需求：需要将枚举类型的字段例如enable（是否启用）转化为enable:1,enableName:是。这种形式返回给前台。
思路：在bean字段上加上枚举类型的注解，通过字段的值和枚举类反射获取枚举的key和value。
枚举注解：
import java.lang.annotation.Documented; import java.lang.annotation.ElementType; import java.lang.annotation.Retention; import java.lang.annotation.RetentionPolicy; import java.lang.annotation.Target; /** * * <p>Title:用于bean字段枚举类型的注解</p> * <p>Description:</p> * @author zhy * @date 2019/02/27 * @version 1.0 */ @Target({ElementType.FIELD}) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface IEnum { String name() default "";//名称 Class<?> clas();//枚举实体 //byte defaultKey() default 0;//默认值 }
枚举接口：（这个也可以不要，预留以防万一要用到）
/** * * <p>Title:</p> * <p>Description:</p> * @author zhy * @version 1.0 */ public interface EnumBase { public String getName(Byte key); }
枚举类
public enum OEnable implements EnumBase { TRUE(1, "启用"),FALSE(0, "停用"); private Byte key; private String name; private OEnable(int key,String name) { this.key = (byte)key; this.name = name; } public Byte getKey() { return key; } public void setKey(Byte key) { this.key = key; } public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public String getName(Byte key) { for (OEnable enable : values()) { if(key == null) return null; if (enable.getKey().equals(key)) { return enable.getName(); } } return null; } }
所有bean的基类，里面包含bean的基本属性。只有当结果集list里的类继承于这个类，我们才需要转换枚举值
import java.util.Date; /** * * <p>Title:所有bean基类</p> * <p>Description:</p> * @author zhy * @version 1.0 */ public class BeanBase { protected Integer pkey;//主键 protected Date createdTime;//创建时间 protected Date updatedTime;//更新时间 protected Integer rowVersion;//版本号 public Integer getPkey() { return pkey; } public void setPkey(Integer pkey) { this.pkey = pkey; } public Date getCreatedTime() { return createdTime; } public void setCreatedTime(Date createdTime) { this.createdTime = createdTime; } public Date getUpdatedTime() { return updatedTime; } public void setUpdatedTime(Date updatedTime) { this.updatedTime = updatedTime; } public Integer getRowVersion() { return rowVersion; } public void setRowVersion(Integer rowVersion) { this.rowVersion = rowVersion; } }
Test类
public class Test extends BeanBase { public String name; @IEnum(clas = OEnable.class) public Byte enable; public String getName() { return name; } public void setName(String name) { this.name = name; } public Byte getEnable() { return enable; } public void setEnable(Byte enable) { this.enable = enable; } }
bean转换工具类，通过反射获取字段信息，注解信息
import java.lang.reflect.Field; import java.lang.reflect.Method; import java.util.ArrayList; import java.util.Arrays; import java.util.HashMap; import java.util.List; import java.util.Map; import com.alibaba.fastjson.JSONObject; public class BeanUtils { /** * * <p>Title:bean字段转换类</p> * <p>Description:</p> * @author zhy * @version 1.0 * @param result * @return */ public static List<Map<String,Object>> ListBeanToJson(List<? extends BeanBase> result) { List<Map<String,Object>> newResult = new ArrayList<Map<String,Object>>(); for (BeanBase t : result) { Map<String, Object> tmap = beanToMap(t); newResult.add(tmap); } return newResult; } @SuppressWarnings("unchecked") public static Map<String, Object> beanToMap(BeanBase t) { Map<String,Object> tmap = new HashMap<String,Object>(); List<Field> fieldList = new ArrayList<>() ; Class<? extends BeanBase> class1 = t.getClass(); while (class1 != null) {//取父类属性 fieldList.addAll(Arrays.asList(class1 .getDeclaredFields())); class1 = (Class<? extends BeanBase>) class1.getSuperclass(); //父类 } try { for (Field field : fieldList) { field.setAccessible(true); IEnum EnumBase = field.getAnnotation(IEnum.class); Object key = field.get(t);//获取字段值 if (EnumBase != null) {//如果有注解 Class<?> clas = EnumBase.clas(); Method getName = clas.getDeclaredMethod("getName", Byte.class);//调用getName方法 if (key != null) {//值不为空，调用枚举类方法 Object[] oo = clas.getEnumConstants(); Object invoke = getName.invoke(oo[0],key); tmap.put(field.getName(), key); tmap.put(field.getName() + "Name", invoke); }else { tmap.put(field.getName(), key); tmap.put(field.getName() + "Name", null); } }else {//没注解填入原本的值 tmap.put(field.getName(), key); } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } return tmap; } public static JSONObject beanToJson(BeanBase t) { Map<String, Object> beanToMap = beanToMap(t); JSONObject result = new JSONObject(); for (String key : beanToMap.keySet()) { result.put(key, beanToMap.get(key)); } return result; } }
