maven依赖：
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<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> |
DynamicBeanEntity.class动态bean类：
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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(); }} |
test.class测试类测试动态生成bean
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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")); }} |
test.class测试类测试链接数据库动态生成bean
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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: */@Componentpublic 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); }} |
DBUtil.class:
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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~
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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()); }} |
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package test.refect; public class Book { private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } } |
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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); } } |
以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。如有错误或未考虑完全的地方，望不吝赐教。
原文链接：https://blog.csdn.net/qq_39898191/article/details/112366508
