jsonConfig处理日期及对象级联问题

Posted 2020-10-05 心和梦的方向

      项目中经常用到ajax请求后台，返回给前台json对象字符串。有些实体包含字段可能有日期、list、以及级联对象情况。因此，我们需要有针对性处理，

例如日期date类型，我们要给它转为我们所想要的格式的日期字符串，返回给前台。list我们要去除掉，级联对象，只提取我们所需要的字段值。

例如实体product：

  1 /**
  2  * 
  3  */
  4 package com.hik.entity;
  5 
  6 import java.util.ArrayList;
  7 import java.util.Date;
  8 import java.util.List;
  9 
 10 import javax.persistence.Column;
 11 import javax.persistence.Entity;
 12 import javax.persistence.GeneratedValue;
 13 import javax.persistence.Id;
 14 import javax.persistence.JoinColumn;
 15 import javax.persistence.ManyToOne;
 16 import javax.persistence.OneToMany;
 17 import javax.persistence.Table;
 18 
 19 import org.hibernate.annotations.GenericGenerator;
 20 
 21 /**
 22  * @ClassName: Product
 23  * @Description: TODO
 24  * @author jed
 25  * @date 2017年2月26日下午7:08:59
 26  *
 27  */
 28 @Entity
 29 @Table(name="t_product")
 30 public class Product {
 31     
 32     private int id;
 33     private String name; //名字
 34     private int price; //价格
 35     private int stock; //存储
 36     private String proPic; //图片
 37     private String description; //描述
 38     private int hot; //默认0不热卖  0:不热卖 ,1：热卖
 39     private Date hotTime; //热卖时间
 40     private int specialPrice;  //特价0不打特价  0:不打热价,1：打特价
 41     private Date specialPriceTime; //特价时间
 42     
 43     private ProductBigType bigType; //商品和商品大类是多对一关系
 44     private ProductSmallType smallType; //商品和商品小类是多对一关系
 45     private List<OrderProduct> orderProductList = new ArrayList<OrderProduct>(); //商品和订单商品是一对多关系
 46     
 47     @Id
 48     @GeneratedValue(generator="_native")
 49     @GenericGenerator(name="_native",strategy="native")
 50     public int getId() {
 51         return id;
 52     }
 53     public void setId(int id) {
 54         this.id = id;
 55     }
 56     
 57     @Column(length=50)
 58     public String getName() {
 59         return name;
 60     }
 61     public void setName(String name) {
 62         this.name = name;
 63     }
 64     public int getPrice() {
 65         return price;
 66     }
 67     public void setPrice(int price) {
 68         this.price = price;
 69     }
 70     public int getStock() {
 71         return stock;
 72     }
 73     public void setStock(int stock) {
 74         this.stock = stock;
 75     }
 76     public String getProPic() {
 77         return proPic;
 78     }
 79     public void setProPic(String proPic) {
 80         this.proPic = proPic;
 81     }
 82     @Column(length=2000)
 83     public String getDescription() {
 84         return description;
 85     }
 86     public void setDescription(String description) {
 87         this.description = description;
 88     }
 89     public int getHot() {
 90         return hot;
 91     }
 92     public void setHot(int hot) {
 93         this.hot = hot;
 94     }
 95     public Date getHotTime() {
 96         return hotTime;
 97     }
 98     public void setHotTime(Date hotTime) {
 99         this.hotTime = hotTime;
100     }
101     public int getSpecialPrice() {
102         return specialPrice;
103     }
104     public void setSpecialPrice(int specialPrice) {
105         this.specialPrice = specialPrice;
106     }
107     public Date getSpecialPriceTime() {
108         return specialPriceTime;
109     }
110     public void setSpecialPriceTime(Date specialPriceTime) {
111         this.specialPriceTime = specialPriceTime;
112     }
113     
114     @ManyToOne
115     @JoinColumn(name="bigTypeId") //外键关联
116     public ProductBigType getBigType() {
117         return bigType;
118     }
119     public void setBigType(ProductBigType bigType) {
120         this.bigType = bigType;
121     }
122     
123     @ManyToOne
124     @JoinColumn(name="smallTypeId") //外键关联
125     public ProductSmallType getSmallType() {
126         return smallType;
127     }
128     public void setSmallType(ProductSmallType smallType) {
129         this.smallType = smallType;
130     }
131     
132     @OneToMany
133     @JoinColumn(name="productId")
134     public List<OrderProduct> getOrderProductList() {
135         return orderProductList;
136     }
137     public void setOrderProductList(List<OrderProduct> orderProductList) {
138         this.orderProductList = orderProductList;
139     }
140     
141     
142 
143 }

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实体对象有Date类型字段，有list，还有级联对象ProductBigType、ProductSmallType。

处理使用到jsonConfig，其中jsonConfig.setExcludes 方法去除不需要的属性，前台不展示。registerJsonValueProcessor 处理得到我们想要的字段值