结果集类Result
import java.util.List; import com.github.pagehelper.PageInfo; public class Result { private boolean success; private String code; private String message; private Object result; public Result() { this.success = true; this.code = "00000000"; this.message = "success"; this.result = ""; } public Result(boolean success, String code, String message, Object result) { this.success = success; this.code = code; this.message = message; this.result = result; } public Result(Object result) { this.success = true; this.code = "00000000"; this.message = "success"; this.result = result; } public Result(boolean success, String code, String message, List<? extends BeanBase> result) { this.success = success; this.code = code; this.message = message; this.result = BeanUtils.ListBeanToJson(result); } public Result(List<? extends BeanBase> result) { this.success = true; this.code = "00000000"; this.message = "success"; this.result = BeanUtils.ListBeanToJson(result); } public Result(BeanBase result) { this.success = true; this.code = "00000000"; this.message = "success"; this.result = BeanUtils.beanToJson(result); } public Result(boolean success, String code, String message, BeanBase result) { this.success = success; this.code = code; this.message = message; this.result = BeanUtils.beanToJson(result); } public Result(String code, String message) { this.success = false; this.code = code; this.message = message; this.result = ""; } public boolean isSuccess() { return this.success; } public void setSuccess(boolean success) { this.success = success; } public String getCode() { return this.code; } public void setCode(String code) { this.code = code; } public String getMessage() { return this.message; } public void setMessage(String message) { this.message = message; } public Object getResult() { return this.result; } public void setResult(Object result) { this.result = result; } }
准备完毕，可以写Controller进行测试了
@RestController @RequestMapping("/") public class TestRest { @RequestMapping("/test") public Result getTestList() { Test test1 = new Test(); test1.setPkey(1); test1.setName("测试1"); test1.setCreatedTime(new Date()); test1.setEnable((byte) 1); Test test2 = new Test(); test2.setPkey(2); test2.setName("测试2"); test2.setCreatedTime(new Date()); test2.setEnable((byte) 2); Test test3 = new Test(); test3.setPkey(3); test3.setName("测试3"); test3.setCreatedTime(new Date()); test3.setEnable((byte) 1); Test test4 = new Test(); test4.setPkey(4); test4.setName("测试4"); test4.setCreatedTime(new Date()); test4.setEnable((byte) 2); List<Test> list = new ArrayList<>(); list.add(test1); list.add(test2); list.add(test3); list.add(test4); return new Result(list); } }
@RestController @RequestMapping("/") public class TestRest { @RequestMapping("/test") public Result getTestList() { Test test1 = new Test(); test1.setPkey(1); test1.setName("测试1"); test1.setCreatedTime(new Date()); test1.setEnable((byte) 1); Test test2 = new Test(); test2.setPkey(2); test2.setName("测试2"); test2.setCreatedTime(new Date()); test2.setEnable((byte) 2); Test test3 = new Test(); test3.setPkey(3); test3.setName("测试3"); test3.setCreatedTime(new Date()); test3.setEnable((byte) 1); Test test4 = new Test(); test4.setPkey(4); test4.setName("测试4"); test4.setCreatedTime(new Date()); test4.setEnable((byte) 2); List<Test> list = new ArrayList<>(); list.add(test1); list.add(test2); list.add(test3); list.add(test4); return new Result(list); } }
返回前端结果
{ "code": "00000000", "message": "success", "result": [ { "updatedTime": null, "rowVersion": null, "enable": 1, "name": "测试1", "createdTime": 1552440256286, "enableName": "启用", "pkey": 1 }, { "updatedTime": null, "rowVersion": null, "enable": 2, "name": "测试2", "createdTime": 1552440256286, "enableName": null, "pkey": 2 }, { "updatedTime": null, "rowVersion": null, "enable": 1, "name": "测试3", "createdTime": 1552440256286, "enableName": "启用", "pkey": 3 }, { "updatedTime": null, "rowVersion": null, "enable": 2, "name": "测试4", "createdTime": 1552440256286, "enableName": null, "pkey": 4 } ], "success": true }