
Connection conn = null;
PreparedStatement prst = null;
String sql = "";
sql = "select table_name from information_schema.tables where table_schema=\'public\'";
conn = DBUtil.getConn();
try {
prst = conn.prepareStatement(sql);
ResultSet rs = prst.executeQuery();
while (rs.next()) {
String tableName = rs.getString(1);
Map attrMap = new HashMap<>();
String findFieldSql = "SELECT format_type(a.atttypid,a.atttypmod) as type,a.attname as name, a.attnotnull as notnull \n" +
"FROM pg_class as c,pg_attribute as a where c.relname = \'" + tableName + "\' and a.attrelid = c.oid and a.attnum>0";
PreparedStatement fieldsPrst = conn.prepareStatement(findFieldSql);
ResultSet fieldsRs = fieldsPrst.executeQuery();
while (fieldsRs.next()) {
String fieldType = fieldsRs.getString(1);
String fieldName = fieldsRs.getString(2);
attrMap.put(fieldName, Object.class);
}
DynmicEntity bean = new DynmicEntity(attrMap);
beans.add(bean);
}
} catch (SQLException e) {
e.printStackTrace();
}
DBUtil.close(prst, conn);
}
}package com.dym.util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
/**
* @author: zhaoxu
* @description:
*/
public class DBUtil {
private final static String URL="jdbc:postgresql://localhost:5432/dynmic";
private final static String NAME="postgres";
private final static String PASS="123456";
private static Connection conn=null;
/**
*
*@Title:DBUtil
*@Description:
*/
public DBUtil(){
}
/**
*
* @Tiltle getConn
* @return Connection
* @Description:返回连接
*/
public static Connection getConn(){
//告诉jvm使用mysql
try {
//加载驱动，string为驱动名字
Class.forName("org.postgresql.Driver");
//连接数据库，得到Connection连接
conn=DriverManager.getConnection(URL,NAME,PASS);
//System.out.println("连接数据库： "+conn);
}catch(ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch(SQLException e){
e.printStackTrace();
}
return conn;
}
//关闭结果对象集
public static void close(ResultSet rs){
if(rs!=null){
try{
rs.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
//关闭编译语句对象
public static void close(PreparedStatement prst){
if(prst!=null){
try{
prst.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
//关闭结果对象集
public static void close(Connection conn){
if(conn!=null){
try{
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
//对于更新操作关闭资源
public static void close(PreparedStatement prst,Connection conn){
close(prst);
close(conn);
}
//关闭所有
public static void close(ResultSet rs,PreparedStatement prst,Connection conn){
close(rs);
close(prst);
close(conn);
}
}补充：java 反射 json动态转实体类
我就废话不多说了，大家还是直接看代码吧~
package test.refect;
public class Student {
// 姓名
private String name;
// 年龄
private String age;
// 住址
private String address;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "Student [name=" + name + ", age=" + age + ", address=" + address + "]";
}
public void sayHello(Book book){
System.out.println(book.getName());
}
}package test.refect;
public class Book {
private String name;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}package test.refect;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.net.URLDecoder;
import java.util.Iterator;
import net.sf.json.JSONObject;
public class Main {
public static void main(String[] args) throws Exception {
//Student str --> Student 主类
String str = "test.refect.Student";
Class<?> clazz = Class.forName(str);
//Book实体 str --> Book 参数类
String bookStr = "test.refect.Book";
Class<?> bookClazz = Class.forName(bookStr);
//json --> Book 将参数类转为JSONOBJECT
String bookJson ="{\"name\":\"Java\"}";
JSONObject jsonObject=JSONObject.fromObject(bookJson);
//实例化参数类
Object bookInStance = bookClazz.newInstance();
// 通过JSONOBJECT 为参数类赋值
Iterator<?> keys = jsonObject.keys();
while (keys.hasNext()) {
Object key = keys.next();
Object value = jsonObject.get(key);
// 替换非法字符
String _key = String.valueOf(key).replaceFirst("\\W", "");
Field field = bookClazz.getDeclaredField(_key);
field.setAccessible(true);
field.set(bookInStance, URLDecoder.decode(String.valueOf(value), "UTF-8"));
field.setAccessible(false);
}
//将参数类注入到主类
Method method = clazz.getDeclaredMethod("sayHello", bookClazz);
//执行主类
method.invoke(clazz.newInstance(), bookInStance);
}
}看完上述内容是否对您有帮助呢？如果还想对相关知识有进一步的了解或阅读更多相关文章，请关注亿速云行业资讯频道，感谢您对亿速云的支持。
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