 1 /**
 2      * 
 3      * @MethodName: list
 4      * @Description: 获取商品
 5      * @author jed
 6      * @date 2017年5月7日下午5:23:23
 7      * @param @return    
 8      * @return String    返回类型
 9      * @return
10      * @throws Exception 
11      *
12      */
13     public String list() throws Exception{
14         PageBean pageBean = new PageBean(Integer.parseInt(page), Integer.parseInt(rows));
15         List<Product> productList = productService.findProductList(productDetail, pageBean);
16         long total = productService.getProductCount(productDetail);
17         JsonConfig jsonConfig = new JsonConfig();
18         jsonConfig.setExcludes(new String[]{"orderProductList"}); //去除要排除的属性   前台不展示
19         jsonConfig.registerJsonValueProcessor(java.util.Date.class, new DateJsonValueProcessor("yyyy-MM-dd")); //日期处理
20         jsonConfig.registerJsonValueProcessor(ProductBigType.class, new ObjectJsonValueProcessor(new String[]{"id","name"}, ProductBigType.class));//商品大类的id和name
21         jsonConfig.registerJsonValueProcessor(ProductSmallType.class, new ObjectJsonValueProcessor(new String[]{"id","name"},ProductSmallType.class )); //商品小类的id和name
22         JSONArray rows = JSONArray.fromObject(productList, jsonConfig);
23         JSONObject result = new JSONObject();
24         result.put("rows", rows);
25         result.put("total", total);
26         ResponseUtil.write(ServletActionContext.getResponse(), result);
27         return null;
28     }

View Code

日期处理类：实现JsonValueProcessor

 1 package com.hik.action;
 2 
 3 import java.text.SimpleDateFormat;
 4 
 5 import net.sf.json.JsonConfig;
 6 import net.sf.json.processors.JsonValueProcessor;
 7 
 8 /**
 9  * json-lib 日期处理类
10  * @author Administrator
11  *
12  */
13 public class DateJsonValueProcessor implements JsonValueProcessor{
14 
15     private String format;  
16     
17     public DateJsonValueProcessor(String format){  
18         this.format = format;  
19     }  
20     
21     public Object processArrayValue(Object value, JsonConfig jsonConfig) {
22         // TODO Auto-generated method stub
23         return null;
24     }
25 
26     public Object processObjectValue(String key, Object value, JsonConfig jsonConfig) {
27         if(value == null)  
28         {  
29             return "";  
30         }  
31         if(value instanceof java.sql.Timestamp)  
32         {  
33             String str = new SimpleDateFormat(format).format((java.sql.Timestamp)value);  
34             return str;  
35         }  
36         if (value instanceof java.util.Date)  
37         {  
38             String str = new SimpleDateFormat(format).format((java.util.Date) value);  
39             return str;  
40         }  
41           
42         return value.toString(); 
43     }
44 
45 }

View Code

对象级联处理：实现JsonValueProcessor

 1 package com.hik.action;
 2 
 3 import java.beans.PropertyDescriptor;
 4 import java.lang.reflect.Method;
 5 
 6 import net.sf.json.JSONObject;
 7 import net.sf.json.JsonConfig;
 8 import net.sf.json.processors.JsonValueProcessor;
 9 
10 /**
11  * 解决对象级联问题
12  * @author Administrator
13  *
14  */
15 public class ObjectJsonValueProcessor implements JsonValueProcessor{
16 
17     /**
18      * 保留的字段
19      */
20     private String[] properties;  
21     
22     /**
23      * 处理类型
24      */
25     private Class<?> clazz;  
26     
27     /**
28      * 构造方法 
29      * @param properties
30      * @param clazz
31      */
32     public ObjectJsonValueProcessor(String[] properties,Class<?> clazz){  
33         this.properties = properties;  
34         this.clazz =clazz;  
35     }  
36     
37     public Object processArrayValue(Object arg0, JsonConfig arg1) {
38         // TODO Auto-generated method stub
39         return null;
40     }
41 
42     public Object processObjectValue(String key, Object value, JsonConfig jsonConfig) {
43         PropertyDescriptor pd = null;  
44         Method method = null;  
45         StringBuffer json = new StringBuffer("{");  
46         try{  
47             for(int i=0;i<properties.length;i++){  
48                 pd = new PropertyDescriptor(properties[i], clazz);  
49                 method = pd.getReadMethod();  
50                 String v = String.valueOf(method.invoke(value));  
51                 json.append("‘"+properties[i]+"‘:‘"+v+"‘");  
52                 json.append(i != properties.length-1?",":"");  
53             }  
54             json.append("}");  
55         }catch (Exception e) {  
56             e.printStackTrace();  
57         }  
58         return JSONObject.fromObject(json.toString());  
59     }
60 
61 }

View Code